Mercurial > dropbear
diff libtomcrypt/src/pk/pkcs1/pkcs_1_mgf1.c @ 285:1b9e69c058d2
propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 13:23:58 +0000 |
parents | |
children | 0cbe8f6dbf9e |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtomcrypt/src/pk/pkcs1/pkcs_1_mgf1.c Wed Mar 08 13:23:58 2006 +0000 @@ -0,0 +1,108 @@ +/* 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, [email protected], http://libtomcrypt.org + */ +#include "tomcrypt.h" + +/** + @file pkcs_1_mgf1.c + The Mask Generation Function (MGF1) for PKCS #1, Tom St Denis +*/ + +#ifdef PKCS_1 + +/** + Perform PKCS #1 MGF1 (internal) + @param seed The seed for MGF1 + @param seedlen The length of the seed + @param hash_idx The index of the hash desired + @param mask [out] The destination + @param masklen The length of the mask desired + @return CRYPT_OK if successful +*/ +int pkcs_1_mgf1(const unsigned char *seed, unsigned long seedlen, + int hash_idx, + unsigned char *mask, unsigned long masklen) +{ + unsigned long hLen, x; + ulong32 counter; + int err; + hash_state *md; + unsigned char *buf; + + LTC_ARGCHK(seed != NULL); + LTC_ARGCHK(mask != NULL); + + /* ensure valid hash */ + if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { + return err; + } + + /* get hash output size */ + hLen = hash_descriptor[hash_idx].hashsize; + + /* allocate memory */ + md = XMALLOC(sizeof(hash_state)); + buf = XMALLOC(hLen); + if (md == NULL || buf == NULL) { + if (md != NULL) { + XFREE(md); + } + if (buf != NULL) { + XFREE(buf); + } + return CRYPT_MEM; + } + + /* start counter */ + counter = 0; + + while (masklen > 0) { + /* handle counter */ + STORE32H(counter, buf); + ++counter; + + /* get hash of seed || counter */ + if ((err = hash_descriptor[hash_idx].init(md)) != CRYPT_OK) { + goto LBL_ERR; + } + if ((err = hash_descriptor[hash_idx].process(md, seed, seedlen)) != CRYPT_OK) { + goto LBL_ERR; + } + if ((err = hash_descriptor[hash_idx].process(md, buf, 4)) != CRYPT_OK) { + goto LBL_ERR; + } + if ((err = hash_descriptor[hash_idx].done(md, buf)) != CRYPT_OK) { + goto LBL_ERR; + } + + /* store it */ + for (x = 0; x < hLen && masklen > 0; x++, masklen--) { + *mask++ = buf[x]; + } + } + + err = CRYPT_OK; +LBL_ERR: +#ifdef LTC_CLEAN_STACK + zeromem(buf, hLen); + zeromem(md, sizeof(hash_state)); +#endif + + XFREE(buf); + XFREE(md); + + return err; +} + +#endif /* PKCS_1 */ + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_mgf1.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2005/05/05 14:35:59 $ */