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45 lines
663 B
C
45 lines
663 B
C
#include <string.h>
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#include "compare.h"
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/* Const-time comparison from SUPERCOP, but here it's only used for
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signature verification, so doesn't need to be const-time. But
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copied the nacl version anyways. */
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int crypto_verify_32_ref(const unsigned char *x, const unsigned char *y)
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{
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unsigned int differentbits = 0;
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#define F(i) differentbits |= x[i] ^ y[i];
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F(0)
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F(1)
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F(2)
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F(3)
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F(4)
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F(5)
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F(6)
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F(7)
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F(8)
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F(9)
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F(10)
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F(11)
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F(12)
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F(13)
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F(14)
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F(15)
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F(16)
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F(17)
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F(18)
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F(19)
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F(20)
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F(21)
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F(22)
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F(23)
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F(24)
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F(25)
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F(26)
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F(27)
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F(28)
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F(29)
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F(30)
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F(31)
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return (1 & ((differentbits - 1) >> 8)) - 1;
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}
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