path: root/NEWS

NEWS for the Nettle 3.9 release

	This release includes bug fixes, several new features, a few
	performance improvements, and one performance regression
	affecting GCM on certain platforms.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.7 and libhogweed.so.6.7, with sonames
	libnettle.so.8 and libhogweed.so.6.

	This release includes a rewrite of the C implementation of
	GHASH (dating from 2011), as well as the plain x86_64 assembly
	version, to use precomputed tables in a different way, with
	tables always accessed in the same sequential manner.

	This should make Nettle's GHASH implementation side-channel
	silent on all platforms, but considerably slower on platforms
	without carry-less mul instructions. E.g., benchmarks of the C
	implementation on x86_64 showed a slowdown of 3 times.

	Bug fixes:

	* Fix bug in ecdsa and gostdsa signature verify operation, for
	  the unlikely corner case that point addition really is point
	  duplication.

	* Fix for chacha on Power7, nettle's assembly used an
	  instruction only available on later processors. Fixed by
	  Mamone Tarsha.

	* GHASH implementation should now be side-channel silent on
	  all architectures.

	* A few portability fixes for *BSD.

	New features:

	* Support for the SM4 block cipher, contributed by Tianjia
          Zhang.

	* Support for the Balloon password hash, contributed by Zoltan
          Fridrich.

	* Support for SIV-GCM authenticated encryption mode,
          contributed by Daiki Ueno.

	* Support for OCB authenticated encryption mode.

	* New exported functions md5_compress, sha1_compress,
	  sha256_compress, sha512_compress, based on patches from
	  Corentin Labbe.

	Optimizations:

	* Improved sha256 performance, in particular for x86_64 and
	  s390x.

	* Use GMP's mpn_sec_tabselect, which is implemented in
	  assembly on many platforms, and delete the similar nettle
	  function. Gives a modest speedup to all ecc operations.

	* Faster poly1305 for x86_64 and ppc64. New ppc code
	  contributed by Mamone Tarsha.

	Miscellaneous:

	* New ASM_FLAGS variable recognized by configure.

	* Delete all arcfour assembly code. Affects 32-bit x86, 32-bit
	  and 64-bit sparc.

	Known issues:

	* Version 6.2.1 of GNU GMP (the most recent GMP release as of
	  this writing) has a known issue for MacOS on 64-bit ARM: GMP
	  assembly files use the reserved x18 register. On this
	  platform it is recommended to use a GMP snapshot where this
	  bug is fixed, and upgrade to a later GMP release when one
	  becomes available.

	* Also on MacOS, Nettle's testsuite may still break due to
	  DYLD_LIBRARY_PATH being discarded under some circumstances.
	  As a workaround, use

	  make check EMULATOR='env DYLD_LIBRARY_PATH=$(TEST_SHLIB_DIR)'

NEWS for the Nettle 3.8.1 release

	This is a bugfix release, fixing a few portability issues
	reported for Nettle-3.8.

	Bug fixes:

	* Avoid non-posix m4 argument references in the chacha
	  implementation for arm64, powerpc64 and s390x. Reported by
	  Christian Weisgerber, fix contributed by Mamone Tarsha.

	* Use explicit .machine pseudo-ops where needed in s390x
	  assembly files. Bug report by Andreas K. Huettel, fix
	  contributed by Mamone Tarsha.

	Optimizations:

	* Implemented runtime detection of cpu features for OpenBSD on
	  arm64. Contributed by Christian Weisgerber.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.6 and libhogweed.so.6.6, with sonames
	libnettle.so.8 and libhogweed.so.6.

NEWS for the Nettle 3.8 release

	This release includes a couple of new features, and many
	performance improvements. It adds assembly code for two more
	architectures: ARM64 and S390x.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.5 and libhogweed.so.6.5, with sonames
	libnettle.so.8 and libhogweed.so.6.

	New features:

	* AES keywrap (RFC 3394), contributed by Nicolas Mora.

	* SM3 hash function, contributed by Tianjia Zhang.

	* New functions cbc_aes128_encrypt, cbc_aes192_encrypt,
	  cbc_aes256_encrypt.

	  On processors where AES is fast enough, e.g., x86_64 with
	  aesni instructions, the overhead of using Nettle's general
	  cbc_encrypt can be significant. The new functions can be
	  implemented in assembly, to do multiple blocks with reduced
	  per-block overhead.

	  Note that there's no corresponding new decrypt functions,
	  since the general cbc_decrypt doesn't suffer from the same
	  performance problem.

	Bug fixes:

	* Fix fat builds for x86_64 windows, these appear to never
          have worked.

	Optimizations:

	* New ARM64 implementation of AES, GCM, Chacha, SHA1 and
	  SHA256, for processors supporting crypto extensions. Great
	  speedups, and fat builds are supported. Contributed by
	  Mamone Tarsha.

	* New s390x implementation of AES, GCM, Chacha, memxor, SHA1,
	  SHA256, SHA512 and SHA3. Great speedups, and fat builds are
	  supported. Contributed by Mamone Tarsha.

	* New PPC64 assembly for ecc modulo/redc operations,
	  contributed by Amitay Isaacs, Martin Schwenke and Alastair
	  D´Silva.

	* The x86_64 AES implementation using aesni instructions has
	  been reorganized with one separate function per key size,
	  each interleaving the processing of two blocks at a time
	  (when the caller processes multiple blocks with each call).
	  This gives a modest performance improvement on some
	  processors.

	* Rewritten and faster x86_64 poly1305 assembly.

	Known issues:

	* Nettle's testsuite doesn't work out-of-the-box on recent
	  MacOS, due to /bin/sh discarding the DYLD_LIBRARY_PATH
	  environment variable. Nettle's test scripts handle this in
	  some cases, but currently fails the test cases that are
	  themselves written as /bin/sh scripts. As a workaround, use

	  make check EMULATOR='env DYLD_LIBRARY_PATH=$(TEST_SHLIB_DIR)'

	Miscellaneous:

	* Updated manual to current makeinfo conventions, with no
	  explicit node pointers. Generate pdf version with texi2pdf,
	  to get working hyper links.

	* Added square root functions for NIST ecc curves, as a
	  preparation for supporting compact point representation.

	* Reworked internal GCM/ghash interfaces, simplifying assembly
	  implementations. Deleted unused GCM C implementation
	  variants with less than 8-bit lookup table.

NEWS for the Nettle 3.7.3 release

	This is bugfix release, fixing bugs that could make the RSA
	decryption functions crash on invalid inputs.

	Upgrading to the new version is strongly recommended. For
	applications that want to support older versions of Nettle,
	the bug can be worked around by adding a check that the RSA
	ciphertext is in the range 0 < ciphertext < n, before
	attempting to decrypt it.

	Thanks to Paul Schaub and Justus Winter for reporting these
	problems.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.4 and libhogweed.so.6.4, with sonames
	libnettle.so.8 and libhogweed.so.6.

	Bug fixes:

	* Fix crash for zero input to rsa_sec_decrypt and
	  rsa_decrypt_tr. Potential denial of service vector.

	* Ensure that all of rsa_decrypt_tr and rsa_sec_decrypt return
	  failure for out of range inputs, instead of either crashing,
	  or silently reducing input modulo n. Potential denial of
	  service vector.

	* Ensure that rsa_decrypt returns failure for out of range
	  inputs, instead of silently reducing input modulo n.

	* Ensure that rsa_sec_decrypt returns failure if the message
	  size is too large for the given key. Unlike the other bugs,
	  this would typically be triggered by invalid local
	  configuration, rather than by processing untrusted remote
	  data.

NEWS for the Nettle 3.7.2 release

	This is a bugfix release, fixing a bug in ECDSA signature
	verification that could lead to a denial of service attack
	(via an assertion failure) or possibly incorrect results. It
	also fixes a few related problems where scalars are required
	to be canonically reduced modulo the ECC group order, but in
	fact may be slightly larger.

	Upgrading to the new version is strongly recommended.

