Elliptic curve cryptography over Galois prime field GF(p) curve. More...

#include <ecc.h>

Public Types
enum class	Type { std_p192r1 , std_p224r1 , std_p256r1 , std_p384r1 , std_p521r1 , std_p256sm2 }
	Standard field type. More...

Public Member Functions
	EccGfp (Type type=Type::std_p256r1)

void	reset (Type type)
	Reset the curve to a new standard type.

bool	valid () const

int	bit_width () const
	Elliptic curve ordinal bit width.

void	generate_key_pair (Bignum &priv_key, EccGfpPoint &pub_key)
	Generate a private and public key pair for this curve. More...

void	private_key (Bignum &)
	Generate a private key. More...

void	public_key (const Bignum &, EccGfpPoint &)
	Generate a public key corresponding to a private key. More...

void	generate_public_key (const Bignum &, EccGfpPoint &)
	Generate a public key from the private key.

Static Public Member Functions
static bool	valid (const EccGfp &)
	Verify the curve. More...

static bool	validate_key_pair (const Bignum &, const EccGfpPoint &)
	Validate a key pair. More...

static void	sign_ecdsa (const void *, int, const EccGfp &, const scc::crypto::Bignum &, scc::crypto::Bignum &, scc::crypto::Bignum &, scc::crypto::Bignum &)
	Sign a message using ECDSA. More...

static void	sign_ecdsa (const void *loc, int len, const EccGfp::Type &t, const scc::crypto::Bignum &rk, scc::crypto::Bignum &tk, scc::crypto::Bignum &x, scc::crypto::Bignum &y)

static bool	verify_ecdsa (const void *, int, const EccGfpPoint &, const scc::crypto::Bignum &, const scc::crypto::Bignum &)
	Verify a message using the ECDSA. More...

static void	dh_shared_secret (const scc::crypto::Bignum &, const EccGfpPoint &, scc::crypto::Bignum &)
	Calculate a shared secret using the Diffie-Hellman scheme. More...

Friends
class	EccGfpPoint

Detailed Description

Elliptic curve cryptography over Galois prime field GF(p) curve.

Uses standard fields only, does not allow custom parameters.

See https://www.secg.org/ for details on ec cryptography.

For X25519 and X448 (montgomery curves), see: https://tools.ietf.org/html/rfc7748

For security considerations, see: https://www.websecurity.digicert.com/content/dam/websitesecurity/digitalassets/desktop/pdfs/whitepaper/Elliptic_Curve_Cryptography_ECC_WP_en_us.pdf

Security level means the equivalent security strength to a symmetric key with the stated bit size. Use of algorithms with security below 128 bits is not recommended.

Definition at line 76 of file ecc.h.

Member Enumeration Documentation

◆ Type

enum scc::crypto::EccGfp::Type

strong

Standard field type.

Enumerator
std_p192r1	standard curve secp192r1 (96 bit security level)
std_p224r1	standard curve secp224r1 (112 bit security level)
std_p256r1	standard curve secp256r1 (128 bit security level)
std_p384r1	standard curve secp384r1 (192 bit security level)
std_p521r1	standard curve secp521r1 (256 bit security level)
std_p256sm2	standard curve secp256sm2

Definition at line 85 of file ecc.h.

Member Function Documentation

◆ dh_shared_secret()

static void scc::crypto::EccGfp::dh_shared_secret	(	const scc::crypto::Bignum &	,
		const EccGfpPoint &	,
		scc::crypto::Bignum &
	)

static

Calculate a shared secret using the Diffie-Hellman scheme.

Parameters

my_private	My private key.
other_public	Other public key.
shared_secret	Shared private key.

Given a private key and other parties public key on a curve, generate a shared secreet key (x coordinate on the curve), which will be the same for both parties.

◆ generate_key_pair()

void scc::crypto::EccGfp::generate_key_pair	(	Bignum &	priv_key,
		EccGfpPoint &	pub_key
	)

inline

Generate a private and public key pair for this curve.

Parameters

priv_key	Private key on the elliptic curve
pub_key	Public key point corresponding to the private key

Definition at line 117 of file ecc.h.

◆ private_key()

void scc::crypto::EccGfp::private_key ( Bignum & )

Generate a private key.

Parameters

priv_key Private key on the elliptic curve

◆ public_key()

void scc::crypto::EccGfp::public_key	(	const Bignum &	,
		EccGfpPoint &
	)

Generate a public key corresponding to a private key.

Parameters

priv_key	Private key on the elliptic curve.
pub_key	Public key point corresponding to the private key

◆ sign_ecdsa()

static void scc::crypto::EccGfp::sign_ecdsa	(	const void *	,
		int	,
		const EccGfp &	,
		const scc::crypto::Bignum &	,
		scc::crypto::Bignum &	,
		scc::crypto::Bignum &	,
		scc::crypto::Bignum &
	)

static

Sign a message using ECDSA.

A curve, temporary private and public key, and a regular private key should be provided.

The signature output is two coordinate points on the elliptic curve.

Generating a signature using ecdsa_secp256r1_sha256 (for example), is a two step process. First generate a hash of the data using sha256, then sign_ecdsa with the hash value.

Parameters

loc	Signing data buffer.
len	Signing data size. Must be > 0.
curve	Elliptical curve.
reg_private	Regular private key derived from the curve.
temp_private	Temporary (ephemeral) private key derived from the curve. Must be different than the regular key.
sig_x	Signature X coordinate output.
sig_y	Signature Y coordinate output.

◆ valid()

static bool scc::crypto::EccGfp::valid ( const EccGfp & )

static

Verify the curve.

Failure means the curve parameters are invalid or insecure.

◆ validate_key_pair()

static bool scc::crypto::EccGfp::validate_key_pair	(	const Bignum &	,
		const EccGfpPoint &
	)

static

Validate a key pair.

Both must be a key pair on the public key's elliptical curve.

Parameters

priv_key	Private key
pub_key	Public key

Public key must be valid on the elliptic curve.

◆ verify_ecdsa()

static bool scc::crypto::EccGfp::verify_ecdsa	(	const void *	,
		int	,
		const EccGfpPoint &	,
		const scc::crypto::Bignum &	,
		const scc::crypto::Bignum &
	)

static

Verify a message using the ECDSA.

Parameters

loc	Signing data buffer.
len	Signing data size. Must be > 0.
reg_public	Regular public key corresponding to the regular private key used to sign.
sig_x	Signature X coordinate.
sig_y	Signature Y coordinate.

Uses the curve associated with the point.

The documentation for this class was generated from the following file:

crypto/pub/crypto/ecc.h

Public Types

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ Type

Member Function Documentation

◆ dh_shared_secret()

◆ generate_key_pair()

◆ private_key()

◆ public_key()

◆ sign_ecdsa()

◆ valid()

◆ validate_key_pair()

◆ verify_ecdsa()