public key cryptography (ECC) with libgcrypt More...

#include "platform.h"
#include <gcrypt.h>
#include <sodium.h>
#include "gnunet_util_lib.h"
#include "benchmark.h"

Include dependency graph for crypto_ecc.c:

Macros
#define	EXTRA_CHECKS 0

#define	CURVE "Ed25519"
	IMPLEMENTATION NOTICE: More...

#define	LOG(kind, ...) GNUNET_log_from (kind, "util-crypto-ecc", __VA_ARGS__)

#define	LOG_STRERROR(kind, syscall) GNUNET_log_from_strerror (kind, "util-crypto-ecc", syscall)

#define	LOG_STRERROR_FILE(kind, syscall, filename) GNUNET_log_from_strerror_file (kind, "util-crypto-ecc", syscall, filename)

#define	LOG_GCRY(level, cmd, rc)
	Log an error message at log-level 'level' that indicates a failure of the command 'cmd' with the message given by gcry_strerror(rc). More...

Functions
static int	key_from_sexp (gcry_mpi_t array, gcry_sexp_t sexp, const char topname, const char *elems)
	Extract values from an S-expression. More...

static gcry_sexp_t	decode_private_ecdsa_key (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv)
	Convert the given private key from the network format to the S-expression that can be used by libgcrypt. More...

void	GNUNET_CRYPTO_ecdsa_key_get_public (const struct GNUNET_CRYPTO_EcdsaPrivateKey priv, struct GNUNET_CRYPTO_EcdsaPublicKey pub)
	Extract the public key for the given private key. More...

void	GNUNET_CRYPTO_eddsa_key_get_public (const struct GNUNET_CRYPTO_EddsaPrivateKey priv, struct GNUNET_CRYPTO_EddsaPublicKey pub)
	Extract the public key for the given private key. More...

void	GNUNET_CRYPTO_ecdhe_key_get_public (const struct GNUNET_CRYPTO_EcdhePrivateKey priv, struct GNUNET_CRYPTO_EcdhePublicKey pub)
	Extract the public key for the given private key. More...

char *	GNUNET_CRYPTO_ecdsa_public_key_to_string (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
	Convert a public key to a string. More...

char *	GNUNET_CRYPTO_eddsa_public_key_to_string (const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
	Convert a public key to a string. More...

char *	GNUNET_CRYPTO_eddsa_private_key_to_string (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv)
	Convert a private key to a string. More...

char *	GNUNET_CRYPTO_ecdsa_private_key_to_string (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv)
	Convert a private key to a string. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdsa_public_key_from_string (const char enc, size_t enclen, struct GNUNET_CRYPTO_EcdsaPublicKey pub)
	Convert a string representing a public key to a public key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_public_key_from_string (const char enc, size_t enclen, struct GNUNET_CRYPTO_EddsaPublicKey pub)
	Convert a string representing a public key to a public key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_private_key_from_string (const char enc, size_t enclen, struct GNUNET_CRYPTO_EddsaPrivateKey priv)
	Convert a string representing a private key to a private key. More...

void	GNUNET_CRYPTO_ecdhe_key_clear (struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
	Clear memory that was used to store a private key. More...

void	GNUNET_CRYPTO_ecdsa_key_clear (struct GNUNET_CRYPTO_EcdsaPrivateKey *pk)
	Clear memory that was used to store a private key. More...

void	GNUNET_CRYPTO_eddsa_key_clear (struct GNUNET_CRYPTO_EddsaPrivateKey *pk)
	Clear memory that was used to store a private key. More...

void	GNUNET_CRYPTO_ecdhe_key_create (struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
	Create a new private key. More...

void	GNUNET_CRYPTO_ecdsa_key_create (struct GNUNET_CRYPTO_EcdsaPrivateKey *pk)
	Create a new private key. More...

void	GNUNET_CRYPTO_eddsa_key_create (struct GNUNET_CRYPTO_EddsaPrivateKey *pk)
	Create a new private key. More...

const struct GNUNET_CRYPTO_EcdsaPrivateKey *	GNUNET_CRYPTO_ecdsa_key_get_anonymous ()
	Get the shared private key we use for anonymous users. More...

static gcry_sexp_t	data_to_ecdsa_value (const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose)
	Convert the data specified in the given purpose argument to an S-expression suitable for signature operations. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdsa_sign_ (const struct GNUNET_CRYPTO_EcdsaPrivateKey priv, const struct GNUNET_CRYPTO_EccSignaturePurpose purpose, struct GNUNET_CRYPTO_EcdsaSignature *sig)
	ECDSA Sign a given block. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_sign_raw (const struct GNUNET_CRYPTO_EddsaPrivateKey priv, void data, size_t size, struct GNUNET_CRYPTO_EddsaSignature *sig)

