mirror of
https://git.tartarus.org/simon/putty.git
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Joris's RSA works; reformat and remove old version
[originally from svn r173]
This commit is contained in:
Simon Tatham
parent
b84caf5446
commit
4b76ca2ab2
499
sshrsa.c
499
sshrsa.c
@ -1,16 +1,10 @@
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/*
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* RSA implementation just sufficient for ssh client-side
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* initialisation step
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* Modified by Joris, Jun 1999.
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*
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* Rewritten for more speed by Joris van Rantwijk, Jun 1999.
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*/
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#define JORIS_RSA
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/*#include <windows.h>
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#define RSADEBUG
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#define DLVL 2
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#include "stel.h"*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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@ -60,386 +54,189 @@ static void freebn(Bignum b) {
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free(b);
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}
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#ifdef JORIS_RSA
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/*
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* Compute c = a * b.
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* Input is in the first len words of a and b.
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* Result is returned in the first 2*len words of c.
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* Compute c = a * b.
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* Input is in the first len words of a and b.
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* Result is returned in the first 2*len words of c.
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*/
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static void bigmul(unsigned short *a, unsigned short *b, unsigned short *c,
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int len)
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{
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int i, j;
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unsigned long ai, t;
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int i, j;
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unsigned long ai, t;
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for (j = len - 1; j >= 0; j--)
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c[j+len] = 0;
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for (i = len - 1; i >= 0; i--) {
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ai = a[i];
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t = 0;
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for (j = len - 1; j >= 0; j--) {
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t += ai * (unsigned long) b[j];
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t += (unsigned long) c[i+j+1];
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c[i+j+1] = t;
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t = t >> 16;
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}
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c[i] = t;
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}
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for (j = len - 1; j >= 0; j--)
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c[j+len] = 0;
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for (i = len - 1; i >= 0; i--) {
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ai = a[i];
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t = 0;
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for (j = len - 1; j >= 0; j--) {
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t += ai * (unsigned long) b[j];
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t += (unsigned long) c[i+j+1];
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c[i+j+1] = (unsigned short)t;
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t = t >> 16;
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}
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c[i] = (unsigned short)t;
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}
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}
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/*
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* Compute a = a % m.
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* Input in first 2*len words of a and first len words of m.
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* Output in first 2*len words of a (of which first len words will be zero).
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* The MSW of m MUST have its high bit set.
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* Compute a = a % m.
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* Input in first 2*len words of a and first len words of m.
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* Output in first 2*len words of a (of which first len words will be zero).
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* The MSW of m MUST have its high bit set.
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*/
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static void bigmod(unsigned short *a, unsigned short *m, int len)
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{
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unsigned short m0, m1;
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unsigned int h;
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int i, k;
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unsigned short m0, m1;
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unsigned int h;
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int i, k;
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/* Special case for len == 1 */
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if (len == 1) {
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a[1] = (((long) a[0] << 16) + a[1]) % m[0];
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a[0] = 0;
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return;
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/* Special case for len == 1 */
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if (len == 1) {
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a[1] = (((long) a[0] << 16) + a[1]) % m[0];
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a[0] = 0;
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return;
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}
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m0 = m[0];
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m1 = m[1];
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for (i = 0; i <= len; i++) {
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unsigned long t;
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unsigned int q, r, c;
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if (i == 0) {
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h = 0;
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} else {
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h = a[i-1];
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a[i-1] = 0;
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}
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m0 = m[0];
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m1 = m[1];
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/* Find q = h:a[i] / m0 */
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t = ((unsigned long) h << 16) + a[i];
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q = t / m0;
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r = t % m0;
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for (i = 0; i <= len; i++) {
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unsigned long t;
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unsigned int q, r, c;
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if (i == 0) {
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h = 0;
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} else {
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h = a[i-1];
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a[i-1] = 0;
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}
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/* Find q = h:a[i] / m0 */
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t = ((unsigned long) h << 16) + a[i];
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q = t / m0;
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r = t % m0;
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/* Refine our estimate of q by looking at
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h:a[i]:a[i+1] / m0:m1 */
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t = (long) m1 * (long) q;
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if (t > ((unsigned long) r << 16) + a[i+1]) {
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q--;
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t -= m1;
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r = (r + m0) & 0xffff; /* overflow? */
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if (r >= m0 && t > ((unsigned long) r << 16) + a[i+1])
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q--;
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}
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/* Substract q * m from a[i...] */
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c = 0;
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for (k = len - 1; k >= 0; k--) {
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t = (long) q * (long) m[k];
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t += c;
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c = t >> 16;
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if ((unsigned short) t > a[i+k]) c++;
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a[i+k] -= (unsigned short) t;
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}
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/* Add back m in case of borrow */
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if (c != h) {
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t = 0;
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for (k = len - 1; k >= 0; k--) {
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t += m[k];
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t += a[i+k];
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a[i+k] = t;
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t = t >> 16;
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}
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}
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/* Refine our estimate of q by looking at
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h:a[i]:a[i+1] / m0:m1 */
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t = (long) m1 * (long) q;
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if (t > ((unsigned long) r << 16) + a[i+1]) {
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q--;
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t -= m1;
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r = (r + m0) & 0xffff; /* overflow? */
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if (r >= m0 && t > ((unsigned long) r << 16) + a[i+1])
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q--;
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}
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/* Substract q * m from a[i...] */
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c = 0;
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for (k = len - 1; k >= 0; k--) {
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t = (long) q * (long) m[k];
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t += c;
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c = t >> 16;
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if ((unsigned short) t > a[i+k]) c++;
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a[i+k] -= (unsigned short) t;
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}
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/* Add back m in case of borrow */
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if (c != h) {
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t = 0;
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for (k = len - 1; k >= 0; k--) {
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t += m[k];
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t += a[i+k];
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a[i+k] = (unsigned short)t;
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t = t >> 16;
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}
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}
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}
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}
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/*
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* Compute (base ^ exp) % mod.
