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#include "os.h"
#include <libsec.h>
typedef struct State{
QLock lock;
int seeded;
uvlong seed;
DES3state des3;
} State;
static State x917state;
static void
X917(uchar *rand, int nrand)
{
int i, m, n8;
uvlong I, x;
/* 1. Compute intermediate value I = Ek(time). */
I = nsec();
triple_block_cipher(x917state.des3.expanded, (uchar*)&I, 0); /* two-key EDE */
/* 2. x[i] = Ek(I^seed); seed = Ek(x[i]^I); */
m = (nrand+7)/8;
for(i=0; i<m; i++){
x = I ^ x917state.seed;
triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);
n8 = (nrand>8) ? 8 : nrand;
memcpy(rand, (uchar*)&x, n8);
rand += 8;
nrand -= 8;
x ^= I;
triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);
x917state.seed = x;
}
}
static void
X917init(void)
{
int n;
uchar mix[128];
uchar key3[3][8];
ulong *ulp;
ulp = (ulong*)key3;
for(n = 0; n < sizeof(key3)/sizeof(ulong); n++)
ulp[n] = truerand();
setupDES3state(&x917state.des3, key3, nil);
X917(mix, sizeof mix);
x917state.seeded = 1;
}
void
genrandom(uchar *p, int n)
{
qlock(&x917state.lock);
if(x917state.seeded == 0)
X917init();
X917(p, n);
qunlock(&x917state.lock);
}
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