PALISADE Lattice Crypto Library: lbcrypto::LPAlgorithmMultipartyBFV< Element

Concrete class for the FHE Multiparty algorithms on BFV. A version of this multiparty scheme built on the BGV scheme is seen here: More...

#include <bfv.h>

Inheritance diagram for lbcrypto::LPAlgorithmMultipartyBFV< Element >:

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Collaboration diagram for lbcrypto::LPAlgorithmMultipartyBFV< Element >:

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Public Member Functions
	LPAlgorithmMultipartyBFV ()

LPKeyPair< Element >	MultipartyKeyGen (CryptoContext< Element > cc, const LPPublicKey< Element > pk1, bool makeSparse=false, bool fresh=false) override

LPKeyPair< Element >	MultipartyKeyGen (CryptoContext< Element > cc, const vector< LPPrivateKey< Element >> &secretKeys, bool makeSparse=false) override

Ciphertext< Element >	MultipartyDecryptMain (const LPPrivateKey< Element > privateKey, ConstCiphertext< Element > ciphertext) const override

Ciphertext< Element >	MultipartyDecryptLead (const LPPrivateKey< Element > privateKey, ConstCiphertext< Element > ciphertext) const override

DecryptResult	MultipartyDecryptFusion (const vector< Ciphertext< Element >> &ciphertextVec, NativePoly *plaintext) const override

LPEvalKey< Element >	MultiKeySwitchGen (const LPPrivateKey< Element > originalPrivateKey, const LPPrivateKey< Element > newPrivateKey, const LPEvalKey< Element > ek) const override

shared_ptr< std::map< usint, LPEvalKey< Element > > >	MultiEvalAutomorphismKeyGen (const LPPrivateKey< Element > privateKey, const shared_ptr< std::map< usint, LPEvalKey< Element >>> eAuto, const std::vector< usint > &indexList) const override

shared_ptr< std::map< usint, LPEvalKey< Element > > >	MultiEvalSumKeyGen (const LPPrivateKey< Element > privateKey, const shared_ptr< std::map< usint, LPEvalKey< Element >>> eSum) const override

LPEvalKey< Element >	MultiAddEvalKeys (LPEvalKey< Element > evalKey1, LPEvalKey< Element > evalKey2) const override

LPEvalKey< Element >	MultiMultEvalKey (LPEvalKey< Element > evalKey, LPPrivateKey< Element > sk) const override

template<class Archive >
void	save (Archive &ar) const

template<class Archive >
void	load (Archive &ar)

std::string	SerializedObjectName () const

Public Member Functions inherited from lbcrypto::LPMultipartyAlgorithm< Element >
virtual DecryptResult	MultipartyDecryptFusion (const vector< Ciphertext< Element >> &ciphertextVec, Poly *plaintext) const

virtual LPPublicKey< Element >	MultiAddPubKeys (LPPublicKey< Element > pubKey1, LPPublicKey< Element > pubKey2) const

virtual shared_ptr< std::map< usint, LPEvalKey< Element > > >	MultiAddEvalSumKeys (const shared_ptr< std::map< usint, LPEvalKey< Element >>> es1, const shared_ptr< std::map< usint, LPEvalKey< Element >>> es2) const

virtual shared_ptr< std::map< usint, LPEvalKey< Element > > >	MultiAddEvalAutomorphismKeys (const shared_ptr< std::map< usint, LPEvalKey< Element >>> es1, const shared_ptr< std::map< usint, LPEvalKey< Element >>> es2) const

virtual LPEvalKey< Element >	MultiAddEvalMultKeys (LPEvalKey< Element > evalKey1, LPEvalKey< Element > evalKey2) const

virtual shared_ptr< std::map< usint, LPEvalKey< Element > > >	MultiEvalAtIndexKeyGen (const LPPrivateKey< Element > secretShare, const shared_ptr< std::map< usint, LPEvalKey< Element >>> eAuto, const std::vector< int32_t > &indexList) const

template<class Archive >
void	save (Archive &ar, std::uint32_t const version) const

template<class Archive >
void	load (Archive &ar, std::uint32_t const version)

std::string	SerializedObjectName () const

Detailed Description

template<class Element>
class lbcrypto::LPAlgorithmMultipartyBFV< Element >

Concrete class for the FHE Multiparty algorithms on BFV. A version of this multiparty scheme built on the BGV scheme is seen here:

Asharov G., Jain A., López-Alt A., Tromer E., Vaikuntanathan V., Wichs D. (2012) Multiparty Computation with Low Communication, Computation and Interaction via Threshold FHE. In: Pointcheval D., Johansson T. (eds) Advances in Cryptology – EUROCRYPT 2012. EUROCRYPT 2012. Lecture Notes in Computer Science, vol 7237. Springer, Berlin, Heidelberg

During offline key generation, this multiparty scheme relies on the clients coordinating their public key generation. To do this, a single client generates a public-secret key pair. This public key is shared with other keys which use an element in the public key to generate their own public keys. The clients generate a shared key pair using a scheme-specific approach, then generate re-encryption keys. Re-encryption keys are uploaded to the server. Clients encrypt data with their public keys and send the encrypted data server. The data is re-encrypted. Computations are then run on the data. The result is sent to each of the clients. One client runs a "Leader" multiparty decryption operation with its own secret key. All other clients run a regular "Main" multiparty decryption with their own secret key. The resulting partially decrypted ciphertext are then fully decrypted with the decryption fusion algorithms.

Template Parameters

Element a ring element.

Constructor & Destructor Documentation

◆ LPAlgorithmMultipartyBFV()

template<class Element >

lbcrypto::LPAlgorithmMultipartyBFV< Element >::LPAlgorithmMultipartyBFV ( )

inline

Default constructor

Member Function Documentation

◆ MultiAddEvalKeys()

template<class Element >

LPEvalKey< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultiAddEvalKeys	(	LPEvalKey< Element >	evalKey1,
		LPEvalKey< Element >	evalKey2
	)		const

overridevirtual

Threshold FHE: Adds two prior evaluation keys

Parameters

evalKey1	first evaluation key.
evalKey2	second evaluation key.

Returns: the new joined key.

Reimplemented from lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultiEvalAutomorphismKeyGen()

template<class Element >

shared_ptr< std::map< usint, LPEvalKey< Element > > > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultiEvalAutomorphismKeyGen	(	const LPPrivateKey< Element >	privateKey,
		const shared_ptr< std::map< usint, LPEvalKey< Element >>>	eAuto,
		const std::vector< usint > &	indexList
	)		const

overridevirtual

Threshold FHE: Generates joined automorphism keys from the current secret share and prior joined automorphism keys

Parameters

privateKey	secret key share.
eAuto	a dictionary with prior joined automorphism keys.
&indexList	a vector of automorphism indices.

Returns: a dictionary with new joined automorphism keys.

Reimplemented from lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultiEvalSumKeyGen()

template<class Element >

shared_ptr< std::map< usint, LPEvalKey< Element > > > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultiEvalSumKeyGen	(	const LPPrivateKey< Element >	privateKey,
		const shared_ptr< std::map< usint, LPEvalKey< Element >>>	eSum
	)		const

overridevirtual

Threshold FHE: Generates joined summation evaluation keys from the current secret share and prior joined summation keys

Parameters

privateKey	secret key share.
eSum	a dictionary with prior joined summation keys.

Returns: new joined summation keys.

Reimplemented from lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultiKeySwitchGen()

template<class Element >

LPEvalKey< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultiKeySwitchGen	(	const LPPrivateKey< Element >	originalPrivateKey,
		const LPPrivateKey< Element >	newPrivateKey,
		const LPEvalKey< Element >	ek
	)		const

overridevirtual

Threshold FHE: Generates a joined evaluation key from the current secret share and a prior joined evaluation key

Parameters

originalPrivateKey	secret key transformed from.
newPrivateKey	secret key transformed to.
ek	the prior joined evaluation key.

Returns: the new joined evaluation key.

Reimplemented from lbcrypto::LPMultipartyAlgorithm< Element >.

Reimplemented in lbcrypto::LPAlgorithmMultipartyBFVrnsB< Element >, and lbcrypto::LPAlgorithmMultipartyBFVrns< Element >.

◆ MultiMultEvalKey()

template<class Element >

LPEvalKey< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultiMultEvalKey	(	LPEvalKey< Element >	evalKey,
		LPPrivateKey< Element >	sk
	)		const

overridevirtual

Threshold FHE: Generates a partial evaluation key for homomorphic multiplication based on the current secret share and an existing partial evaluation key

Parameters

evalKey	prior evaluation key.
sk	current secret share.