	Even when no assert is triggered in ecdsa_verify, ECC point
	multiplication may get invalid intermediate values as input,
	and produce incorrect results. It's trivial to construct
	alleged signatures that result in invalid intermediate values.
	It appears difficult to construct an alleged signature that
	makes the function misbehave in such a way that an invalid
	signature is accepted as valid, but such attacks can't be
	ruled out without further analysis.

	Thanks to Guido Vranken for setting up the fuzzer tests that
	uncovered this problem.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.3 and libhogweed.so.6.3, with sonames
	libnettle.so.8 and libhogweed.so.6.

	Bug fixes:

	* Fixed bug in ecdsa_verify, and added a corresponding test
          case.

	* Similar fixes to ecc_gostdsa_verify and gostdsa_vko.

	* Similar fixes to eddsa signatures. The problem is less severe
          for these curves, because (i) the potentially out or range
          value is derived from output of a hash function, making it
          harder for the attacker to to hit the narrow range of
          problematic values, and (ii) the ecc operations are
          inherently more robust, and my current understanding is that
          unless the corresponding assert is hit, the verify
          operation should complete with a correct result.

	* Fix to ecdsa_sign, which with a very low probability could
          return out of range signature values, which would be
          rejected immediately by a verifier.

NEWS for the Nettle 3.7.1 release

	This is primarily a bug fix release, fixing a couple of
	problems found in Nettle-3.7.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.2 and libhogweed.so.6.2, with sonames
	libnettle.so.8 and libhogweed.so.6.

	Bug fixes:

	* Fix bug in chacha counter update logic. The problem affected
	  ppc64 and ppc64el, with the new altivec assembly code
	  enabled. Reported by Andreas Metzler, after breakage in
	  GnuTLS tests on ppc64.

	* Support for big-endian ARM platforms has been restored.
	  Fixes contributed by Michael Weiser.

	* Fix build problem on OpenBSD/powerpc64, reported by Jasper
	  Lievisse Adriaanse.

	* Fix corner case bug in ECDSA verify, it would produce
	  incorrect result in the unlikely case of an all-zero
	  message hash. Reported by Guido Vranken.

	New features:

	* Support for pbkdf2_hmac_sha384 and pbkdf2_hmac_sha512,
	  contributed by Nicolas Mora.

	Miscellaneous:

	* Poorly performing ARM Neon code for doing single-block
	  Salsa20 and Chacha has been deleted. The code to do two or
	  three blocks in parallel, introduced in Nettle-3.7, is
	  unchanged.

NEWS for the Nettle 3.7 release

	This release adds one new feature, the bcrypt password hashing
	function, and lots of optimizations. There's also one
	important change to how Nettle is configured: Fat builds are
	now on by default.

	The release adds PowerPC64 assembly for a few algorithms,
	resulting in great speedups. Benchmarked on a Power9 machine,
	speedup was 13 times for AES256-CTR and AES256-GCM, and 3.5
	times for Chacha. For fat builds (now the default), the new
	code is used automatically, on processors supporting the needed
	instruction set extensions.

	The new version is intended to be fully source and binary
	compatible with Nettle-3.6. The shared library names are
	libnettle.so.8.1 and libhogweed.so.6.1, with sonames
	libnettle.so.8 and libhogweed.so.6.

	New features:

	* Support for bcrypt, contributed by Stephen R. van den Berg.

	Optimizations:

	* Much faster AES and GCM on PowerPC64 processors supporting
	  the corresponding crypto extensions. Contributed by Mamone
	  Tarsha.

	* Speed of Chacha improved on PowerPC64, x86_64 and ARM Neon.

	* Speed of Salsa20 improved on x86_64 and ARM Neon.

	* Overhaul of some elliptic curve primitives, improving ECDSA
	  signature speed.

	Configure:

	* Fat builds are enabled by default on the architectures where
	  it is supported (x86_64, arm and powerpc64). To disable
	  runtime selection, and instead specify the processor flavor
	  at configure time, you need to pass --disable-fat to the
	  configure script.

	Known issues:

	* The ARM assembly code in this release doesn't work correctly
	  on big-endian ARM systems. This will hopefully be fixed in a
	  later release.

	Miscellaneous:

	* Use a few more gmp-6.1 functions: mpn_cnd_add_n,
	  mpn_cnd_sub_n, mpn_cnd_swap. Delete corresponding internal
	  Nettle functions.

	* Convert all assembly files to use the default m4 quote
	  characters.

NEWS for the Nettle 3.6 release

	This release adds a couple of new features, most notable being
	support for ED448 signatures.

	It is not binary compatible with earlier releases. The shared
	library names are libnettle.so.8.0 and libhogweed.so.6.0, with
	sonames libnettle.so.8 and libhogweed.so.6. The changed
	sonames are mainly to avoid upgrade problems with recent
	GnuTLS versions, that depend on Nettle internals outside of
	the advertised ABI. But also because of the removal of
	internal poly1305 functions which were undocumented but
	declared in an installed header file, see Interface changes
	below.

	New features:

	* Support for Curve448 and ED448 signatures. Contributed by
	  Daiki Ueno.

	* Support for SHAKE256 (SHA3 variant with arbitrary output
	  size). Contributed by Daiki Ueno.

	* Support for SIV-CMAC (Synthetic Initialization Vector) mode,
	  contributed by Nikos Mavrogiannopoulos.

	* Support for CMAC64, contributed by Dmitry Baryshkov.

	* Support for the "CryptoPro" variant of the GOST hash
	  function, as gosthash94cp. Contributed by Dmitry Baryshkov.

	* Support for GOST DSA signatures, including GOST curves
	  gc256b and gc512a. Contributed by Dmitry Baryshkov.

	* Support for Intel CET in x86 and x86_64 assembly files, if
	  enabled via CFLAGS (gcc --fcf-protection=full). Contributed
	  by H.J. Lu and Simo Sorce.

	* A few new functions to improve support for the Chacha
	  variant with 96-bit nonce and 32-bit block counter (the
	  existing functions use nonce and counter of 64-bit each),
	  and functions to set the counter. Contributed by Daiki Ueno.

	* New interface, struct nettle_mac, for MAC (message
	  authentication code) algorithms. This abstraction is only
	  for MACs that don't require a per-message nonce. For HMAC,
	  the key size is fixed, and equal the digest size of the
	  underlying hash function.

	Bug fixes:

	* Fix bug in cfb8_decrypt. Previously, the IV was not updated
	  correctly in the case of input data shorter than the block
	  size. Reported by Stephan Mueller, fixed by Daiki Ueno.

	* Fix configure check for __builtin_bswap64, the incorrect
	  check would result in link errors on platforms missing this
	  function. Patch contributed by George Koehler.

	* All use of old-fashioned suffix rules in the Makefiles have
	  been replaced with %-pattern rules. Nettle's use of suffix
	  rules in earlier versions depended on undocumented GNU make
	  behavior, which is being deprecated in GNU make 4.3.

	  Building with other make programs than GNU make is untested
	  and unsupported. (Building with BSD make or Solaris make
	  used to work years ago, but has not been tested recently).

	Interface changes:

	* Declarations of internal poly1305.h functions have been
	  removed from the header file poly1305.h, to make it clear
	  that they are not part of the advertised API or ABI.

	Miscellaneous:

	* Building the public key support of nettle now requires GMP
	  version 6.1.0 or later (unless --enable-mini-gmp is used).

	* A fair amount of changes to ECC internals, with a few
	  deleted and a few new fields in the internal struct
	  ecc_curve. Files and functions have been renamed to more
	  consistently match the curve name, e.g., ecc-256.c has been
	  renamed to ecc-secp256r1.c.

	* Documentation for chacha-poly1305 updated. It is no longer
	  experimental. The implementation was updated to follow RFC
	  8439 in Nettle-3.1, but that was not documented or announced
	  at the time.

NEWS for the Nettle 3.5.1 release

	The Nettle-3.5.1 corrects a packaging mistake in Nettle-3.5.
	The new directory x86_64/sha_ni were missing in the tar file,
	breaking x86_64 builds with --enable-fat, and producing worse
	performance than promised for builds with --enable-x86-sha-ni.
	Also a few unused in-progress assembly files were accidentally
	included in the tar file.

