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exchange/src/include/taler_crypto_lib.h
Christian Grothoff 59398cfd76
separate util.c and url.c
2020-01-19 20:33:07 +01:00

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/*
This file is part of TALER
Copyright (C) 2014-2018 Taler Systems SA
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file include/taler_crypto_lib.h
* @brief taler-specific crypto functions
* @author Sree Harsha Totakura <sreeharsha@totakura.in>
* @author Christian Grothoff <christian@grothoff.org>
*/
#ifndef TALER_CRYPTO_LIB_H
#define TALER_CRYPTO_LIB_H
#include <gnunet/gnunet_util_lib.h>
#include "taler_util.h"
#include <gcrypt.h>
/* ****************** Coin crypto primitives ************* */
GNUNET_NETWORK_STRUCT_BEGIN
/**
* @brief Type of public keys for Taler reserves.
*/
struct TALER_ReservePublicKeyP
{
/**
* Taler uses EdDSA for reserves.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of private keys for Taler reserves.
*/
struct TALER_ReservePrivateKeyP
{
/**
* Taler uses EdDSA for reserves.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
};
/**
* @brief Type of signatures used with Taler reserves.
*/
struct TALER_ReserveSignatureP
{
/**
* Taler uses EdDSA for reserves.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
};
/**
* @brief Type of public keys to for merchant authorizations.
* Merchants can issue refunds using the corresponding
* private key.
*/
struct TALER_MerchantPublicKeyP
{
/**
* Taler uses EdDSA for merchants.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of private keys for merchant authorizations.
* Merchants can issue refunds using the corresponding
* private key.
*/
struct TALER_MerchantPrivateKeyP
{
/**
* Taler uses EdDSA for merchants.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
};
/**
* @brief Type of signatures made by merchants.
*/
struct TALER_MerchantSignatureP
{
/**
* Taler uses EdDSA for merchants.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_sig;
};
/**
* @brief Type of transfer public keys used during refresh
* operations.
*/
struct TALER_TransferPublicKeyP
{
/**
* Taler uses ECDHE for transfer keys.
*/
struct GNUNET_CRYPTO_EcdhePublicKey ecdhe_pub;
};
/**
* @brief Type of transfer public keys used during refresh
* operations.
*/
struct TALER_TransferPrivateKeyP
{
/**
* Taler uses ECDHE for melting session keys.
*/
struct GNUNET_CRYPTO_EcdhePrivateKey ecdhe_priv;
};
/**
* @brief Type of online public keys used by the exchange to sign
* messages.
*/
struct TALER_ExchangePublicKeyP
{
/**
* Taler uses EdDSA for online exchange message signing.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of online public keys used by the exchange to
* sign messages.
*/
struct TALER_ExchangePrivateKeyP
{
/**
* Taler uses EdDSA for online signatures sessions.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
};
/**
* @brief Type of signatures used by the exchange to sign messages online.
*/
struct TALER_ExchangeSignatureP
{
/**
* Taler uses EdDSA for online signatures sessions.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
};
/**
* @brief Type of the offline master public key used by the exchange.
*/
struct TALER_MasterPublicKeyP
{
/**
* Taler uses EdDSA for the long-term offline master key.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of the public key used by the auditor.
*/
struct TALER_AuditorPublicKeyP
{
/**
* Taler uses EdDSA for the auditor's signing key.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of signatures used by the auditor.
*/
struct TALER_AuditorSignatureP
{
/**
* Taler uses EdDSA signatures for auditors.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_sig;
};
/**
* @brief Type of the offline master public keys used by the exchange.
*/
struct TALER_MasterPrivateKeyP
{
/**
* Taler uses EdDSA for the long-term offline master key.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
};
/**
* @brief Type of signatures by the offline master public key used by the exchange.
*/
struct TALER_MasterSignatureP
{
/**
* Taler uses EdDSA for the long-term offline master key.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
};
/**
* @brief Type of public keys for Taler coins. The same key material is used
* for EdDSA and ECDHE operations.
*/
struct TALER_CoinSpendPublicKeyP
{
/**
* Taler uses EdDSA for coins when signing deposit requests.
*/
struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
};
/**
* @brief Type of private keys for Taler coins. The same key material is used
* for EdDSA and ECDHE operations.
*/
struct TALER_CoinSpendPrivateKeyP
{
/**
* Taler uses EdDSA for coins when signing deposit requests.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
};
/**
* @brief Type of signatures made with Taler coins.
*/
struct TALER_CoinSpendSignatureP
{
/**
* Taler uses EdDSA for coins.
*/
struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
};
/**
* @brief Type of blinding keys for Taler.
*/
struct TALER_DenominationBlindingKeyP
{
/**
* Taler uses RSA for blind signatures.
