зеркало из https://github.com/github/putty.git
53 строки
1.4 KiB
C
53 строки
1.4 KiB
C
/*
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* SHA core transform algorithm, used here solely as a `stirring'
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* function for the PuTTY random number pool. Implemented directly
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* from the specification by Simon Tatham.
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*/
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#include "ssh.h"
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#define rol(x,y) ( ((x) << (y)) | (((word32)x) >> (32-y)) )
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void SHATransform(word32 *digest, word32 *block) {
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word32 w[80];
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word32 a,b,c,d,e;
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int t;
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for (t = 0; t < 16; t++)
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w[t] = block[t];
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for (t = 16; t < 80; t++) {
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word32 tmp = w[t-3] ^ w[t-8] ^ w[t-14] ^ w[t-16];
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w[t] = rol(tmp, 1);
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}
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a = digest[0];
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b = digest[1];
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c = digest[2];
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d = digest[3];
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e = digest[4];
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for (t = 0; t < 20; t++) {
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word32 tmp = rol(a, 5) + ( (b&c) | (d&~b) ) + e + w[t] + 0x5a827999;
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e = d; d = c; c = rol(b, 30); b = a; a = tmp;
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}
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for (t = 20; t < 40; t++) {
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word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0x6ed9eba1;
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e = d; d = c; c = rol(b, 30); b = a; a = tmp;
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}
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for (t = 40; t < 60; t++) {
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word32 tmp = rol(a, 5) + ( (b&c) | (b&d) | (c&d) ) + e + w[t] + 0x8f1bbcdc;
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e = d; d = c; c = rol(b, 30); b = a; a = tmp;
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}
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for (t = 60; t < 80; t++) {
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word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0xca62c1d6;
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e = d; d = c; c = rol(b, 30); b = a; a = tmp;
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}
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digest[0] += a;
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digest[1] += b;
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digest[2] += c;
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digest[3] += d;
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digest[4] += e;
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}
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