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49 lines
1.1 KiB
49 lines
1.1 KiB
#include <string.h> |
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#include "crypto_sign.h" |
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#include "crypto_verify_32.h" |
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#include "crypto_hash_sha512.h" |
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#include "ge25519.h" |
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int crypto_sign_open( |
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unsigned char *m,unsigned long long *mlen, |
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const unsigned char *sm,unsigned long long smlen, |
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const unsigned char *pk |
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) |
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{ |
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unsigned char pkcopy[32]; |
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unsigned char rcopy[32]; |
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unsigned char hram[64]; |
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unsigned char rcheck[32]; |
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ge25519 get1, get2; |
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sc25519 schram, scs; |
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if (smlen < 64) goto badsig; |
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if (sm[63] & 224) goto badsig; |
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if (ge25519_unpackneg_vartime(&get1,pk)) goto badsig; |
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memmove(pkcopy,pk,32); |
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memmove(rcopy,sm,32); |
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sc25519_from32bytes(&scs, sm+32); |
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memmove(m,sm,smlen); |
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memmove(m + 32,pkcopy,32); |
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crypto_hash_sha512(hram,m,smlen); |
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sc25519_from64bytes(&schram, hram); |
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ge25519_double_scalarmult_vartime(&get2, &get1, &schram, &scs); |
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ge25519_pack(rcheck, &get2); |
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if (crypto_verify_32(rcopy,rcheck) == 0) { |
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memmove(m,m + 64,smlen - 64); |
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memset(m + smlen - 64,0,64); |
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*mlen = smlen - 64; |
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return 0; |
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} |
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badsig: |
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*mlen = (unsigned long long) -1; |
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memset(m,0,smlen); |
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return -1; |
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}
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