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Joris's RSA works; reformat and remove old version

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[originally from svn r173]
This commit is contained in:
Simon Tatham 1999-07-06 19:38:54 +00:00
parent b84caf5446
commit 4b76ca2ab2
1 changed files with 148 additions and 351 deletions
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213
sshrsa.c
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@ -1,16 +1,10 @@
/* /*
* RSA implementation just sufficient for ssh client-side * RSA implementation just sufficient for ssh client-side
* initialisation step * initialisation step
* Modified by Joris, Jun 1999. *
* Rewritten for more speed by Joris van Rantwijk, Jun 1999.
*/ */
#define JORIS_RSA
/*#include <windows.h>
#define RSADEBUG
#define DLVL 2
#include "stel.h"*/
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
@ -60,8 +54,6 @@ static void freebn(Bignum b) {
free(b); free(b);
} }
#ifdef JORIS_RSA
/* /*
* Compute c = a * b. * Compute c = a * b.
* Input is in the first len words of a and b. * Input is in the first len words of a and b.
@ -82,14 +74,13 @@ static void bigmul(unsigned short *a, unsigned short *b, unsigned short *c,
for (j = len - 1; j >= 0; j--) { for (j = len - 1; j >= 0; j--) {
t += ai * (unsigned long) b[j]; t += ai * (unsigned long) b[j];
t += (unsigned long) c[i+j+1]; t += (unsigned long) c[i+j+1];
c[i+j+1] = t; c[i+j+1] = (unsigned short)t;
t = t >> 16; t = t >> 16;
} }
c[i] = t; c[i] = (unsigned short)t;
} }
} }
/* /*
* Compute a = a % m. * Compute a = a % m.
* Input in first 2*len words of a and first len words of m. * Input in first 2*len words of a and first len words of m.
@ -155,14 +146,13 @@ static void bigmod(unsigned short *a, unsigned short *m, int len)
for (k = len - 1; k >= 0; k--) { for (k = len - 1; k >= 0; k--) {
t += m[k]; t += m[k];
t += a[i+k]; t += a[i+k];
a[i+k] = t; a[i+k] = (unsigned short)t;
t = t >> 16; t = t >> 16;
} }
} }
} }
} }
/* /*
* Compute (base ^ exp) % mod. * Compute (base ^ exp) % mod.
* The base MUST be smaller than the modulus. * The base MUST be smaller than the modulus.
@ -247,199 +237,6 @@ static void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result)
for (i = 0; i < mlen; i++) n[i] = 0; free(n); for (i = 0; i < mlen; i++) n[i] = 0; free(n);
} }
#else
static int msb(Bignum r) {
int i;
int j;
unsigned short n;
for (i=r[0]; i>0; i--)
if (r[i])
break;
j = (i-1)*16;
n = r[i];
if (n & 0xFF00) j += 8, n >>= 8;
if (n & 0x00F0) j += 4, n >>= 4;
if (n & 0x000C) j += 2, n >>= 2;
if (n & 0x0002) j += 1, n >>= 1;
return j;
}
static void add(Bignum r1, Bignum r2, Bignum result) {
int i;
long stuff = 0;
enter((">add\n"));
debug(r1);
debug(r2);
for (i = 1 ;; i++) {
if (i <= r1[0])
stuff += r1[i];
if (i <= r2[0])
stuff += r2[i];
if (i <= result[0])
result[i] = stuff & 0xFFFFU;
if (i > r1[0] && i > r2[0] && i >= result[0])
break;
stuff >>= 16;
}
debug(result);
leave(("<add\n"));
}
static void sub(Bignum r1, Bignum r2, Bignum result) {
int i;
long stuff = 0;
enter((">sub\n"));
debug(r1);
debug(r2);
for (i = 1 ;; i++) {
if (i <= r1[0])
stuff += r1[i];
if (i <= r2[0])
stuff -= r2[i];
if (i <= result[0])
result[i] = stuff & 0xFFFFU;
if (i > r1[0] && i > r2[0] && i >= result[0])
break;
stuff = stuff<0 ? -1 : 0;
}
debug(result);
leave(("<sub\n"));
}
static int ge(Bignum r1, Bignum r2) {
int i;
enter((">ge\n"));
debug(r1);
debug(r2);
if (r1[0] < r2[0])
i = r2[0];
else
i = r1[0];
while (i > 0) {
unsigned short n1 = (i > r1[0] ? 0 : r1[i]);
unsigned short n2 = (i > r2[0] ? 0 : r2[i]);
if (n1 > n2) {
dmsg(("greater\n"));
leave(("<ge\n"));
return 1; /* r1 > r2 */
} else if (n1 < n2) {
dmsg(("less\n"));
leave(("<ge\n"));
return 0; /* r1 < r2 */
}
i--;
}
dmsg(("equal\n"));
leave(("<ge\n"));
return 1; /* r1 = r2 */
}
static void modmult(Bignum r1, Bignum r2, Bignum modulus, Bignum result) {
Bignum temp = newbn(modulus[0]+1);
Bignum tmp2 = newbn(modulus[0]+1);
int i;
int bit, bits, digit, smallbit;
enter((">modmult\n"));
debug(r1);
debug(r2);
debug(modulus);
for (i=1; i<=result[0]; i++)
result[i] = 0; /* result := 0 */
for (i=1; i<=temp[0]; i++)
temp[i] = (i > r2[0] ? 0 : r2[i]); /* temp := r2 */
bits = 1+msb(r1);
for (bit = 0; bit < bits; bit++) {
digit = 1 + bit / 16;
smallbit = bit % 16;
debug(temp);
if (digit <= r1[0] && (r1[digit] & (1<<smallbit))) {
dmsg(("bit %d\n", bit));
add(temp, result, tmp2);
if (ge(tmp2, modulus))
sub(tmp2, modulus, result);
else
add(tmp2, Zero, result);
debug(result);
}
add(temp, temp, tmp2);
if (ge(tmp2, modulus))
sub(tmp2, modulus, temp);
else
add(tmp2, Zero, temp);
}
freebn(temp);
freebn(tmp2);
debug(result);
leave(("<modmult\n"));
}
static void modpow(Bignum r1, Bignum r2, Bignum modulus, Bignum result) {
Bignum temp = newbn(modulus[0]+1);
Bignum tmp2 = newbn(modulus[0]+1);
int i;
int bit, bits, digit, smallbit;
enter((">modpow\n"));
debug(r1);
debug(r2);
debug(modulus);
for (i=1; i<=result[0]; i++)
result[i] = (i==1); /* result := 1 */
for (i=1; i<=temp[0]; i++)
temp[i] = (i > r1[0] ? 0 : r1[i]); /* temp := r1 */
bits = 1+msb(r2);
for (bit = 0; bit < bits; bit++) {
digit = 1 + bit / 16;
smallbit = bit % 16;
debug(temp);
if (digit <= r2[0] && (r2[digit] & (1<<smallbit))) {
dmsg(("bit %d\n", bit));
modmult(temp, result, modulus, tmp2);
add(tmp2, Zero, result);
debug(result);
}
modmult(temp, temp, modulus, tmp2);
add(tmp2, Zero, temp);
}
freebn(temp);
freebn(tmp2);
debug(result);
leave(("<modpow\n"));
}
#endif
int makekey(unsigned char *data, struct RSAKey *result, int makekey(unsigned char *data, struct RSAKey *result,
unsigned char **keystr) { unsigned char **keystr) {
unsigned char *p = data; unsigned char *p = data;