dippe.h File Reference

This is a decentralized inner-product predicate encryption scheme by Yan Michalevsky and Marc Joye: "Decentralized Policy-Hiding Attribute-Based Encryption with Receiver Privacy". More...

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Data Structures
struct	cfe_dippe
struct	cfe_dippe_cipher
struct	cfe_dippe_pub_key
struct	cfe_dippe_sec_key
struct	cfe_dippe_user_sec_key

Typedefs
typedef struct cfe_dippe	cfe_dippe
typedef struct cfe_dippe_cipher	cfe_dippe_cipher
typedef struct cfe_dippe_pub_key	cfe_dippe_pub_key
typedef struct cfe_dippe_sec_key	cfe_dippe_sec_key
typedef struct cfe_dippe_user_sec_key	cfe_dippe_user_sec_key

Functions
void	cfe_dippe_init (cfe_dippe *dippe, size_t assump_size)
void	cfe_dippe_free (cfe_dippe *dippe)
cfe_error	cfe_dippe_attribute_vector_init (cfe_vec *av, size_t num_attrib, size_t pattern[], size_t pat_len)
cfe_error	cfe_dippe_exact_threshold_policy_vector_init (cfe_vec *pv, cfe_dippe *dippe, size_t num_attrib, size_t pattern[], size_t pat_len, size_t threshold)
cfe_error	cfe_dippe_conjunction_policy_vector_init (cfe_vec *pv, cfe_dippe *dippe, size_t num_attrib, size_t pattern[], size_t pat_len)
void	cfe_dippe_cipher_init (cfe_dippe_cipher *cipher, cfe_dippe *dippe, size_t pol_size)
void	cfe_dippe_cipher_free (cfe_dippe_cipher *cipher)
void	cfe_dippe_pub_key_init (cfe_dippe_pub_key *pk, cfe_dippe *dippe)
void	cfe_dippe_pub_key_free (cfe_dippe_pub_key *pk)
void	cfe_dippe_sec_key_init (cfe_dippe_sec_key *sk, cfe_dippe *dippe)
void	cfe_dippe_sec_key_free (cfe_dippe_sec_key *sk)
void	cfe_dippe_user_sec_key_init (cfe_dippe_user_sec_key *usk, cfe_dippe *dippe)
void	cfe_dippe_user_sec_key_free (cfe_dippe_user_sec_key *usk)
void	cfe_dippe_generate_master_keys (cfe_dippe_pub_key *pk, cfe_dippe_sec_key *sk, cfe_dippe *dippe)
cfe_error	cfe_dippe_encrypt (cfe_dippe_cipher *cipher, cfe_dippe *dippe, cfe_dippe_pub_key *pks[], size_t pks_len, cfe_vec *pv, FP12_BN254 *msg)
cfe_error	cfe_dippe_keygen (cfe_dippe_user_sec_key *usk, cfe_dippe *dippe, size_t usk_id, cfe_dippe_pub_key *pks[], size_t pks_len, cfe_dippe_sec_key *sk, cfe_vec *av, char *gid, size_t gid_len)
cfe_error	cfe_dippe_decrypt (FP12_BN254 *result, cfe_dippe *dippe, cfe_dippe_user_sec_key *usks, size_t usks_len, cfe_dippe_cipher *cipher, cfe_vec *av, char gid[], size_t gid_len)

Detailed Description

This is a decentralized inner-product predicate encryption scheme by Yan Michalevsky and Marc Joye: "Decentralized Policy-Hiding Attribute-Based Encryption with Receiver Privacy".

