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author | Nikos Mavrogiannopoulos <nmav@gnutls.org> | 2010-07-23 20:38:31 +0200 |
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committer | Nikos Mavrogiannopoulos <nmav@gnutls.org> | 2010-07-23 20:38:31 +0200 |
commit | 08edf1b4f10d6b5d2a265d7210944f044f607729 (patch) | |
tree | 1f5492f1f0293b3c39c04a2aa1cd18cd2267361a /doc/cha-intro-tls.texi | |
parent | 36c75f9fc791c1e32d1d324c0264857406b4a6f9 (diff) | |
download | gnutls-08edf1b4f10d6b5d2a265d7210944f044f607729.tar.gz |
Simplified documentation.
Diffstat (limited to 'doc/cha-intro-tls.texi')
-rw-r--r-- | doc/cha-intro-tls.texi | 55 |
1 files changed, 12 insertions, 43 deletions
diff --git a/doc/cha-intro-tls.texi b/doc/cha-intro-tls.texi index 9d180ad88a..2ab1b4271c 100644 --- a/doc/cha-intro-tls.texi +++ b/doc/cha-intro-tls.texi @@ -539,9 +539,14 @@ authentication. @end multitable -The first column provides an estimation of the year until these -parameters are considered safe and the rest of the columns list the -parameters for the various algorithms. +The first column provides a security parameter in a number of bits. This +gives an indication of the number of combinations to be tried by an adversary +to brute force a key. For example to test all possible keys in a 112 bit security parameter +@math{2^{112}} combinations have to be tried. For today's technology this is infeasible. +The next two columns correlate the security +parameter with actual bit sizes of parameters for DH, RSA, SRP and ECC algorithms. +A mapping to @code{gnutls_sec_param_t} value is given for each security parameter, on +the next column, and finally a brief description of the level. Note however that the values suggested here are nothing more than an educated guess that is valid today. There are no guarrantees that an @@ -553,47 +558,11 @@ TLS are selected in a conservative way and such catastrophic breakthroughs or failures are believed to be unlikely. NIST publication SP 800-57 @xcite{NISTSP80057} contains a similar -table that extends beyond the key sizes given above. +table. -@multitable @columnfractions .15 .20 .20 .20 - -@item Bits of security -@tab Symmetric key algorithms -@tab RSA key size, DSA, DH and SRP prime size -@tab ECC key size - -@item 80 -@tab 2TDEA -@tab 1024 -@tab 160-223 - -@item 112 -@tab 3DES -@tab 2048 -@tab 224-255 - -@item 128 -@tab AES-128 -@tab 3072 -@tab 256-383 - -@item 192 -@tab AES-192 -@tab 7680 -@tab 384-511 - -@item 256 -@tab AES-256 -@tab 15360 -@tab 512+ - -@end multitable - -The recommendations are fairly consistent. - -When using @acronym{GnuTLS} and -bit sizes are required as input it is recommended to use the following -functions: +When using @acronym{GnuTLS} and a decision on bit sizes for a public +key algorithm is required, use of the following functions is +recommended: @itemize @item @ref{gnutls_pk_bits_to_sec_param} |