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misc/poly1305-gen-example.pike
42 строки
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Niels Möller
Add tests for edge cases in poly1305 digest folding.
28 янв 2022, 21:35
28 янв 2022, 21:35
483ccbc
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#! /usr/bin/pike void write_little_endian(int x) { for (int i = 0; i < 16; i++, x >>= 8) { write("%02x", x & 0xff); } } int main (int argc, array(string) argv) { int p = (1<<130) - 5; int mask = 0x0ffffffc0ffffffc0ffffffc0fffffff; int digest = (argc > 1) ? (int) argv[1] % p : 0; int r = random(1<<128) & mask; int r2 = r*r%p; for (;;) { int m0 = random(1<<128) | (1<<128); /* We want m0 r^2 + m1 r = digest (mod p), or m1 = (digest - m0 r^2 ) r^-1 (mod p) To be a valid message, this must also satisfy (m1 >> 128) == 1 */ int m1 = r->invert(p) * (digest - m0 * r2) % p; if ((m1 >> 128) == 1) { write ("r = 0x%x\n", r); write ("m0 = 0x%x\n", m0); write ("m1 = 0x%x\n", m1); write ("out = 0x%x\n\n", digest); write ("r = le "); write_little_endian(r); write ("\nm0 = le "); write_little_endian(m0); write ("\nm1 = le "); write_little_endian(m1); write ("\nout = le "); write_little_endian(digest); write("\n"); if ((m0*r2 + m1*r) % p != digest) error("inconsistent result"); return 0; } } }