62 lines
1.2 KiB
C
62 lines
1.2 KiB
C
#include "os.h"
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#include <libsec.h>
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typedef struct State{
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QLock lock;
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int seeded;
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uint64_t seed;
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DES3state des3;
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} State;
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static State x917state;
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static void
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X917(uint8_t *rand, int nrand)
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{
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int i, m, n8;
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uint64_t I, x;
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/* 1. Compute intermediate value I = Ek(time). */
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I = jehanne_nsec();
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triple_block_cipher(x917state.des3.expanded, (uint8_t*)&I, 0); /* two-key EDE */
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/* 2. x[i] = Ek(I^seed); seed = Ek(x[i]^I); */
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m = (nrand+7)/8;
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for(i=0; i<m; i++){
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x = I ^ x917state.seed;
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triple_block_cipher(x917state.des3.expanded, (uint8_t*)&x, 0);
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n8 = (nrand>8) ? 8 : nrand;
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jehanne_memcpy(rand, (uint8_t*)&x, n8);
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rand += 8;
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nrand -= 8;
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x ^= I;
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triple_block_cipher(x917state.des3.expanded, (uint8_t*)&x, 0);
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x917state.seed = x;
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}
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}
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static void
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X917init(void)
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{
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int n;
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uint8_t mix[128];
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uint8_t key3[3][8];
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uint32_t *ulp;
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ulp = (uint32_t*)key3;
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for(n = 0; n < sizeof(key3)/sizeof(uint32_t); n++)
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ulp[n] = jehanne_truerand();
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setupDES3state(&x917state.des3, key3, nil);
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X917(mix, sizeof mix);
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x917state.seeded = 1;
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}
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void
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genrandom(uint8_t *p, int n)
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{
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jehanne_qlock(&x917state.lock);
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if(x917state.seeded == 0)
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X917init();
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X917(p, n);
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jehanne_qunlock(&x917state.lock);
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}
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