include/beecrypt/elgamal.h File Reference

ElGamal algorithm. More...

#include "beecrypt/mpbarrett.h"

Include dependency graph for elgamal.h:

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Functions
BEECRYPTAPI int	elgv1sign (const mpbarrett *p, const mpbarrett *n, const mpnumber *g, randomGeneratorContext *, const mpnumber *hm, const mpnumber *x, mpnumber *r, mpnumber *s)
	This function performs raw ElGamal signing, variant 1.
BEECRYPTAPI int	elgv3sign (const mpbarrett *p, const mpbarrett *n, const mpnumber *g, randomGeneratorContext *, const mpnumber *hm, const mpnumber *x, mpnumber *r, mpnumber *s)
	This function performs raw ElGamal signing, variant 3.
BEECRYPTAPI int	elgv1vrfy (const mpbarrett *p, const mpbarrett *n, const mpnumber *g, const mpnumber *hm, const mpnumber *y, const mpnumber *r, const mpnumber *s)
	This function performs raw ElGamal verification, variant 1.
BEECRYPTAPI int	elgv3vrfy (const mpbarrett *p, const mpbarrett *n, const mpnumber *g, const mpnumber *hm, const mpnumber *y, const mpnumber *r, const mpnumber *s)
	This function performs raw ElGamal verification, variant 3.

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Detailed Description

ElGamal algorithm.

For more information on this algorithm, see: "Handbook of Applied Cryptography", 11.5.2: "The ElGamal signature scheme", p. 454-459

Two of the signature variants in Note 11.70 are implemented.

Todo:

Implement ElGamal encryption and decryption.

Todo:

Explore the possibility of using simultaneous multiple exponentiation, as described in HAC, 14.87 (iii).

Author:

Bob Deblier <bob.deblier@telenet.be>

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Function Documentation

int elgv1sign	(	const mpbarrett *	p,
		const mpbarrett *	n,
		const mpnumber *	g,
		randomGeneratorContext *	rgc,
		const mpnumber *	hm,
		const mpnumber *	x,
		mpnumber *	r,
		mpnumber *	s
	)

This function performs raw ElGamal signing, variant 1.

Signing equations:

• 
• 

Parameters:

	p	The prime.
	n	The reducer mod (p-1).
	g	The generator.
	rgc	The pseudo-random generat
	hm	The hash to be signed.
	x	The private key value.
	r	The signature's r value.
	s	The signature's s value.

Return values:

	0	on success.
	-1	on failure.

int elgv1vrfy	(	const mpbarrett *	p,
		const mpbarrett *	n,
		const mpnumber *	g,
		const mpnumber *	hm,
		const mpnumber *	y,
		const mpnumber *	r,
		const mpnumber *	s
	)

This function performs raw ElGamal verification, variant 1.

Verifying equations:

• Check and
• 
• 
• Check

Parameters:

	p	The prime.
	n	The reducer mod (p-1).
	g	The generator.
	hm	The hash to be signed.
	y	The public key value.
	r	The signature's r value.
	s	The signature's s value.

Return values:

	1	on success.
	0	on failure.

int elgv3sign	(	const mpbarrett *	p,
		const mpbarrett *	n,
		const mpnumber *	g,
		randomGeneratorContext *	rgc,
		const mpnumber *	hm,
		const mpnumber *	x,
		mpnumber *	r,
		mpnumber *	s
	)

This function performs raw ElGamal signing, variant 3.

Signing equations:

• 
• 

Parameters:

	p	The prime.
	n	The reducer mod (p-1).
	g	The generator.
	rgc	The pseudo-random generat
	hm	The hash to be signed.
	x	The private key value.
	r	The signature's r value.
	s	The signature's s value.

Return values:

	0	on success.
	-1	on failure.

int elgv3vrfy	(	const mpbarrett *	p,
		const mpbarrett *	n,
		const mpnumber *	g,
		const mpnumber *	hm,
		const mpnumber *	y,
		const mpnumber *	r,
		const mpnumber *	s
	)

This function performs raw ElGamal verification, variant 3.

Verifying equations:

• Check and
• 
• 
• Check

Parameters:

	p	The prime.
	n	The reducer mod (p-1).
	g	The generator.
	hm	The hash to be signed.
	y	The public key value.
	r	The signature's r value.
	s	The signature's s value.

Return values:

	1	on success.
	0	on failure.