	These problems are corrected in Nettle-3.5.1. There are no
	other changes, and also the library version numbers are
	unchanged.

NEWS for the Nettle 3.5 release

	This release adds a couple of new features and optimizations,
	and deletes or deprecates a few obsolete features. It is *not*
	binary (ABI) compatible with earlier versions. Except for
	deprecations listed below, it is intended to be fully
	source-level (API) compatible with Nettle-3.4.1.

	The shared library names are libnettle.so.7.0 and
	libhogweed.so.5.0, with sonames libnettle.so.7 and
	libhogweed.so.5.

	Changes in behavior:

	* Nettle's gcm_crypt will now call the underlying block cipher
	  to process more than one block at a time. This is not a
	  change to the documented behavior, but unfortunately breaks
	  assumptions accidentally made in GnuTLS, up to and including
	  version 3.6.1.

	New features:

	* Support for CFB8 (Cipher Feedback Mode, processing a single
	  octet per block cipher operation), contributed by Dmitry
	  Eremin-Solenikov.

	* Support for CMAC (RFC 4493), contributed by Nikos
	  Mavrogiannopoulos.

	* Support for XTS mode, contributed by Simo Sorce.

	Optimizations:

	* Improved performance of the x86_64 AES implementation using
	  the aesni instructions. Gives a large speedup for operations
	  processing multiple blocks at a time (including CTR mode,
	  GCM mode, and CBC decrypt, but *not* CBC encrypt).

	* Improved performance for CTR mode, for the common case of
	  16-byte block size. Pass more data at a time to underlying
	  block cipher, and fill the counter blocks more efficiently.
	  Extension to also handle GCM mode efficiently contributed
	  by Nikos Mavrogiannopoulos.

	* New x86_64 implementation of sha1 and sha256, for processors
	  supporting the sha_ni instructions. Speedup of 3-5 times on
	  affected processors.

	* Improved parameters for the precomputation of tables used
	  for ecc signatures. Roughly 10%-15% speedup of the ecdsa
	  sign operation using the secp_256r1, secp_384r1 and
	  secp_521r1 curves, and 25% speedup of ed25519 sign
	  operation, benchmarked on x86_64. Table sizes unchanged,
	  around 16 KB per curve.

	* In ARM fat builds, automatically select Neon implementation
	  of Chacha, where possible. Contributed by Yuriy M.
	  Kaminskiy.

	Deleted features:

	* The header file des-compat.h and everything declared therein
	  has been deleted, as announced earlier. This file provided a
	  subset of the old libdes/ssleay/openssl interface for DES
	  and triple-DES. DES is still supported, via the functions
	  declared in des.h.

	* Functions using the old struct aes_ctx have been marked as
	  deprecated. Use the fixed key size interface instead, e.g.,
	  struct aes256_ctx, introduced in Nettle-3.0.

	* The header file nettle-stdint.h, and corresponding autoconf
	  tests, have been deleted. Nettle now requires that the
	  compiler/libc provides <stdint.h>.

	Miscellaneous:

	* Support for big-endian ARM systems, contributed by Michael
	  Weiser.

	* The programs aesdata, desdata, twofishdata, shadata and
	  gcmdata are no longer built by default. Makefile
	  improvements contributed by Jay Foad.

	* The "example" program examples/eratosthenes.c has been
	  deleted.

	* The contents of hash context structs, and the deprecated
	  aes_ctx struct, have been reorganized, to enable later
	  optimizations.

	The shared library names are libnettle.so.7.0 and
	libhogweed.so.5.0.

NEWS for the Nettle 3.4.1 release

	This release fixes a few bugs, and makes the RSA private key
	operations side channel silent. The RSA improvements are
	contributed by Simo Sorce and Red Hat, and include one new
	public function, rsa_sec_decrypt, see below.

	All functions using RSA private keys are now side-channel
	silent, meaning that they try hard to avoid any branches or
	memory accesses depending on secret data. This applies both to
	the bignum calculations, which now use GMP's mpn_sec_* family
	of functions, and the processing of PKCS#1 padding needed for
	RSA decryption.

	Nettle's ECC functions were already side-channel silent, while
	the DSA functions still aren't. There's also one caveat
	regarding the improved RSA functions: due to small table
	lookups in relevant mpn_sec_* functions in GMP-6.1.2, the
	lowest and highest few bits of the secret factors p and q may
	still leak. I'm not aware of any attacks on RSA where knowing
	a few bits of the factors makes a significant difference. This
	leak will likely be plugged in later GMP versions.

	Changes in behavior:

	* The functions rsa_decrypt and rsa_decrypt_tr may now clobber
	  all of the provided message buffer, independent of the
	  actual message length. They are side-channel silent, in that
	  branches and memory accesses don't depend on the validity or
	  length of the message. Side-channel leakage from the
	  caller's use of length and return value may still provide an
	  oracle useable for a Bleichenbacher-style chosen ciphertext
	  attack. Which is why the new function rsa_sec_decrypt is
	  recommended.

	New features:

	* A new function rsa_sec_decrypt. It differs from
	  rsa_decrypt_tr in that the length of the decrypted message
	  is given a priori, and PKCS#1 padding indicating a different
	  length is treated as an error. For applications that may be
	  subject to chosen ciphertext attacks, it is recommended to
	  initialize the message area with random data, call this
	  function, and ignore the return value. This applies in
	  particular to RSA-based key exchange in the TLS protocol.

	Bug fixes:

	* Fix bug in pkcs1-conv, missing break statements in the
	  parsing of PEM input files.

	* Fix link error on the pss-mgf1-test test, affecting builds
	  without public key support.

	Performance regression:

	* All RSA private key operations employing RSA blinding, i.e.,
	  rsa_decrypt_tr, rsa_*_sign_tr, the new rsa_sec_decrypt, and
	  rsa_compute_root_tr, are significantly slower. This is
	  because (i) RSA blinding now use side-channel silent
	  operations, (ii) blinding includes a modular inversion, and
	  (iii) side-channel silent modular inversion, implemented as
	  mpn_sec_invert, is very expensive. A 60% slowdown for
	  2048-bit RSA keys have been measured.

	Miscellaneous:

	* Building the public key support of nettle now requires GMP
	  version 6.0 or later (unless --enable-mini-gmp is used).

	The shared library names are libnettle.so.6.5 and
	libhogweed.so.4.5, with sonames still libnettle.so.6 and
	libhogweed.so.4. It is intended to be fully binary compatible
	with nettle-3.1.

NEWS for the Nettle 3.4 release

	This release fixes bugs and adds a few new features. It also
	addresses an ABI compatibility issue affecting Nettle-3.1 and
	later, see below.

	Bug fixes:

	* Fixed an improper use of GMP mpn_mul, breaking curve2559 and
	  eddsa on certain platforms. Reported by Sergei Trofimovich.

	* Fixed memory leak when handling invalid signatures in
	  ecdsa_verify. Fix contributed by Nikos Mavrogiannopoulos.

	* Fix compilation error with --enable-fat om ARM. Fix
	  contributed by Andreas Schneider.

	* Reorganized the way certain data items are made available.

	  Short version: Nettle header files now define the symbols
	  nettle_hashes, nettle_ciphers, and nettle_aeads, as
	  preprocessor macros invoking a corresponding accessor
	  function. For backwards ABI compatibility, the symbols are
	  still present in the compiled libraries, and with the same
	  sizes as in nettle-3.3.

	New features:

	* Support for RSA-PSS signatures, contributed by Daiki Ueno.

	* Support for the HKDF key derivation function, defined by RFC
	  5869. Contributed by Nikos Mavrogiannopoulos.

	* Support for the Cipher Feedback Mode (CFB), contributed by
	  Dmitry Eremin-Solenikov.

