diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/pk/rsa/rsa_exptmod.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/pk/rsa/rsa_exptmod.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/pk/rsa/rsa_exptmod.c b/core/lib/libtomcrypt/src/pk/rsa/rsa_exptmod.c new file mode 100644 index 0000000..1f533fa --- /dev/null +++ b/core/lib/libtomcrypt/src/pk/rsa/rsa_exptmod.c @@ -0,0 +1,221 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* 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://libtom.org + * + * Added RSA blinding --nmav + */ +#include "tomcrypt.h" + +/** + @file rsa_exptmod.c + RSA PKCS exptmod, Tom St Denis +*/ + +#ifdef LTC_MRSA + +/** + Compute an RSA modular exponentiation + @param in The input data to send into RSA + @param inlen The length of the input (octets) + @param out [out] The destination + @param outlen [in/out] The max size and resulting size of the output + @param which Which exponent to use, e.g. PK_PRIVATE or PK_PUBLIC + @param key The RSA key to use + @return CRYPT_OK if successful +*/ +int rsa_exptmod(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen, int which, + rsa_key *key) +{ + void *tmp, *tmpa, *tmpb; +#ifdef LTC_RSA_BLINDING + void *rnd, *rndi /* inverse of rnd */; +#endif + unsigned long x; + int err, no_crt; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + LTC_ARGCHK(key != NULL); + + /* is the key of the right type for the operation? */ + if (which == PK_PRIVATE && (key->type != PK_PRIVATE)) { + return CRYPT_PK_NOT_PRIVATE; + } + + /* must be a private or public operation */ + if (which != PK_PRIVATE && which != PK_PUBLIC) { + return CRYPT_PK_INVALID_TYPE; + } + + /* init and copy into tmp */ + if ((err = mp_init_multi(&tmp, &tmpa, &tmpb, +#ifdef LTC_RSA_BLINDING + &rnd, &rndi, +#endif /* LTC_RSA_BLINDING */ + NULL)) != CRYPT_OK) + { return err; } + if ((err = mp_read_unsigned_bin(tmp, (unsigned char *)in, (int)inlen)) != CRYPT_OK) + { goto error; } + + /* sanity check on the input */ + if (mp_cmp(key->N, tmp) == LTC_MP_LT) { + err = CRYPT_PK_INVALID_SIZE; + goto error; + } + + /* are we using the private exponent and is the key optimized? */ +#ifdef LTC_LINARO_FIX_RSAWITHOUTCRT + if ((which == PK_PRIVATE) && (key->dP == NULL)) { + /* + * Fix when CRT optimization parameters are not there + * In such a case, we directly use the private key + */ + LTC_ARGCHK(key->dQ == NULL); + LTC_ARGCHK(key->qP == NULL); + LTC_ARGCHK(key->p == NULL); + LTC_ARGCHK(key->q == NULL); + /* exptmod it */ + if ((err = mp_exptmod(tmp, key->d, key->N, tmp)) != CRYPT_OK) { goto error; } + } else +#endif + if (which == PK_PRIVATE) { +#ifdef LTC_RSA_BLINDING + /* do blinding */ + err = mp_rand(rnd, mp_get_digit_count(key->N)); + if (err != CRYPT_OK) { + goto error; + } + + /* rndi = 1/rnd mod N */ + err = mp_invmod(rnd, key->N, rndi); + if (err != CRYPT_OK) { + goto error; + } + + /* rnd = rnd^e */ + err = mp_exptmod( rnd, key->e, key->N, rnd); + if (err != CRYPT_OK) { + goto error; + } + + /* tmp = tmp*rnd mod N */ + err = mp_mulmod( tmp, rnd, key->N, tmp); + if (err != CRYPT_OK) { + goto error; + } +#endif /* LTC_RSA_BLINDING */ + + no_crt = (key->dP == NULL) || (mp_get_digit_count(key->dP) == 0); + + if (no_crt) { + /* + * In case CRT optimization parameters are not provided, + * the private key is directly used to exptmod it + */ + if ((err = mp_exptmod(tmp, key->d, key->N, tmp)) != CRYPT_OK) { goto error; } + } else { + /* tmpa = tmp^dP mod p */ + if ((err = mp_exptmod(tmp, key->dP, key->p, tmpa)) != CRYPT_OK) { goto error; } + + /* tmpb = tmp^dQ mod q */ + if ((err = mp_exptmod(tmp, key->dQ, key->q, tmpb)) != CRYPT_OK) { goto error; } + + /* tmp = (tmpa - tmpb) * qInv (mod p) */ + if ((err = mp_sub(tmpa, tmpb, tmp)) != CRYPT_OK) { goto error; } + if ((err = mp_mulmod(tmp, key->qP, key->p, tmp)) != CRYPT_OK) { goto error; } + + /* tmp = tmpb + q * tmp */ + if ((err = mp_mul(tmp, key->q, tmp)) != CRYPT_OK) { goto error; } + if ((err = mp_add(tmp, tmpb, tmp)) != CRYPT_OK) { goto error; } + } + + #ifdef LTC_RSA_BLINDING + /* unblind */ + err = mp_mulmod( tmp, rndi, key->N, tmp); + if (err != CRYPT_OK) { + goto error; + } + #endif + + #ifdef LTC_RSA_CRT_HARDENING + if (!no_crt) { + if ((err = mp_exptmod(tmp, key->e, key->N, tmpa)) != CRYPT_OK) { goto error; } + if ((err = mp_read_unsigned_bin(tmpb, (unsigned char *)in, (int)inlen)) != CRYPT_OK) { goto error; } + if (mp_cmp(tmpa, tmpb) != LTC_MP_EQ) { err = CRYPT_ERROR; goto error; } + } + #endif + } else { + /* exptmod it */ + if ((err = mp_exptmod(tmp, key->e, key->N, tmp)) != CRYPT_OK) { goto error; } + } + + /* read it back */ + x = (unsigned long)mp_unsigned_bin_size(key->N); + if (x > *outlen) { + *outlen = x; + err = CRYPT_BUFFER_OVERFLOW; + goto error; + } + + /* this should never happen ... */ + if (mp_unsigned_bin_size(tmp) > mp_unsigned_bin_size(key->N)) { + err = CRYPT_ERROR; + goto error; + } + *outlen = x; + + /* convert it */ + zeromem(out, x); + if ((err = mp_to_unsigned_bin(tmp, out+(x-mp_unsigned_bin_size(tmp)))) != CRYPT_OK) { goto error; } + + /* clean up and return */ + err = CRYPT_OK; +error: + mp_clear_multi( +#ifdef LTC_RSA_BLINDING + rndi, rnd, +#endif /* LTC_RSA_BLINDING */ + tmpb, tmpa, tmp, NULL); + return err; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_exptmod.c,v $ */ +/* $Revision: 1.18 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |