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Diffstat (limited to 'src/crypto/modes/cfb.c')
-rw-r--r-- | src/crypto/modes/cfb.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/crypto/modes/cfb.c b/src/crypto/modes/cfb.c new file mode 100644 index 0000000..738a438 --- /dev/null +++ b/src/crypto/modes/cfb.c @@ -0,0 +1,230 @@ +/* ==================================================================== + * Copyright (c) 2008 The OpenSSL Project. 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. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED 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 OpenSSL PROJECT OR + * ITS 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. + * ==================================================================== */ + +#include <openssl/modes.h> + +#include <assert.h> +#include <string.h> + +#include "internal.h" + + +void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, + const void *key, uint8_t ivec[16], int *num, int enc, + block128_f block) { + unsigned int n; + size_t l = 0; + + assert(in && out && key && ivec && num); + assert((16 % sizeof(size_t)) == 0); + + n = *num; + + if (enc) { + while (n && len) { + *(out++) = ivec[n] ^= *(in++); + --len; + n = (n + 1) % 16; + } +#if STRICT_ALIGNMENT + if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { + while (l < len) { + if (n == 0) { + (*block)(ivec, ivec, key); + } + out[l] = ivec[n] ^= in[l]; + ++l; + n = (n + 1) % 16; + } + *num = n; + return; + } +#endif + while (len >= 16) { + (*block)(ivec, ivec, key); + for (; n < 16; n += sizeof(size_t)) { + *(size_t *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n); + } + len -= 16; + out += 16; + in += 16; + n = 0; + } + if (len) { + (*block)(ivec, ivec, key); + while (len--) { + out[n] = ivec[n] ^= in[n]; + ++n; + } + } + *num = n; + return; + } else { + while (n && len) { + uint8_t c; + *(out++) = ivec[n] ^ (c = *(in++)); + ivec[n] = c; + --len; + n = (n + 1) % 16; + } + if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { + while (l < len) { + unsigned char c; + if (n == 0) { + (*block)(ivec, ivec, key); + } + out[l] = ivec[n] ^ (c = in[l]); + ivec[n] = c; + ++l; + n = (n + 1) % 16; + } + *num = n; + return; + } + while (len >= 16) { + (*block)(ivec, ivec, key); + for (; n < 16; n += sizeof(size_t)) { + size_t t = *(size_t *)(in + n); + *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t; + *(size_t *)(ivec + n) = t; + } + len -= 16; + out += 16; + in += 16; + n = 0; + } + if (len) { + (*block)(ivec, ivec, key); + while (len--) { + uint8_t c; + out[n] = ivec[n] ^ (c = in[n]); + ivec[n] = c; + ++n; + } + } + *num = n; + return; + } +} + + +/* This expects a single block of size nbits for both in and out. Note that + it corrupts any extra bits in the last byte of out */ +static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits, + const void *key, uint8_t ivec[16], int enc, + block128_f block) { + int n, rem, num; + uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one + byte off the end */ + + if (nbits <= 0 || nbits > 128) { + return; + } + + /* fill in the first half of the new IV with the current IV */ + memcpy(ovec, ivec, 16); + /* construct the new IV */ + (*block)(ivec, ivec, key); + num = (nbits + 7) / 8; + if (enc) { + /* encrypt the input */ + for (n = 0; n < num; ++n) { + out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); + } + } else { + /* decrypt the input */ + for (n = 0; n < num; ++n) { + out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; + } + } + /* shift ovec left... */ + rem = nbits % 8; + num = nbits / 8; + if (rem == 0) { + memcpy(ivec, ovec + num, 16); + } else { + for (n = 0; n < 16; ++n) { + ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); + } + } + + /* it is not necessary to cleanse ovec, since the IV is not secret */ +} + +/* N.B. This expects the input to be packed, MS bit first */ +void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits, + const void *key, uint8_t ivec[16], int *num, + int enc, block128_f block) { + size_t n; + uint8_t c[1], d[1]; + + assert(in && out && key && ivec && num); + assert(*num == 0); + + for (n = 0; n < bits; ++n) { + c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; + cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); + out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | + ((d[0] & 0x80) >> (unsigned int)(n % 8)); + } +} + +void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, + size_t length, const void *key, + unsigned char ivec[16], int *num, int enc, + block128_f block) { + size_t n; + + assert(in && out && key && ivec && num); + assert(*num == 0); + + for (n = 0; n < length; ++n) { + cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); + } +} + |