Mercurial > dropbear
comparison src/pk/ecc/ecc_encrypt_key.c @ 380:d5faf4814ddb libtomcrypt-orig libtomcrypt-1.16
Update to LibTomCrypt 1.16
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 11 Jan 2007 02:22:00 +0000 |
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280:59400faa4b44 | 380:d5faf4814ddb |
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis | |
2 * | |
3 * LibTomCrypt is a library that provides various cryptographic | |
4 * algorithms in a highly modular and flexible manner. | |
5 * | |
6 * The library is free for all purposes without any express | |
7 * guarantee it works. | |
8 * | |
9 * Tom St Denis, [email protected], http://libtomcrypt.com | |
10 */ | |
11 | |
12 /* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b | |
13 * | |
14 * All curves taken from NIST recommendation paper of July 1999 | |
15 * Available at http://csrc.nist.gov/cryptval/dss.htm | |
16 */ | |
17 #include "tomcrypt.h" | |
18 | |
19 /** | |
20 @file ecc_encrypt_key.c | |
21 ECC Crypto, Tom St Denis | |
22 */ | |
23 | |
24 #ifdef MECC | |
25 | |
26 /** | |
27 Encrypt a symmetric key with ECC | |
28 @param in The symmetric key you want to encrypt | |
29 @param inlen The length of the key to encrypt (octets) | |
30 @param out [out] The destination for the ciphertext | |
31 @param outlen [in/out] The max size and resulting size of the ciphertext | |
32 @param prng An active PRNG state | |
33 @param wprng The index of the PRNG you wish to use | |
34 @param hash The index of the hash you want to use | |
35 @param key The ECC key you want to encrypt to | |
36 @return CRYPT_OK if successful | |
37 */ | |
38 int ecc_encrypt_key(const unsigned char *in, unsigned long inlen, | |
39 unsigned char *out, unsigned long *outlen, | |
40 prng_state *prng, int wprng, int hash, | |
41 ecc_key *key) | |
42 { | |
43 unsigned char *pub_expt, *ecc_shared, *skey; | |
44 ecc_key pubkey; | |
45 unsigned long x, y, pubkeysize; | |
46 int err; | |
47 | |
48 LTC_ARGCHK(in != NULL); | |
49 LTC_ARGCHK(out != NULL); | |
50 LTC_ARGCHK(outlen != NULL); | |
51 LTC_ARGCHK(key != NULL); | |
52 | |
53 /* check that wprng/cipher/hash are not invalid */ | |
54 if ((err = prng_is_valid(wprng)) != CRYPT_OK) { | |
55 return err; | |
56 } | |
57 | |
58 if ((err = hash_is_valid(hash)) != CRYPT_OK) { | |
59 return err; | |
60 } | |
61 | |
62 if (inlen > hash_descriptor[hash].hashsize) { | |
63 return CRYPT_INVALID_HASH; | |
64 } | |
65 | |
66 /* make a random key and export the public copy */ | |
67 if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { | |
68 return err; | |
69 } | |
70 | |
71 pub_expt = XMALLOC(ECC_BUF_SIZE); | |
72 ecc_shared = XMALLOC(ECC_BUF_SIZE); | |
73 skey = XMALLOC(MAXBLOCKSIZE); | |
74 if (pub_expt == NULL || ecc_shared == NULL || skey == NULL) { | |
75 if (pub_expt != NULL) { | |
76 XFREE(pub_expt); | |
77 } | |
78 if (ecc_shared != NULL) { | |
79 XFREE(ecc_shared); | |
80 } | |
81 if (skey != NULL) { | |
82 XFREE(skey); | |
83 } | |
84 ecc_free(&pubkey); | |
85 return CRYPT_MEM; | |
86 } | |
87 | |
88 pubkeysize = ECC_BUF_SIZE; | |
89 if ((err = ecc_export(pub_expt, &pubkeysize, PK_PUBLIC, &pubkey)) != CRYPT_OK) { | |
90 ecc_free(&pubkey); | |
91 goto LBL_ERR; | |
92 } | |
93 | |
94 /* make random key */ | |
95 x = ECC_BUF_SIZE; | |
96 if ((err = ecc_shared_secret(&pubkey, key, ecc_shared, &x)) != CRYPT_OK) { | |
97 ecc_free(&pubkey); | |
98 goto LBL_ERR; | |
99 } | |
100 ecc_free(&pubkey); | |
101 y = MAXBLOCKSIZE; | |
102 if ((err = hash_memory(hash, ecc_shared, x, skey, &y)) != CRYPT_OK) { | |
103 goto LBL_ERR; | |
104 } | |
105 | |
106 /* Encrypt key */ | |
107 for (x = 0; x < inlen; x++) { | |
108 skey[x] ^= in[x]; | |
109 } | |
110 | |
111 err = der_encode_sequence_multi(out, outlen, | |
112 LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash].OIDlen, hash_descriptor[hash].OID, | |
113 LTC_ASN1_OCTET_STRING, pubkeysize, pub_expt, | |
114 LTC_ASN1_OCTET_STRING, inlen, skey, | |
115 LTC_ASN1_EOL, 0UL, NULL); | |
116 | |
117 LBL_ERR: | |
118 #ifdef LTC_CLEAN_STACK | |
119 /* clean up */ | |
120 zeromem(pub_expt, ECC_BUF_SIZE); | |
121 zeromem(ecc_shared, ECC_BUF_SIZE); | |
122 zeromem(skey, MAXBLOCKSIZE); | |
123 #endif | |
124 | |
125 XFREE(skey); | |
126 XFREE(ecc_shared); | |
127 XFREE(pub_expt); | |
128 | |
129 return err; | |
130 } | |
131 | |
132 #endif | |
133 /* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_encrypt_key.c,v $ */ | |
134 /* $Revision: 1.4 $ */ | |
135 /* $Date: 2006/11/21 00:10:18 $ */ | |
136 |