Typedef Documentation

cfe_dippe

typedef struct cfe_dippe cfe_dippe

cfe_dippe represents the DIPPE scheme

cfe_dippe_cipher

typedef struct cfe_dippe_cipher cfe_dippe_cipher

cfe_dippe_cipher represents the ciphertext of the DIPPE scheme

cfe_dippe_pub_key

typedef struct cfe_dippe_pub_key cfe_dippe_pub_key

cfe_dippe_pub_key represents the public key of the DIPPE scheme

cfe_dippe_sec_key

typedef struct cfe_dippe_sec_key cfe_dippe_sec_key

cfe_dippe_sec_key represents the secret key of the DIPPE scheme

cfe_dippe_user_sec_key

typedef struct cfe_dippe_user_sec_key cfe_dippe_user_sec_key

cfe_dippe_sec_key represents the user secret key of the DIPPE scheme

Function Documentation

cfe_dippe_init()

void cfe_dippe_init	(	cfe_dippe *	dippe,
		size_t	assump_size
	)

Initializes the DIPPE scheme and generates the global parameters

Parameters

dippe	A pointer to a cfe_dippe struct
assump_size	The size of the underlying assumption

cfe_dippe_free()

void cfe_dippe_free

(

cfe_dippe *

dippe

)

Clears the scheme and frees allocated memory

Parameters

dippe

A pointer to a cfe_dippe struct

cfe_dippe_attribute_vector_init()

cfe_error cfe_dippe_attribute_vector_init	(	cfe_vec *	av,
		size_t	num_attrib,
		size_t	pattern[],
		size_t	pat_len
	)

Prepares an attribute vector

Parameters

av	A pointer to a cfe_vec struct; Represents the resulting attribute vector
num_attrib	Number of attributes
pattern	Array of indices to define the attribute vector
pat_len	Length of the pattern array

Returns

Error code

cfe_dippe_exact_threshold_policy_vector_init()

cfe_error cfe_dippe_exact_threshold_policy_vector_init	(	cfe_vec *	pv,
		cfe_dippe *	dippe,
		size_t	num_attrib,
		size_t	pattern[],
		size_t	pat_len,
		size_t	threshold
	)

Prepares an exact threshold policy vector

Parameters

pv	A pointer to a cfe_vec struct; Represents the resulting policy vector
dippe	A pointer to a cfe_dippe struct
num_attrib	Number of attributes
pattern	Array of indices to define the policy vector
pat_len	Length of the pattern array
threshold	Threshold value

Returns

Error code

cfe_dippe_conjunction_policy_vector_init()

cfe_error cfe_dippe_conjunction_policy_vector_init	(	cfe_vec *	pv,
		cfe_dippe *	dippe,
		size_t	num_attrib,
		size_t	pattern[],
		size_t	pat_len
	)

Prepares a conjunction policy vector

Parameters

pv	A pointer to a cfe_vec struct; Represents the resulting policy vector
dippe	A pointer to a cfe_dippe struct
num_attrib	Number of attributes
pattern	Array of indices to define the policy vector
pat_len	Length of the pattern array

Returns

Error code

cfe_dippe_cipher_init()

void cfe_dippe_cipher_init	(	cfe_dippe_cipher *	cipher,
		cfe_dippe *	dippe,
		size_t	pol_size
	)

Prepares a cipher struct

Parameters

cipher	A pointer to a cfe_dippe_cipher struct
dippe	A pointer to a cfe_dippe struct
pol_size	Length of the cipher

cfe_dippe_cipher_free()

void cfe_dippe_cipher_free

(

cfe_dippe_cipher *

cipher

)

Clears the ciphertext and frees allocated memory

Parameters

cipher

A pointer to a cfe_dippe_cipher struct

cfe_dippe_pub_key_init()

void cfe_dippe_pub_key_init	(	cfe_dippe_pub_key *	pk,
		cfe_dippe *	dippe
	)

Prepares a public key struct

Parameters

pk	A pointer to a cfe_dippe_pub_key struct
dippe	A pointer to a cfe_dippe struct

cfe_dippe_pub_key_free()

void cfe_dippe_pub_key_free

(

cfe_dippe_pub_key *

pk

)

Clears the public key and frees allocated memory

Parameters

pk	A pointer to a cfe_dippe_pub_key struct

cfe_dippe_sec_key_init()

void cfe_dippe_sec_key_init	(	cfe_dippe_sec_key *	sk,
		cfe_dippe *	dippe
	)

Prepares a secret key struct

Parameters

sk	A pointer to a cfe_dippe_sec_key struct
dippe	A pointer to a cfe_dippe struct

cfe_dippe_sec_key_free()

void cfe_dippe_sec_key_free

(

cfe_dippe_sec_key *

sk

)

