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-rw-r--r--ed25519.c139
1 files changed, 139 insertions, 0 deletions
diff --git a/ed25519.c b/ed25519.c
new file mode 100644
index 00000000..da9673a0
--- /dev/null
+++ b/ed25519.c
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+/* $OpenBSD: */
+
+/* Public Domain, from supercop-20130419/crypto_sign/ed25519/ref/ed25519.c */
+
+#include "crypto_api.h"
+
+#include "ge25519.h"
+
+static void get_hram(unsigned char *hram, const unsigned char *sm, const unsigned char *pk, unsigned char *playground, unsigned long long smlen)
+{
+ unsigned long long i;
+
+ for (i = 0;i < 32;++i) playground[i] = sm[i];
+ for (i = 32;i < 64;++i) playground[i] = pk[i-32];
+ for (i = 64;i < smlen;++i) playground[i] = sm[i];
+
+ crypto_hash_sha512(hram,playground,smlen);
+}
+
+
+int crypto_sign_ed25519_keypair(
+ unsigned char *pk,
+ unsigned char *sk
+ )
+{
+ sc25519 scsk;
+ ge25519 gepk;
+ unsigned char extsk[64];
+ int i;
+
+ randombytes(sk, 32);
+ crypto_hash_sha512(extsk, sk, 32);
+ extsk[0] &= 248;
+ extsk[31] &= 127;
+ extsk[31] |= 64;
+
+ sc25519_from32bytes(&scsk,extsk);
+
+ ge25519_scalarmult_base(&gepk, &scsk);
+ ge25519_pack(pk, &gepk);
+ for(i=0;i<32;i++)
+ sk[32 + i] = pk[i];
+ return 0;
+}
+
+int crypto_sign_ed25519(
+ unsigned char *sm,unsigned long long *smlen,
+ const unsigned char *m,unsigned long long mlen,
+ const unsigned char *sk
+ )
+{
+ sc25519 sck, scs, scsk;
+ ge25519 ger;
+ unsigned char r[32];
+ unsigned char s[32];
+ unsigned char extsk[64];
+ unsigned long long i;
+ unsigned char hmg[crypto_hash_sha512_BYTES];
+ unsigned char hram[crypto_hash_sha512_BYTES];
+
+ crypto_hash_sha512(extsk, sk, 32);
+ extsk[0] &= 248;
+ extsk[31] &= 127;
+ extsk[31] |= 64;
+
+ *smlen = mlen+64;
+ for(i=0;i<mlen;i++)
+ sm[64 + i] = m[i];
+ for(i=0;i<32;i++)
+ sm[32 + i] = extsk[32+i];
+
+ crypto_hash_sha512(hmg, sm+32, mlen+32); /* Generate k as h(extsk[32],...,extsk[63],m) */
+
+ /* Computation of R */
+ sc25519_from64bytes(&sck, hmg);
+ ge25519_scalarmult_base(&ger, &sck);
+ ge25519_pack(r, &ger);
+
+ /* Computation of s */
+ for(i=0;i<32;i++)
+ sm[i] = r[i];
+
+ get_hram(hram, sm, sk+32, sm, mlen+64);
+
+ sc25519_from64bytes(&scs, hram);
+ sc25519_from32bytes(&scsk, extsk);
+ sc25519_mul(&scs, &scs, &scsk);
+
+ sc25519_add(&scs, &scs, &sck);
+
+ sc25519_to32bytes(s,&scs); /* cat s */
+ for(i=0;i<32;i++)
+ sm[32 + i] = s[i];
+
+ return 0;
+}
+
+int crypto_sign_ed25519_open(
+ unsigned char *m,unsigned long long *mlen,
+ const unsigned char *sm,unsigned long long smlen,
+ const unsigned char *pk
+ )
+{
+ unsigned int i;
+ int ret;
+ unsigned char t2[32];
+ ge25519 get1, get2;
+ sc25519 schram, scs;
+ unsigned char hram[crypto_hash_sha512_BYTES];
+
+ *mlen = (unsigned long long) -1;
+ if (smlen < 64) return -1;
+
+ if (ge25519_unpackneg_vartime(&get1, pk)) return -1;
+
+ get_hram(hram,sm,pk,m,smlen);
+
+ sc25519_from64bytes(&schram, hram);
+
+ sc25519_from32bytes(&scs, sm+32);
+
+ ge25519_double_scalarmult_vartime(&get2, &get1, &schram, &ge25519_base, &scs);
+ ge25519_pack(t2, &get2);
+
+ ret = crypto_verify_32(sm, t2);
+
+ if (!ret)
+ {
+ for(i=0;i<smlen-64;i++)
+ m[i] = sm[i + 64];
+ *mlen = smlen-64;
+ }
+ else
+ {
+ for(i=0;i<smlen-64;i++)
+ m[i] = 0;
+ }
+ return ret;
+}