	* New accessor functions: nettle_get_hashes,
	  nettle_get_ciphers, nettle_get_aeads, nettle_get_secp_192r1,
	  nettle_get_secp_224r1, nettle_get_secp_256r1,
	  nettle_get_secp_384r1, nettle_get_secp_521r1.

	  For source-level compatibility with future versions,
	  applications are encouraged to migrate to using these
	  functions instead of referring to the corresponding data
	  items directly.

	Miscellaneous:

	* The base16 and base64 functions now use the type char * for
	  ascii data, rather than uint8_t *. This eliminates the last
	  pointer-signedness warnings when building Nettle. This is a
	  minor API change, and applications may need to be adjusted,
	  but the ABI is unaffected on all platforms I'm aware of.

	* The contents of the header file nettle/version.h is now
	  architecture independent, except in --enable-mini-gmp
	  configurations.

	ABI issue:

	  Since the breakage was a bit subtle, let me document it
	  here. The nettle and hogweed libraries export a couple of
	  data symbols, and for some of these, the size was never
	  intended to be part of the ABI. E.g.,

	    extern const struct nettle_hash * const nettle_hashes[];

	  which is an NULL-terminated array.

	  It turns out the sizes nevertheless may leak into the ABI, and
	  that increasing the sizes can break old executables linked
	  with a newer version of the library.

	  When linking a classic non-PIE executable with a shared
	  library, we get ELF relocations of type R_X86_64_COPY for
	  references to data items. These mean that the linker allocates
	  space for the data item in the data segment of executable, at
	  a fixed address determined at link-time, and with size
	  extracted from the version of the .so-file seen when linking.

	  At load time, the run time linker then copies the contents of
	  the symbol from the .so file to that location, and uses the
	  copy instead of the version loaded with the .so-file. And if
	  the data item in the .so file used at load time is larger than
	  the data item seen at link time, it is silently truncated in
	  the process.

	  So when SHA3 hashes were was added to the nettle_hashes array
	  in the nettle-3.3 release, this way of linking produces a
	  truncated array at load time, no longer NULL-terminated.

	  We will get similar problems for planned extensions of the
	  internal struct ecc_curve, and exported data items like

	    extern const struct ecc_curve nettle_secp_256r1;

	  where the ecc_curve struct is only forward declared in the
	  public headers. To prepare, applications should migrate to
	  using the new function nettle_get_secp_256r1, and similarly
	  for the other curves.

	  In some future version, the plan is to add a leading
	  underscore to the name of the actual data items. E.g.,
	  nettle_hashes --> _nettle_hashes, breaking the ABI, while
	  keeping the nettle_get_hashes function and the nettle_hashes
	  macro as the supported ways to access it. We will also
	  rename nettle_secp_256r1 --> _nettle_secp_256r1, breaking
	  both ABI and API.

	  Note that data items like nettle_sha256 are *not* affected,
	  since the size and layout of this struct is considered part
	  of the ABI, and R_X86_64_COPY-relocations then work fine.

	The shared library names are libnettle.so.6.4 and
	libhogweed.so.4.4, with sonames still libnettle.so.6 and
	libhogweed.so.4. It is intended to be fully binary compatible
	with nettle-3.1.

NEWS for the Nettle 3.3 release

	This release fixes a couple of bugs, and improves resistance
	to side-channel attacks on RSA and DSA private key operations.

	Changes in behavior:

	* Invalid private RSA keys, with an even modulo, are now
	  rejected by rsa_private_key_prepare. (Earlier versions
	  allowed such keys, even if results of using them were bogus).

	  Nettle applications are required to call
	  rsa_private_key_prepare and check the return value, before
	  using any other RSA private key functions; failing to do so
	  may result in crashes for invalid private keys. As a
	  workaround for versions of Gnutls which don't use
	  rsa_private_key_prepare, additional checks for even moduli
	  are added to the rsa_*_tr functions which are used by all
	  recent versions of Gnutls.

	* Ignore bit 255 of the x coordinate of the input point to
	  curve25519_mul, as required by RFC 7748. To differentiate at
	  compile time, curve25519.h defines the constant
	  NETTLE_CURVE25519_RFC7748.

	Security:

	* RSA and DSA now use side-channel silent modular
	  exponentiation, to defend against attacks on the private key
	  from evil processes sharing the same processor cache. This
	  attack scenario is of particular relevance when running an
	  HTTPS server on a virtual machine, where you don't know who
	  you share the cache hardware with.

	  (Private key operations on elliptic curves were already
	  side-channel silent).

	Bug fixes:

	* Fix sexp-conv crashes on invalid input. Reported by Hanno
	  Böck.

	* Fix out-of-bounds read in des_weak_p. Fixed by Nikos
	  Mavrogiannopoulos.

	* Fix a couple of formally undefined shift operations,
	  reported by Nikos Mavrogiannopoulos.

	* Fix compilation with c89. Reported by Henrik Grubbström.

	New features:

	* New function memeql_sec, for side-channel silent comparison
	  of two memory areas.

	Miscellaneous:

	* Building the public key support of nettle now requires GMP
	  version 5.0 or later (unless --enable-mini-gmp is used).

	* Filenames of windows DLL libraries now include major number
	  only. So the dll names change at the same time as the
	  corresponding soname on ELF platforms. Fixed by Nikos
	  Mavrogiannopoulos.

	* Eliminate most pointer-signedness warnings. In the process,
	  the strings representing expression type for sexp_interator
	  functions were changed from const uint8_t * to const char *.
	  These functions are undocumented, and it doesn't change the
	  ABI on any platform I'm aware of.

	The shared library names are libnettle.so.6.3 and
	libhogweed.so.4.3, with sonames still libnettle.so.6 and
	libhogweed.so.4. It is intended to be fully binary compatible
	with nettle-3.1.

NEWS for the Nettle 3.2 release

	Bug fixes:

	* The SHA3 implementation is updated according to the FIPS 202
	  standard. It is not interoperable with earlier versions of
	  Nettle. Thanks to Nikos Mavrogiannopoulos. To easily
	  differentiate at compile time, sha3.h defines the constant
	  NETTLE_SHA3_FIPS202.

	* Fix corner-case carry propagation bugs affecting elliptic
	  curve operations on the curves secp_256r1 and secp_384r1 on
	  certain platforms, including x86_64. Reported by Hanno Böck.

	New features:

	* New functions for RSA private key operations, identified by
	  the "_tr" suffix, with better resistance to side channel
	  attacks and to hardware or software failures which could
	  break the CRT optimization. See the Nettle manual for
	  details. Initial patch by Nikos Mavrogiannopoulos.

	* New functions nettle_version_major, nettle_version_minor, as
	  a run-time variant of the compile-time constants
	  NETTLE_VERSION_MAJOR and NETTLE_VERSION_MINOR.

	Optimizations:

	* New ARM Neon implementation of the chacha stream cipher.

	Miscellaneous:

	* ABI detection on mips, with improved default libdir
	  location. Contributed by Klaus Ziegler.

	* Fixes for ARM assembly syntax, to work better with the clang
	  assembler. Thanks to Jukka Ukkonen.

	* Disabled use of ifunc relocations for fat builds, to fix
	  problems most easily triggered by using dlopen RTLD_NOW.

	The shared library names are libnettle.so.6.2 and
	libhogweed.so.4.2, with sonames still libnettle.so.6 and
	libhogweed.so.4. It is intended to be fully binary compatible
	with nettle-3.1.

NEWS for the Nettle 3.1.1 release

	This release fixes a couple of non-critical bugs.

	Bug fixes:

	* By accident, nettle-3.1 disabled the assembly code for the
	  secp_224r1 and secp_521r1 elliptic curves on all x86_64
	  configurations, making signature operations on those curves
	  10%-30% slower. This code is now re-enabled.

	* The x86_64 assembly implementation of gcm hashing has been
          fixed to work with the Sun/Oracle assembler.

	The shared library names are libnettle.so.6.1 and
	libhogweed.so.4.1, with sonames still libnettle.so.6 and
	libhogweed.so.4. It is intended to be fully binary compatible
	with nettle-3.1.

