/*
This file is part of GNUnet.
- (C) 2001-2013 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2001-2013 GNUnet e.V.
- GNUnet 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.
+ GNUnet is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ or (at your option) any later version.
GNUnet 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 GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ Affero General Public License for more details.
*/
/**
* @author Gerd Knorr <kraxel@bytesex.org>
* @author Ioana Patrascu
* @author Tzvetan Horozov
+ * @author Jeffrey Burdges <burdges@gnunet.org>
+ *
+ * @defgroup crypto Crypto library: cryptographic operations
+ * Provides cryptographic primitives.
+ *
+ * @see [Documentation](https://gnunet.org/crypto-api)
*
- * @defgroup crypto Cryptographic operations
- * @defgroup hash Hashing and operations on hashes
+ * @defgroup hash Crypto library: hash operations
+ * Provides hashing and operations on hashes.
+ *
+ * @see [Documentation](https://gnunet.org/crypto-api)
*/
#ifndef GNUNET_CRYPTO_LIB_H
#endif
/**
- * @brief A 512-bit hashcode
+ * @brief A 512-bit hashcode. These are the default length for GNUnet, using SHA-512.
+ */
+struct GNUNET_HashCode
+{
+ uint32_t bits[512 / 8 / sizeof (uint32_t)]; /* = 16 */
+};
+
+
+
+/**
+ * @brief A 256-bit hashcode. Used under special conditions, like when space
+ * is critical and security is not impacted by it.
*/
-struct GNUNET_HashCode;
+struct GNUNET_ShortHashCode
+{
+ uint32_t bits[256 / 8 / sizeof (uint32_t)]; /* = 8 */
+};
+
/**
* The identity of the host (wraps the signing key of the peer).
struct GNUNET_PeerIdentity;
#include "gnunet_common.h"
-#include "gnunet_scheduler_lib.h"
#include <gcrypt.h>
-/**
- * @brief A 512-bit hashcode
- */
-struct GNUNET_HashCode
-{
- uint32_t bits[512 / 8 / sizeof (uint32_t)]; /* = 16 */
-};
-
-
/**
* Maximum length of an ECC signature.
* Note: round up to multiple of 8 minus 2 for alignment.
/**
- * Paillier public key.
+ * Paillier private key.
*/
struct GNUNET_CRYPTO_PaillierPrivateKey
{
struct GNUNET_CRYPTO_PaillierCiphertext
{
/**
- * guaranteed minimum number of homomorphic operations with this ciphertext
+ * Guaranteed minimum number of homomorphic operations with this ciphertext,
+ * in network byte order (NBO).
*/
int32_t remaining_ops GNUNET_PACKED;
GNUNET_CRYPTO_seed_weak_random (int32_t seed);
+/**
+ * @ingroup hash
+ * Calculate the checksum of a buffer in one step.
+ *
+ * @param buf buffer to calculate CRC over
+ * @param len number of bytes in @a buf
+ * @return crc8 value
+ */
+uint8_t
+GNUNET_CRYPTO_crc8_n (const void *buf,
+ size_t len);
+
+
/**
* Perform an incremental step in a CRC16 (for TCP/IP) calculation.
*
* @return updated crc sum (must be subjected to #GNUNET_CRYPTO_crc16_finish to get actual crc16)
*/
uint32_t
-GNUNET_CRYPTO_crc16_step (uint32_t sum, const void *buf, size_t len);
+GNUNET_CRYPTO_crc16_step (uint32_t sum,
+ const void *buf,
+ size_t len);
/**
* @return crc16 value
*/
uint16_t
-GNUNET_CRYPTO_crc16_n (const void *buf, size_t len);
+GNUNET_CRYPTO_crc16_n (const void *buf,
+ size_t len);
+
+
/**
* @return the resulting CRC32 checksum
*/
int32_t
-GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
+GNUNET_CRYPTO_crc32_n (const void *buf,
+ size_t len);
/**
* @param length buffer length
*/
void
-GNUNET_CRYPTO_random_block (enum GNUNET_CRYPTO_Quality mode, void *buffer, size_t length);
+GNUNET_CRYPTO_random_block (enum GNUNET_CRYPTO_Quality mode,
+ void *buffer,
+ size_t length);
/**
* @ingroup crypto
* @return a random value in the interval [0,@a i) (exclusive).
*/
uint32_t
-GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
+GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode,
+ uint32_t i);
/**
* @return random 64-bit number
*/
uint64_t
-GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max);
+GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode,
+ uint64_t max);
/**
* @return the permutation array (allocated from heap)
*/
unsigned int *
-GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n);
+GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode,
+ unsigned int n);
/**
* @return the size of the encrypted block, -1 for errors
*/
ssize_t
-GNUNET_CRYPTO_symmetric_encrypt (const void *block, size_t size,
+GNUNET_CRYPTO_symmetric_encrypt (const void *block,
+ size_t size,
const struct GNUNET_CRYPTO_SymmetricSessionKey *sessionkey,
const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
void *result);
* @return -1 on failure, size of decrypted block on success
*/
ssize_t
-GNUNET_CRYPTO_symmetric_decrypt (const void *block, size_t size,
+GNUNET_CRYPTO_symmetric_decrypt (const void *block,
+ size_t size,
const struct GNUNET_CRYPTO_SymmetricSessionKey *sessionkey,
const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
void *result);
* safely cast to char*, a '\\0' termination is set).
*/
void
-GNUNET_CRYPTO_hash_to_enc (const struct GNUNET_HashCode * block,
+GNUNET_CRYPTO_hash_to_enc (const struct GNUNET_HashCode *block,
struct GNUNET_CRYPTO_HashAsciiEncoded *result);
* @return #GNUNET_OK on success, #GNUNET_SYSERR if result has the wrong encoding
*/
int
-GNUNET_CRYPTO_hash_from_string2 (const char *enc, size_t enclen,
+GNUNET_CRYPTO_hash_from_string2 (const char *enc,
+ size_t enclen,
struct GNUNET_HashCode *result);
* @param ret pointer to where to write the hashcode
*/
void
-GNUNET_CRYPTO_hash (const void *block, size_t size, struct GNUNET_HashCode * ret);
+GNUNET_CRYPTO_hash (const void *block,
+ size_t size,
+ struct GNUNET_HashCode *ret);
+
+
+/**
+ * Context for cummulative hashing.
+ */
+struct GNUNET_HashContext;
+
+
+/**
+ * Start incremental hashing operation.
+ *
+ * @return context for incremental hash computation
+ */
+struct GNUNET_HashContext *
+GNUNET_CRYPTO_hash_context_start (void);
+
+
+/**
+ * Add data to be hashed.
+ *
+ * @param hc cummulative hash context
+ * @param buf data to add
+ * @param size number of bytes in @a buf
+ */
+void
+GNUNET_CRYPTO_hash_context_read (struct GNUNET_HashContext *hc,
+ const void *buf,
+ size_t size);
+
+
+/**
+ * Finish the hash computation.
+ *
+ * @param hc hash context to use, is freed in the process
+ * @param r_hash where to write the latest / final hash code
+ */
+void
+GNUNET_CRYPTO_hash_context_finish (struct GNUNET_HashContext *hc,
+ struct GNUNET_HashCode *r_hash);
+
+
+/**
+ * Abort hashing, do not bother calculating final result.
