taler/exchange
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[age restriction] progress 19/19 (final) - Use Edx25519 for crypto

Browse Source 
We switch from EcDSA to Edx25519 for the underlying signature scheme.

Edx25519 is implemented in gnunet, starting with (gnunet-)commit
ce38d1f6c9bd7857a1c3bc2094a0ee9752b86c32.
This commit is contained in:
Özgür Kesim 2022-03-28 11:04:00 +02:00
parent d61a19c275
commit a2386abadb
Signed by: oec
GPG Key ID: 3D76A56D79EDD9D7
2 changed files with 74 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/include/taler_crypto_lib.h
View File

@ -386,10 +386,17 @@ struct TALER_CoinSpendSignatureP
*/
struct TALER_AgeCommitmentPrivateKeyP
{
#ifdef AGE_RESTRICTION_WITH_ECDSA
/**
* Taler uses EcDSA for coins when signing age verification attestation.
*/
struct GNUNET_CRYPTO_EcdsaPrivateKey priv;
#else
/**
* Taler uses Edx25519 for coins when signing age verification attestation.
*/
struct GNUNET_CRYPTO_Edx25519PrivateKey priv;
#endif
};
@ -398,10 +405,17 @@ struct TALER_AgeCommitmentPrivateKeyP
*/
struct TALER_AgeCommitmentPublicKeyP
{
#ifdef AGE_RESTRICTION_WITH_ECDSA
/**
* Taler uses EcDSA for coins when signing age verification attestation.
*/
struct GNUNET_CRYPTO_EcdsaPublicKey pub;
#else
/**
* Taler uses Edx25519 for coins when signing age verification attestation.
*/
struct GNUNET_CRYPTO_Edx25519PublicKey pub;
#endif
};
@ -1174,7 +1188,11 @@ struct TALER_AgeCommitmentHash
*/
struct TALER_AgeAttestation
{
#ifdef AGE_RESTRICTION_WITH_ECDSA
struct GNUNET_CRYPTO_EcdsaSignature signature;
#else
struct GNUNET_CRYPTO_Edx25519Signature signature;
#endif
};
extern const struct TALER_AgeCommitmentHash TALER_ZeroAgeCommitmentHash;

73
src/util/age_restriction.c
View File

@ -47,8 +47,7 @@ TALER_age_commitment_hash (
{
GNUNET_CRYPTO_hash_context_read (hash_context,
&commitment->keys[i],
sizeof(struct
GNUNET_CRYPTO_EcdsaPublicKey));
sizeof(commitment->keys[i]));
}
GNUNET_CRYPTO_hash_context_finish (hash_context,
@ -128,13 +127,23 @@ TALER_age_restriction_commit (
if (i < num_priv)
pkey = &new->proof.keys[i];
#ifndef AGE_RESTRICTION_WITH_ECDSA
GNUNET_CRYPTO_edx25519_key_create_from_seed (&salti,
sizeof(salti),
&pkey->priv);
GNUNET_CRYPTO_edx25519_key_get_public (&pkey->priv,
&new->commitment.keys[i].pub);
}
return GNUNET_OK;
#else
if (GNUNET_OK !=
GNUNET_CRYPTO_kdf (pkey,
sizeof (*pkey),
&salti,
sizeof (salti),
"age commitment",
strlen ("age derivation"),
strlen ("age commitment"),
NULL, 0))
goto FAIL;
@ -154,6 +163,7 @@ FAIL:
if (NULL != new->proof.keys)
GNUNET_free (new->proof.keys);
return GNUNET_SYSERR;
#endif
}
@ -163,8 +173,6 @@ TALER_age_commitment_derive (
const uint64_t salt,
struct TALER_AgeCommitmentProof *new)
{
char label[sizeof(uint64_t) + 1] = {0};
GNUNET_assert (NULL != new);
GNUNET_assert (orig->proof.num <=
orig->commitment.num);
@ -184,13 +192,34 @@ TALER_age_commitment_derive (
new->proof.num,
struct TALER_AgeCommitmentPrivateKeyP);
#ifndef AGE_RESTRICTION_WITH_ECDSA
/* 1. Derive the public keys */
for (size_t i = 0; i < orig->commitment.num; i++)
{
/* Because GNUNET_CRYPTO_ecdsa_public_key_derive expects char * (and calls
* strlen on it), we must avoid 0's in the label. */
uint64_t nz_salt = salt | 0x8040201008040201;
memcpy (label, &nz_salt, sizeof(nz_salt));
GNUNET_CRYPTO_edx25519_public_key_derive (
&orig->commitment.keys[i].pub,
&salt,
sizeof(salt),
&new->commitment.keys[i].pub);
}
/* 2. Derive the private keys */
for (size_t i = 0; i < orig->proof.num; i++)
{
GNUNET_CRYPTO_edx25519_private_key_derive (
&orig->proof.keys[i].priv,
&salt,
sizeof(salt),
&new->proof.keys[i].priv);
}
#else
char label[sizeof(uint64_t) + 1] = {0};
/* Because GNUNET_CRYPTO_ecdsa_public_key_derive expects char * (and calls
* strlen on it), we must avoid 0's in the label. */
uint64_t nz_salt = salt | 0x8040201008040201;
memcpy (label, &nz_salt, sizeof(nz_salt));
/* 1. Derive the public keys */
for (size_t i = 0; i < orig->commitment.num; i++)
{
@ -212,6 +241,7 @@ TALER_age_commitment_derive (
new->proof.keys[i].priv = *priv;
GNUNET_free (priv);
}
#endif
return GNUNET_OK;
}
@ -276,9 +306,14 @@ TALER_age_commitment_attest (
.age = age
};
GNUNET_CRYPTO_ecdsa_sign (&cp->proof.keys[group - 1].priv,
&at,
&attest->signature);
#ifndef AGE_RESTRICTION_WITH_ECDSA
#define sign(a,b,c) GNUNET_CRYPTO_edx25519_sign (a,b,c)
#else
#define sign(a,b,c) GNUNET_CRYPTO_ecdsa_sign (a,b,c)
#endif
sign (&cp->proof.keys[group - 1].priv,
&at,
&attest->signature);
}
return GNUNET_OK;
@ -316,11 +351,15 @@ TALER_age_commitment_verify (
.age = age,
};
return
GNUNET_CRYPTO_ecdsa_verify (TALER_SIGNATURE_WALLET_AGE_ATTESTATION,
&at,
&attest->signature,
&comm->keys[group - 1].pub);
#ifndef AGE_RESTRICTION_WITH_ECDSA
#define verify(a,b,c,d) GNUNET_CRYPTO_edx25519_verify (a,b,c,d)
#else
#define verify(a,b,c,d) GNUNET_CRYPTO_ecdsa_verify (a,b,c,d)
#endif
return verify (TALER_SIGNATURE_WALLET_AGE_ATTESTATION,
&at,
&attest->signature,
&comm->keys[group - 1].pub);
}
}