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_sign_ (const struct GNUNET_CRYPTO_EddsaPrivateKey priv, const struct GNUNET_CRYPTO_EccSignaturePurpose purpose, struct GNUNET_CRYPTO_EddsaSignature *sig)
	EdDSA sign a given block. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdsa_verify_ (uint32_t purpose, const struct GNUNET_CRYPTO_EccSignaturePurpose validate, const struct GNUNET_CRYPTO_EcdsaSignature sig, const struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
	Verify ECDSA signature. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_verify_ (uint32_t purpose, const struct GNUNET_CRYPTO_EccSignaturePurpose validate, const struct GNUNET_CRYPTO_EddsaSignature sig, const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
	Verify EdDSA signature. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecc_ecdh (const struct GNUNET_CRYPTO_EcdhePrivateKey priv, const struct GNUNET_CRYPTO_EcdhePublicKey pub, struct GNUNET_HashCode *key_material)
	Derive key material from a public and a private ECC key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_ecdh (const struct GNUNET_CRYPTO_EddsaPrivateKey priv, const struct GNUNET_CRYPTO_EcdhePublicKey pub, struct GNUNET_HashCode *key_material)
	Derive key material from a ECDH public key and a private EdDSA key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdsa_ecdh (const struct GNUNET_CRYPTO_EcdsaPrivateKey priv, const struct GNUNET_CRYPTO_EcdhePublicKey pub, struct GNUNET_HashCode *key_material)
	Derive key material from a ECDH public key and a private ECDSA key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdh_eddsa (const struct GNUNET_CRYPTO_EcdhePrivateKey priv, const struct GNUNET_CRYPTO_EddsaPublicKey pub, struct GNUNET_HashCode *key_material)
	Derive key material from a EdDSA public key and a private ECDH key. More...

enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdh_ecdsa (const struct GNUNET_CRYPTO_EcdhePrivateKey priv, const struct GNUNET_CRYPTO_EcdsaPublicKey pub, struct GNUNET_HashCode *key_material)
	Derive key material from a EcDSA public key and a private ECDH key. More...

Detailed Description

public key cryptography (ECC) with libgcrypt

Author: Christian Grothoff; Florian Dold

Definition in file crypto_ecc.c.

Macro Definition Documentation

◆ EXTRA_CHECKS

#define EXTRA_CHECKS 0

Definition at line 34 of file crypto_ecc.c.

◆ CURVE

#define CURVE "Ed25519"

IMPLEMENTATION NOTICE:

ECDSA: We use a non-standard curve for ECDSA: Ed25519. For performance reasons, we use cryptographic operations from libsodium wherever we can get away with it, even though libsodium itself does not support ECDSA. This is why the sign and verifiy functionality from libgcrypt is required and used.

EdDSA: We use a standard EdDSA construction. (We still use libgcrypt for hashing and RNG, but not EC)

ECDHE: For both EdDSA and ECDSA keys, we use libsodium for ECDHE due to performance benefits over libgcrypt. Name of the curve we are using. Note that we have hard-coded structs that use 256 bits, so using a bigger curve will require changes that break stuff badly. The name of the curve given here must be agreed by all peers and be supported by libgcrypt.

Definition at line 59 of file crypto_ecc.c.

◆ LOG

#define LOG	(	kind,
		...
	)	GNUNET_log_from (kind, "util-crypto-ecc", __VA_ARGS__)

Definition at line 61 of file crypto_ecc.c.

◆ LOG_STRERROR

#define LOG_STRERROR	(	kind,
		syscall
	)	GNUNET_log_from_strerror (kind, "util-crypto-ecc", syscall)

Definition at line 63 of file crypto_ecc.c.

◆ LOG_STRERROR_FILE

#define LOG_STRERROR_FILE	(	kind,
		syscall,
		filename
	)	GNUNET_log_from_strerror_file (kind, "util-crypto-ecc", syscall, filename)

Definition at line 66 of file crypto_ecc.c.

◆ LOG_GCRY

#define LOG_GCRY	(	level,
		cmd,
		rc
	)

Value:

  do                                                  \
  {                                                   \
    LOG (level,                                       \
         _ ("`%s' failed at %s:%d with error: %s\n"), \
         cmd,                                         \
         __FILE__,                                    \
         __LINE__,                                    \
         gcry_strerror (rc));                         \
  } while (0)

Log an error message at log-level 'level' that indicates a failure of the command 'cmd' with the message given by gcry_strerror(rc).