NEWS for the Nettle 3.1 release

	This release adds a couple of new features.

	The library is mostly source-level compatible with nettle-3.0.
	It is however not binary compatible, due to the introduction
	of versioned symbols, and extensions to the base64 context
	structs. The shared library names are libnettle.so.6.0 and
	libhogweed.so.4.0, with sonames libnettle.so.6 and
	libhogweed.so.4.

	Bug fixes:

	* Fixed a missing include of <limits.h>, which made the
	  camellia implementation fail on all 64-bit non-x86
	  platforms.

	* Eliminate out-of-bounds reads in the C implementation of
	  memxor (related to valgrind's --partial-loads-ok flag).

	Interface changes:

	* Declarations of many internal functions are moved from ecc.h
	  to ecc-internal.h. The functions are undocumented, and
	  luckily they're apparently also unused by applications, so I
	  don't expect any problems from this change.

	New features:

	* Support for curve25519 and for EdDSA25519 signatures.

	* Support for "fat builds" on x86_64 and arm, where the
	  implementation of certain functions is selected at run-time
	  depending on available cpu features. Configure with
	  --enable-fat to try this out. If it turns out to work well
	  enough, it will likely be enabled by default in later
	  releases.

	* Support for building the hogweed library (public key
	  support) using "mini-gmp", a small but slower implementation
	  of a subset of the GMP interfaces. Note that builds using
	  mini-gmp are *not* binary compatible with regular builds,
	  and more likely to leak side-channel information.

	  One intended use-case is for small embedded applications
	  which need to verify digital signatures.

	* The shared libraries are now built with versioned symbols.
	  Should reduce problems in case a program links explicitly to
	  nettle and/or hogweed, and to gnutls, and the program and
	  gnutls expect different versions.

	* Support for "URL-safe" base64 encoding and decoding, as
          specified in RFC 4648. Contributed by Amos Jeffries.

	Optimizations:

	* New x86_64 implementation of AES, using the "aesni"
	  instructions. Autodetected in fat builds. In non-fat builds,
	  it has to be enabled explicitly with --enable-x86-aesni.

	Build system:

	* Use the same object files for both static and shared
	  libraries. This eliminates the *.po object files which were
	  confusing to some tools (as well as humans). Like before,
	  PIC code is used by default; to build a non-pic static
	  library, configure with --disable-pic --disable-shared.

	Miscellaneous:

	* Made type-checking hack in CBC_ENCRYPT and similar macros
	  stricter, to generate warnings if they are used with
	  functions which have a length argument smaller than size_t.

NEWS for the Nettle 3.0 release

	This is a major release, including several interface changes,
	and new features, some of which are a bit experimental.
	Feedback is highly appreciated.

	It is *not* binary (ABI) compatible with earlier versions. It
	is mostly source-level (API) compatible, with a couple of
	incompatibilities noted below. The shared library names are
	libnettle.so.5.0 and libhogweed.so.3.0, with sonames
	libnettle.so.5 and libhogweed.so.3.
	
	There may be some problems in the new interfaces and new
	features which really need incompatible fixes. It is likely
	that there will be an update in the form of a 3.1 release in
	the not too distant future, with small but incompatible
	changes, and if that happens, bugfix-only releases 3.0.x are
	unlikely. Users and applications which desire better API and
	ABI stability are advised to stay with nettle-2.7.x (latest
	version is now 2.7.1) until the dust settles.

	Interface changes:

	* For the many _set_key functions, it is now consider the
	  normal case to have a fixed key size, with no key_size
	  arguments. _set_key functions with a length parameter are
	  provided only for algorithms with a truly variable keysize,
	  and where it makes sense for backwards compatibility.

	  INCOMPATIBLE CHANGE: cast128_set_key no longer accepts a key
	  size argument. The old function is available under a new
	  name, cast5_set_key.

	  INCOMPATIBLE CHANGE: The function typedef
	  nettle_set_key_func no longer accepts a key size argument.
	  In particular, this affects users of struct nettle_cipher.

	* The nettle_cipher abstraction (in nettle-meta.h) is
	  restricted to block ciphers only. The encrypt and decrypt
	  functions now take a const argument for the context.

	  INCOMPATIBLE CHANGE: nettle_arcfour, i.e., the nettle_cipher
	  abstraction for the arcfour stream cipher, is deleted.

	  INCOMPATIBLE CHANGE: New type, nettle_cipher_func, for the
	  encrypt and decrypt fields of struct nettle_cipher.

	* New DSA interface, with a separate struct dsa_param to
	  represent the underlying group, and generalized dsa_sign and
	  dsa_verify functions which don't care about the hash
	  function used. Limited backwards compatibility provided in
	  dsa-compat.h.

	  INCOMPATIBLE CHANGE: Declarations of the old interface,
	  e.g., struct dsa_public_key, dsa_sha1_sign, etc, is moved to
	  dsa-compat.h.

	  INCOMPATIBLE CHANGE: The various key conversion functions,
	  e.g., dsa_keypair_to_sexp, all use the new DSA interface, with
	  no backwards compatible functions.

	  INCOMPATIBLE CHANGE: dsa_generate_keypair also uses the new
	  interface. dsa-compat.h declares a function
	  dsa_compat_generate_keypair, implementing the old
	  interface, and #defines dsa_generate_keypair to refer to
	  this backwards compatible function.

	* New AES and Camellia interfaces. There are now separate
	  context structs for each key size, e.g., aes128_ctx and
	  camellia256_ctx, and corresponding new functions. The old
	  interface, with struct aes_ctx and struct camellia_ctx, is
	  kept for backwards compatibility, but might be removed in
	  later versions.

	* The type of most length arguments is changed from unsigned
	  to size_t. The memxor functions have their pointer arguments
	  changed from uint8_t * to void *, for consistency with
	  related libc functions.

	* For hash functions, the constants *_DATA_SIZE have been
	  renamed to *_BLOCK_SIZE. Old names kept for backwards
	  compatibility.

	Removed features:

	* The nettle_next_prime function has been deleted.
	  Applications should use GMP's mpz_nextprime instead.

	* Deleted the RSAREF compatibility, including the header file
	  rsa-compat.h and everything declared therein.

	* Also under consideration for removal is des-compat.h and
	  everything declared therein. This implements a subset of the
	  old libdes/ssleay/openssl interface for DES and triple-DES,
	  and it is poorly tested. If anyone uses this interface,
	  please speak up! Otherwise, it will likely be removed in the
	  next release.
	
	Bug fixes:

	* Building with ./configure --disable-static now works.

	* Use GMP's allocation functions for temporary storage related
	  to bignums, to avoid potentially large stack allocations.

	* Fixes for shared libraries on M$ Windows.

	New features:

	* Support for Poly1305-AES MAC.

	* Support for the ChaCha stream cipher and EXPERIMENTAL
	  support for the ChaCha-Poly1305 AEAD mode. Specifications
	  are still in flux, and future releases may do incompatible
	  changes to track standardization. Currently uses 256-bit key
	  and 64-bit nonce.

	* Support for EAX mode.

	* Support for CCM mode. Contributed by Owen Kirby.

	* Additional variants of SHA512 with output size of 224 and
	  256 bits. Contributed by Joachim Strömbergson.

	* New interface, struct nettle_aead, for mechanisms providing
	  authenticated encryption with associated data (AEAD).

	* DSA: Support a wider range for the size of q and a wider
	  range for the digest size.

	Optimizations:

	* New x86_64 assembly for GCM and MD5. Modest speedups on the
	  order of 10%-20%.

	Miscellaneous:

	* SHA3 is now documented as EXPERIMENTAL. Nettle currently
	  implements SHA3 as specified at the time Keccak won the SHA3
	  competition. However, the final standard specified by NIST
	  is likely to be incompatible, in which case future releases
	  may do incompatible changes to track standardization.

	* The portability fix for the rotation macros, mentioned in
	  NEWS for 2.7.1, actually didn't make it into that release.
	  It is included now.