*/
struct GNUNET_CRYPTO_RsaBlindingKeySecret bks;
};
/**
* Commitment value for the refresh protocol.
* See #TALER_refresh_get_commitment().
*/
struct TALER_RefreshCommitmentP
{
/**
* The commitment is a hash code.
*/
struct GNUNET_HashCode session_hash;
};
GNUNET_NETWORK_STRUCT_END
/**
* @brief Type of (unblinded) coin signatures for Taler.
*/
struct TALER_DenominationSignature
{
/**
* Taler uses RSA for blinding.
*/
struct GNUNET_CRYPTO_RsaSignature *rsa_signature;
};
/**
* @brief Type of public signing keys for verifying blindly signed coins.
*/
struct TALER_DenominationPublicKey
{
/**
* Taler uses RSA for signing coins.
*/
struct GNUNET_CRYPTO_RsaPublicKey *rsa_public_key;
};
/**
* @brief Type of private signing keys for blind signing of coins.
*/
struct TALER_DenominationPrivateKey
{
/**
* Taler uses RSA for signing coins.
*/
struct GNUNET_CRYPTO_RsaPrivateKey *rsa_private_key;
};
/**
* @brief Public information about a coin (including the public key
* of the coin, the denomination key and the signature with
* the denomination key).
*/
struct TALER_CoinPublicInfo
{
/**
* The coin's public key.
*/
struct TALER_CoinSpendPublicKeyP coin_pub;
/**
* Hash of the public key representing the denomination of the coin that is
* being deposited.
*/
struct GNUNET_HashCode denom_pub_hash;
/**
* (Unblinded) signature over @e coin_pub with @e denom_pub,
* which demonstrates that the coin is valid.
*/
struct TALER_DenominationSignature denom_sig;
};
/**
* Details for one of the /deposit operations that the
* exchange combined into a single wire transfer.
*/
struct TALER_TrackTransferDetails
{
/**
* Hash of the proposal data.
*/
struct GNUNET_HashCode h_contract_terms;
/**
* Which coin was deposited?
*/
struct TALER_CoinSpendPublicKeyP coin_pub;
/**
* Value of the deposit (including fee).
*/
struct TALER_Amount coin_value;
/**
* Fee charged by the exchange for the deposit.
*/
struct TALER_Amount coin_fee;
};
/**
* Check if a coin is valid; that is, whether the denomination key exists,
* is not expired, and the signature is correct.
*
* @param coin_public_info the coin public info to check for validity
* @param denom_pub denomination key, must match @a coin_public_info's `denom_pub_hash`
* @return #GNUNET_YES if the coin is valid,
* #GNUNET_NO if it is invalid
* #GNUNET_SYSERR if an internal error occured
*/
int
TALER_test_coin_valid (const struct TALER_CoinPublicInfo *coin_public_info,
const struct TALER_DenominationPublicKey *denom_pub);
GNUNET_NETWORK_STRUCT_BEGIN
/**
* Header for serializations of coin-specific information about the
* fresh coins we generate. These are the secrets that arise during
* planchet generation, which is the first stage of creating a new
* coin.
*/
struct TALER_PlanchetSecretsP
{
/**
* Private key of the coin.
*/
struct TALER_CoinSpendPrivateKeyP coin_priv;
/**
* The blinding key.
*/
struct TALER_DenominationBlindingKeyP blinding_key;
};
GNUNET_NETWORK_STRUCT_END
/**
* Details about a planchet that the customer wants to obtain
* a withdrawal authorization. This is the information that
* will need to be sent to the exchange to obtain the blind
* signature required to turn a planchet into a coin.
*/
struct TALER_PlanchetDetail
{
/**
* Hash of the denomination public key.
*/
struct GNUNET_HashCode denom_pub_hash;
/**
* Hash of the coin's public key. Kept around so we do not need to
* compute it again. Can be recomputed by hashing the public key
* of @a coin_priv if storage is at a premium.
*/
struct GNUNET_HashCode c_hash;
/**
* Blinded coin (see GNUNET_CRYPTO_rsa_blind()). Note: is malloc()'ed!
*/
char *coin_ev;
/**
* Number of bytes in @a coin_ev.
*/
size_t coin_ev_size;
};
/**
* Information about a (fresh) coin, returned from the API when we
* finished creating a coin. Note that @e sig needs to be freed
* using the appropriate code.
*/
struct TALER_FreshCoin
{
/**
* The exchange's signature over the coin's public key.
*/
struct TALER_DenominationSignature sig;
/**
* The coin's private key.
*/
struct TALER_CoinSpendPrivateKeyP coin_priv;
};
GNUNET_NETWORK_STRUCT_BEGIN
/**
* @brief Secret used to decrypt the key to decrypt link secrets.