Returns: the new joined key.

Reimplemented from lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultipartyDecryptFusion()

template<class Element >

DecryptResult lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultipartyDecryptFusion	(	const vector< Ciphertext< Element >> &	ciphertextVec,
		NativePoly *	plaintext
	)		const

overridevirtual

Threshold FHE: Method for combining the partially decrypted ciphertexts and getting the final decryption in the clear as a NativePoly.

Parameters

&ciphertextVec	vector of "partial" decryptions.
*plaintext	the plaintext output as a NativePoly.

Returns: the decoding result.

Implements lbcrypto::LPMultipartyAlgorithm< Element >.

Reimplemented in lbcrypto::LPAlgorithmMultipartyBFVrnsB< Element >, and lbcrypto::LPAlgorithmMultipartyBFVrns< Element >.

◆ MultipartyDecryptLead()

template<class Element >

Ciphertext< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultipartyDecryptLead	(	const LPPrivateKey< Element >	privateKey,
		ConstCiphertext< Element >	ciphertext
	)		const

overridevirtual

Threshold FHE: Method for decryption operation run by the lead decryption client.

Parameters

privateKey	secret key share used for decryption.
ciphertext	ciphertext id decrypted.

Implements lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultipartyDecryptMain()

template<class Element >

Ciphertext< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultipartyDecryptMain	(	const LPPrivateKey< Element >	privateKey,
		ConstCiphertext< Element >	ciphertext
	)		const

overridevirtual

Threshold FHE: "Partial" decryption computed by all parties except for the lead one.

Parameters

privateKey	secret key share used for decryption.
ciphertext	ciphertext that is being decrypted.

Implements lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultipartyKeyGen() [1/2]

template<class Element >

LPKeyPair< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultipartyKeyGen	(	CryptoContext< Element >	cc,
		const LPPublicKey< Element >	pk1,
		bool	makeSparse = `false`,
		bool	fresh = `false`
	)

overridevirtual

Threshold FHE: Generation of a public key derived from a previous joined public key (for prior secret shares) and the secret key share of the current party.

Parameters

cc	cryptocontext for the keys to be generated.
pk1	joined public key from prior parties.
makeSparse	set to true if ring reduce by a factor of 2 is to be used. NOT SUPPORTED BY ANY SCHEME ANYMORE.
fresh	set to true if proxy re-encryption is used in the multi-party protocol or star topology is used

Returns: key pair including the secret share for the current party and joined public key

Implements lbcrypto::LPMultipartyAlgorithm< Element >.

◆ MultipartyKeyGen() [2/2]

template<class Element >

LPKeyPair< Element > lbcrypto::LPAlgorithmMultipartyBFV< Element >::MultipartyKeyGen	(	CryptoContext< Element >	cc,
		const vector< LPPrivateKey< Element >> &	secretKeys,
		bool	makeSparse = `false`
	)

overridevirtual

Threshold FHE: Generates a public key from a vector of secret shares. ONLY FOR DEBUGGIN PURPOSES. SHOULD NOT BE USED IN PRODUCTION.

Parameters

cc	cryptocontext for the keys to be generated.
secretkeys	secrete key sahres.
makeSparse	set to true if ring reduce by a factor of 2 is to be used. NOT SUPPORTED BY ANY SCHEME ANYMORE.

Returns: key pair including the private for the current party and joined public key

Implements lbcrypto::LPMultipartyAlgorithm< Element >.

The documentation for this class was generated from the following files:

src/pke/include/scheme/bfv/bfv.h
src/pke/lib/scheme/bfv/bfv.cpp

Public Member Functions

Detailed Description

template<class Element> class lbcrypto::LPAlgorithmMultipartyBFV< Element >

Constructor & Destructor Documentation

◆ LPAlgorithmMultipartyBFV()

Member Function Documentation

◆ MultiAddEvalKeys()

◆ MultiEvalAutomorphismKeyGen()

◆ MultiEvalSumKeyGen()

◆ MultiKeySwitchGen()

◆ MultiMultEvalKey()

◆ MultipartyDecryptFusion()

◆ MultipartyDecryptLead()

◆ MultipartyDecryptMain()

◆ MultipartyKeyGen() [1/2]

◆ MultipartyKeyGen() [2/2]

template<class Element>
class lbcrypto::LPAlgorithmMultipartyBFV< Element >