From: Simon Josefsson Date: Fri, 21 Sep 2012 06:10:50 +0000 (+0200) Subject: Implement concrete PBKDF2 functions. X-Git-Tag: nettle_2.6_release_20130116~53 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90320ba2a897ffa2d3e43baee3b3972f0cb85421;p=thirdparty%2Fnettle.git Implement concrete PBKDF2 functions. --- diff --git a/ChangeLog b/ChangeLog index 049c3ddc..efb578e0 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2012-09-20 Simon Josefsson + + * pbkdf2-hmac-sha1.c, pbkdf2-hmac-sha256.c: New files. + * pbkdf2.h (pbkdf2_hmac_sha1, pbkdf2_hmac_sha256): New prototypes. + * Makefile.in (nettle_SOURCES): Add pbkdf2-hmac-sha1.c and + pbkdf2-hmac-sha256.c. + * nettle.texinfo (Key derivation functions): Improve. + * testsuite/pbkdf2-test.c (test_main): Test new functions. + 2012-09-20 Niels Möller * pbkdf2.c (pbkdf2): Reordered arguments, for consistency. diff --git a/Makefile.in b/Makefile.in index 7c6cf337..9904be5d 100644 --- a/Makefile.in +++ b/Makefile.in @@ -77,7 +77,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \ des3.c des-compat.c \ hmac.c hmac-md5.c hmac-ripemd160.c hmac-sha1.c \ hmac-sha224.c hmac-sha256.c hmac-sha384.c hmac-sha512.c \ - pbkdf2.c \ + pbkdf2.c pbkdf2-hmac-sha1.c pbkdf2-hmac-sha256.c \ knuth-lfib.c \ md2.c md2-meta.c md4.c md4-meta.c \ md5.c md5-compress.c md5-compat.c md5-meta.c \ diff --git a/nettle.texinfo b/nettle.texinfo index a333779a..c73861bf 100644 --- a/nettle.texinfo +++ b/nettle.texinfo @@ -2123,12 +2123,19 @@ a given symmetric key derives other symmetric keys. A sub-class of KDFs is the @dfn{password-based key derivation functions} (@acronym{PBKDFs}), which take as input a password or passphrase, and its purpose is typically to strengthen it and protect against certain pre-computation -attacks by using salting and expensive computation. The most well known -PBKDF is the @code{PKCS #5 PBKDF2} described in @cite{RFC 2898} which -uses a pseudorandom function such as @acronym{HMAC-SHA1}. +attacks by using salting and expensive computation. -Nettle's @acronym{PBKDF2} function is defined in @file{}. -It contains a function: +@subsection @acronym{PBKDF2} +The most well known PBKDF is the @code{PKCS #5 PBKDF2} described in +@cite{RFC 2898} which uses a pseudorandom function such as +@acronym{HMAC-SHA1}. + +Nettle's @acronym{PBKDF2} functions are defined in +@file{}. There is an abstract function that operate on +any PRF implemented via the @code{nettle_hash_update_func}, +@code{nettle_hash_digest_func} interfaces. There is also helper macros +and concrete functions PBKDF2-HMAC-SHA1 and PBKDF2-HMAC-SHA256. First, +the abstract function: @deftypefun void pbkdf2 (void *mac_ctx, nettle_hash_update_func *update, nettle_hash_digest_func *digest, unsigned digest_size, unsigned iterations, unsigned salt_length, const uint8_t *salt, unsigned length, uint8_t *dst) Derive symmetric key from a password according to PKCS #5 PBKDF2. The @@ -2141,6 +2148,44 @@ desired derived output length @var{length}. The output buffer is @var{dst} which must have room for at least @var{length} octets. @end deftypefun +Like for CBC and HMAC, there is a macros to help use the functions +correctly. + +@deffn Macro PBKDF2 (@var{ctx}, @var{update}, @var{digest}, @var{digest_size}, @var{iterations}, @var{salt_length}, @var{salt}, @var{length}, @var{dst}) +@var{ctx} is a pointer to a context struct passed to the @var{update} +and @var{digest} functions (of the types @code{nettle_hash_update_func} +and @code{nettle_hash_digest_func} respectively) to implement the +underlying PRF with digest size of @var{digest_size}. Inputs are the +salt @var{salt} of length @var{salt_length}, the iteration counter +@var{iterations} (> 0), and the desired derived output length +@var{length}. The output buffer is @var{dst} which must have room for +at least @var{length} octets. +@end deffn + +@subsection Concrete @acronym{PBKDF2} functions +Now we come to the specialized @acronym{PBKDF2} functions, which are +easier to use than the general @acronym{PBKDF2} function. + +@subsubsection @acronym{PBKDF2-HMAC-SHA1} + +@deftypefun void pbkdf2_hmac_sha1 (unsigned @var{key_length}, const uint8_t *@var{key}, unsigned @var{iterations}, unsigned @var{salt_length}, const uint8_t *@var{salt}, unsigned @var{length}, uint8_t *@var{dst}) +PBKDF2 with HMAC-SHA1. Derive @var{length} bytes of key into buffer +@var{dst} using the password @var{key} of length @var{key_length} and +salt @var{salt} of length @var{salt_length}, with iteration counter +@var{iterations} (> 0). The output buffer is @var{dst} which must have +room for at least @var{length} octets. +@end deftypefun + +@subsubsection @acronym{PBKDF2-HMAC-SHA256} + +@deftypefun void pbkdf2_hmac_sha256 (unsigned @var{key_length}, const uint8_t *@var{key}, unsigned @var{iterations}, unsigned @var{salt_length}, const uint8_t *@var{salt}, unsigned @var{length}, uint8_t *@var{dst}) +PBKDF2 with HMAC-SHA256. Derive @var{length} bytes of key into buffer +@var{dst} using the password @var{key} of length @var{key_length} and +salt @var{salt} of length @var{salt_length}, with iteration counter +@var{iterations} (> 0). The output buffer is @var{dst} which must have +room for at least @var{length} octets. +@end deftypefun + @node Public-key algorithms, Randomness, Key derivation functions, Reference @comment node-name, next, previous, up @section Public-key algorithms diff --git a/pbkdf2-hmac-sha1.c b/pbkdf2-hmac-sha1.c new file mode 100644 index 00000000..91855037 --- /dev/null +++ b/pbkdf2-hmac-sha1.c @@ -0,0 +1,45 @@ +/* pbkdf2-hmac-sha1.c + * + * PKCS #5 PBKDF2 used with HMAC-SHA1, see RFC 2898. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2012 Simon Josefsson + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02111-1301, USA. + */ + +#if HAVE_CONFIG_H +# include "config.h" +#endif + +#include "pbkdf2.h" + +#include "hmac.h" + +void +pbkdf2_hmac_sha1 (unsigned key_length, const uint8_t *key, + unsigned iterations, + unsigned salt_length, const uint8_t *salt, + unsigned length, uint8_t *dst) +{ + struct hmac_sha1_ctx sha1ctx; + + hmac_sha1_set_key (&sha1ctx, key_length, key); + PBKDF2 (&sha1ctx, hmac_sha1_update, hmac_sha1_digest, + SHA1_DIGEST_SIZE, iterations, salt_length, salt, length, dst); +} diff --git a/pbkdf2-hmac-sha256.c b/pbkdf2-hmac-sha256.c new file mode 100644 index 00000000..448f676d --- /dev/null +++ b/pbkdf2-hmac-sha256.c @@ -0,0 +1,45 @@ +/* pbkdf2-hmac-sha256.c + * + * PKCS #5 PBKDF2 used with HMAC-SHA256, see RFC 2898. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2012 Simon Josefsson + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02111-1301, USA. + */ + +#if HAVE_CONFIG_H +# include "config.h" +#endif + +#include "pbkdf2.h" + +#include "hmac.h" + +void +pbkdf2_hmac_sha256 (unsigned key_length, const uint8_t *key, + unsigned iterations, + unsigned salt_length, const uint8_t *salt, + unsigned length, uint8_t *dst) +{ + struct hmac_sha256_ctx sha256ctx; + + hmac_sha256_set_key (&sha256ctx, key_length, key); + PBKDF2 (&sha256ctx, hmac_sha256_update, hmac_sha256_digest, + SHA256_DIGEST_SIZE, iterations, salt_length, salt, length, dst); +} diff --git a/pbkdf2.h b/pbkdf2.h index aa615676..bf152544 100644 --- a/pbkdf2.h +++ b/pbkdf2.h @@ -35,6 +35,8 @@ extern "C" /* Namespace mangling */ #define pbkdf2 nettle_pbkdf2 +#define pbkdf2_hmac_sha1 nettle_pbkdf2_hmac_sha1 +#define pbkdf2_hmac_sha256 nettle_pbkdf2_hmac_sha256 void pbkdf2 (void *mac_ctx, @@ -54,6 +56,20 @@ pbkdf2 (void *mac_ctx, (digest_size), (iterations), \ (salt_length), (salt), (length), (dst))) +/* PBKDF2 with specific PRFs. */ + +void +pbkdf2_hmac_sha1 (unsigned key_length, const uint8_t *key, + unsigned iterations, + unsigned salt_length, const uint8_t *salt, + unsigned length, uint8_t *dst); + +void +pbkdf2_hmac_sha256 (unsigned key_length, const uint8_t *key, + unsigned iterations, + unsigned salt_length, const uint8_t *salt, + unsigned length, uint8_t *dst); + #ifdef __cplusplus } #endif diff --git a/testsuite/pbkdf2-test.c b/testsuite/pbkdf2-test.c index 6ef58328..c0d2eaec 100644 --- a/testsuite/pbkdf2-test.c +++ b/testsuite/pbkdf2-test.c @@ -12,6 +12,14 @@ ASSERT(dk[expect->length] == 17); \ } while (0) +#define PBKDF2_HMAC_TEST(f, key, c, salt, expect) \ + do { \ + dk[expect->length] = 17; \ + f (key, c, salt, expect->length, dk); \ + ASSERT(MEMEQ (expect->length, dk, expect->data)); \ + ASSERT(dk[expect->length] == 17); \ + } while (0) + #define MAX_DKLEN 25 void @@ -69,4 +77,13 @@ test_main (void) PBKDF2_TEST (&sha256ctx, hmac_sha256_update, hmac_sha256_digest, SHA256_DIGEST_SIZE, 80000, LDATA("NaCl"), SHEX("4ddcd8f60b98be21830cee5ef22701f9")); + + /* Test convenience functions. */ + + PBKDF2_HMAC_TEST(pbkdf2_hmac_sha1, LDATA("password"), 1, LDATA("salt"), + SHEX("0c60c80f961f0e71f3a9b524af6012062fe037a6")); + + PBKDF2_HMAC_TEST(pbkdf2_hmac_sha256, LDATA("passwd"), 1, LDATA("salt"), + SHEX("55ac046e56e3089fec1691c22544b605")); + }