annotate src/pk/rsa/rsa_decrypt_key.c @ 280:59400faa4b44 libtomcrypt-orig libtomcrypt-1.05

Re-import libtomcrypt 1.05 for cleaner propagating. From crypt-1.05.tar.bz2, SHA1 of 88250202bb51570dc64f7e8f1c943cda9479258f
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 12:58:00 +0000
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children d5faf4814ddb
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59400faa4b44 Re-import libtomcrypt 1.05 for cleaner propagating.
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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.org
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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 rsa_decrypt_key.c
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15 RSA PKCS #1 OAEP Decryption, Tom St Denis
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16 */
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17
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18 #ifdef MRSA
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19
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20 /**
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21 (PKCS #1 v2.0) decrypt then OAEP depad
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22 @param in The ciphertext
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23 @param inlen The length of the ciphertext (octets)
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24 @param out [out] The plaintext
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25 @param outlen [in/out] The max size and resulting size of the plaintext (octets)
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26 @param lparam The system "lparam" value
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27 @param lparamlen The length of the lparam value (octets)
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28 @param hash_idx The index of the hash desired
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29 @param stat [out] Result of the decryption, 1==valid, 0==invalid
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30 @param key The corresponding private RSA key
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31 @return CRYPT_OK if succcessul (even if invalid)
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32 */
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33 int rsa_decrypt_key(const unsigned char *in, unsigned long inlen,
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34 unsigned char *out, unsigned long *outlen,
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35 const unsigned char *lparam, unsigned long lparamlen,
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36 int hash_idx, int *stat,
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37 rsa_key *key)
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38 {
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39 unsigned long modulus_bitlen, modulus_bytelen, x;
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40 int err;
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41 unsigned char *tmp;
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42
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43 LTC_ARGCHK(out != NULL);
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44 LTC_ARGCHK(outlen != NULL);
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45 LTC_ARGCHK(key != NULL);
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46 LTC_ARGCHK(stat != NULL);
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47
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48 /* default to invalid */
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49 *stat = 0;
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50
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51 /* valid hash ? */
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52 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
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53 return err;
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54 }
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55
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56 /* get modulus len in bits */
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57 modulus_bitlen = mp_count_bits(&(key->N));
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58
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59 /* outlen must be at least the size of the modulus */
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60 modulus_bytelen = mp_unsigned_bin_size(&(key->N));
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61 if (modulus_bytelen != inlen) {
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62 return CRYPT_INVALID_PACKET;
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63 }
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64
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65 /* allocate ram */
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66 tmp = XMALLOC(inlen);
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67 if (tmp == NULL) {
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68 return CRYPT_MEM;
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69 }
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70
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71 /* rsa decode the packet */
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72 x = inlen;
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73 if ((err = rsa_exptmod(in, inlen, tmp, &x, PK_PRIVATE, key)) != CRYPT_OK) {
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74 XFREE(tmp);
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75 return err;
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76 }
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77
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78 /* now OAEP decode the packet */
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79 err = pkcs_1_oaep_decode(tmp, x, lparam, lparamlen, modulus_bitlen, hash_idx,
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80 out, outlen, stat);
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81 XFREE(tmp);
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82 return err;
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83 }
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84
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85 #endif /* MRSA */
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86
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87
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88
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89
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90
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91 /* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_decrypt_key.c,v $ */
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92 /* $Revision: 1.3 $ */
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93 /* $Date: 2005/05/05 14:35:59 $ */