paillier.h File Reference

Paillier scheme. More...

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Data Structures
struct	cfe_paillier

Typedefs
typedef struct cfe_paillier	cfe_paillier

Functions
cfe_error	cfe_paillier_init (cfe_paillier *s, size_t l, size_t lambda, size_t bit_len, mpz_t bound_x, mpz_t bound_y)
void	cfe_paillier_free (cfe_paillier *s)
void	cfe_paillier_copy (cfe_paillier *res, cfe_paillier *s)
void	cfe_paillier_master_keys_init (cfe_vec *msk, cfe_vec *mpk, cfe_paillier *s)
cfe_error	cfe_paillier_generate_master_keys (cfe_vec *msk, cfe_vec *mpk, cfe_paillier *s)
cfe_error	cfe_paillier_derive_fe_key (mpz_t fe_key, cfe_paillier *s, cfe_vec *msk, cfe_vec *y)
void	cfe_paillier_ciphertext_init (cfe_vec *ciphertext, cfe_paillier *s)
cfe_error	cfe_paillier_encrypt (cfe_vec *ciphertext, cfe_paillier *s, cfe_vec *x, cfe_vec *mpk)
cfe_error	cfe_paillier_decrypt (mpz_t res, cfe_paillier *s, cfe_vec *ciphertext, mpz_t key, cfe_vec *y)

Detailed Description

Paillier scheme.

Typedef Documentation

cfe_paillier

typedef struct cfe_paillier cfe_paillier

cfe_paillier represents common properties of the scheme.

Function Documentation

cfe_paillier_init()

cfe_error cfe_paillier_init	(	cfe_paillier *	s,
		size_t	l,
		size_t	lambda,
		size_t	bit_len,
		mpz_t	bound_x,
		mpz_t	bound_y
	)

Initializes a new instance of the scheme. It accepts the length of input vectors l, security parameter lambda, the bit length of prime numbers (giving security to the scheme, it should be such that factoring two primes with such a bit length takes at least 2^lambda operations), and boundX and boundY by which coordinates of input vectors and inner product vectors are bounded. It returns an error in the case the scheme could not be properly configured, or if the precondition boundX, boundY < (n / l)^(1/2) is not satisfied.

Parameters

s	A pointer to an uninitialized struct representing the scheme
l	The length of input vectors
lambda	The security parameter
bit_len	Number of bits for generating prime numbers
bound_x	The bound by which the coordinates of encrypted vectors are bounded
bound_y	The bound by which the coordinates of inner product vectors are bounded

Returns

Error code

cfe_paillier_free()

void cfe_paillier_free

(

cfe_paillier *

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_paillier struct)

cfe_paillier_copy()

void cfe_paillier_copy	(	cfe_paillier *	res,
		cfe_paillier *	s
	)

Reconstructs the scheme with the same configuration parameters from an already existing Paillier scheme instance.

Parameters

res	A pointer to an uninitialized paillier struct
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)

cfe_paillier_master_keys_init()

void cfe_paillier_master_keys_init	(	cfe_vec *	msk,
		cfe_vec *	mpk,
		cfe_paillier *	s
	)

Initializes the vectors which represent the master secret key and master public key.

Parameters

msk	A pointer to an uninitialized vector
mpk	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)

cfe_paillier_generate_master_keys()

cfe_error cfe_paillier_generate_master_keys	(	cfe_vec *	msk,
		cfe_vec *	mpk,
		cfe_paillier *	s
	)

Generates a master secret key and master public key for the scheme.

Parameters

msk	A pointer to a vector (master secret key will be stored here)
mpk	A pointer to a vector (master public key will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)

Returns

Error code

cfe_paillier_derive_fe_key()

cfe_error cfe_paillier_derive_fe_key	(	mpz_t	fe_key,
		cfe_paillier *	s,
		cfe_vec *	msk,
		cfe_vec *	y
	)

Takes master secret key and input vector y, and returns the functional encryption key. In case the key could not be derived, it returns an error.

Parameters

fe_key	The resulting functional encryption key (the value will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)
msk	A pointer to the master secret key
y	A pointer to the inner product vector

Returns

Error code

cfe_paillier_ciphertext_init()

void cfe_paillier_ciphertext_init	(	cfe_vec *	ciphertext,
		cfe_paillier *	s
	)

Initializes the vector which represents the ciphertext.

Parameters

ciphertext	A pointer to an uninitialized vector
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)

cfe_paillier_encrypt()

cfe_error cfe_paillier_encrypt	(	cfe_vec *	ciphertext,
		cfe_paillier *	s,
		cfe_vec *	x,
		cfe_vec *	mpk
	)

Encrypts input vector x with the provided master public key. It returns a ciphertext vector. If encryption failed, an error is returned.

Parameters

ciphertext	A pointer to a vector (the resulting ciphertext will be stored here)
s	A pointer to an instance of the scheme (initialized cfe_paillier struct)
x	A pointer to the input vector
mpk	A pointer to the master public key

Returns

Error code

cfe_paillier_decrypt()

cfe_error cfe_paillier_decrypt	(	mpz_t	res,
		cfe_paillier *	s,
		cfe_vec *	ciphertext,
		mpz_t	key,
		cfe_vec *	y
	)

Accepts the encrypted vector, functional encryption key, and a plaintext vector y. It returns the inner product of x and y. 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_paillier struct)
ciphertext	A pointer to the ciphertext vector
key	The functional encryption key
y	A pointer to the inner product vector

Returns

Error code