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https://github.com/henrydcase/pqc.git
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ac2c20045c
* Add McEliece reference implementations * Add Vec implementations of McEliece * Add sse implementations * Add AVX2 implementations * Get rid of stuff not supported by Mac ABI * restrict to two cores * Ditch .data files * Remove .hidden from all .S files * speed up duplicate consistency tests by batching * make cpuinfo more robust * Hope to stabilize macos cpuinfo without ccache * Revert "Hope to stabilize macos cpuinfo without ccache" This reverts commit 6129c3cabe1abbc8b956bc87e902a698e32bf322. * Just hardcode what's available at travis * Fixed-size types in api.h * namespace all header files in mceliece * Ditch operations.h * Get rid of static inline functions * fixup! Ditch operations.h
93 lines
1.8 KiB
C
93 lines
1.8 KiB
C
/*
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This file is for Niederreiter decryption
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*/
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#include "decrypt.h"
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#include <stdio.h>
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#include "benes.h"
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#include "bm.h"
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#include "gf.h"
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#include "params.h"
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#include "root.h"
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#include "synd.h"
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#include "util.h"
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/* Niederreiter decryption with the Berlekamp decoder */
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/* intput: sk, secret key */
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/* c, ciphertext */
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/* output: e, error vector */
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/* return: 0 for success; 1 for failure */
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int PQCLEAN_MCELIECE6960119_CLEAN_decrypt(unsigned char *e, const unsigned char *sk, const unsigned char *c) {
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int i, w = 0;
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uint16_t check;
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unsigned char r[ SYS_N / 8 ];
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gf g[ SYS_T + 1 ];
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gf L[ SYS_N ];
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gf s[ SYS_T * 2 ];
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gf s_cmp[ SYS_T * 2 ];
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gf locator[ SYS_T + 1 ];
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gf images[ SYS_N ];
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gf t;
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//
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for (i = 0; i < SYND_BYTES; i++) {
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r[i] = c[i];
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}
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r[i - 1] &= (1 << ((GFBITS * SYS_T) % 8)) - 1;
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for (i = SYND_BYTES; i < SYS_N / 8; i++) {
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r[i] = 0;
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}
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for (i = 0; i < SYS_T; i++) {
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g[i] = PQCLEAN_MCELIECE6960119_CLEAN_load2(sk);
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g[i] &= GFMASK;
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sk += 2;
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}
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g[ SYS_T ] = 1;
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PQCLEAN_MCELIECE6960119_CLEAN_support_gen(L, sk);
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PQCLEAN_MCELIECE6960119_CLEAN_synd(s, g, L, r);
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PQCLEAN_MCELIECE6960119_CLEAN_bm(locator, s);
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PQCLEAN_MCELIECE6960119_CLEAN_root(images, locator, L);
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//
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for (i = 0; i < SYS_N / 8; i++) {
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e[i] = 0;
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}
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for (i = 0; i < SYS_N; i++) {
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t = PQCLEAN_MCELIECE6960119_CLEAN_gf_iszero(images[i]) & 1;
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e[ i / 8 ] |= t << (i % 8);
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w += t;
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}
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PQCLEAN_MCELIECE6960119_CLEAN_synd(s_cmp, g, L, e);
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//
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check = (uint16_t)w;
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check ^= SYS_T;
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for (i = 0; i < SYS_T * 2; i++) {
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check |= s[i] ^ s_cmp[i];
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}
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check -= 1;
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check >>= 15;
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return check ^ 1;
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}
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