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) {
43 unsigned char *p = data;
50 result->bits = (result->bits << 8) + *p++;
58 result->bytes = b = (w+7)/8; /* bits -> bytes */
59 w = (w+15)/16; /* bits -> words */
63 if (keystr) *keystr = p; /* point at key string, second time */
68 unsigned char byte = *p++;
70 bn[j][1+i/2] |= byte<<8;
79 result->exponent = bn[0];
80 result->modulus = bn[1];
85 void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
92 memmove(data+key->bytes-length, data, length);
96 for (i = 2; i < key->bytes-length-1; i++) {
98 data[i] = random_byte();
99 } while (data[i] == 0);
101 data[key->bytes-length-1] = 0;
103 w = (key->bytes+1)/2;
111 for (i=key->bytes; i-- ;) {
112 unsigned char byte = *p++;
114 b1[1+i/2] |= byte<<8;
121 modpow(b1, key->exponent, key->modulus, b2);
126 for (i=key->bytes; i-- ;) {
131 b = b2[1+i/2] & 0xFF;
139 int rsastr_len(struct RSAKey *key) {
144 return 4 * (ex[0]+md[0]) + 10;
147 void rsastr_fmt(char *str, struct RSAKey *key) {
154 for (i=1; i<=ex[0]; i++) {
155 sprintf(str+len, "%04x", ex[i]);
156 len += strlen(str+len);
159 for (i=1; i<=md[0]; i++) {
160 sprintf(str+len, "%04x", md[i]);
161 len += strlen(str+len);
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);