	* cast128_set_key rewritten for clarity, also eliminating a
	  couple of compiler warnings.

	* New command line tool nettle-pbkdf2.

NEWS for the 2.7.1 release

        This is a bugfix release.

        Bug fixes:

        * Fixed a bug in the new ECC code. The ecc_j_to_a function
          called GMP:s mpn_mul_n (via ecc_modp_mul) with overlapping
          input and output arguments, which is not supported.

        * The assembly files for SHA1, SHA256 and AES depend on ARMv6
          instructions, breaking nettle-2.7 for pre-v6 ARM processors.
          The configure script now enables those assembly files only
          when building for ARMv6 or later.
          
        * Use a more portable C expression for rotations. The
          previous version used the following "standard" expression
          for 32-bit rotation:

            (x << n) | (x >> (32 - n))

          But this gives undefined behavior (according to the C
          specification) for n = 0. The rotate expression is replaced
          by the more portable:

            (x << n) | (x >> ((-n)&31))

          This change affects only CAST128, which uses non-constant
          rotation counts. Unfortunately, the new expression is poorly
          optimized by released versions of gcc, making CAST128 a bit
          slower. This is being fixed by the gcc hackers, see
          http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57157.
          
        The following problems have been reported, but are *not* fixed
        in this release:

        * ARM assembly files use instruction syntax which is not
          supported by all assemblers. Workaround: Use a current
          version of GNU as, or configure with --disable-assembler.

        * Configuring with --disable-static doesn't work on windows.
        
        The libraries are intended to be binary compatible with
        nettle-2.2 and later. The shared library names are
        libnettle.so.4.7 and libhogweed.so.2.5, with sonames still
        libnettle.so.4 and libhogweed.so.2.
	
NEWS for the 2.7 release

	This release includes an implementation of elliptic curve
	cryptography (ECC) and optimizations for the ARM architecture.
	This work was done at the offices of South Pole AB, and
	generously funded by the .SE Internet Fund.

	Bug fixes:

	* Fixed a bug in the buffer handling for incremental SHA3
	  hashing, with a possible buffer overflow. Patch by Edgar
	  E. Iglesias.

	New features:

	* Support for ECDSA signatures. Elliptic curve operations over
	  the following curves: secp192r1, secp224r1, secp256r1,
	  secp384r1 and secp521r1, including x86_64 and ARM assembly
	  for the most important primitives.
	  
	* Support for UMAC, including x86_64 and ARM assembly.

	* Support for 12-round salsa20, "salsa20r12", as specified by
	  eSTREAM. Contributed by Nikos Mavrogiannopoulos.
	
	Optimizations:

	* ARM assembly code for several additional algorithms,
	  including AES, Salsa20, and the SHA family of hash
	  functions. 

	* x86_64 assembly for SHA256, SHA512, and SHA3. (SHA3 assembly
          was included in the 2.6 release, but disabled due to poor
          performance on some AMD processors. Hopefully, that
          performance problem is fixed now).
	
	The ARM code was tested and benchmarked on Cortex-A9. Some of
	the functions use "neon" instructions. The configure script
	decides if neon instructions can be used, and the command line
	options --enable-arm-neon and --disable-arm-neon can be used
	to override its choice. Feedback appreciated.
	  
	The libraries are intended to be binary compatible with
	nettle-2.2 and later. The shared library names are
	libnettle.so.4.6 and libhogweed.so.2.4, with sonames still
	libnettle.so.4 and libhogweed.so.2.

NEWS for the 2.6 release

	Bug fixes:

	* Fixed a bug in ctr_crypt. For zero length (which should be a
	  NOP), it sometimes incremented the counter. Reported by Tim
	  Kosse.

	* Fixed a small memory leak in nettle_realloc and
          nettle_xrealloc.

	New features:

	* Support for PKCS #5 PBKDF2, to generate a key from a
          password or passphrase. Contributed by Simon Josefsson.
          Specification in RFC 2898 and test vectors in RFC 6070.

	* Support for SHA3.
	  
	* Support for the GOST R 34.11-94 hash algorithm. Ported from
	  librhash by Nikos Mavrogiannopoulos. Written by Aleksey
	  Kravchenko. More information in RFC4357. Test vectors taken
	  from the GOST hash wikipedia page.

	Miscellaneous:

	* The include file <nettle/sha.h> has been split into
          <nettle/sha1.h> and <nettle/sha2.h>. For now, sha.h is kept
          for backwards compatibility and it simply includes both
          files, but applications are encouraged to use the new names.
          The new SHA3 functions are declared in <nettle/sha3.h>.

	* Testsuite can be run under valgrind, using

	  make check EMULATOR='$(VALGRIND)'

	  For this to work, test programs and other executables now
	  deallocate storage.
	  
	* New configure options --disable-documentation and
          --disable-static. Contributed by Sam Thursfield and Alon
	  Bar-Lev, respectively.
	  
	* The section on hash functions in the manual is split into
          separate nodes for recommended hash functions and legacy
          hash functions.

	* Various smaller improvements, most of them portability
          fixes. Credits go to David Woodhouse, Tim Rühsen, Martin
          Storsjö, Nikos Mavrogiannopoulos, Fredrik Thulin and Dennis
          Clarke.

	Finally, a note on the naming of the various "SHA" hash
	functions. Naming is a bit inconsistent; we have, e.g.,

	  SHA1: sha1_digest
	  SHA2: sha256_digest   (not sha2_256_digest)
	  SHA3: sha3_256_digest

	Renaming the SHA2 functions to make Nettle's naming more
	consistent has been considered, but the current naming follows
	common usage. Most documents (including the specification for
	SHA2) refer to 256-bit SHA2 as "SHA-256" or "SHA256" rather
	than "SHA2-256".

	The libraries are intended to be binary compatible with
	nettle-2.2 and later. The shared library names are
	libnettle.so.4.5 and libhogweed.so.2.3, with sonames still
	libnettle.so.4 and libhogweed.so.2

NEWS for the 2.5 release

	This release includes important portability fixes for Windows
	and MacOS. There are also a few new features.

	First a *warning*: Some internal functions have been removed
	from the library. Since the functions in question are internal
	and not documented, this is not considered a change of ABI or
	API. Programs explicitly using any of these functions will
	break.
	
	* The function pkcs1_signature_prefix has been renamed to
	  _pkcs1_signature_prefix, and with slightly different
	  behavior.

	* The file nettle-internal.c is no longer included in the
          library (the features defined there are used by the
          benchmark and test programs, and were never intended for
          public use).

	New features:

	* Support for the salsa20 stream cipher, including x86_64
          assembler. Originally contributed by Simon Josefsson, based
          on the reference implementation, then further optimized.

	* Tentative interface for timing-resistant RSA functions,
          contributed by Nikos Mavrogiannopoulos.

	* A more general interface for PKCS#1 signatures, taking the
          input in the form of a "DigestInfo". Suggested by Nikos
          Mavrogiannopoulos.

	Configuration:
	
	* Building of shared libraries (./configure --enable-shared)
          is now enabled by default.

	* Various portability fixes for MacOS and M$ Windows. A lot of
	  this work done by Martin Storsjö.

	* In particular, Nettle now hopefully works on 64-bit Windows
	  builds, "W64", including the x86_64 assembly code.

	Miscellaneous:
	
	* Documentation and example programs for the base16 and base64
	  functions. Was contributed by Jeronimo Pellegrini back in
	  2006, but unfortunately forgotten until now.

	* Use an additional table to avoid GF2^8 multiplications in
	  aes_invert_key (mainly used by aes_set_decrypt_key). Also
	  tabulate round constants in aes_set_encrypt_key.

	* The nettle repository has been migrated from cvs to git,
	  with a public repository at
	  http://git.lysator.liu.se/nettle. To make it independent of
	  the LSH repository, a few files have been moved around.
	  While at it, files have also been converted from latin-1 to
	  utf-8.

