lwe_fs.h File Reference

LWE scheme. More...

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Data Structures
struct	cfe_lwe_fs

Typedefs
typedef struct cfe_lwe_fs	cfe_lwe_fs

Functions
cfe_error	cfe_lwe_fs_init (cfe_lwe_fs *s, size_t l, size_t n, mpz_t bound_x, mpz_t bound_y)
void	cfe_lwe_fs_sec_key_init (cfe_mat *SK, cfe_lwe_fs *s)
void	cfe_lwe_fs_generate_sec_key (cfe_mat *SK, cfe_lwe_fs *s)
void	cfe_lwe_fs_pub_key_init (cfe_mat *PK, cfe_lwe_fs *s)
cfe_error	cfe_lwe_fs_generate_pub_key (cfe_mat *PK, cfe_lwe_fs *s, cfe_mat *SK)
void	cfe_lwe_fs_fe_key_init (cfe_vec *z_y, cfe_lwe_fs *s)
cfe_error	cfe_lwe_fs_derive_fe_key (cfe_vec *z_y, cfe_lwe_fs *s, cfe_vec *y, cfe_mat *SK)
void	cfe_lwe_fs_ciphertext_init (cfe_vec *ct, cfe_lwe_fs *s)
cfe_error	cfe_lwe_fs_encrypt (cfe_vec *ct, cfe_lwe_fs *s, cfe_vec *x, cfe_mat *PK)
cfe_error	cfe_lwe_fs_decrypt (mpz_t res, cfe_lwe_fs *s, cfe_vec *ct, cfe_vec *z_y, cfe_vec *y)
void	cfe_lwe_fs_free (cfe_lwe_fs *s)

Detailed Description

LWE scheme.

Typedef Documentation

cfe_lwe_fs

typedef struct cfe_lwe_fs cfe_lwe_fs

lwe_fs represents common properties of the scheme.

Function Documentation

cfe_lwe_fs_init()

cfe_error cfe_lwe_fs_init	(	cfe_lwe_fs *	s,
		size_t	l,
		size_t	n,
		mpz_t	bound_x,
		mpz_t	bound_y
	)

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_x	The bound by which coordinates of the encrypted vectors are bounded
bound_y	The bound by which coordinates of the inner product vectors are bounded

Returns

Error code

cfe_lwe_fs_sec_key_init()

void cfe_lwe_fs_sec_key_init	(	cfe_mat *	SK,
		cfe_lwe_fs *	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_lwe_fs struct)

cfe_lwe_fs_generate_sec_key()

void cfe_lwe_fs_generate_sec_key	(	cfe_mat *	SK,
		cfe_lwe_fs *	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_lwe_fs struct)

cfe_lwe_fs_pub_key_init()

void cfe_lwe_fs_pub_key_init	(	cfe_mat *	PK,
		cfe_lwe_fs *	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_lwe_fs struct)

cfe_lwe_fs_generate_pub_key()

cfe_error cfe_lwe_fs_generate_pub_key	(	cfe_mat *	PK,
		cfe_lwe_fs *	s,
		cfe_mat *	SK
	)

Generates a public key for the scheme.

Parameters

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

Returns

Error code

cfe_lwe_fs_fe_key_init()

void cfe_lwe_fs_fe_key_init	(	cfe_vec *	z_y,
		cfe_lwe_fs *	s
	)

Initializes the vector which represents the functional encryption key.

Parameters

z_y	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_lwe_fs struct)

cfe_lwe_fs_derive_fe_key()

cfe_error cfe_lwe_fs_derive_fe_key	(	cfe_vec *	z_y,
		cfe_lwe_fs *	s,
		cfe_vec *	y,
		cfe_mat *	SK
	)

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

Parameters

z_y	A pointer to an initialized functional encryption key, which will be stored here
s	A pointer to an instance of the scheme (initialized cfe_lwe_fs struct)
y	A pointer to the input vector
SK	A pointer to the master secret key

Returns

Error code

cfe_lwe_fs_ciphertext_init()

void cfe_lwe_fs_ciphertext_init	(	cfe_vec *	ct,
		cfe_lwe_fs *	s
	)

Initializes the vector which represents the ciphertext.

Parameters

ct	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_lwe_fs struct)

cfe_lwe_fs_encrypt()

cfe_error cfe_lwe_fs_encrypt	(	cfe_vec *	ct,
		cfe_lwe_fs *	s,
		cfe_vec *	x,
		cfe_mat *	PK
	)

Encrypts input vector x with the provided master public key.

Parameters

ct	A pointer to a vector (the resulting ciphertext will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_lwe_fs struct)
x	A pointer to the input vector
PK	A pointer to a matrix - master public key.

Returns

Error code

cfe_lwe_fs_decrypt()

cfe_error cfe_lwe_fs_decrypt	(	mpz_t	res,
		cfe_lwe_fs *	s,
		cfe_vec *	ct,
		cfe_vec *	z_y,
		cfe_vec *	y
	)

Accepts the encrypted vector, functional encryption key, and a plaintext vector. It returns the inner product. If decryption failed, an error is returned.

Parameters

res	The result of the decryption (the value will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_lwe_fs struct)
ct	A pointer to the vector representing the ciphertext
z_y	A pointer to the functional encryption key vector
y	A pointer to the inner product vector

Returns

Error code

cfe_lwe_fs_free()

void cfe_lwe_fs_free

(

cfe_lwe_fs *

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_lwe_fs struct)