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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.com |
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10 */ |
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11 #include "tomcrypt.h" |
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12 |
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13 /** |
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14 @file f8_encrypt.c |
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15 F8 implementation, encrypt data, Tom St Denis |
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16 */ |
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17 |
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18 #ifdef LTC_F8_MODE |
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19 |
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20 /** |
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21 F8 encrypt |
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22 @param pt Plaintext |
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23 @param ct [out] Ciphertext |
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24 @param len Length of plaintext (octets) |
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25 @param f8 F8 state |
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26 @return CRYPT_OK if successful |
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27 */ |
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28 int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8) |
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29 { |
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30 int err, x; |
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31 unsigned char buf[MAXBLOCKSIZE]; |
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32 LTC_ARGCHK(pt != NULL); |
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33 LTC_ARGCHK(ct != NULL); |
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34 LTC_ARGCHK(f8 != NULL); |
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35 if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) { |
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36 return err; |
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37 } |
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38 |
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39 /* is blocklen/padlen valid? */ |
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40 if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) || |
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41 f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) { |
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42 return CRYPT_INVALID_ARG; |
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43 } |
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44 |
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45 zeromem(buf, sizeof(buf)); |
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46 |
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47 /* make sure the pad is empty */ |
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48 if (f8->padlen == f8->blocklen) { |
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49 /* xor of IV, MIV and blockcnt == what goes into cipher */ |
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50 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4))); |
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51 ++(f8->blockcnt); |
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52 for (x = 0; x < f8->blocklen; x++) { |
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53 f8->IV[x] ^= f8->MIV[x] ^ buf[x]; |
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54 } |
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55 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) { |
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56 return err; |
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57 } |
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58 f8->padlen = 0; |
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59 } |
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60 |
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61 #ifdef LTC_FAST |
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62 if (f8->padlen == 0) { |
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63 while (len >= (unsigned long)f8->blocklen) { |
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64 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4))); |
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65 ++(f8->blockcnt); |
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66 for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) { |
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67 *((LTC_FAST_TYPE*)(&ct[x])) = *((LTC_FAST_TYPE*)(&pt[x])) ^ *((LTC_FAST_TYPE*)(&f8->IV[x])); |
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68 *((LTC_FAST_TYPE*)(&f8->IV[x])) ^= *((LTC_FAST_TYPE*)(&f8->MIV[x])) ^ *((LTC_FAST_TYPE*)(&buf[x])); |
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69 } |
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70 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) { |
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71 return err; |
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72 } |
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73 len -= x; |
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74 pt += x; |
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75 ct += x; |
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76 } |
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77 } |
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78 #endif |
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79 |
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80 while (len > 0) { |
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81 if (f8->padlen == f8->blocklen) { |
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82 /* xor of IV, MIV and blockcnt == what goes into cipher */ |
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83 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4))); |
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84 ++(f8->blockcnt); |
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85 for (x = 0; x < f8->blocklen; x++) { |
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86 f8->IV[x] ^= f8->MIV[x] ^ buf[x]; |
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87 } |
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88 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) { |
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89 return err; |
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90 } |
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91 f8->padlen = 0; |
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92 } |
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93 *ct++ = *pt++ ^ f8->IV[f8->padlen++]; |
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94 --len; |
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95 } |
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96 return CRYPT_OK; |
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97 } |
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98 |
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99 #endif |
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100 |
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101 /* $Source: /cvs/libtom/libtomcrypt/src/modes/f8/f8_encrypt.c,v $ */ |
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102 /* $Revision: 1.6 $ */ |
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103 /* $Date: 2006/11/05 04:16:32 $ */ |