	The libraries are intended to be binary compatible with
	nettle-2.2 and later. The shared library names are
	libnettle.so.4.4 and libhogweed.so.2.2, with sonames still
	libnettle.so.4 and libhogweed.so.2

NEWS for the 2.4 release

	This is a bugfix release only. It turned out ripemd160 in the
	2.3 release was broken on all big-endian systems, due to a
	missing include of config.h. nettle-2.4 fixes this.

	The library is intended to be binary compatible with
	nettle-2.2 and nettle-2.3. The shared library names are
	libnettle.so.4.3 and libhogweed.so.2.1, with sonames still
	libnettle.so.4 and libhogweed.so.2.
	
NEWS for the 2.3 release

	* Support for the ripemd-160 hash function.

	* Generates and installs nettle.pc and hogweed.pc files, for
          use with pkg-config. Feedback appreciated. For projects
          using autoconf, the traditional non-pkg-config ways of
          detecting libraries, and setting LIBS and LDFLAGS, is still
          recommended.

	* Fixed a bug which made the testsuite fail in the GCM test on
	  certain platforms. Should not affect any documented features
	  of the library.

	* Reorganization of the code for the various Merkle-Damgård
	  hash functions. Some fields in the context structs for md4,
	  md5 and sha1 have been renamed, for consistency.
	  Applications should not peek inside these structs, and the
	  ABI is unchanged.
	  
	* In the manual, fixed mis-placed const in certain function
          prototypes.

	The library is intended to be binary compatible with
	nettle-2.2. The shared library names are libnettle.so.4.2 and
	libhogweed.so.2.1, with sonames still libnettle.so.4 and
	libhogweed.so.2.

NEWS for the 2.2 release

	Licensing change:
     	
	* Relicensed as LGPL v2.1 or later (user's option).

	* Replaced blowfish and serpent implementation. New code is
          based on the LGPLed code in libgcrypt.

	New features:

	* Support for Galois/Counter Mode (GCM).

	* New interface for enumerating (most) available algorithms,
	  contributed by Daniel Kahn Gillmor.

	* New tool nettle-hash. Can generate hash digests using any
	  supported hash function, with output compatible with md5sum
	  and friends from GNU coreutils. Checking (like md5sum -c)
	  not yet implemented.

	Bug fixes:

	* The old serpent code had a byte order bug (introduced by
	  yours truly about ten years ago). New serpent implementation
	  does not interoperate with earlier versions of nettle.

	* Fixed ABI-dependent libdir default for Linux-based systems
	  which do not follow the Linux File Hierarchy Standard, e.g.,
	  Debian GNU/Linux.

	Optimizations:
	
	* x86_64 implemention of serpent.

	* x86_64 implemention of camellia.

	* Optimized memxor using word rather than byte operations.
          Both generic C and x86_64 assembler.

	* Eliminated a memcpy for in-place CBC decrypt.
	
	Miscellaneous:

	* In command line tools, no longer support -? for requesting
          help, since using it without shell quoting is a dangerous
          habit. Use long option --help instead.

	The shared library names are libnettle.so.4.1 and
	libhogweed.so.2.1, with sonames libnettle.so.4 and
	libhogweed.so.2.

NEWS for the 2.1 release

	*Important*: this release breaks source and binary
	compatibility for the digital signature functions, and for the
	DES and BLOWFISH ciphers which have weak keys.

	Incompatible changes:

	* The functions rsa_md5_sign, rsa_sha1_sign and
          rsa_sha256_sign, and the corresponding _digest variants, now
          have a return value which callers should check. The functions
          return failure if the key is too small for the type of
          signature.

	* The functions dsa_sign and dsa_verify are renamed to
          dsa_sha1_sign and dsa_sha1_verify. The _-digest variants are
          renamed similarly. These functions now have a return value
          which callers should check, and they return failure if the
          number q is not of the appropriate size.

	* The return value from des_set_key, des3_set_key and
	  blowfish_set_key now indicates whether or not the given key
	  is weak. But in either case, the key setup is done, and
	  applications that don't care about weak keys can ignore the
	  return value.

	  The incompatible part of this change is that enum des_error
	  and enum blowfish_error has been deleted, and so has the
	  status attribute in struct des_ctx, struct des3_ctx, and
	  struct blowfish_ctx.

	The shared library names are libnettle.so.4.0 and
	libhogweed.so.2.0, with sonames libnettle.so.4 and
	libhogweed.so.2.

	Other changes:

	* Support for the Camellia block cipher, including an
          assembler implementation for x86_32.

	* New function aes_invert_key, useful for applications that
	  need both encryption and decryption using the same AES key.
	  
	* des_set_key and des3_set_key no longer check the key parity
	  bits. Parity bits are silently ignored. A new function
	  des_check_parity is provided, for applications that care
	  about the DES parity bits.

	* Support for sha224, sha384 and sha512.

	* Support for digital signatures using rsa-sha512 and
          dsa-sha256. Due to lack of official test vectors and interop
          testing, this support should be considered somewhat
          experimental.

	* Key generation for RSA and DSA changed to use Maurer's
	  algorithm to generate provably prime numbers (as usual, the
	  mathematical proof does not guaranteee that the
	  implementation is bug free).
	  
	* x86_64 assembler implementation actually included in the
	  distribution (was accidentally left out in nettle-2.0).

	* Configure script now detects if the compiler uses a 32-bit
          or 64-bit ABI on x86_64 (prevously did this for sparc only).
          Also sets the default location for installing libraries
          (libdir) depending on system type and the ABI used.

	* Added the nettle and gmp libraries as dependencies when
          linking shared library libhogweed.so. On systems using
          shared libraries where such dependencies work (in
          particular, ELF systems), it is sufficient to link
          applications with -lhogweed. For static linking -lhogweed
          -lnettle -lgmp is still required.

	* The program pkcs1-conv is extended to also handle dsa keys.
          Contributed by Magnus Holmgren.

	* Slightly improved sha1 performance on x86.

NEWS for the 2.0 release

	This release breaks binary compatibility by splitting the
	library into two. Some other smaller changes that are not
	backwards compatible are also done at the same time.

	* The nettle library is split into two libraries, libnettle
	  and libhogweed. libnettle contains the symmetric crypto
	  algorithms that don't depend on GMP, while libhogweed
	  contains the public key algorithms that depend on GMP.
	  Using a single library worked fine with static linking, but
	  not with dynamic linking. Consider an application that uses
	  nettle and which doesn't use any public key cryptography. If
	  this application is linked dynamically to nettle, it would
	  have to be linked also with GMP if and only if public key
	  support was enabled when the nettle library was installed.

	  The library names are libnettle.so.3.0 and
	  libhogweed.so.1.0, with sonames libnettle.so.3 and
	  libhogweed.so.1.

	* Function typedefs have been changed to non-pointer types.
	  E.g, the

	    typedef void (nettle_hash_init_func *)(void *ctx);

	  of previous versions is replaced by

	    typedef void (nettle_hash_init_func)(void *ctx);

	  This makes it possible to use the type when declaring
	  functions, like

	    nettle_hash_init_func foo_hash_init;

	    void foo_hash_init(void *ctx) { ... }

	* Changes to the yarrow256 interface. The automatic seed file
	  generation, and the seed_file member in struct
	  yarrow256_ctx, has been removed. To generate a new seed
	  file, use yarrow256_random. The function
	  yarrow256_force_reseed has been replaced by the two
	  functions yarrow256_fast_reseed and yarrow256_slow_reseed,
	  which were previously static. This interface change makes it
	  easier to mix in the current content of the seed file before
	  overwriting it with newly generated data.

	Other changes:

	* Nettle manual now contributed to the public domain, to
          enable remixing into documentation of programs that use
          Nettle.	  

	* The sexp-conv program preserves comments when using the
	  advanced syntax for output. Optionally locks the output
	  file.

	* The base64 decoder recognizes ASCII FF (form feed) and VT
          (vertical tab) as white space.

	* New x86_64 implementations of AES and SHA1. On a 2.2 GHz
          opteron, SHA1 was benchmarked at 250 MByte/s, and AES-128 at
          110 MByte/s.

