1 /* 2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (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 /* 11 * DES low level APIs are deprecated for public use, but still ok for internal 12 * use. 13 */ 14 #include "internal/deprecated.h" 15 16 #include "des_local.h" 17 18 /* 19 * The input and output are loaded in multiples of 8 bits. What this means is 20 * that if you have numbits=12 and length=2 the first 12 bits will be 21 * retrieved from the first byte and half the second. The second 12 bits 22 * will come from the 3rd and half the 4th byte. 23 */ 24 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 25 long length, DES_key_schedule *schedule, 26 DES_cblock *ivec) 27 { 28 register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; 29 register DES_LONG mask0, mask1; 30 register long l = length; 31 register int num = numbits; 32 DES_LONG ti[2]; 33 unsigned char *iv; 34 35 if (num > 64) 36 return; 37 if (num > 32) { 38 mask0 = 0xffffffffL; 39 if (num >= 64) 40 mask1 = mask0; 41 else 42 mask1 = (1L << (num - 32)) - 1; 43 } else { 44 if (num == 32) 45 mask0 = 0xffffffffL; 46 else 47 mask0 = (1L << num) - 1; 48 mask1 = 0x00000000L; 49 } 50 51 iv = &(*ivec)[0]; 52 c2l(iv, v0); 53 c2l(iv, v1); 54 ti[0] = v0; 55 ti[1] = v1; 56 while (l-- > 0) { 57 ti[0] = v0; 58 ti[1] = v1; 59 DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); 60 vv0 = ti[0]; 61 vv1 = ti[1]; 62 c2ln(in, d0, d1, n); 63 in += n; 64 d0 = (d0 ^ vv0) & mask0; 65 d1 = (d1 ^ vv1) & mask1; 66 l2cn(d0, d1, out, n); 67 out += n; 68 69 if (num == 32) { 70 v0 = v1; 71 v1 = vv0; 72 } else if (num == 64) { 73 v0 = vv0; 74 v1 = vv1; 75 } else if (num > 32) { /* && num != 64 */ 76 v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; 77 v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; 78 } else { /* num < 32 */ 79 80 v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; 81 v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; 82 } 83 } 84 iv = &(*ivec)[0]; 85 l2c(v0, iv); 86 l2c(v1, iv); 87 v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; 88 } 89