2 ------------------------------------------------------------------------------
3 http://burtleburtle.net/bob/rand/isaac.html
4 rand.c: By Bob Jenkins. My random number generator, ISAAC. Public Domain
6 960327: Creation (addition of randinit, really)
7 970719: use context, not global variables, for internal state
8 980324: make a portable version
9 010626: Note this is public domain
10 ------------------------------------------------------------------------------
14 #include "libradius.h"
16 #define RANDSIZL (8) /* I recommend 8 for crypto, 4 for simulations */
17 #define RANDSIZ (1<<RANDSIZL)
19 #define ind(mm,x) ((mm)[(x>>2)&(RANDSIZ-1)])
20 #define rngstep(mix,a,b,mm,m,m2,r,x) \
23 a = ((a^(mix)) + *(m2++)) & 0xffffffff; \
24 *(m++) = y = (ind(mm,x) + a + b) & 0xffffffff; \
25 *(r++) = b = (ind(mm,y>>RANDSIZL) + x) & 0xffffffff; \
28 void lrad_isaac(lrad_randctx *ctx)
30 register uint32_t a,b,x,y,*m,*mm,*m2,*r,*mend;
31 mm=ctx->randmem; r=ctx->randrsl;
32 a = ctx->randa; b = (ctx->randb + (++ctx->randc)) & 0xffffffff;
33 for (m = mm, mend = m2 = m+(RANDSIZ/2); m<mend; )
35 rngstep( a<<13, a, b, mm, m, m2, r, x);
36 rngstep( a>>6 , a, b, mm, m, m2, r, x);
37 rngstep( a<<2 , a, b, mm, m, m2, r, x);
38 rngstep( a>>16, a, b, mm, m, m2, r, x);
40 for (m2 = mm; m2<mend; )
42 rngstep( a<<13, a, b, mm, m, m2, r, x);
43 rngstep( a>>6 , a, b, mm, m, m2, r, x);
44 rngstep( a<<2 , a, b, mm, m, m2, r, x);
45 rngstep( a>>16, a, b, mm, m, m2, r, x);
47 ctx->randb = b; ctx->randa = a;
51 #define mix(a,b,c,d,e,f,g,h) \
53 a^=b<<11; d+=a; b+=c; \
54 b^=c>>2; e+=b; c+=d; \
55 c^=d<<8; f+=c; d+=e; \
56 d^=e>>16; g+=d; e+=f; \
57 e^=f<<10; h+=e; f+=g; \
58 f^=g>>4; a+=f; g+=h; \
59 g^=h<<8; b+=g; h+=a; \
60 h^=a>>9; c+=h; a+=b; \
63 /* if (flag==1), then use the contents of randrsl[] to initialize mm[]. */
64 void lrad_randinit(lrad_randctx *ctx, int flag)
67 uint32_t a,b,c,d,e,f,g,h;
69 ctx->randa = ctx->randb = ctx->randc = 0;
72 a=b=c=d=e=f=g=h=0x9e3779b9; /* the golden ratio */
74 for (i=0; i<4; ++i) { /* scramble it */
79 /* initialize using the contents of r[] as the seed */
80 for (i=0; i<RANDSIZ; i+=8) {
81 a+=r[i ]; b+=r[i+1]; c+=r[i+2]; d+=r[i+3];
82 e+=r[i+4]; f+=r[i+5]; g+=r[i+6]; h+=r[i+7];
84 m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
85 m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
87 /* do a second pass to make all of the seed affect all of m */
88 for (i=0; i<RANDSIZ; i+=8) {
89 a+=m[i ]; b+=m[i+1]; c+=m[i+2]; d+=m[i+3];
90 e+=m[i+4]; f+=m[i+5]; g+=m[i+6]; h+=m[i+7];
92 m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
93 m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
96 for (i=0; i<RANDSIZ; i+=8) {
97 /* fill in mm[] with messy stuff */
99 m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
100 m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
104 lrad_isaac(ctx); /* fill in the first set of results */
105 ctx->randcnt=RANDSIZ; /* prepare to use the first set of results */
111 * For testing. Output should be the same as
113 * http://burtleburtle.net/bob/rand/randvect.txt
120 ctx.randa = ctx.randb = ctx.randc = (uint32_t)0;
122 for (i=0; i<256; ++i) ctx.randrsl[i]=(uint32_t)0;
123 lrad_randinit(&ctx, 1);
124 for (i=0; i<2; ++i) {
126 for (j=0; j<256; ++j) {
127 printf("%.8lx",ctx.randrsl[j]);
128 if ((j&7)==7) printf("\n");