lbcrypto::LPCryptoParametersBFV< Element > Class Template Reference

This is the parameters class for the BFV encryption scheme. This scheme is also referred to as the FV scheme. More...

#include <bfv.h>

Inheritance diagram for lbcrypto::LPCryptoParametersBFV< Element >:

Collaboration diagram for lbcrypto::LPCryptoParametersBFV< Element >:

Public Member Functions
	LPCryptoParametersBFV ()
	LPCryptoParametersBFV (const LPCryptoParametersBFV &rhs)
	LPCryptoParametersBFV (shared_ptr< ParmType > params, const PlaintextModulus &plaintextModulus, float distributionParameter, float assuranceMeasure, float securityLevel, usint relinWindow, const IntType &delta=IntType(0), MODE mode=RLWE, const IntType &bigModulus=IntType(0), const IntType &bigRootOfUnity=IntType(0), const IntType &bigModulusArb=IntType(0), const IntType &bigRootOfUnityArb=IntType(0), int depth=1, int maxDepth=2)
	LPCryptoParametersBFV (shared_ptr< ParmType > params, EncodingParams encodingParams, float distributionParameter, float assuranceMeasure, float securityLevel, usint relinWindow, const IntType &delta=IntType(0), MODE mode=RLWE, const IntType &bigModulus=IntType(0), const IntType &bigRootOfUnity=IntType(0), const IntType &bigModulusArb=IntType(0), const IntType &bigRootOfUnityArb=IntType(0), int depth=1, int maxDepth=2)
	LPCryptoParametersBFV (shared_ptr< ParmType > params, EncodingParams encodingParams, float distributionParameter, float assuranceMeasure, SecurityLevel securityLevel, usint relinWindow, const IntType &delta=IntType(0), MODE mode=RLWE, const IntType &bigModulus=IntType(0), const IntType &bigRootOfUnity=IntType(0), const IntType &bigModulusArb=IntType(0), const IntType &bigRootOfUnityArb=IntType(0), int depth=1, int maxDepth=2)
virtual	~LPCryptoParametersBFV ()
const IntType &	GetDelta () const
const IntType &	GetBigModulus () const
const IntType &	GetBigRootOfUnity () const
const IntType &	GetBigModulusArb () const
const IntType &	GetBigRootOfUnityArb () const
void	SetDelta (const IntType &delta)
void	SetBigModulus (const IntType &bigModulus)
void	SetBigRootOfUnity (const IntType &bigRootOfUnity)
void	SetBigModulusArb (const IntType &bigModulusArb)
void	SetBigRootOfUnityArb (const IntType &bigRootOfUnityArb)
bool	operator== (const LPCryptoParameters< Element > &rhs) const
void	PrintParameters (std::ostream &os) 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
template<>
	LPCryptoParametersBFV (const LPCryptoParametersBFV &rhs)
template<>
	LPCryptoParametersBFV (shared_ptr< ParmType > params, const PlaintextModulus &plaintextModulus, float distributionParameter, float assuranceMeasure, float securityLevel, usint relinWindow, const BigInteger &delta, MODE mode, const BigInteger &bigModulus, const BigInteger &bigRootOfUnity, const BigInteger &bigModulusArb, const BigInteger &bigRootOfUnityArb, int depth, int maxDepth)
template<>
	LPCryptoParametersBFV (shared_ptr< ParmType > params, EncodingParams encodingParams, float distributionParameter, float assuranceMeasure, float securityLevel, usint relinWindow, const BigInteger &delta, MODE mode, const BigInteger &bigModulus, const BigInteger &bigRootOfUnity, const BigInteger &bigModulusArb, const BigInteger &bigRootOfUnityArb, int depth, int maxDepth)
Public Member Functions inherited from lbcrypto::LPCryptoParametersRLWE< Element >
	LPCryptoParametersRLWE ()
	LPCryptoParametersRLWE (const LPCryptoParametersRLWE &rhs)
	LPCryptoParametersRLWE (shared_ptr< typename Element::Params > params, EncodingParams encodingParams, float distributionParameter, float assuranceMeasure, float securityLevel, usint relinWindow, int depth=1, int maxDepth=2, MODE mode=RLWE)
	LPCryptoParametersRLWE (shared_ptr< typename Element::Params > params, EncodingParams encodingParams, float distributionParameter, float assuranceMeasure, SecurityLevel stdLevel, usint relinWindow, int depth=1, int maxDepth=2, MODE mode=RLWE)
virtual	~LPCryptoParametersRLWE ()
float	GetDistributionParameter () const
float	GetAssuranceMeasure () const
float	GetSecurityLevel () const
usint	GetRelinWindow () const
int	GetDepth () const
size_t	GetMaxDepth () const
MODE	GetMode () const
SecurityLevel	GetStdLevel () const
const Element::DggType &	GetDiscreteGaussianGenerator () const
void	SetDistributionParameter (float distributionParameter)
void	SetAssuranceMeasure (float assuranceMeasure)
void	SetSecurityLevel (float securityLevel)
void	SetStdLevel (SecurityLevel securityLevel)
void	SetRelinWindow (usint relinWindow)
void	SetDepth (int depth)
void	SetMaxDepth (size_t maxDepth)
void	SetMode (MODE mode)
bool	operator== (const LPCryptoParameters< Element > &rhs) const
void	PrintParameters (std::ostream &os) 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
Public Member Functions inherited from lbcrypto::LPCryptoParameters< Element >
virtual const PlaintextModulus &	GetPlaintextModulus () const
virtual const shared_ptr< typename Element::Params >	GetElementParams () const
virtual const EncodingParams	GetEncodingParams () const
virtual void	SetPlaintextModulus (const PlaintextModulus &plaintextModulus)
virtual bool	operator!= (const LPCryptoParameters< Element > &cmp) const
virtual void	SetElementParams (shared_ptr< typename Element::Params > params)
virtual void	SetEncodingParams (EncodingParams encodingParams)
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)

