crypto_ecc_gnsrecord.c File Reference

public key cryptography (ECC) for GNS records (LSD0001) More...

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

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Macros
#define	CURVE   "Ed25519"

Functions
static void	derive_h (const void *pub, size_t pubsize, const char *label, const char *context, struct GNUNET_HashCode *hc)
	Derive the 'h' value for key derivation, where 'h = H(l,P)'.
enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_eddsa_sign_derived (const struct GNUNET_CRYPTO_EddsaPrivateKey *pkey, const char *label, const char *context, const struct GNUNET_CRYPTO_SignaturePurpose *purpose, struct GNUNET_CRYPTO_EddsaSignature *sig)
	This is a signature function for EdDSA which takes a private key and derives it using the label and context before signing.
enum GNUNET_GenericReturnValue	GNUNET_CRYPTO_ecdsa_sign_derived (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv, const char *label, const char *context, const struct GNUNET_CRYPTO_SignaturePurpose *purpose, struct GNUNET_CRYPTO_EcdsaSignature *sig)
	This is a signature function for ECDSA which takes a private key, derives/blinds it and signs the message.
struct GNUNET_CRYPTO_EcdsaPrivateKey *	GNUNET_CRYPTO_ecdsa_private_key_derive (const struct GNUNET_CRYPTO_EcdsaPrivateKey *priv, const char *label, const char *context)
	Derive a private key from a given private key and a label.
void	GNUNET_CRYPTO_ecdsa_public_key_derive (const struct GNUNET_CRYPTO_EcdsaPublicKey *pub, const char *label, const char *context, struct GNUNET_CRYPTO_EcdsaPublicKey *result)
	Derive a public key from a given public key and a label.
void	GNUNET_CRYPTO_eddsa_private_key_derive (const struct GNUNET_CRYPTO_EddsaPrivateKey *priv, const char *label, const char *context, struct GNUNET_CRYPTO_EddsaPrivateScalar *result)
	Derive a private scalar from a given private key and a label.
void	GNUNET_CRYPTO_eddsa_public_key_derive (const struct GNUNET_CRYPTO_EddsaPublicKey *pub, const char *label, const char *context, struct GNUNET_CRYPTO_EddsaPublicKey *result)
	Derive a public key from a given public key and a label.
void	GNUNET_CRYPTO_eddsa_key_get_public_from_scalar (const struct GNUNET_CRYPTO_EddsaPrivateScalar *priv, struct GNUNET_CRYPTO_EddsaPublicKey *pkey)
	Extract the public key of the given private scalar.

Detailed Description

public key cryptography (ECC) for GNS records (LSD0001)

Author

Christian Grothoff

Florian Dold

Martin Schanzenbach

Definition in file crypto_ecc_gnsrecord.c.

Macro Definition Documentation

CURVE

#define CURVE   "Ed25519"

Definition at line 34 of file crypto_ecc_gnsrecord.c.

Function Documentation

derive_h()

static void derive_h ( const void *  pub, size_t  pubsize, const char *  label, const char *  context, struct GNUNET_HashCode *  hc  )

static

Derive the 'h' value for key derivation, where 'h = H(l,P)'.

Parameters

pub	public key for deriviation
pubsize	the size of the public key
label	label for deriviation
context	additional context to use for HKDF of 'h'; typically the name of the subsystem/application
hc	where to write the result

NOTE: While (H)KDF calls this value a salt it is not necessary for it to be a random value. It is more common to use a NULL value here (https://www.rfc-editor.org/rfc/rfc8446#section-7.1) But it is safe either way (See RFC 5869)

Definition at line 48 of file crypto_ecc_gnsrecord.c.

{
  static const char *const salt = "key-derivation";
 
  GNUNET_CRYPTO_hkdf_gnunet (
    hc,
    sizeof(*hc),
    salt,
    strlen (salt),
    pub,
    pubsize,
    GNUNET_CRYPTO_kdf_arg_string (label),
    GNUNET_CRYPTO_kdf_arg_string (context));
}

References context, GNUNET_CRYPTO_hkdf_gnunet, GNUNET_CRYPTO_kdf_arg_string, pub, and salt.

Referenced by GNUNET_CRYPTO_ecdsa_private_key_derive(), GNUNET_CRYPTO_ecdsa_public_key_derive(), GNUNET_CRYPTO_eddsa_private_key_derive(), and GNUNET_CRYPTO_eddsa_public_key_derive().

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