+ *
+ * @param hc hash context to destroy
+ */
+void
+GNUNET_CRYPTO_hash_context_abort (struct GNUNET_HashContext *hc);
/**
*/
void
GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
- const void *plaintext, size_t plaintext_len,
- struct GNUNET_HashCode * hmac);
+ const void *plaintext,
+ size_t plaintext_len,
+ struct GNUNET_HashCode *hmac);
/**
* @param cls closure
* @param res resulting hash, NULL on error
*/
-typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
- const struct GNUNET_HashCode *res);
+typedef void
+(*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
+ const struct GNUNET_HashCode *res);
/**
*/
struct GNUNET_CRYPTO_FileHashContext *
GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
- const char *filename, size_t blocksize,
+ const char *filename,
+ size_t blocksize,
GNUNET_CRYPTO_HashCompletedCallback callback,
void *callback_cls);
void
GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
const struct GNUNET_CRYPTO_SymmetricSessionKey *rkey,
- const void *salt, size_t salt_len, ...);
+ const void *salt, size_t salt_len,
+ ...);
/**
* @return #GNUNET_YES on success
*/
int
-GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
- const void *xts, size_t xts_len, const void *skm,
- size_t skm_len, ...);
+GNUNET_CRYPTO_hkdf (void *result,
+ size_t out_len,
+ int xtr_algo,
+ int prf_algo,
+ const void *xts,
+ size_t xts_len,
+ const void *skm,
+ size_t skm_len,
+ ...);
/**
* @return #GNUNET_YES on success
*/
int
-GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
- const void *xts, size_t xts_len, const void *skm,
- size_t skm_len, va_list argp);
+GNUNET_CRYPTO_hkdf_v (void *result,
+ size_t out_len,
+ int xtr_algo,
+ int prf_algo,
+ const void *xts,
+ size_t xts_len,
+ const void *skm,
+ size_t skm_len,
+ va_list argp);
/**
* @return #GNUNET_YES on success
*/
int
-GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts,
- size_t xts_len, const void *skm, size_t skm_len,
+GNUNET_CRYPTO_kdf_v (void *result,
+ size_t out_len,
+ const void *xts,
+ size_t xts_len,
+ const void *skm,
+ size_t skm_len,
va_list argp);
+/**
+ * Deterministically generate a pseudo-random number uniformly from the
+ * integers modulo a libgcrypt mpi.
+ *
+ * @param[out] r MPI value set to the FDH
+ * @param n MPI to work modulo
+ * @param xts salt
+ * @param xts_len length of @a xts
+ * @param skm source key material
+ * @param skm_len length of @a skm
+ * @param ctx context string
+ */
+void
+GNUNET_CRYPTO_kdf_mod_mpi (gcry_mpi_t *r,
+ gcry_mpi_t n,
+ const void *xts, size_t xts_len,
+ const void *skm, size_t skm_len,
+ const char *ctx);
+
+
/**
* @ingroup hash
* @brief Derive key
* @return #GNUNET_YES on success
*/
int
-GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts,
- size_t xts_len, const void *skm, size_t skm_len, ...);
+GNUNET_CRYPTO_kdf (void *result,
+ size_t out_len,
+ const void *xts,
+ size_t xts_len,
+ const void *skm,
+ size_t skm_len,
+ ...);
/**
struct GNUNET_CRYPTO_EddsaPublicKey *pub);
+
/**
* @ingroup crypto
* Extract the public key for the given private key.
GNUNET_CRYPTO_ecdsa_public_key_to_string (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub);
+/**
+ * Convert a private key to a string.
+ *
+ * @param priv key to convert
+ * @return string representing @a pub
+ */
+char *
+GNUNET_CRYPTO_eddsa_private_key_to_string (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv);
+
+
/**
* Convert a public key to a string.
*
struct GNUNET_CRYPTO_EcdsaPublicKey *pub);
+/**
+ * Convert a string representing a private key to a private key.
+ *
+ * @param enc encoded public key
+ * @param enclen number of bytes in @a enc (without 0-terminator)
+ * @param priv where to store the private key
+ * @return #GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_eddsa_private_key_from_string (const char *enc,
+ size_t enclen,
+ struct GNUNET_CRYPTO_EddsaPrivateKey *pub);
+
+
/**
* Convert a string representing a public key to a public key.
*
struct GNUNET_CRYPTO_EddsaPrivateKey *
GNUNET_CRYPTO_eddsa_key_create_from_file (const char *filename);
+
+/**
+ * Forward declaration to simplify #include-structure.
