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131 lines
5.2 KiB
131 lines
5.2 KiB
/* crypto/des/ofb_enc.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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#include "des_locl.h" |
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/* |
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* The input and output are loaded in multiples of 8 bits. What this means is |
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* that if you hame numbits=12 and length=2 the first 12 bits will be |
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* retrieved from the first byte and half the second. The second 12 bits |
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* will come from the 3rd and half the 4th byte. |
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*/ |
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void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, |
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long length, DES_key_schedule *schedule, |
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DES_cblock *ivec) |
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{ |
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register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; |
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register DES_LONG mask0, mask1; |
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register long l = length; |
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register int num = numbits; |
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DES_LONG ti[2]; |
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unsigned char *iv; |
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if (num > 64) |
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return; |
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if (num > 32) { |
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mask0 = 0xffffffffL; |
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if (num >= 64) |
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mask1 = mask0; |
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else |
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mask1 = (1L << (num - 32)) - 1; |
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} else { |
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if (num == 32) |
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mask0 = 0xffffffffL; |
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else |
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mask0 = (1L << num) - 1; |
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mask1 = 0x00000000L; |
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} |
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iv = &(*ivec)[0]; |
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c2l(iv, v0); |
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c2l(iv, v1); |
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ti[0] = v0; |
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ti[1] = v1; |
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while (l-- > 0) { |
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ti[0] = v0; |
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ti[1] = v1; |
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DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); |
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vv0 = ti[0]; |
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vv1 = ti[1]; |
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c2ln(in, d0, d1, n); |
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in += n; |
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d0 = (d0 ^ vv0) & mask0; |
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d1 = (d1 ^ vv1) & mask1; |
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l2cn(d0, d1, out, n); |
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out += n; |
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if (num == 32) { |
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v0 = v1; |
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v1 = vv0; |
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} else if (num == 64) { |
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v0 = vv0; |
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v1 = vv1; |
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} else if (num > 32) { /* && num != 64 */ |
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v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; |
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v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; |
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} else { /* num < 32 */ |
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v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; |
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v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; |
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} |
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} |
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iv = &(*ivec)[0]; |
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l2c(v0, iv); |
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l2c(v1, iv); |
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v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; |
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}
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