diff options
Diffstat (limited to 'libtomcrypt/src/misc/pkcs5/pkcs_5_2.c')
| -rw-r--r-- | libtomcrypt/src/misc/pkcs5/pkcs_5_2.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/libtomcrypt/src/misc/pkcs5/pkcs_5_2.c b/libtomcrypt/src/misc/pkcs5/pkcs_5_2.c new file mode 100644 index 0000000..6e8d161 --- /dev/null +++ b/libtomcrypt/src/misc/pkcs5/pkcs_5_2.c @@ -0,0 +1,129 @@ +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com + */ +#include <tomcrypt.h> + +/** + @file pkcs_5_2.c + PKCS #5, Algorithm #2, Tom St Denis +*/ +#ifdef PKCS_5 + +/** + Execute PKCS #5 v2 + @param password The input password (or key) + @param password_len The length of the password (octets) + @param salt The salt (or nonce) + @param salt_len The length of the salt (octets) + @param iteration_count # of iterations desired for PKCS #5 v2 [read specs for more] + @param hash_idx The index of the hash desired + @param out [out] The destination for this algorithm + @param outlen [in/out] The max size and resulting size of the algorithm output + @return CRYPT_OK if successful +*/ +int pkcs_5_alg2(const unsigned char *password, unsigned long password_len, + const unsigned char *salt, unsigned long salt_len, + int iteration_count, int hash_idx, + unsigned char *out, unsigned long *outlen) +{ + int err, itts; + ulong32 blkno; + unsigned long stored, left, x, y; + unsigned char *buf[2]; + hmac_state *hmac; + + LTC_ARGCHK(password != NULL); + LTC_ARGCHK(salt != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + + /* test hash IDX */ + if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { + return err; + } + + buf[0] = XMALLOC(MAXBLOCKSIZE * 2); + hmac = XMALLOC(sizeof(hmac_state)); + if (hmac == NULL || buf[0] == NULL) { + if (hmac != NULL) { + XFREE(hmac); + } + if (buf[0] != NULL) { + XFREE(buf[0]); + } + return CRYPT_MEM; + } + /* buf[1] points to the second block of MAXBLOCKSIZE bytes */ + buf[1] = buf[0] + MAXBLOCKSIZE; + + left = *outlen; + blkno = 1; + stored = 0; + while (left != 0) { + /* process block number blkno */ + zeromem(buf[0], MAXBLOCKSIZE*2); + + /* store current block number and increment for next pass */ + STORE32H(blkno, buf[1]); + ++blkno; + + /* get PRF(P, S||int(blkno)) */ + if ((err = hmac_init(hmac, hash_idx, password, password_len)) != CRYPT_OK) { + goto LBL_ERR; + } + if ((err = hmac_process(hmac, salt, salt_len)) != CRYPT_OK) { + goto LBL_ERR; + } + if ((err = hmac_process(hmac, buf[1], 4)) != CRYPT_OK) { + goto LBL_ERR; + } + x = MAXBLOCKSIZE; + if ((err = hmac_done(hmac, buf[0], &x)) != CRYPT_OK) { + goto LBL_ERR; + } + + /* now compute repeated and XOR it in buf[1] */ + XMEMCPY(buf[1], buf[0], x); + for (itts = 1; itts < iteration_count; ++itts) { + if ((err = hmac_memory(hash_idx, password, password_len, buf[0], x, buf[0], &x)) != CRYPT_OK) { + goto LBL_ERR; + } + for (y = 0; y < x; y++) { + buf[1][y] ^= buf[0][y]; + } + } + + /* now emit upto x bytes of buf[1] to output */ + for (y = 0; y < x && left != 0; ++y) { + out[stored++] = buf[1][y]; + --left; + } + } + *outlen = stored; + + err = CRYPT_OK; +LBL_ERR: +#ifdef LTC_CLEAN_STACK + zeromem(buf[0], MAXBLOCKSIZE*2); + zeromem(hmac, sizeof(hmac_state)); +#endif + + XFREE(hmac); + XFREE(buf[0]); + + return err; +} + +#endif + + +/* $Source: /cvs/libtom/libtomcrypt/src/misc/pkcs5/pkcs_5_2.c,v $ */ +/* $Revision: 1.5 $ */ +/* $Date: 2006/03/31 14:15:35 $ */ |