ring_lwe.h File Reference

LWE scheme. More...

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Data Structures
struct	cfe_ring_lwe

Typedefs
typedef struct cfe_ring_lwe	cfe_ring_lwe

Functions
cfe_error	cfe_ring_lwe_init (cfe_ring_lwe *s, size_t l, size_t n, mpz_t bound, mpz_t p, mpz_t q, mpf_t sigma)
void	cfe_ring_lwe_sec_key_init (cfe_mat *SK, cfe_ring_lwe *s)
void	cfe_ring_lwe_generate_sec_key (cfe_mat *SK, cfe_ring_lwe *s)
void	cfe_ring_lwe_pub_key_init (cfe_mat *PK, cfe_ring_lwe *s)
cfe_error	cfe_ring_lwe_generate_pub_key (cfe_mat *PK, cfe_ring_lwe *s, cfe_mat *SK)
void	cfe_ring_lwe_fe_key_init (cfe_vec *sk_y, cfe_ring_lwe *s)
cfe_error	cfe_ring_lwe_derive_fe_key (cfe_vec *sk_y, cfe_ring_lwe *s, cfe_mat *SK, cfe_vec *y)
void	cfe_ring_lwe_ciphertext_init (cfe_mat *CT, cfe_ring_lwe *s)
cfe_error	cfe_ring_lwe_encrypt (cfe_mat *CT, cfe_ring_lwe *s, cfe_mat *x, cfe_mat *PK)
void	cfe_ring_lwe_decrypted_init (cfe_vec *res, cfe_ring_lwe *s)
cfe_error	cfe_ring_lwe_decrypt (cfe_vec *res, cfe_ring_lwe *s, cfe_mat *ct, cfe_vec *sk_y, cfe_vec *y)
void	cfe_ring_lwe_free (cfe_ring_lwe *s)

Detailed Description

LWE scheme.

Typedef Documentation

cfe_ring_lwe

typedef struct cfe_ring_lwe cfe_ring_lwe

cfe_ring_lwe represents common properties of the scheme.

Function Documentation

cfe_ring_lwe_init()

cfe_error cfe_ring_lwe_init	(	cfe_ring_lwe *	s,
		size_t	l,
		size_t	n,
		mpz_t	bound,
		mpz_t	p,
		mpz_t	q,
		mpf_t	sigma
	)

Configures a new instance of the scheme.

Parameters

s	A pointer to an uninitialized struct representing the scheme
l	The length of input vectors
n	The security parameter of the scheme
bound	The bound by which coordinates of the input vectors are bounded
p	Modulus for the inner product
q	Modulus for ciphertext and keys vectors are bounded
sigma	Standard deviation

Returns

Error code

cfe_ring_lwe_sec_key_init()

void cfe_ring_lwe_sec_key_init	(	cfe_mat *	SK,
		cfe_ring_lwe *	s
	)

Initializes the matrix which represents the secret key.

Parameters

SK	A pointer to an uninitialized matrix
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_generate_sec_key()

void cfe_ring_lwe_generate_sec_key	(	cfe_mat *	SK,
		cfe_ring_lwe *	s
	)

Generates a private secret key for the scheme.

Parameters

SK	A pointer to a matrix (master secret key will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_pub_key_init()

void cfe_ring_lwe_pub_key_init	(	cfe_mat *	PK,
		cfe_ring_lwe *	s
	)

Initializes the matrix which represents the public key.

Parameters

PK	A pointer to an uninitialized matrix
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_generate_pub_key()

cfe_error cfe_ring_lwe_generate_pub_key	(	cfe_mat *	PK,
		cfe_ring_lwe *	s,
		cfe_mat *	SK
	)

Generates a public key for the scheme.

Parameters

PK	A pointer to a matrix (public key will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)
SK	A pointer to an initialized matrix representing the secret key.

Returns

Error code

cfe_ring_lwe_fe_key_init()

void cfe_ring_lwe_fe_key_init	(	cfe_vec *	sk_y,
		cfe_ring_lwe *	s
	)

Initializes the vector which represents the functional encryption key.

Parameters

sk_y	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_derive_fe_key()

cfe_error cfe_ring_lwe_derive_fe_key	(	cfe_vec *	sk_y,
		cfe_ring_lwe *	s,
		cfe_mat *	SK,
		cfe_vec *	y
	)

Takes master secret key and inner product vector, and returns the functional encryption key.

Parameters

sk_y	A pointer to a vector (the functional encryption key will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)
SK	A pointer to the master secret key
y	A pointer to the inner product vector

Returns

Error code

cfe_ring_lwe_ciphertext_init()

void cfe_ring_lwe_ciphertext_init	(	cfe_mat *	CT,
		cfe_ring_lwe *	s
	)

Initializes the matrix which represents the ciphertext.

Parameters

CT	A pointer to an uninitialized matrix
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_encrypt()

cfe_error cfe_ring_lwe_encrypt	(	cfe_mat *	CT,
		cfe_ring_lwe *	s,
		cfe_mat *	x,
		cfe_mat *	PK
	)

Encrypts input matrix x with the provided master public key.

Parameters

CT	A pointer to a matrix (the resulting ciphertext will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)
x	A pointer to the input matrix
PK	A pointer to the matrix representing the public key.

Returns

Error code

cfe_ring_lwe_decrypted_init()

void cfe_ring_lwe_decrypted_init	(	cfe_vec *	res,
		cfe_ring_lwe *	s
	)

Initialized the vector which represents the result of the decryption.

Parameters

res	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)

cfe_ring_lwe_decrypt()

cfe_error cfe_ring_lwe_decrypt	(	cfe_vec *	res,
		cfe_ring_lwe *	s,
		cfe_mat *	ct,
		cfe_vec *	sk_y,
		cfe_vec *	y
	)

Accepts the encrypted matrix X, functional encryption key, and an inner product vector y. It returns the product y^T * X. If decryption failed, an error is returned.

Parameters

res	A pointer to a vector (result of the decryption will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)
ct	A pointer to the ciphertext matrix
sk_y	The functional encryption key
y	A pointer to the inner product vector

Returns

Error code

cfe_ring_lwe_free()

void cfe_ring_lwe_free

(

cfe_ring_lwe *

s

)

Frees the memory occupied by the struct members. It does not free memory occupied by the struct itself.

Parameters

s	A pointer to an instance of the scheme (initialized cfe_ring_lwe struct)