mirror of
https://github.com/RfidResearchGroup/proxmark3.git
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f4d0ffd1b9
ADD: a prng.c to collect some different PRNG's i've ran into ADD: some changes the tea implementation ADD: a enhanced version - SwapEndian64ex
40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
//-----------------------------------------------------------------------------
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//-----------------------------------------------------------------------------
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// Burtle Prng - Modified. 42iterations instead of 20.
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// ref: http://burtleburtle.net/bob/rand/smallprng.html
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//-----------------------------------------------------------------------------
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#include "prng.h"
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#define rot(x,k) (((x)<<(k))|((x)>>(32-(k))))
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uint32_t burtle_get_mod( prng_ctx *x ) {
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uint32_t e = x->a - rot(x->b, 21);
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x->a = x->b ^ rot(x->c, 19);
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x->b = x->c + rot(x->d, 6);
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x->c = x->d + e;
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x->d = e + x->a;
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return x->d;
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}
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void burtle_init_mod(prng_ctx *x, uint32_t seed ) {
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x->a = 0xf1ea5eed;
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x->b = x->c = x->d = seed;
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for (uint8_t i=0; i < 42; ++i) {
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(void)burtle_get_mod(x);
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}
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}
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void burtle_init(prng_ctx *x, uint32_t seed ) {
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uint32_t i;
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x->a = 0xf1ea5eed, x->b = x->c = x->d = seed;
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for (i=0; i < 20; ++i) {
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(void)burtle_get_mod(x);
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}
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}
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uint32_t GetSimplePrng( uint32_t seed ){
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seed *= 0x19660D;
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seed += 0x3C6EF35F;
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return seed;
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}
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