*/
struct TALER_TransferSecretP
{
/**
* Secret used to derive private inputs for refreshed coins.
* Must be (currently) a hash as this is what
* GNUNET_CRYPTO_ecc_ecdh() returns to us.
*/
struct GNUNET_HashCode key;
};
/**
* Length of the raw value in the Taler wire transfer identifier
* (in binary representation).
*/
#define TALER_BANK_TRANSFER_IDENTIFIER_LEN 32
/**
* #TALER_BANK_TRANSFER_IDENTIFIER_LEN as a string.
*/
#define TALER_BANK_TRANSFER_IDENTIFIER_LEN_STR "32"
/**
* Raw value of a wire transfer subjects, without the checksum.
*/
struct TALER_WireTransferIdentifierRawP
{
/**
* Raw value. Note that typical payment systems (SEPA, ACH) support
* at least two lines of 27 ASCII characters to encode a transaction
* subject or "details", for a total of 54 characters. (The payment
* system protocols often support more lines, but the forms presented
* to customers are usually limited to 54 characters.)
*
* With a Base32-encoding of 5 bit per character, this gives us 270
* bits or (rounded down) 33 bytes. So we use the first 32 bytes to
* encode the actual value (i.e. a 256-bit / 32-byte public key or
* a hash code), and the last byte for a minimalistic checksum.
*/
uint8_t raw[TALER_BANK_TRANSFER_IDENTIFIER_LEN];
};
/**
* Binary information encoded in Crockford's Base32 in wire transfer
* subjects of transfers from Taler to a merchant. The actual value
* is chosen by the exchange and has no particular semantics, other than
* being unique so that the exchange can lookup details about the wire
* transfer when needed.
*/
struct TALER_WireTransferIdentifierP
{
/**
* Raw value.
*/
struct TALER_WireTransferIdentifierRawP raw;
/**
* Checksum using CRC8 over the @e raw data.
*/
uint8_t crc8;
};
GNUNET_NETWORK_STRUCT_END
/**
* Setup information for a fresh coin, deriving the coin private key
* and the blinding factor from the @a secret_seed with a KDF salted
* by the @a coin_num_salt.
*
* @param secret_seed seed to use for KDF to derive coin keys
* @param coin_num_salt number of the coin to include in KDF
* @param[out] ps value to initialize
*/
void
TALER_planchet_setup_refresh (const struct TALER_TransferSecretP *secret_seed,
uint32_t coin_num_salt,
struct TALER_PlanchetSecretsP *ps);
/**
* Setup information for a fresh coin.
*
* @param[out] ps value to initialize
*/
void
TALER_planchet_setup_random (struct TALER_PlanchetSecretsP *ps);
/**
* Prepare a planchet for tipping. Creates and blinds a coin.
*
* @param dk denomination key for the coin to be created
* @param ps secret planchet internals (for #TALER_planchet_to_coin)
* @param[out] pd set to the planchet detail for TALER_MERCHANT_tip_pickup() and
* other withdraw operations
* @return #GNUNET_OK on success
*/
int
TALER_planchet_prepare (const struct TALER_DenominationPublicKey *dk,
const struct TALER_PlanchetSecretsP *ps,
struct TALER_PlanchetDetail *pd);
/**
* Obtain a coin from the planchet's secrets and the blind signature
* of the exchange.
*
* @param dk denomination key, must match what was given to #TALER_planchet_prepare()
* @param blind_sig blind signature from the exchange
* @param ps secrets from #TALER_planchet_prepare()
* @param c_hash hash of the coin's public key for verification of the signature
* @param[out] coin set to the details of the fresh coin
* @return #GNUNET_OK on success
*/
int
TALER_planchet_to_coin (const struct TALER_DenominationPublicKey *dk,
const struct GNUNET_CRYPTO_RsaSignature *blind_sig,
const struct TALER_PlanchetSecretsP *ps,
const struct GNUNET_HashCode *c_hash,
struct TALER_FreshCoin *coin);
/* ****************** Refresh crypto primitives ************* */
/**
* Given the coin and the transfer private keys, compute the
* transfer secret. (Technically, we only need one of the two
* private keys, but the caller currently trivially only has
* the two private keys, so we derive one of the public keys
* internally to this function.)
*
* @param coin_priv coin key
* @param trans_priv transfer private key
* @param[out] ts computed transfer secret
*/
void
TALER_link_derive_transfer_secret (const struct
TALER_CoinSpendPrivateKeyP *coin_priv,
const struct
TALER_TransferPrivateKeyP *trans_priv,
struct TALER_TransferSecretP *ts);
/**
* Decrypt the shared @a secret from the information in the
* @a trans_priv and @a coin_pub.
