qcmdpc.h File Reference

#include <bitpunch/config.h>
#include <bitpunch/code/codectx.h>
#include <bitpunch/math/gf2.h>
#include <bitpunch/debugio.h>

Go to the source code of this file.

Macros
#define	BPU_QCMDPC_PARAM_MAX_ITER   10
	maximum count of iterations in decoding More...
#define	BPU_QCMDPC_PARAM_DELTA   5
	starting param delta (threshold) for decode1 algorithm More...
#define	BPU_QCMDPC_PARAM_DELTA_B   0
	threshold for decode2 More...
#define	BPU_QCMDPC_MAX_B_VALUES   5
	count of precalculated values for decode2 algorithm More...

Functions
int	BPU_mecsQcmdpcEncode (BPU_T_GF2_Vector *out, const BPU_T_GF2_Vector *in, const struct _BPU_T_Code_Ctx *ctx)
int	BPU_mecsQcmdpcDecrypt (BPU_T_GF2_Vector *out, const BPU_T_GF2_Vector *in, const struct _BPU_T_Code_Ctx *ctx)
int	BPU_mecsQcmdpcDecode1 (BPU_T_GF2_Vector *error_vec, const BPU_T_GF2_Vector *cipher_text, int delta, const struct _BPU_T_Code_Ctx *ctx)
int	BPU_mecsQcmdpcDecode2 (BPU_T_GF2_Vector *error_vec, const BPU_T_GF2_Vector *cipher_text, const struct _BPU_T_Code_Ctx *ctx)
void	BPU_mecsQcmdpcCalcSyndrom (BPU_T_GF2_Vector *syndrom, const BPU_T_GF2_Vector *cipher_text, const struct _BPU_T_Code_Ctx *ctx)
int	BPU_mecsQcmdpcTestGHmatrices (const BPU_T_GF2_QC_Matrix *G, const BPU_T_GF2_Sparse_Qc_Matrix *H)
int	BPU_mecsQcmdpcGenKeys (BPU_T_Code_Ctx *ctx)

Macro Definition Documentation

#define BPU_QCMDPC_MAX_B_VALUES   5

count of precalculated values for decode2 algorithm

Definition at line 40 of file qcmdpc.h.

#define BPU_QCMDPC_PARAM_DELTA   5

starting param delta (threshold) for decode1 algorithm

Definition at line 36 of file qcmdpc.h.

#define BPU_QCMDPC_PARAM_DELTA_B   0

threshold for decode2

Definition at line 39 of file qcmdpc.h.

#define BPU_QCMDPC_PARAM_MAX_ITER   10

maximum count of iterations in decoding

Definition at line 33 of file qcmdpc.h.

Function Documentation

void BPU_mecsQcmdpcCalcSyndrom	(	BPU_T_GF2_Vector *	syndrom,
		const BPU_T_GF2_Vector *	cipher_text,
		const struct _BPU_T_Code_Ctx *	ctx
	)

Calc syndrom of cipher_text.

Parameters

syndrom	output computed syndrom of cipher text
cipher_text	cipher text
ctx	QC-MDPC McEliece context

Definition at line 231 of file qcmdpc.c.

int BPU_mecsQcmdpcDecode1	(	BPU_T_GF2_Vector *	error_vec,
		const BPU_T_GF2_Vector *	cipher_text,
		int	delta,
		const struct _BPU_T_Code_Ctx *	ctx
	)

Decoding algorithm 1 for QC-MDPC codes capable of correct param_t errors. It has non-zero probability of DECODING FAUILURE RATE (=<0.00000%). Slower than algorithm 2. Better DFR than algorithm 2. Can be parametrized by param_max_iter, param_delta (threshold tolerance value).

Parameters

error_vec	output error vector
cipher_text	input cipher text
delta	param delta (threshold tolerance parameter)
ctx	QC-MDPC McEliece context

Returns

0 if OK, else error

Definition at line 110 of file qcmdpc.c.

int BPU_mecsQcmdpcDecode2	(	BPU_T_GF2_Vector *	error_vec,
		const BPU_T_GF2_Vector *	cipher_text,
		const struct _BPU_T_Code_Ctx *	ctx
	)

Decoding algorithm 2 for QC-MDPC codes capable of correct param_t errors. It has non-zero probability of DECODING FAUILURE RATE (=<0.00009%). Faster than algorithm 1. Worse DFR than algorithm 1. Can be parametrized by param_max_iter, param_delta_B (precomputed threshold values).

Parameters

error_vec	output error vector
cipher_text	input cipher text
ctx	QC-MDPC McEliece context

Returns

0 if OK, else error

Definition at line 175 of file qcmdpc.c.

int BPU_mecsQcmdpcDecrypt	(	BPU_T_GF2_Vector *	out,
		const BPU_T_GF2_Vector *	in,
		const struct _BPU_T_Code_Ctx *	ctx
	)

McEliece QC-MDPC decrypt

Parameters

out	message
in	cipher text
ctx	QC-MDPC McEliece context

Returns

0 if OK, else error

Definition at line 65 of file qcmdpc.c.

int BPU_mecsQcmdpcEncode	(	BPU_T_GF2_Vector *	out,
		const BPU_T_GF2_Vector *	in,
		const struct _BPU_T_Code_Ctx *	ctx
	)

McEliece QC-MDPC encode

Parameters

out	cipher text
in	message
ctx	QC-MDPC McEliece context

Returns

0 if OK, else error

Definition at line 23 of file qcmdpc.c.

int BPU_mecsQcmdpcGenKeys

(

BPU_T_Code_Ctx *

ctx

)

Generate key pair of QC-MDPC code for McEliece cryptosystem. Generator matrix G is not sparse. Its public key. Parity-check matrix H is in sparse form. Its private key. Params of code are set as global constants in crypto.h header file.

Parameters

ctx	QC-MDPC McEliece context

Returns

0 if OK, else error

Definition at line 247 of file qcmdpc.c.

int BPU_mecsQcmdpcTestGHmatrices	(	const BPU_T_GF2_QC_Matrix *	G,
		const BPU_T_GF2_Sparse_Qc_Matrix *	H
	)

Test if generated matrices G x H^T = 0

Parameters

G	generator matrix of code
H	parity-check matrix of code

Returns

0 if OK, 1 if error

Definition at line 413 of file qcmdpc.c.