Clears the secret key and frees allocated memory

Parameters

sk	A pointer to a cfe_dippe_sec_key struct

cfe_dippe_user_sec_key_init()

void cfe_dippe_user_sec_key_init	(	cfe_dippe_user_sec_key *	usk,
		cfe_dippe *	dippe
	)

Prepares a user secret key struct

Parameters

usk	A pointer to a cfe_dippe_user_sec_key struct
dippe	A pointer to a cfe_dippe struct

cfe_dippe_user_sec_key_free()

void cfe_dippe_user_sec_key_free

(

cfe_dippe_user_sec_key *

usk

)

Clears the user secret key and frees allocated memory

Parameters

usk	A pointer to a cfe_dippe_user_sec_key struct

cfe_dippe_generate_master_keys()

void cfe_dippe_generate_master_keys	(	cfe_dippe_pub_key *	pk,
		cfe_dippe_sec_key *	sk,
		cfe_dippe *	dippe
	)

Initializes an authority and generates its public and private key

Parameters

pk	A pointer to a cfe_dippe_pub_key struct; Represents the public key that is about to be populated
sk	A pointer to a cfe_dippe_sec_key struct; Represents the secret key that is about to be populated
dippe	A pointer to a cfe_dippe struct

cfe_dippe_encrypt()

cfe_error cfe_dippe_encrypt	(	cfe_dippe_cipher *	cipher,
		cfe_dippe *	dippe,
		cfe_dippe_pub_key *	pks[],
		size_t	pks_len,
		cfe_vec *	pv,
		FP12_BN254 *	msg
	)

Encrypts a given message under the provided policy

Parameters

cipher	A pointer to a cfe_dippe_cipher struct; Represents the ciphertext that is about to be populated
dippe	A pointer to a cfe_dippe struct
pks	An array containing references to cfe_dippe_pub_key structs;
pks_len	Length of the public key array
pv	A reference to a cfe_vec struct; Represents the policy under which the message will be encrypted
msg	A reference to a FP12_BN254 struct; Represents the message that is about to be encrypted

Returns

Error code

cfe_dippe_keygen()

cfe_error cfe_dippe_keygen	(	cfe_dippe_user_sec_key *	usk,
		cfe_dippe *	dippe,
		size_t	usk_id,
		cfe_dippe_pub_key *	pks[],
		size_t	pks_len,
		cfe_dippe_sec_key *	sk,
		cfe_vec *	av,
		char *	gid,
		size_t	gid_len
	)

Used with an authority's secret key to create a new user secret key for a given attribute vector

Parameters

usk	A pointer to a cfe_dippe_user_sec_key struct; Represents the user secret key that is about to be populated
dippe	A pointer to a cfe_dippe struct
usk_id	Index of the given attribute vector for which a user secret key will be created
pks	An array containing references to cfe_dippe_pub_key structs
pks_len	Length of the public key array
sk	Secret key
av	A pointer to a cfe_vec struct; Represents the attribute vector
gid	String that represents a unique user; Required for collusion prevention
gid_len	Length of gid to prevent non NULL terminated strings

Returns

Error code

cfe_dippe_decrypt()

cfe_error cfe_dippe_decrypt	(	FP12_BN254 *	result,
		cfe_dippe *	dippe,
		cfe_dippe_user_sec_key *	usks,
		size_t	usks_len,
		cfe_dippe_cipher *	cipher,
		cfe_vec *	av,
		char	gid[],
		size_t	gid_len
	)

Restores the underlying message of a given ciphertext

Parameters

result	A pointer to a FP12_BN254 struct; Represents the resulting message
dippe	A pointer to a cfe_dippe struct
usks	An array containing cfe_dippe_user_sec_key structs; Represents the set of user secretes key used for decryption
usks_len	Length of the user secret key array
cipher	A pointer to a cfe_dippe_cipher struct; Represents the ciphertext that is about to be decrypted
av	A pointer to a cfe_vec struct; Represents the attribute vector
gid	String that represents a unique user; Required for collusion prevention
gid_len	Length of gid to prevent non NULL terminated strings