From 4b55cec6419f939c00488442f9f8d13fef341e46 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=96zg=C3=BCr=20Kesim?= Date: Sun, 22 Jan 2023 22:05:35 +0100 Subject: [PATCH] WiP: age-withdraw: added exchange confirmation signature --- ...taler-exchange-httpd_age-withdraw_reveal.c | 0 src/include/taler_crypto_lib.h | 4 +- src/util/exchange_signatures.c | 56 +++++++++++- src/util/wallet_signatures.c | 86 +++++++++++++++++++ 4 files changed, 143 insertions(+), 3 deletions(-) create mode 100644 src/exchange/taler-exchange-httpd_age-withdraw_reveal.c diff --git a/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c b/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c new file mode 100644 index 000000000..e69de29bb diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h index 460ab60d4..882b846a3 100644 --- a/src/include/taler_crypto_lib.h +++ b/src/include/taler_crypto_lib.h @@ -5779,7 +5779,7 @@ TALER_age_commitment_attest ( /** - * @brief Verify the attestation for an given age and age commitment + * @brief Verify the attestation for a given age and age commitment * * @param commitment The age commitment that went into the attestation. Only the public keys are needed. * @param age Age (not age group) for which the an attestation should be done @@ -5806,7 +5806,7 @@ TALER_age_commitment_verify ( enum TALER_ErrorCode TALER_exchange_online_age_withdraw_confirmation_sign ( TALER_ExchangeSignCallback scb, - const struct TALER_AgeWithdrawCommitmentHashP *awch, + const struct TALER_AgeWithdrawCommitmentHashP *h_commitment, uint32_t noreveal_index, struct TALER_ExchangePublicKeyP *pub, struct TALER_ExchangeSignatureP *sig); diff --git a/src/util/exchange_signatures.c b/src/util/exchange_signatures.c index 21dad5299..9ca9e6cfa 100644 --- a/src/util/exchange_signatures.c +++ b/src/util/exchange_signatures.c @@ -359,7 +359,61 @@ TALER_exchange_online_melt_confirmation_verify ( } -/* TODO:oec: add signature for age-withdraw and reveal */ +GNUNET_NETWORK_STRUCT_BEGIN + +/** + * @brief Format of the block signed by the Exchange in response to a + * successful "/reserves/$RESERVE_PUB/age-withdraw" request. Hereby the + * exchange affirms that the commitment along with the maximum age group and + * the amount were accepted. This also commits the exchange to a particular + * index to not be revealed during the reveal. + */ +struct TALER_AgeWithdrawConfirmationPS +{ + /** + * Purpose is #TALER_SIGNATURE_EXCHANGE_CONFIRM_AGE_WITHDRAW. Signed by a + * `struct TALER_ExchangePublicKeyP` using EdDSA. + */ + struct GNUNET_CRYPTO_EccSignaturePurpose purpose; + + /** + * Commitment made in the /reserves/$RESERVE_PUB/age-withdraw. + */ + struct TALER_AgeWithdrawCommitmentHashP h_commitment GNUNET_PACKED; + + /** + * Index that the client will not have to reveal, in NBO. + * Must be smaller than #TALER_CNC_KAPPA. + */ + uint32_t noreveal_index GNUNET_PACKED; + +}; + +GNUNET_NETWORK_STRUCT_END + +enum TALER_ErrorCode +TALER_exchange_online_age_withdraw_confirmation_sign ( + TALER_ExchangeSignCallback scb, + const struct TALER_AgeWithdrawCommitmentHashP *h_commitment, + uint32_t noreveal_index, + struct TALER_ExchangePublicKeyP *pub, + struct TALER_ExchangeSignatureP *sig) +{ + + struct TALER_AgeWithdrawConfirmationPS confirm = { + .purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_AGE_WITHDRAW), + .purpose.size = htonl (sizeof (confirm)), + .h_commitment = *h_commitment, + .noreveal_index = htonl (noreveal_index) + }; + + return scb (&confirm.purpose, + pub, + sig); +} + + +/* TODO:oec: add signature for age-withdraw, age-reveal */ GNUNET_NETWORK_STRUCT_BEGIN diff --git a/src/util/wallet_signatures.c b/src/util/wallet_signatures.c index c457668e9..4aa5bd7e1 100644 --- a/src/util/wallet_signatures.c +++ b/src/util/wallet_signatures.c @@ -604,6 +604,92 @@ TALER_wallet_withdraw_verify ( } +GNUNET_NETWORK_STRUCT_BEGIN + +/** + * @brief Format used for to generate the signature on a request to + * age-withdraw from a reserve. + */ +struct TALER_AgeWithdrawRequestPS +{ + + /** + * Purpose must be #TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW. + * Used with an EdDSA signature of a `struct TALER_ReservePublicKeyP`. + */ + struct GNUNET_CRYPTO_EccSignaturePurpose purpose; + + /** + * Hash of the commitment of n*kappa coins + */ + struct TALER_AgeWithdrawCommitmentHashP h_commitment GNUNET_PACKED; + + /** + * Value of the coin being exchanged (matching the denomination key) + * plus the transaction fee. We include this in what is being + * signed so that we can verify a reserve's remaining total balance + * without needing to access the respective denomination key + * information each time. + */ + struct TALER_AmountNBO amount_with_fee; + + /** + * Maximum age group that the coins are going to be restricted to. + */ + uint32_t max_age_group; +}; + + +GNUNET_NETWORK_STRUCT_END + +void +TALER_wallet_age_withdraw_sign ( + const struct TALER_AgeWithdrawCommitmentHashP *h_commitment, + const struct TALER_Amount *amount_with_fee, + uint32_t max_age_group, + const struct TALER_ReservePrivateKeyP *reserve_priv, + struct TALER_ReserveSignatureP *reserve_sig) +{ + struct TALER_AgeWithdrawRequestPS req = { + .purpose.size = htonl (sizeof (req)), + .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_RESERVE_AGE_WITHDRAW), + .h_commitment = *h_commitment, + .max_age_group = max_age_group + }; + + TALER_amount_hton (&req.amount_with_fee, + amount_with_fee); + GNUNET_CRYPTO_eddsa_sign (&reserve_priv->eddsa_priv, + &req, + &reserve_sig->eddsa_signature); +} + + +enum GNUNET_GenericReturnValue +TALER_wallet_age_withdraw_verify ( + const struct TALER_AgeWithdrawCommitmentHashP *h_commitment, + const struct TALER_Amount *amount_with_fee, + uint32_t max_age_group, + const struct TALER_ReservePublicKeyP *reserve_pub, + const struct TALER_ReserveSignatureP *reserve_sig) +{ + struct TALER_AgeWithdrawRequestPS awsrd = { + .purpose.size = htonl (sizeof (awsrd)), + .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_RESERVE_AGE_WITHDRAW), + .h_commitment = *h_commitment, + .max_age_group = max_age_group + }; + + TALER_amount_hton (&awsrd.amount_with_fee, + amount_with_fee); + return GNUNET_CRYPTO_eddsa_verify ( + TALER_SIGNATURE_WALLET_RESERVE_AGE_WITHDRAW, + &awsrd, + &reserve_sig->eddsa_signature, + &reserve_pub->eddsa_pub); +} + + GNUNET_NETWORK_STRUCT_BEGIN