2 * RSA implementation just sufficient for ssh client-side
5 * Rewritten for more speed by Joris van Rantwijk, Jun 1999.
12 #if defined TESTMODE || defined RSADEBUG
16 #define debug(x) bndebug(#x,x)
18 static void bndebug(char *name, Bignum b) {
20 int w = 50-level-strlen(name)-5*b[0];
24 dprintf("%*s%s%*s", level, "", name, w, "");
25 for (i=b[0]; i>0; i--)
26 dprintf(" %04x", b[i]);
29 #define dmsg(x) do {if(level<DLVL){dprintf("%*s",level,"");printf x;}} while(0)
30 #define enter(x) do { dmsg(x); level += 4; } while(0)
31 #define leave(x) do { level -= 4; dmsg(x); } while(0)
41 int makekey(unsigned char *data, struct RSAKey *result,
42 unsigned char **keystr, int order) {
43 unsigned char *p = data;
48 result->bits = (result->bits << 8) + *p++;
51 * order=0 means exponent then modulus (the keys sent by the
52 * server). order=1 means modulus then exponent (the keys
53 * stored in a keyfile).
57 p += ssh1_read_bignum(p, &result->exponent);
58 result->bytes = (((p[0] << 8) + p[1]) + 7) / 8;
59 if (keystr) *keystr = p+2;
60 p += ssh1_read_bignum(p, &result->modulus);
62 p += ssh1_read_bignum(p, &result->exponent);
67 int makeprivate(unsigned char *data, struct RSAKey *result) {
68 return ssh1_read_bignum(data, &result->private_exponent);
71 void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
78 memmove(data+key->bytes-length, data, length);
82 for (i = 2; i < key->bytes-length-1; i++) {
84 data[i] = random_byte();
85 } while (data[i] == 0);
87 data[key->bytes-length-1] = 0;
97 for (i=key->bytes; i-- ;) {
98 unsigned char byte = *p++;
100 b1[1+i/2] |= byte<<8;
107 modpow(b1, key->exponent, key->modulus, b2);
112 for (i=key->bytes; i-- ;) {
117 b = b2[1+i/2] & 0xFF;
125 Bignum rsadecrypt(Bignum input, struct RSAKey *key) {
127 ret = newbn(key->modulus[0]);
128 modpow(input, key->private_exponent, key->modulus, ret);
132 int rsastr_len(struct RSAKey *key) {
137 return 4 * (ex[0]+md[0]) + 10;
140 void rsastr_fmt(char *str, struct RSAKey *key) {
147 for (i=1; i<=ex[0]; i++) {
148 sprintf(str+len, "%04x", ex[i]);
149 len += strlen(str+len);
152 for (i=1; i<=md[0]; i++) {
153 sprintf(str+len, "%04x", md[i]);
154 len += strlen(str+len);
159 void freersakey(struct RSAKey *key) {
160 if (key->modulus) freebn(key->modulus);
161 if (key->exponent) freebn(key->exponent);
162 if (key->private_exponent) freebn(key->private_exponent);
163 if (key->comment) free(key->comment);
178 unsigned short P1[2] = { 1, p1 };
179 unsigned short P2[2] = { 1, p2 };
180 unsigned short P3[2] = { 1, p3 };
181 unsigned short bigmod[5] = { 4, 0, 0, 0, 32768U };
182 unsigned short mod[5] = { 4, 0, 0, 0, 0 };
183 unsigned short a[5] = { 4, 0, 0, 0, 0 };
184 unsigned short b[5] = { 4, 0, 0, 0, 0 };
185 unsigned short c[5] = { 4, 0, 0, 0, 0 };
186 unsigned short One[2] = { 1, 1 };
187 unsigned short Two[2] = { 1, 2 };
190 modmult(P1, P2, bigmod, a); debug(a);
191 modmult(a, P3, bigmod, mod); debug(mod);
193 sub(P1, One, a); debug(a);
194 sub(P2, One, b); debug(b);
195 modmult(a, b, bigmod, c); debug(c);
196 sub(P3, One, a); debug(a);
197 modmult(a, c, bigmod, b); debug(b);
199 modpow(Two, b, mod, a); debug(a);