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41 lines
983 B
C
41 lines
983 B
C
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#include <string.h>
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#include "crypto_sign.h"
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#include "crypto_hash_sha512.h"
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#include "ge.h"
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#include "sc.h"
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/* NEW: Compare to pristine crypto_sign()
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Uses explicit private key for nonce derivation and as scalar,
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instead of deriving both from a master key.
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*/
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int crypto_sign_modified(
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unsigned char *sm,unsigned long long *smlen,
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const unsigned char *m,unsigned long long mlen,
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const unsigned char *sk
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)
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{
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unsigned char pk[32];
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unsigned char az[64];
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unsigned char nonce[64];
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unsigned char hram[64];
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ge_p3 R;
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memmove(pk,sk + 32,32);
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*smlen = mlen + 64;
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memmove(sm + 64,m,mlen);
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memmove(sm + 32,sk,32); /* NEW: Use privkey directly for nonce derivation */
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crypto_hash_sha512(nonce,sm + 32,mlen + 32);
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memmove(sm + 32,pk,32);
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sc_reduce(nonce);
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ge_scalarmult_base(&R,nonce);
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ge_p3_tobytes(sm,&R);
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crypto_hash_sha512(hram,sm,mlen + 64);
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sc_reduce(hram);
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sc_muladd(sm + 32,hram,sk,nonce); /* NEW: Use privkey directly */
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return 0;
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}
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