diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c b/core/lib/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c new file mode 100644 index 0000000..0b1dde3 --- /dev/null +++ b/core/lib/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c @@ -0,0 +1,138 @@ +/* + * 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 + */ +#include "tomcrypt.h" + +/*! \file pkcs_1_v1_5_encode.c + * + * PKCS #1 v1.5 Padding (Andreas Lange) + */ + +#ifdef LTC_PKCS_1 + +/*! \brief PKCS #1 v1.5 encode. + * + * \param msg The data to encode + * \param msglen The length of the data to encode (octets) + * \param block_type Block type to use in padding (\sa ltc_pkcs_1_v1_5_blocks) + * \param modulus_bitlen The bit length of the RSA modulus + * \param prng An active PRNG state (only for LTC_PKCS_1_EME) + * \param prng_idx The index of the PRNG desired (only for LTC_PKCS_1_EME) + * \param out [out] The destination for the encoded data + * \param outlen [in/out] The max size and resulting size of the encoded data + * + * \return CRYPT_OK if successful + */ +int pkcs_1_v1_5_encode(const unsigned char *msg, + unsigned long msglen, + int block_type, + unsigned long modulus_bitlen, + prng_state *prng, + int prng_idx, + unsigned char *out, + unsigned long *outlen) +{ + unsigned long modulus_len, ps_len, i; + unsigned char *ps; + int result; + + /* valid block_type? */ + if ((block_type != LTC_PKCS_1_EMSA) && + (block_type != LTC_PKCS_1_EME)) { + return CRYPT_PK_INVALID_PADDING; + } + + if (block_type == LTC_PKCS_1_EME) { /* encryption padding, we need a valid PRNG */ + if ((result = prng_is_valid(prng_idx)) != CRYPT_OK) { + return result; + } + } + + modulus_len = (modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0); + + /* test message size */ + if ((msglen + 11) > modulus_len) { + return CRYPT_PK_INVALID_SIZE; + } + + if (*outlen < modulus_len) { + *outlen = modulus_len; + result = CRYPT_BUFFER_OVERFLOW; + goto bail; + } + + /* generate an octets string PS */ + ps = &out[2]; + ps_len = modulus_len - msglen - 3; + + if (block_type == LTC_PKCS_1_EME) { + /* now choose a random ps */ + if (prng_descriptor[prng_idx]->read(ps, ps_len, prng) != ps_len) { + result = CRYPT_ERROR_READPRNG; + goto bail; + } + + /* transform zero bytes (if any) to non-zero random bytes */ + for (i = 0; i < ps_len; i++) { + while (ps[i] == 0) { + if (prng_descriptor[prng_idx]->read(&ps[i], 1, prng) != 1) { + result = CRYPT_ERROR_READPRNG; + goto bail; + } + } + } + } else { + XMEMSET(ps, 0xFF, ps_len); + } + + /* create string of length modulus_len */ + out[0] = 0x00; + out[1] = (unsigned char)block_type; /* block_type 1 or 2 */ + out[2 + ps_len] = 0x00; + XMEMCPY(&out[2 + ps_len + 1], msg, msglen); + *outlen = modulus_len; + + result = CRYPT_OK; +bail: + return result; +} /* pkcs_1_v1_5_encode */ + +#endif /* #ifdef LTC_PKCS_1 */ + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |