genrandom.c (1171B)
1 #include "os.h" 2 #include <mp.h> 3 #include <libsec.h> 4 5 typedef struct State{ 6 QLock lock; 7 int seeded; 8 uvlong seed; 9 DES3state des3; 10 } State; 11 static State x917state; 12 13 static void 14 X917(uchar *rand, int nrand) 15 { 16 int i, m, n8; 17 uvlong I, x; 18 19 /* 1. Compute intermediate value I = Ek(time). */ 20 I = nsec(); 21 triple_block_cipher(x917state.des3.expanded, (uchar*)&I, 0); /* two-key EDE */ 22 23 /* 2. x[i] = Ek(I^seed); seed = Ek(x[i]^I); */ 24 m = (nrand+7)/8; 25 for(i=0; i<m; i++){ 26 x = I ^ x917state.seed; 27 triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0); 28 n8 = (nrand>8) ? 8 : nrand; 29 memcpy(rand, (uchar*)&x, n8); 30 rand += 8; 31 nrand -= 8; 32 x ^= I; 33 triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0); 34 x917state.seed = x; 35 } 36 } 37 38 static void 39 X917init(void) 40 { 41 int n; 42 uchar mix[128]; 43 uchar key3[3][8]; 44 ulong *ulp; 45 46 ulp = (ulong*)key3; 47 for(n = 0; n < sizeof(key3)/sizeof(ulong); n++) 48 ulp[n] = truerand(); 49 setupDES3state(&x917state.des3, key3, nil); 50 X917(mix, sizeof mix); 51 x917state.seeded = 1; 52 } 53 54 void 55 genrandom(uchar *p, int n) 56 { 57 qlock(&x917state.lock); 58 if(x917state.seeded == 0) 59 X917init(); 60 X917(p, n); 61 qunlock(&x917state.lock); 62 }