Definition at line 74 of file crypto_ecc.c.

Function Documentation

◆ key_from_sexp()

static int key_from_sexp	(	gcry_mpi_t *	array,
		gcry_sexp_t	sexp,
		const char *	topname,
		const char *	elems
	)

static

Extract values from an S-expression.

Parameters

array	where to store the result(s)
sexp	S-expression to parse
topname	top-level name in the S-expression that is of interest
elems	names of the elements to extract

Returns: 0 on success

Definition at line 96 of file crypto_ecc.c.

 {
   gcry_sexp_t list;
   gcry_sexp_t l2;
   unsigned int idx;
  
   list = gcry_sexp_find_token (sexp, topname, 0);
   if (! list)
     return 1;
   l2 = gcry_sexp_cadr (list);
   gcry_sexp_release (list);
   list = l2;
   if (! list)
     return 2;
  
   idx = 0;
   for (const char *s = elems; *s; s++, idx++)
   {
     l2 = gcry_sexp_find_token (list, s, 1);
     if (! l2)
     {
       for (unsigned int i = 0; i < idx; i++)
       {
         gcry_free (array[i]);
         array[i] = NULL;
       }
       gcry_sexp_release (list);
       return 3;     /* required parameter not found */
     }
     array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
     gcry_sexp_release (l2);
     if (! array[idx])
     {
       for (unsigned int i = 0; i < idx; i++)
       {
         gcry_free (array[i]);
         array[i] = NULL;
       }
       gcry_sexp_release (list);
       return 4;     /* required parameter is invalid */
     }
   }
   gcry_sexp_release (list);
   return 0;
 }

References list.

◆ decode_private_ecdsa_key()

static gcry_sexp_t decode_private_ecdsa_key ( const struct GNUNET_CRYPTO_EcdsaPrivateKey * priv )

static

Convert the given private key from the network format to the S-expression that can be used by libgcrypt.

Parameters

priv	private key to decode

Returns: NULL on error

Definition at line 154 of file crypto_ecc.c.

 {
   gcry_sexp_t result;
   int rc;
   uint8_t d[32];
  
   for (size_t i = 0; i<32; i++)
     d[i] = priv->d[31 - i];
  
   rc = gcry_sexp_build (&result,
                         NULL,
                         "(private-key(ecc(curve \"" CURVE "\")"
                         "(d %b)))",
                         32,
                         d);
   if (0 != rc)
   {
     LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
     GNUNET_assert (0);
   }
 #if EXTRA_CHECKS
   if (0 != (rc = gcry_pk_testkey (result)))
   {
     LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
     GNUNET_assert (0);
   }
 #endif
   return result;
 }

References CURVE, GNUNET_CRYPTO_EcdsaPrivateKey::d, GNUNET_assert, GNUNET_ERROR_TYPE_ERROR, LOG_GCRY, and result.

◆ data_to_ecdsa_value()

static gcry_sexp_t data_to_ecdsa_value ( const struct GNUNET_CRYPTO_EccSignaturePurpose * purpose )

static

Convert the data specified in the given purpose argument to an S-expression suitable for signature operations.

Parameters

purpose data to convert

Returns: converted s-expression

Definition at line 512 of file crypto_ecc.c.

 {
   gcry_sexp_t data;
   int rc;
  
 /* See #5398 */
 #if 1
   struct GNUNET_HashCode hc;
  
   GNUNET_CRYPTO_hash (purpose, ntohl (purpose->size), &hc);
   if (0 != (rc = gcry_sexp_build (&data,
                                   NULL,
                                   "(data(flags rfc6979)(hash %s %b))",
                                   "sha512",
                                   (int) sizeof(hc),
                                   &hc)))
   {
     LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
     return NULL;
   }
 #else
   if (0 != (rc = gcry_sexp_build (&data,
                                   NULL,
                                   "(data(flags rfc6979)(hash %s %b))",
                                   "sha512",
                                   ntohl (purpose->size),
                                   purpose)))
   {
     LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
     return NULL;
   }
 #endif
   return data;
 }

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ EXTRA_CHECKS

◆ CURVE

◆ LOG

◆ LOG_STRERROR

◆ LOG_STRERROR_FILE

◆ LOG_GCRY

Function Documentation

◆ key_from_sexp()

◆ decode_private_ecdsa_key()

◆ data_to_ecdsa_value()