*
* @param trans_priv transfer private key
* @param coin_pub coin public key
* @param[out] transfer_secret set to the shared secret
*/
void
TALER_link_reveal_transfer_secret (const struct
TALER_TransferPrivateKeyP *trans_priv,
const struct
TALER_CoinSpendPublicKeyP *coin_pub,
struct TALER_TransferSecretP *transfer_secret);
/**
* Decrypt the shared @a secret from the information in the
* @a trans_priv and @a coin_pub.
*
* @param trans_pub transfer private key
* @param coin_priv coin public key
* @param[out] transfer_secret set to the shared secret
*/
void
TALER_link_recover_transfer_secret (const struct
TALER_TransferPublicKeyP *trans_pub,
const struct
TALER_CoinSpendPrivateKeyP *coin_priv,
struct TALER_TransferSecretP *
transfer_secret);
/**
* Information about a coin to be created during a refresh operation.
*/
struct TALER_RefreshCoinData
{
/**
* The denomination's public key.
*/
const struct TALER_DenominationPublicKey *dk;
/**
* The envelope with the blinded coin.
*/
char *coin_ev;
/**
* Number of bytes in @a coin_ev
*/
size_t coin_ev_size;
};
/**
* One of the #TALER_CNC_KAPPA commitments.
*/
struct TALER_RefreshCommitmentEntry
{
/**
* Transfer public key of this commitment.
*/
struct TALER_TransferPublicKeyP transfer_pub;
/**
* Array of @e num_new_coins new coins to be created.
*/
struct TALER_RefreshCoinData *new_coins;
};
/**
* Compute the commitment for a /refresh/melt operation from
* the respective public inputs.
*
* @param[out] rc set to the value the wallet must commit to
* @param kappa number of transfer public keys involved (must be #TALER_CNC_KAPPA)
* @param num_new_coins number of new coins to be created
* @param rcs array of @a kappa commitments
* @param coin_pub public key of the coin to be melted
* @param amount_with_fee amount to be melted, including fee
*/
void
TALER_refresh_get_commitment (struct TALER_RefreshCommitmentP *rc,
uint32_t kappa,
uint32_t num_new_coins,
const struct TALER_RefreshCommitmentEntry *rcs,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_Amount *amount_with_fee);
/* **************** /wire account offline signing **************** */
/**
* Compute the hash of the given wire details. The resulting
* hash is what is signed by the master key.
*
* @param payto_uri bank account
* @param[out] hc set to the hash
*/
void
TALER_exchange_wire_signature_hash (const char *payto_uri,
struct GNUNET_HashCode *hc);
/**
* Check the signature in @a master_sig.
*
* @param payto_uri URL that is signed
* @param master_pub master public key of the exchange
* @param master_sig signature of the exchange
* @return #GNUNET_OK if signature is valid
*/
int
TALER_exchange_wire_signature_check (const char *payto_uri,
const struct
TALER_MasterPublicKeyP *master_pub,
const struct
TALER_MasterSignatureP *master_sig);
/**
* Create a signed wire statement for the given account.
*
* @param payto_uri account specification
* @param master_priv private key to sign with
* @param[out] master_sig where to write the signature
*/
void
TALER_exchange_wire_signature_make (const char *payto_uri,
const struct
TALER_MasterPrivateKeyP *master_priv,
struct TALER_MasterSignatureP *master_sig);
/**
* Compute the hash of the given wire details. The resulting
* @a hc is what will be put into the contract between customer
* and merchant for signing by both parties.
*
* @param payto_uri bank account
* @param salt salt used to eliminate brute-force inversion
* @param[out] hc set to the hash
*/
void
TALER_merchant_wire_signature_hash (const char *payto_uri,
const char *salt,
struct GNUNET_HashCode *hc);
/**
* Check the signature in @a wire_s.
*
* @param payto_uri URL that is signed
* @param salt the salt used to salt the @a payto_uri when hashing
* @param merch_pub public key of the merchant
* @param merch_sig signature of the merchant
* @return #GNUNET_OK if signature is valid
*/
int
TALER_merchant_wire_signature_check (const char *payto_uri,
const char *salt,
const struct
TALER_MerchantPublicKeyP *merch_pub,
const struct
TALER_MerchantSignatureP *merch_sig);
/**
* Create a signed wire statement for the given account.
*
* @param payto_uri account specification
* @param salt the salt used to salt the @a payto_uri when hashing
* @param merch_priv private key to sign with
* @param[out] merch_sig where to write the signature
*/
void
TALER_merchant_wire_signature_make (const char *payto_uri,
const char *salt,
const struct
TALER_MerchantPrivateKeyP *merch_priv,
struct TALER_MerchantSignatureP *merch_sig);
#endif
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