+ */
struct GNUNET_CONFIGURATION_Handle;
GNUNET_CRYPTO_eddsa_key_create (void);
+/**
+ * @ingroup crypto
+ * Create a new private key. Clear with #GNUNET_CRYPTO_ecdhe_key_clear().
+ *
+ * @param[out] pk set to fresh private key;
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
+ */
+int
+GNUNET_CRYPTO_ecdhe_key_create2 (struct GNUNET_CRYPTO_EcdhePrivateKey *pk);
+
+
/**
* @ingroup crypto
* Create a new private key. Caller must free return value.
void
GNUNET_CRYPTO_ecdsa_key_clear (struct GNUNET_CRYPTO_EcdsaPrivateKey *pk);
+
/**
* @ingroup crypto
* Clear memory that was used to store a private key.
GNUNET_CRYPTO_get_peer_identity (const struct GNUNET_CONFIGURATION_Handle *cfg,
struct GNUNET_PeerIdentity *dst);
+
/**
* Compare two Peer Identities.
*
const struct GNUNET_PeerIdentity *second);
+/**
+ * Internal structure used to cache pre-calculated values for DLOG calculation.
+ */
+struct GNUNET_CRYPTO_EccDlogContext;
+
+
+/**
+ * Point on a curve (always for Curve25519) encoded in a format suitable
+ * for network transmission (ECDH), see http://cr.yp.to/ecdh.html.
+ */
+struct GNUNET_CRYPTO_EccPoint
+{
+ /**
+ * Q consists of an x- and a y-value, each mod p (256 bits), given
+ * here in affine coordinates and Ed25519 standard compact format.
+ */
+ unsigned char q_y[256 / 8];
+};
+
+
+/**
+ * Do pre-calculation for ECC discrete logarithm for small factors.
+ *
+ * @param max maximum value the factor can be
+ * @param mem memory to use (should be smaller than @a max), must not be zero.
+ * @return NULL on error
+ */
+struct GNUNET_CRYPTO_EccDlogContext *
+GNUNET_CRYPTO_ecc_dlog_prepare (unsigned int max,
+ unsigned int mem);
+
+
+/**
+ * Calculate ECC discrete logarithm for small factors.
+ * Opposite of #GNUNET_CRYPTO_ecc_dexp().
+ *
+ * @param dlc precalculated values, determine range of factors
+ * @param input point on the curve to factor
+ * @return INT_MAX if dlog failed, otherwise the factor
+ */
+int
+GNUNET_CRYPTO_ecc_dlog (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_point_t input);
+
+
+/**
+ * Multiply the generator g of the elliptic curve by @a val
+ * to obtain the point on the curve representing @a val.
+ * Afterwards, point addition will correspond to integer
+ * addition. #GNUNET_CRYPTO_ecc_dlog() can be used to
+ * convert a point back to an integer (as long as the
+ * integer is smaller than the MAX of the @a edc context).
+ *
+ * @param edc calculation context for ECC operations
+ * @param val value to encode into a point
+ * @return representation of the value as an ECC point,
+ * must be freed using #GNUNET_CRYPTO_ecc_free()
+ */
+gcry_mpi_point_t
+GNUNET_CRYPTO_ecc_dexp (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ int val);
+
+
+/**
+ * Multiply the generator g of the elliptic curve by @a val
+ * to obtain the point on the curve representing @a val.
+ *
+ * @param edc calculation context for ECC operations
+ * @param val (positive) value to encode into a point
+ * @return representation of the value as an ECC point,
+ * must be freed using #GNUNET_CRYPTO_ecc_free()
+ */
+gcry_mpi_point_t
+GNUNET_CRYPTO_ecc_dexp_mpi (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_t val);
+
+
+/**
+ * Multiply the point @a p on the elliptic curve by @a val.
+ *
+ * @param edc calculation context for ECC operations
+ * @param p point to multiply
+ * @param val (positive) value to encode into a point
+ * @return representation of the value as an ECC point,
+ * must be freed using #GNUNET_CRYPTO_ecc_free()
+ */
+gcry_mpi_point_t
+GNUNET_CRYPTO_ecc_pmul_mpi (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_point_t p,
+ gcry_mpi_t val);
+
+
+/**
+ * Convert point value to binary representation.
