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comparison libtomcrypt/src/pk/ecc/ecc_sign_hash.c @ 1471:6dba84798cd5

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Update to libtomcrypt 1.18.1, merged with Dropbear changes
author Matt Johnston <matt@ucc.asn.au>
date Fri, 09 Feb 2018 21:44:05 +0800
parents f849a5ca2efc
children 8305ebe45940
comparison
equal deleted inserted replaced
1470:8bba51a55704 1471:6dba84798cd5
3 * LibTomCrypt is a library that provides various cryptographic 3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner. 4 * algorithms in a highly modular and flexible manner.
5 * 5 *
6 * The library is free for all purposes without any express 6 * The library is free for all purposes without any express
7 * guarantee it works. 7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtom.org
10 */ 8 */
11 9
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" 10 #include "tomcrypt.h"
11
12 #ifdef LTC_MECC
18 13
19 /** 14 /**
20 @file ecc_sign_hash.c 15 @file ecc_sign_hash.c
21 ECC Crypto, Tom St Denis 16 ECC Crypto, Tom St Denis
22 */ 17 */
23 18
24 #if defined(LTC_MECC) && defined(LTC_DER) 19 static int _ecc_sign_hash(const unsigned char *in, unsigned long inlen,
25
26 /**
27 Sign a message digest
28 @param in The message digest to sign
29 @param inlen The length of the digest
30 @param out [out] The destination for the signature
31 @param outlen [in/out] The max size and resulting size of the signature
32 @param prng An active PRNG state
33 @param wprng The index of the PRNG you wish to use
34 @param key A private ECC key
35 @return CRYPT_OK if successful
36 */
37 int ecc_sign_hash(const unsigned char *in, unsigned long inlen,
38 unsigned char *out, unsigned long *outlen, 20 unsigned char *out, unsigned long *outlen,
39 prng_state *prng, int wprng, ecc_key *key) 21 prng_state *prng, int wprng, ecc_key *key, int sigformat)
40 { 22 {
41 ecc_key pubkey; 23 ecc_key pubkey;
42 void *r, *s, *e, *p; 24 void *r, *s, *e, *p;
43 int err; 25 int err, max_iterations = LTC_PK_MAX_RETRIES;
26 unsigned long pbits, pbytes, i, shift_right;
27 unsigned char ch, buf[MAXBLOCKSIZE];
44 28
45 LTC_ARGCHK(in != NULL); 29 LTC_ARGCHK(in != NULL);
46 LTC_ARGCHK(out != NULL); 30 LTC_ARGCHK(out != NULL);
47 LTC_ARGCHK(outlen != NULL); 31 LTC_ARGCHK(outlen != NULL);
48 LTC_ARGCHK(key != NULL); 32 LTC_ARGCHK(key != NULL);
59 43
60 if ((err = prng_is_valid(wprng)) != CRYPT_OK) { 44 if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
61 return err; 45 return err;
62 } 46 }
63 47
64 /* get the hash and load it as a bignum into 'e' */
65 /* init the bignums */ 48 /* init the bignums */
66 if ((err = mp_init_multi(&r, &s, &p, &e, NULL)) != CRYPT_OK) { 49 if ((err = mp_init_multi(&r, &s, &p, &e, NULL)) != CRYPT_OK) {
67 return err; 50 return err;
68 } 51 }
69 if ((err = mp_read_radix(p, (char *)key->dp->order, 16)) != CRYPT_OK) { goto errnokey; } 52 if ((err = mp_read_radix(p, (char *)key->dp->order, 16)) != CRYPT_OK) { goto errnokey; }
70 if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, (int)inlen)) != CRYPT_OK) { goto errnokey; } 53
54 /* get the hash and load it as a bignum into 'e' */
55 pbits = mp_count_bits(p);
56 pbytes = (pbits+7) >> 3;
57 if (pbits > inlen*8) {
58 if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, inlen)) != CRYPT_OK) { goto errnokey; }
59 }
60 else if (pbits % 8 == 0) {
61 if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, pbytes)) != CRYPT_OK) { goto errnokey; }
62 }
63 else {
64 shift_right = 8 - pbits % 8;
