mirror of
https://github.com/servalproject/serval-dna.git
synced 2024-12-28 00:48:54 +00:00
bf9710fd5a
This only affects build_android, if nacl-gcc-prep is run then build/`uname -s` will be created.
104 lines
2.2 KiB
C
104 lines
2.2 KiB
C
#include "api.h"
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#include "crypto_sign.h"
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#include "crypto_hash_sha512.h"
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#include "randombytes.h"
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#include "crypto_verify_32.h"
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#include "ge25519.h"
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int crypto_sign_keypair(
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unsigned char *pk,
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unsigned char *sk
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)
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{
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sc25519 scsk;
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ge25519 gepk;
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randombytes(sk, 32);
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crypto_hash_sha512(sk, sk, 32);
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sk[0] &= 248;
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sk[31] &= 127;
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sk[31] |= 64;
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sc25519_from32bytes(&scsk,sk);
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ge25519_scalarmult_base(&gepk, &scsk);
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ge25519_pack(pk, &gepk);
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return 0;
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}
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int crypto_sign(
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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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sc25519 sck, scs, scsk;
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ge25519 ger;
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unsigned char r[32];
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unsigned char s[32];
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unsigned long long i;
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unsigned char hmg[crypto_hash_sha512_BYTES];
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unsigned char hmr[crypto_hash_sha512_BYTES];
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*smlen = mlen+64;
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for(i=0;i<mlen;i++)
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sm[32 + i] = m[i];
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for(i=0;i<32;i++)
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sm[i] = sk[32+i];
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crypto_hash_sha512(hmg, sm, mlen+32); /* Generate k as h(m,sk[32],...,sk[63]) */
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sc25519_from64bytes(&sck, hmg);
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ge25519_scalarmult_base(&ger, &sck);
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ge25519_pack(r, &ger);
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for(i=0;i<32;i++)
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sm[i] = r[i];
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crypto_hash_sha512(hmr, sm, mlen+32); /* Compute h(m,r) */
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sc25519_from64bytes(&scs, hmr);
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sc25519_mul(&scs, &scs, &sck);
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sc25519_from32bytes(&scsk, sk);
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sc25519_add(&scs, &scs, &scsk);
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sc25519_to32bytes(s,&scs); /* cat s */
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for(i=0;i<32;i++)
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sm[mlen+32+i] = s[i];
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return 0;
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}
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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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int i;
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unsigned char t1[32], t2[32];
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ge25519 get1, get2, gepk;
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sc25519 schmr, scs;
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unsigned char hmr[crypto_hash_sha512_BYTES];
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if (ge25519_unpack_vartime(&get1, sm)) return -1;
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if (ge25519_unpack_vartime(&gepk, pk)) return -1;
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crypto_hash_sha512(hmr,sm,smlen-32);
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sc25519_from64bytes(&schmr, hmr);
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ge25519_scalarmult(&get1, &get1, &schmr);
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ge25519_add(&get1, &get1, &gepk);
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ge25519_pack(t1, &get1);
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sc25519_from32bytes(&scs, &sm[smlen-32]);
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ge25519_scalarmult_base(&get2, &scs);
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ge25519_pack(t2, &get2);
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for(i=0;i<smlen-64;i++)
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m[i] = sm[i + 32];
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*mlen = smlen-64;
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return crypto_verify_32(t1, t2);
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}
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