+ *
+ * @param edc calculation context for ECC operations
+ * @param point computational point representation
+ * @param[out] bin binary point representation
+ */
+void
+GNUNET_CRYPTO_ecc_point_to_bin (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_point_t point,
+ struct GNUNET_CRYPTO_EccPoint *bin);
+
+
+/**
+ * Convert binary representation of a point to computational representation.
+ *
+ * @param edc calculation context for ECC operations
+ * @param bin binary point representation
+ * @return computational representation
+ */
+gcry_mpi_point_t
+GNUNET_CRYPTO_ecc_bin_to_point (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ const struct GNUNET_CRYPTO_EccPoint *bin);
+
+
+/**
+ * Add two points on the elliptic curve.
+ *
+ * @param edc calculation context for ECC operations
+ * @param a some value
+ * @param b some value
+ * @return @a a + @a b, must be freed using #GNUNET_CRYPTO_ecc_free()
+ */
+gcry_mpi_point_t
+GNUNET_CRYPTO_ecc_add (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_point_t a,
+ gcry_mpi_point_t b);
+
+
+/**
+ * Obtain a random point on the curve and its
+ * additive inverse. Both returned values
+ * must be freed using #GNUNET_CRYPTO_ecc_free().
+ *
+ * @param edc calculation context for ECC operations
+ * @param[out] r set to a random point on the curve
+ * @param[out] r_inv set to the additive inverse of @a r
+ */
+void
+GNUNET_CRYPTO_ecc_rnd (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_point_t *r,
+ gcry_mpi_point_t *r_inv);
+
+
+/**
+ * Obtain a random scalar for point multiplication on the curve and
+ * its multiplicative inverse.
+ *
+ * @param edc calculation context for ECC operations
+ * @param[out] r set to a random scalar on the curve
+ * @param[out] r_inv set to the multiplicative inverse of @a r
+ */
+void
+GNUNET_CRYPTO_ecc_rnd_mpi (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_t *r,
+ gcry_mpi_t *r_inv);
+
+
+/**
+ * Generate a random value mod n.
+ *
+ * @param edc ECC context
+ * @return random value mod n.
+ */
+gcry_mpi_t
+GNUNET_CRYPTO_ecc_random_mod_n (struct GNUNET_CRYPTO_EccDlogContext *edc);
+
+
+/**
+ * Free a point value returned by the API.
+ *
+ * @param p point to free
+ */
+void
+GNUNET_CRYPTO_ecc_free (gcry_mpi_point_t p);
+
+
+/**
+ * Release precalculated values.
+ *
+ * @param dlc dlog context
+ */
+void
+GNUNET_CRYPTO_ecc_dlog_release (struct GNUNET_CRYPTO_EccDlogContext *dlc);
+
+
/**
* @ingroup crypto
* Derive key material from a public and a private ECC key.
struct GNUNET_HashCode *key_material);
+/**
+ * @ingroup crypto
+ * Derive key material from a ECDH public key and a private EdDSA key.
+ * Dual to #GNUNET_CRRYPTO_ecdh_eddsa.
+ *
+ * @param priv private key from EdDSA to use for the ECDH (x)
+ * @param pub public key to use for the ECDH (yG)
+ * @param key_material where to write the key material H(h(x)yG)
+ * @return #GNUNET_SYSERR on error, #GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_eddsa_ecdh (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv,
+ const struct GNUNET_CRYPTO_EcdhePublicKey *pub,
+ struct GNUNET_HashCode *key_material);
+
+/**
+ * @ingroup crypto
+ * Derive key material from a ECDH public key and a private ECDSA key.
+ * Dual to #GNUNET_CRRYPTO_ecdh_ecdsa.
+ *
+ * @param priv private key from ECDSA to use for the ECDH (x)
+ * @param pub public key to use for the ECDH (yG)
+ * @param key_material where to write the key material H(h(x)yG)
+ * @return #GNUNET_SYSERR on error, #GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_ecdsa_ecdh (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv,
+ const struct GNUNET_CRYPTO_EcdhePublicKey *pub,
+ struct GNUNET_HashCode *key_material);
+
+
+/**
+ * @ingroup crypto
+ * Derive key material from a EdDSA public key and a private ECDH key.
+ * Dual to #GNUNET_CRRYPTO_eddsa_ecdh.
+ *
+ * @param priv private key to use for the ECDH (y)
+ * @param pub public key from EdDSA to use for the ECDH (X=h(x)G)
+ * @param key_material where to write the key material H(yX)=H(h(x)yG)
+ * @return #GNUNET_SYSERR on error, #GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_ecdh_eddsa (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
+ const struct GNUNET_CRYPTO_EddsaPublicKey *pub,
+ struct GNUNET_HashCode *key_material);
+
+/**
+ * @ingroup crypto
+ * Derive key material from a EcDSA public key and a private ECDH key.
+ * Dual to #GNUNET_CRRYPTO_ecdsa_ecdh.
+ *
+ * @param priv private key to use for the ECDH (y)
+ * @param pub public key from ECDSA to use for the ECDH (X=h(x)G)
+ * @param key_material where to write the key material H(yX)=H(h(x)yG)
+ * @return #GNUNET_SYSERR on error, #GNUNET_OK on success
+ */
+int
+GNUNET_CRYPTO_ecdh_ecdsa (const struct GNUNET_CRYPTO_EcdhePrivateKey *priv,
+ const struct GNUNET_CRYPTO_EcdsaPublicKey *pub,
+ struct GNUNET_HashCode *key_material);
+
+
/**
* @ingroup crypto
* EdDSA sign a given block.
int
GNUNET_CRYPTO_paillier_hom_get_remaining (const struct GNUNET_CRYPTO_PaillierCiphertext *c);
+
+/* ********* Chaum-style RSA-based blind signatures ******************* */
+
+
+
+
+/**
+ * The private information of an RSA key pair.
+ */
+struct GNUNET_CRYPTO_RsaPrivateKey;
+
+/**
+ * The public information of an RSA key pair.
+ */
+struct GNUNET_CRYPTO_RsaPublicKey;
+
+/**
+ * Constant-size pre-secret for blinding key generation.
+ */
+struct GNUNET_CRYPTO_RsaBlindingKeySecret
+{
+ /**
+ * Bits used to generate the blinding key. 256 bits
+ * of entropy is enough.
+ */
+ uint32_t pre_secret[8] GNUNET_PACKED;
+};
+
+/**
+ * @brief an RSA signature
+ */
+struct GNUNET_CRYPTO_RsaSignature;
+
+
+/**
+ * Create a new private key. Caller must free return value.
+ *
+ * @param len length of the key in bits (i.e. 2048)
+ * @return fresh private key
+ */
+struct GNUNET_CRYPTO_RsaPrivateKey *
+GNUNET_CRYPTO_rsa_private_key_create (unsigned int len);
+
+
+/**
+ * Free memory occupied by the private key.
+ *
+ * @param key pointer to the memory to free
+ */
+void
+GNUNET_CRYPTO_rsa_private_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *key);
+
+
+/**
+ * Encode the private key in a format suitable for
+ * storing it into a file.
+ *
+ * @param key the private key
+ * @param[out] buffer set to a buffer with the encoded key
+ * @return size of memory allocatedin @a buffer
+ */
+size_t
+GNUNET_CRYPTO_rsa_private_key_encode (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
+ char **buffer);
+
+
+/**
+ * Decode the private key from the data-format back
+ * to the "normal", internal format.
+ *
+ * @param buf the buffer where the private key data is stored
+ * @param len the length of the data in @a buf
+ * @return NULL on error
+ */
+struct GNUNET_CRYPTO_RsaPrivateKey *
+GNUNET_CRYPTO_rsa_private_key_decode (const char *buf,
+ size_t len);
+
+
+/**
+ * Duplicate the given private key
+ *
+ * @param key the private key to duplicate
+ * @return the duplicate key; NULL upon error
+ */
+struct GNUNET_CRYPTO_RsaPrivateKey *
+GNUNET_CRYPTO_rsa_private_key_dup (const struct GNUNET_CRYPTO_RsaPrivateKey *key);
+
+
+/**
+ * Extract the public key of the given private key.
+ *
+ * @param priv the private key
+ * @retur NULL on error, otherwise the public key
+ */
+struct GNUNET_CRYPTO_RsaPublicKey *
+GNUNET_CRYPTO_rsa_private_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey *priv);
+
+
+/**
+ * Compute hash over the public key.
+ *
+ * @param key public key to hash
+ * @param hc where to store the hash code
+ */
+void
+GNUNET_CRYPTO_rsa_public_key_hash (const struct GNUNET_CRYPTO_RsaPublicKey *key,
+ struct GNUNET_HashCode *hc);
+
+
+/**
+ * Obtain the length of the RSA key in bits.
+ *
+ * @param key the public key to introspect
+ * @return length of the key in bits
+ */
+unsigned int
+GNUNET_CRYPTO_rsa_public_key_len (const struct GNUNET_CRYPTO_RsaPublicKey *key);
+
+
+/**
+ * Free memory occupied by the public key.
+ *
+ * @param key pointer to the memory to free
+ */
+void
+GNUNET_CRYPTO_rsa_public_key_free (struct GNUNET_CRYPTO_RsaPublicKey *key);
+
+
+/**
+ * Encode the public key in a format suitable for
+ * storing it into a file.
+ *
+ * @param key the private key
+ * @param[out] buffer set to a buffer with the encoded key
+ * @return size of memory allocated in @a buffer
+ */
+size_t
+GNUNET_CRYPTO_rsa_public_key_encode (const struct GNUNET_CRYPTO_RsaPublicKey *key,
+ char **buffer);
+
+
+/**
+ * Decode the public key from the data-format back
+ * to the "normal", internal format.
+ *
+ * @param buf the buffer where the public key data is stored
+ * @param len the length of the data in @a buf
+ * @return NULL on error
+ */
+struct GNUNET_CRYPTO_RsaPublicKey *
+GNUNET_CRYPTO_rsa_public_key_decode (const char *buf,
+ size_t len);
+
+
+/**
+ * Duplicate the given public key
+ *
+ * @param key the public key to duplicate
+ * @return the duplicate key; NULL upon error
+ */
+struct GNUNET_CRYPTO_RsaPublicKey *
+GNUNET_CRYPTO_rsa_public_key_dup (const struct GNUNET_CRYPTO_RsaPublicKey *key);
+
+
+/**
+ * Compare the values of two signatures.
+ *
+ * @param s1 one signature
+ * @param s2 the other signature
+ * @return 0 if the two are equal
+ */
+int
+GNUNET_CRYPTO_rsa_signature_cmp (struct GNUNET_CRYPTO_RsaSignature *s1,
+ struct GNUNET_CRYPTO_RsaSignature *s2);
+
+/**
+ * Compare the values of two private keys.
+ *
+ * @param p1 one private key
+ * @param p2 the other private key
+ * @return 0 if the two are equal
+ */
+int
+GNUNET_CRYPTO_rsa_private_key_cmp (struct GNUNET_CRYPTO_RsaPrivateKey *p1,
+ struct GNUNET_CRYPTO_RsaPrivateKey *p2);
+
+
+/**
+ * Compare the values of two public keys.
+ *
+ * @param p1 one public key
+ * @param p2 the other public key
+ * @return 0 if the two are equal
+ */
+int
+GNUNET_CRYPTO_rsa_public_key_cmp (struct GNUNET_CRYPTO_RsaPublicKey *p1,
+ struct GNUNET_CRYPTO_RsaPublicKey *p2);
+
+
+/**
+ * Blinds the given message with the given blinding key
+ *
+ * @param hash hash of the message to sign
+ * @param bkey the blinding key
+ * @param pkey the public key of the signer
+ * @param[out] buf set to a buffer with the blinded message to be signed
+ * @param[out] buf_size number of bytes stored in @a buf
+ * @return #GNUNET_YES if successful, #GNUNET_NO if RSA key is malicious
+ */
+int
+GNUNET_CRYPTO_rsa_blind (const struct GNUNET_HashCode *hash,
+ const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
+ struct GNUNET_CRYPTO_RsaPublicKey *pkey,
+ char **buf,
+ size_t *buf_size);
+
+
+/**
+ * Sign a blinded value, which must be a full domain hash of a message.
+ *
+ * @param key private key to use for the signing
+ * @param msg the (blinded) message to sign
+ * @param msg_len number of bytes in @a msg to sign
+ * @return NULL on error, signature on success
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+GNUNET_CRYPTO_rsa_sign_blinded (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
+ const void *msg,
+ size_t msg_len);
+
+
+/**
+ * Create and sign a full domain hash of a message.
+ *
+ * @param key private key to use for the signing
+ * @param hash the hash of the message to sign
+ * @return NULL on error, including a malicious RSA key, signature on success
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+GNUNET_CRYPTO_rsa_sign_fdh (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
+ const struct GNUNET_HashCode *hash);
+
+
+/**
+ * Free memory occupied by signature.
+ *
+ * @param sig memory to free
+ */
+void
+GNUNET_CRYPTO_rsa_signature_free (struct GNUNET_CRYPTO_RsaSignature *sig);
+
+
+/**
+ * Encode the given signature in a format suitable for storing it into a file.
+ *
+ * @param sig the signature
+ * @param[out] buffer set to a buffer with the encoded key
+ * @return size of memory allocated in @a buffer
+ */
+size_t
+GNUNET_CRYPTO_rsa_signature_encode (const struct GNUNET_CRYPTO_RsaSignature *sig,
+ char **buffer);
+
+
+/**
+ * Decode the signature from the data-format back to the "normal", internal
+ * format.
+ *
+ * @param buf the buffer where the public key data is stored
+ * @param len the length of the data in @a buf
+ * @return NULL on error
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+GNUNET_CRYPTO_rsa_signature_decode (const char *buf,
+ size_t len);
+
+
+/**
+ * Duplicate the given rsa signature
+ *
+ * @param sig the signature to duplicate
+ * @return the duplicate key; NULL upon error
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+GNUNET_CRYPTO_rsa_signature_dup (const struct GNUNET_CRYPTO_RsaSignature *sig);
+
+
+/**
+ * Unblind a blind-signed signature. The signature should have been generated
+ * with #GNUNET_CRYPTO_rsa_sign() using a hash that was blinded with
+ * #GNUNET_CRYPTO_rsa_blind().
+ *
+ * @param sig the signature made on the blinded signature purpose
+ * @param bks the blinding key secret used to blind the signature purpose
+ * @param pkey the public key of the signer
+ * @return unblinded signature on success, NULL if RSA key is bad or malicious.
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+GNUNET_CRYPTO_rsa_unblind (const struct GNUNET_CRYPTO_RsaSignature *sig,
+ const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
+ struct GNUNET_CRYPTO_RsaPublicKey *pkey);
+
+
+/**
+ * Verify whether the given hash corresponds to the given signature and the
+ * signature is valid with respect to the given public key.
+ *
+ * @param hash the message to verify to match the @a sig
+ * @param sig signature that is being validated
+ * @param public_key public key of the signer
+ * @returns #GNUNET_YES if ok, #GNUNET_NO if RSA key is malicious, #GNUNET_SYSERR if signature
+ */
+int
+GNUNET_CRYPTO_rsa_verify (const struct GNUNET_HashCode *hash,
+ const struct GNUNET_CRYPTO_RsaSignature *sig,
+ const struct GNUNET_CRYPTO_RsaPublicKey *public_key);
+
+
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif