2 * RSA implementation just sufficient for ssh client-side
5 * Rewritten for more speed by Joris van Rantwijk, Jun 1999.
15 int makekey(unsigned char *data, struct RSAKey *result,
16 unsigned char **keystr, int order) {
17 unsigned char *p = data;
23 result->bits = (result->bits << 8) + *p++;
28 * order=0 means exponent then modulus (the keys sent by the
29 * server). order=1 means modulus then exponent (the keys
30 * stored in a keyfile).
34 p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
36 result->bytes = (((p[0] << 8) + p[1]) + 7) / 8;
37 if (keystr) *keystr = p+2;
38 p += ssh1_read_bignum(p, result ? &result->modulus : NULL);
40 p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
45 int makeprivate(unsigned char *data, struct RSAKey *result) {
46 return ssh1_read_bignum(data, &result->private_exponent);
49 void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
54 memmove(data+key->bytes-length, data, length);
58 for (i = 2; i < key->bytes-length-1; i++) {
60 data[i] = random_byte();
61 } while (data[i] == 0);
63 data[key->bytes-length-1] = 0;
72 for (i=key->bytes; i-- ;) {
73 unsigned char byte = *p++;
80 b2 = modpow(b1, key->exponent, key->modulus);
83 for (i=key->bytes; i-- ;) {
96 Bignum rsadecrypt(Bignum input, struct RSAKey *key) {
98 ret = modpow(input, key->private_exponent, key->modulus);
102 int rsastr_len(struct RSAKey *key) {
107 return 4 * (ex[0]+md[0]) + 20;
110 void rsastr_fmt(char *str, struct RSAKey *key) {
112 int len = 0, i, nibbles;
113 static const char hex[] = "0123456789abcdef";
118 len += sprintf(str+len, "0x");
120 nibbles = (3 + ssh1_bignum_bitcount(ex))/4; if (nibbles<1) nibbles=1;
121 for (i=nibbles; i-- ;)
122 str[len++] = hex[(bignum_byte(ex, i/2) >> (4*(i%2))) & 0xF];
124 len += sprintf(str+len, ",0x");
126 nibbles = (3 + ssh1_bignum_bitcount(md))/4; if (nibbles<1) nibbles=1;
127 for (i=nibbles; i-- ;)
128 str[len++] = hex[(bignum_byte(md, i/2) >> (4*(i%2))) & 0xF];
134 * Generate a fingerprint string for the key. Compatible with the
135 * OpenSSH fingerprint code.
137 void rsa_fingerprint(char *str, int len, struct RSAKey *key) {
138 struct MD5Context md5c;
139 unsigned char digest[16];
140 char buffer[16*3+40];
144 numlen = ssh1_bignum_length(key->modulus) - 2;
145 for (i = numlen; i-- ;) {
146 unsigned char c = bignum_byte(key->modulus, i);
147 MD5Update(&md5c, &c, 1);
149 numlen = ssh1_bignum_length(key->exponent) - 2;
150 for (i = numlen; i-- ;) {
151 unsigned char c = bignum_byte(key->exponent, i);
152 MD5Update(&md5c, &c, 1);
154 MD5Final(digest, &md5c);
156 sprintf(buffer, "%d ", ssh1_bignum_bitcount(key->modulus));
157 for (i = 0; i < 16; i++)
158 sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
159 strncpy(str, buffer, len); str[len-1] = '\0';
161 if (key->comment && slen < len-1) {
163 strncpy(str+slen+1, key->comment, len-slen-1);
168 void freersakey(struct RSAKey *key) {
169 if (key->modulus) freebn(key->modulus);
170 if (key->exponent) freebn(key->exponent);
171 if (key->private_exponent) freebn(key->private_exponent);
172 if (key->comment) free(key->comment);