	* Performance of AES increased by 20-30% on x86.

	* New programs in the examples directory: erathostenes and
          next-prime.
	
NEWS for the 1.15 release

	Added support for PKCS#1 style RSA signatures using SHA256,
	according to RFC 3447. Currently lacks interoperability
	testing.
	
	Header files are now C++ aware, so C++ programs using Nettle
	should now use plain

	  #include <nettle/foo.h>

	rather than

	  #extern "C" {
	  #include <nettle/foo.h>
	  }

	as was the recommendation for the previous version. This
	breaks source-level compatibility with C++, even though
	there's full binary compatibility.

	The file rfc1750.txt (which is considered non-free by debian)
	has been removed from the distribution. The file was used as input
	for the Yarrow testcase, and has been replaced by the short
	story "The Gold-bug" by Edgar Allan Poe. Anyway, RFC 1750 is
	obsoleted by RFC 4086.

	Fixes for Darwin shared library support, contributed by Grant
	Robinsson.

	Example programs now use a supplied getopt.c.

	Configure tests for assemblers with a logarithmic .align
	directive.

	The library is intended to be upwards binary compatible with
	earlier versions. The library name is libnettle.so.2.6, soname
	is still libnettle.so.2.
		
NEWS for the 1.14 release

	Experimental support for reading keys in PKCS#1 ASN1/DER
	format, and a new command line tool pkcs1-conv.
	
	Improved MD5 performance on x86.

	Fixed support for sparc64.

	Reorganized AES code. Better performance for all three
	implementations (C, x86 assembler, sparc assembler).

	New sparc assembler for arcfour. Compared to the code
	generated by gcc, the new code is about 25% faster on old
	sparcs, and 6 times faster on ultrasparc.

	Replaced the internal function nettle_mpz_from_octets with a
	call to mpz_import, if available in the installed GMP library.

	More Makefile fixes; it now seems to work to build with
	the the make programs on Solaris and FreeBSD (although
	--disable-dependency-tracking is required for the latter).

	The library is intended to be binary compatible with earlier
	versions. The library name is libnettle.so.2.5, soname is
	still libnettle.so.2.

NEWS for the 1.13 release

	Fixed problem with broken m4 on bsd, which resulted in
	corrupted x86 assembler for sha1.

	Nettle probably works on windows: I've been able to cross
	compile it with ./configure --host=i586-mingw32msvc (without
	public-key support), and the testsuite binaries seem to run
	fine in Wine.

	Implemented CTR mode.

	Improved sha1 performance on x86.

	Configure check to figure out if symbols in assembler files
	need a leading underscore.

	Improved benchmark program. Displays cycles per byte and block,
	and compares with openssl (if openssl is installed).
	
	Terminating newline in output from sexp-conv --hash.

	The library is intended to be binary compatible with earlier
	versions. The library name is libnettle.so.2.4. However, the
	interface for the internal function _nettle_sha1_compress has
	changed; any program that calls this function directly will
	break.

NEWS for the 1.12 release
	
	Fixed a bug in the configure script.

	Updated the description of aes_set_encrypt_key and
	aes_set_decrypt_key in the manual.

NEWS for the 1.11 release

	Nettle no longer uses automake. Side effects:

	  * Dependency tracking is enabled only for gcc-3 (help with
	    supporting dependency tracking with other compilers is
	    appreciated).
	  
	  * Makefile compatibility with make programs other than GNU
	    make is mostly unknown, please report any problems.

	Support for arctwo.

	Fixes to the libdes compatibility code. Declarations should
	now match openssl/libdes better. des_cbc_cksum pads
	input with NUL's, if it's not an integral number of blocks (in
	general, such unreversible padding is a bad idea).

	By default, also the static library is compiled as position
	independent code. This is needed on some systems to make it
	possible to link nettle into a dynamically loaded module. Use
	the configure flag --disable-pic if this is not desired.

	Stricter constness typing for the sexp_iterator_assoc and
	sexp_iterator_check_types arguments.

	Minor tweaks of arcfour on x86 cpu:s, to speed it up on older
	x86 variants such as PII and PPro.

	The shared library is intended to be binary compatible with
	nettle-1.8 - nettle-1.10. Only the minor version number of the
	shared library is increased. The soname is still
	libnettle.so.2.

NEWS for the 1.10 release

	Nettle should now compile also on Tru64, Darwin, FreeBSD and
	Windows. (The only tested windows build uses the rntcl rsh
	wrapper to run the command line M$ C compiler "cl". See
	http://pike.ida.liu.se for those tools, I don't know all
	details about the Pike team's windows setup).

	There are some known testsuite failures, on Windows and on one
	of the xenofarm HPUX machines, see
	http://www.lysator.liu.se/~nisse/xeno-lsh/latest.html. Help
	tracking these down is appreciated.

	There are no new features.
	
	This release is intended to be binary compatible with
	nettle-1.8 and nettle-1.9.
	
NEWS for the 1.9 release

	Optimized C implementation of arcfour. Optimized x86
	implementations of arcfour and sha1.

	Improved benchmark program.
	
	Fixed bug in the rsa-encrypt example program.

	Fixed bug in make install, some of the header files were
	forgotten.
	
	Portability fixes. Fixes to make Nettle compile on systems
	without gmp. This version has been tested on GNU/Linux,
	Solaris, HPUX and AIX.

	The shared library is intended to be binary compatible with
	nettle-1.8. Only the minor version number of the shared
	library is increased.

NEWS for the 1.8 release

	New example programs, demonstrating encrypting and decrypting
	files using RSA, and random sessions keys for bulk encryption
	and message authentication.

	Support for systems that don't have alloca. On such systems,
	some of Nettle's functions have arbitrary limits applied to
	their input.

	Uses AX_CREATE_STDINT_H, to support systems without
	inttypes.h.

	Support for the md2 and md4 hash functions.
	 
	New name mangling, to reduce the risk of link collisions. All
	functions (except memxor) now use a nettle_ or _nettle_ prefix
	when seen by the linker. For most functions, the header file
	that declares a function also uses #define to provide a
	shorter more readable name without the prefix.

	The shared library soname for this version is libnettle.so.2.
	
NEWS for the 1.7 release

	Implemented DSA.

	Renamed RSA functions for consistency. Now it's
	rsa_public_key_init, not rsa_init_public_key, etc.

	Both RSA and DSA now have sign/verify functions that take the
	hash digest as argument.

	A rewritten and much more powerful sexp-conv program.

	Other changes to the sexp code, in particular updating it to
	the latest SPKI draft.

	Building nettle as a shared library (ELF only) seems to work.
	The version number is increased, so the library "soname" for
	this release is "libnettle.so.1".

	Bugfixes. Fixes for build and portability problems.

NEWS for the 1.6 release

	Optimized assembler implementations of aes, for sparc and x86.

	The aes interface has changed slightly. The function
	aes_set_key is no more. Instead one has to use
	aes_set_encrypt_key or aes_set_decrypt_key. Sorry about that. 

	New example programs, rsa-keygen, rsa-sign and rsa-verify,
	located in the examples directory.

	New configure option --enable-shared, which builds a shared
	library. Not tested.

	New experimental features, including sexp parsing and
	formatting, and changes to base64 encoding and decoding. The
	interfaces to these functions are subject to change, and are
	documented only in the source code.
	
NEWS for the 1.5 release

	RSA support. Key generation and signatures.
	
	Support for HMAC (RFC-2104).

	An implementation of the Yarrow-256 PRNG.

	New sections in the manual.
	
	Changed the interface for hash functions. The md5_digest
	function is now equivalent to the old sequence of md5_final,
	md5_digest, md5_init, and similarly for the other hashing
	algorithms. This makes the interface simpler.

NEWS for the 1.0 release

	Fixed twofish bug spotted by Jean-Pierre Stierlin.

	Added des3 and cbc.
	
	New RFC-1321-like interface in nettle/md5-compat.h, suggested
	by Assar Westerlund.

	New libdes-style compatibility interface in nettle/des-compat.h.