| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. |
| 3 | * |
| 4 | * Licensed under the OpenSSL license (the "License"). You may not use |
| 5 | * this file except in compliance with the License. You can obtain a copy |
| 6 | * in the file LICENSE in the source distribution or at |
| 7 | * https://www.openssl.org/source/license.html |
| 8 | */ |
| 9 | |
| 10 | #include "des_local.h" |
| 11 | |
| 12 | /* |
| 13 | * The input and output are loaded in multiples of 8 bits. What this means is |
| 14 | * that if you have numbits=12 and length=2 the first 12 bits will be |
| 15 | * retrieved from the first byte and half the second. The second 12 bits |
| 16 | * will come from the 3rd and half the 4th byte. |
| 17 | */ |
| 18 | void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, |
| 19 | long length, DES_key_schedule *schedule, |
| 20 | DES_cblock *ivec) |
| 21 | { |
| 22 | register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; |
| 23 | register DES_LONG mask0, mask1; |
| 24 | register long l = length; |
| 25 | register int num = numbits; |
| 26 | DES_LONG ti[2]; |
| 27 | unsigned char *iv; |
| 28 | |
| 29 | if (num > 64) |
| 30 | return; |
| 31 | if (num > 32) { |
| 32 | mask0 = 0xffffffffL; |
| 33 | if (num >= 64) |
| 34 | mask1 = mask0; |
| 35 | else |
| 36 | mask1 = (1L << (num - 32)) - 1; |
| 37 | } else { |
| 38 | if (num == 32) |
| 39 | mask0 = 0xffffffffL; |
| 40 | else |
| 41 | mask0 = (1L << num) - 1; |
| 42 | mask1 = 0x00000000L; |
| 43 | } |
| 44 | |
| 45 | iv = &(*ivec)[0]; |
| 46 | c2l(iv, v0); |
| 47 | c2l(iv, v1); |
| 48 | ti[0] = v0; |
| 49 | ti[1] = v1; |
| 50 | while (l-- > 0) { |
| 51 | ti[0] = v0; |
| 52 | ti[1] = v1; |
| 53 | DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); |
| 54 | vv0 = ti[0]; |
| 55 | vv1 = ti[1]; |
| 56 | c2ln(in, d0, d1, n); |
| 57 | in += n; |
| 58 | d0 = (d0 ^ vv0) & mask0; |
| 59 | d1 = (d1 ^ vv1) & mask1; |
| 60 | l2cn(d0, d1, out, n); |
| 61 | out += n; |
| 62 | |
| 63 | if (num == 32) { |
| 64 | v0 = v1; |
| 65 | v1 = vv0; |
| 66 | } else if (num == 64) { |
| 67 | v0 = vv0; |
| 68 | v1 = vv1; |
| 69 | } else if (num > 32) { /* && num != 64 */ |
| 70 | v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; |
| 71 | v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; |
| 72 | } else { /* num < 32 */ |
| 73 | |
| 74 | v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; |
| 75 | v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; |
| 76 | } |
| 77 | } |
| 78 | iv = &(*ivec)[0]; |
| 79 | l2c(v0, iv); |
| 80 | l2c(v1, iv); |
| 81 | v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; |
| 82 | } |