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* The base MUST be smaller than the modulus.
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* The most significant word of mod MUST be non-zero.
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* We assume that the result array is the same size as the mod array.
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* Compute (base ^ exp) % mod.
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* The base MUST be smaller than the modulus.
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* The most significant word of mod MUST be non-zero.
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* We assume that the result array is the same size as the mod array.
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*/
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static void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result)
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{
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unsigned short *a, *b, *n, *m;
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int mshift;
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int mlen, i, j;
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unsigned short *a, *b, *n, *m;
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int mshift;
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int mlen, i, j;
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/* Allocate m of size mlen, copy mod to m */
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/* We use big endian internally */
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mlen = mod[0];
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m = malloc(mlen * sizeof(unsigned short));
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for (j = 0; j < mlen; j++) m[j] = mod[mod[0] - j];
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/* Allocate m of size mlen, copy mod to m */
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/* We use big endian internally */
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mlen = mod[0];
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m = malloc(mlen * sizeof(unsigned short));
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for (j = 0; j < mlen; j++) m[j] = mod[mod[0] - j];
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/* Shift m left to make msb bit set */
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for (mshift = 0; mshift < 15; mshift++)
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if ((m[0] << mshift) & 0x8000) break;
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if (mshift) {
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for (i = 0; i < mlen - 1; i++)
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m[i] = (m[i] << mshift) | (m[i+1] >> (16-mshift));
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m[mlen-1] = m[mlen-1] << mshift;
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}
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/* Shift m left to make msb bit set */
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for (mshift = 0; mshift < 15; mshift++)
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if ((m[0] << mshift) & 0x8000) break;
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if (mshift) {
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for (i = 0; i < mlen - 1; i++)
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m[i] = (m[i] << mshift) | (m[i+1] >> (16-mshift));
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m[mlen-1] = m[mlen-1] << mshift;
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}
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/* Allocate n of size mlen, copy base to n */
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n = malloc(mlen * sizeof(unsigned short));
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i = mlen - base[0];
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for (j = 0; j < i; j++) n[j] = 0;
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for (j = 0; j < base[0]; j++) n[i+j] = base[base[0] - j];
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/* Allocate n of size mlen, copy base to n */
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n = malloc(mlen * sizeof(unsigned short));
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i = mlen - base[0];
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for (j = 0; j < i; j++) n[j] = 0;
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for (j = 0; j < base[0]; j++) n[i+j] = base[base[0] - j];
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/* Allocate a and b of size 2*mlen. Set a = 1 */
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a = malloc(2 * mlen * sizeof(unsigned short));
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b = malloc(2 * mlen * sizeof(unsigned short));
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for (i = 0; i < 2*mlen; i++) a[i] = 0;
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a[2*mlen-1] = 1;
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/* Allocate a and b of size 2*mlen. Set a = 1 */
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a = malloc(2 * mlen * sizeof(unsigned short));
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b = malloc(2 * mlen * sizeof(unsigned short));
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for (i = 0; i < 2*mlen; i++) a[i] = 0;
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a[2*mlen-1] = 1;
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/* Skip leading zero bits of exp. */
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i = 0; j = 15;
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while (i < exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) {
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j--;
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if (j < 0) { i++; j = 15; }
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}
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/* Skip leading zero bits of exp. */
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i = 0; j = 15;
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while (i < exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) {
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j--;
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if (j < 0) { i++; j = 15; }
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}
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/* Main computation */
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while (i < exp[0]) {
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while (j >= 0) {
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bigmul(a + mlen, a + mlen, b, mlen);
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bigmod(b, m, mlen);
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if ((exp[exp[0] - i] & (1 << j)) != 0) {
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bigmul(b + mlen, n, a, mlen);
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bigmod(a, m, mlen);
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} else {
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unsigned short *t;
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t = a; a = b; b = t;
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}
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j--;
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}
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i++; j = 15;
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}
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/* Fixup result in case the modulus was shifted */
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if (mshift) {
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for (i = mlen - 1; i < 2*mlen - 1; i++)
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a[i] = (a[i] << mshift) | (a[i+1] >> (16-mshift));
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a[2*mlen-1] = a[2*mlen-1] << mshift;
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/* Main computation */
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while (i < exp[0]) {
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while (j >= 0) {
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bigmul(a + mlen, a + mlen, b, mlen);
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bigmod(b, m, mlen);
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if ((exp[exp[0] - i] & (1 << j)) != 0) {
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bigmul(b + mlen, n, a, mlen);
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bigmod(a, m, mlen);
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for (i = 2*mlen - 1; i >= mlen; i--)
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a[i] = (a[i] >> mshift) | (a[i-1] << (16-mshift));
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} else {
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unsigned short *t;
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t = a; a = b; b = t;
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}
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j--;
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}
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/* Copy result to buffer */
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for (i = 0; i < mlen; i++)
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result[result[0] - i] = a[i+mlen];
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/* Free temporary arrays */
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for (i = 0; i < 2*mlen; i++) a[i] = 0; free(a);
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for (i = 0; i < 2*mlen; i++) b[i] = 0; free(b);
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for (i = 0; i < mlen; i++) m[i] = 0; free(m);
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for (i = 0; i < mlen; i++) n[i] = 0; free(n);
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}
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#else
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static int msb(Bignum r) {
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int i;
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int j;
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unsigned short n;
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for (i=r[0]; i>0; i--)
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if (r[i])
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break;
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j = (i-1)*16;
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n = r[i];
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if (n & 0xFF00) j += 8, n >>= 8;
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if (n & 0x00F0) j += 4, n >>= 4;
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if (n & 0x000C) j += 2, n >>= 2;
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if (n & 0x0002) j += 1, n >>= 1;
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return j;
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}
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static void add(Bignum r1, Bignum r2, Bignum result) {
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int i;
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long stuff = 0;
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enter((">add\n"));
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debug(r1);
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debug(r2);
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for (i = 1 ;; i++) {
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if (i <= r1[0])
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stuff += r1[i];
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if (i <= r2[0])
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stuff += r2[i];
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if (i <= result[0])
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result[i] = stuff & 0xFFFFU;
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if (i > r1[0] && i > r2[0] && i >= result[0])
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break;
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stuff >>= 16;
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i++; j = 15;
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}
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debug(result);
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leave(("<add\n"));
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}
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static void sub(Bignum r1, Bignum r2, Bignum result) {
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int i;
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long stuff = 0;
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enter((">sub\n"));
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debug(r1);
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debug(r2);
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for (i = 1 ;; i++) {
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if (i <= r1[0])
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stuff += r1[i];
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if (i <= r2[0])
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stuff -= r2[i];
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if (i <= result[0])
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result[i] = stuff & 0xFFFFU;
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if (i > r1[0] && i > r2[0] && i >= result[0])
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break;
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stuff = stuff<0 ? -1 : 0;
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/* Fixup result in case the modulus was shifted */
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if (mshift) {
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for (i = mlen - 1; i < 2*mlen - 1; i++)
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a[i] = (a[i] << mshift) | (a[i+1] >> (16-mshift));
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a[2*mlen-1] = a[2*mlen-1] << mshift;
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bigmod(a, m, mlen);
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for (i = 2*mlen - 1; i >= mlen; i--)
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a[i] = (a[i] >> mshift) | (a[i-1] << (16-mshift));
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}
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debug(result);
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leave(("<sub\n"));
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/* Copy result to buffer */
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for (i = 0; i < mlen; i++)
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result[result[0] - i] = a[i+mlen];
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/* Free temporary arrays */
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for (i = 0; i < 2*mlen; i++) a[i] = 0; free(a);
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for (i = 0; i < 2*mlen; i++) b[i] = 0; free(b);
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for (i = 0; i < mlen; i++) m[i] = 0; free(m);
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for (i = 0; i < mlen; i++) n[i] = 0; free(n);
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}
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static int ge(Bignum r1, Bignum r2) {
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int i;
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enter((">ge\n"));
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debug(r1);
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debug(r2);
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if (r1[0] < r2[0])
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i = r2[0];
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else
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i = r1[0];
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while (i > 0) {
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unsigned short n1 = (i > r1[0] ? 0 : r1[i]);
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unsigned short n2 = (i > r2[0] ? 0 : r2[i]);
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if (n1 > n2) {
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dmsg(("greater\n"));
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leave(("<ge\n"));
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return 1; /* r1 > r2 */
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} else if (n1 < n2) {
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dmsg(("less\n"));
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leave(("<ge\n"));
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return 0; /* r1 < r2 */
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}
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i--;
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}
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dmsg(("equal\n"));
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leave(("<ge\n"));
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return 1; /* r1 = r2 */
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}
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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,
|
||||
unsigned char **keystr) {
|
||||
unsigned char *p = data;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user