65 for (i=0, ch=0; i<pbytes; i++) {
66 buf[i] = ch;
67 ch = (in[i] << (8-shift_right));
68 buf[i] = buf[i] ^ (in[i] >> shift_right);
69 }
70 if ((err = mp_read_unsigned_bin(e, (unsigned char *)buf, pbytes)) != CRYPT_OK) { goto errnokey; }
71 }
71 72
72 /* make up a key and export the public copy */ 73 /* make up a key and export the public copy */
73 for (;;) { 74 do {
74 if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { 75 if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) {
75 goto errnokey; 76 goto errnokey;
76 } 77 }
77 78
78 /* find r = x1 mod n */ 79 /* find r = x1 mod n */
90 ecc_free(&pubkey); 91 ecc_free(&pubkey);
91 if (mp_iszero(s) == LTC_MP_NO) { 92 if (mp_iszero(s) == LTC_MP_NO) {
92 break; 93 break;
93 } 94 }
94 } 95 }
96 } while (--max_iterations > 0);
97
98 if (max_iterations == 0) {
99 goto errnokey;
95 } 100 }
96 101
97 /* store as SEQUENCE { r, s -- integer } */ 102 if (sigformat == 1) {
103 /* RFC7518 format */
104 if (*outlen < 2*pbytes) { err = CRYPT_MEM; goto errnokey; }
105 zeromem(out, 2*pbytes);
106 i = mp_unsigned_bin_size(r);
107 if ((err = mp_to_unsigned_bin(r, out + (pbytes - i))) != CRYPT_OK) { goto errnokey; }
108 i = mp_unsigned_bin_size(s);
109 if ((err = mp_to_unsigned_bin(s, out + (2*pbytes - i))) != CRYPT_OK) { goto errnokey; }
110 *outlen = 2*pbytes;
111 err = CRYPT_OK;
112 }
113 else {
114 /* store as ASN.1 SEQUENCE { r, s -- integer } */
98 err = der_encode_sequence_multi(out, outlen, 115 err = der_encode_sequence_multi(out, outlen,
99 LTC_ASN1_INTEGER, 1UL, r, 116 LTC_ASN1_INTEGER, 1UL, r,
100 LTC_ASN1_INTEGER, 1UL, s, 117 LTC_ASN1_INTEGER, 1UL, s,
101 LTC_ASN1_EOL, 0UL, NULL); 118 LTC_ASN1_EOL, 0UL, NULL);
119 }
102 goto errnokey; 120 goto errnokey;
103 error: 121 error:
104 ecc_free(&pubkey); 122 ecc_free(&pubkey);
105 errnokey: 123 errnokey:
106 mp_clear_multi(r, s, p, e, NULL); 124 mp_clear_multi(r, s, p, e, NULL);
107 return err; 125 return err;
108 } 126 }
109 127
128 /**
129 Sign a message digest
130 @param in The message digest to sign
131 @param inlen The length of the digest
132 @param out [out] The destination for the signature
133 @param outlen [in/out] The max size and resulting size of the signature
134 @param prng An active PRNG state
135 @param wprng The index of the PRNG you wish to use
136 @param key A private ECC key
137 @return CRYPT_OK if successful
138 */
139 int ecc_sign_hash(const unsigned char *in, unsigned long inlen,
140 unsigned char *out, unsigned long *outlen,
141 prng_state *prng, int wprng, ecc_key *key)
142 {
143 return _ecc_sign_hash(in, inlen, out, outlen, prng, wprng, key, 0);
144 }
145
146 /**
147 Sign a message digest in RFC7518 format
148 @param in The message digest to sign
149 @param inlen The length of the digest
150 @param out [out] The destination for the signature
151 @param outlen [in/out] The max size and resulting size of the signature
152 @param prng An active PRNG state
153 @param wprng The index of the PRNG you wish to use
154 @param key A private ECC key
155 @return CRYPT_OK if successful
156 */
157 int ecc_sign_hash_rfc7518(const unsigned char *in, unsigned long inlen,
158 unsigned char *out, unsigned long *outlen,
159 prng_state *prng, int wprng, ecc_key *key)
160 {
161 return _ecc_sign_hash(in, inlen, out, outlen, prng, wprng, key, 1);
162 }
163
110 #endif 164 #endif
111 /* $Source$ */
112 /* $Revision$ */
113 /* $Date$ */
114 165
166 /* ref: $Format:%D$ */
167 /* git commit: $Format:%H$ */
168 /* commit time: $Format:%ai$ */