diff options
author | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-01-21 18:19:03 +0000 |
---|---|---|
committer | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-01-21 18:19:03 +0000 |
commit | 48080209fa53b6ea88c86e9f445c431b4cd1e47b (patch) | |
tree | 27d8768fb1d25696d3c40b42535eb5e073c278da /libgo/go/crypto/cipher/ctr.go | |
parent | bff898fbbe4358a4b7e337852df4d6043e0bd3f5 (diff) | |
download | gcc-48080209fa53b6ea88c86e9f445c431b4cd1e47b.tar.gz |
Remove the types float and complex.
Update to current version of Go library.
Update testsuite for removed types.
* go-lang.c (go_langhook_init): Omit float_type_size when calling
go_create_gogo.
* go-c.h: Update declaration of go_create_gogo.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@169098 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libgo/go/crypto/cipher/ctr.go')
-rw-r--r-- | libgo/go/crypto/cipher/ctr.go | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/libgo/go/crypto/cipher/ctr.go b/libgo/go/crypto/cipher/ctr.go new file mode 100644 index 00000000000..04436ec23b0 --- /dev/null +++ b/libgo/go/crypto/cipher/ctr.go @@ -0,0 +1,51 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Counter (CTR) mode. + +// CTR converts a block cipher into a stream cipher by +// repeatedly encrypting an incrementing counter and +// xoring the resulting stream of data with the input. + +// See NIST SP 800-38A, pp 13-15 + +package cipher + +type ctr struct { + b Block + ctr []byte + out []byte + outUsed int +} + +// NewCTR returns a Stream which encrypts/decrypts using the given Block in +// counter mode. The length of iv must be the same as the Block's block size. +func NewCTR(block Block, iv []byte) Stream { + return &ctr{ + b: block, + ctr: dup(iv), + out: make([]byte, len(iv)), + outUsed: len(iv), + } +} + +func (x *ctr) XORKeyStream(dst, src []byte) { + for i := 0; i < len(src); i++ { + if x.outUsed == len(x.ctr) { + x.b.Encrypt(x.out, x.ctr) + x.outUsed = 0 + + // Increment counter + for i := len(x.ctr) - 1; i >= 0; i-- { + x.ctr[i]++ + if x.ctr[i] != 0 { + break + } + } + } + + dst[i] = src[i] ^ x.out[x.outUsed] + x.outUsed++ + } +} |