Static Public Member Functions
static uint32_t	SerializedVersion ()
Static Public Member Functions inherited from lbcrypto::LPCryptoParameters< Element >
static uint32_t	SerializedVersion ()

Additional Inherited Members
Protected Member Functions inherited from lbcrypto::LPCryptoParameters< Element >
	LPCryptoParameters (const PlaintextModulus &plaintextModulus)
	LPCryptoParameters (shared_ptr< typename Element::Params > params, const PlaintextModulus &plaintextModulus)
	LPCryptoParameters (shared_ptr< typename Element::Params > params, EncodingParams encodingParams)
	LPCryptoParameters (LPCryptoParameters< Element > *from, shared_ptr< typename Element::Params > newElemParms)
Protected Attributes inherited from lbcrypto::LPCryptoParametersRLWE< Element >
float	m_distributionParameter
float	m_assuranceMeasure
float	m_securityLevel
usint	m_relinWindow
int	m_depth
uint32_t	m_maxDepth
MODE	m_mode
SecurityLevel	m_stdLevel
Element::DggType	m_dgg

Detailed Description

template<class Element>
class lbcrypto::LPCryptoParametersBFV< Element >

This is the parameters class for the BFV encryption scheme. This scheme is also referred to as the FV scheme.

The BFV scheme parameter guidelines are introduced here:

• Junfeng Fan and Frederik Vercauteren. Somewhat Practical Fully Homomorphic Encryption. Cryptology ePrint Archive, Report 2012/144. (https://eprint.iacr.org/2012/144.pdf)

We used the optimized parameter selection from the designs here:

• Lepoint T., Naehrig M. (2014) A Comparison of the Homomorphic Encryption Schemes FV and YASHE. In: Pointcheval D., Vergnaud D. (eds) Progress in Cryptology – AFRICACRYPT 2014. AFRICACRYPT 2014. Lecture Notes in Computer Science, vol 8469. Springer, Cham. (https://eprint.iacr.org/2014/062.pdf)

Template Parameters

Element

a ring element type.

Constructor & Destructor Documentation

LPCryptoParametersBFV() [1/5]

template<class Element >

lbcrypto::LPCryptoParametersBFV< Element >::LPCryptoParametersBFV

(

)

Default constructor.

LPCryptoParametersBFV() [2/5]

template<class Element >

lbcrypto::LPCryptoParametersBFV< Element >::LPCryptoParametersBFV

(

const LPCryptoParametersBFV< Element > &

rhs

)

Copy constructor.

Parameters

rhs

- source

LPCryptoParametersBFV() [3/5]

template<class Element >

lbcrypto::LPCryptoParametersBFV< Element >::LPCryptoParametersBFV	(	shared_ptr< ParmType >	params,
		const PlaintextModulus &	plaintextModulus,
		float	distributionParameter,
		float	assuranceMeasure,
		float	securityLevel,
		usint	relinWindow,
		const IntType &	delta = IntType(0),
		MODE	mode = RLWE,
		const IntType &	bigModulus = IntType(0),
		const IntType &	bigRootOfUnity = IntType(0),
		const IntType &	bigModulusArb = IntType(0),
		const IntType &	bigRootOfUnityArb = IntType(0),
		int	depth = 1,
		int	maxDepth = 2
	)

Constructor that initializes values. Note that it is possible to set parameters in a way that is overall infeasible for actual use. There are fewer degrees of freedom than parameters provided. Typically one chooses the basic noise, assurance and security parameters as the typical community-accepted values, then chooses the plaintext modulus and depth as needed. The element parameters should then be choosen to provide correctness and security. In some cases we would need to operate over already encrypted/provided ciphertext and the depth needs to be pre-computed for initial settings.

Parameters

&params	Element parameters. This will depend on the specific class of element being used.
&plaintextModulus	Plaintext modulus, typically denoted as p in most publications.
distributionParameter	Noise distribution parameter, typically denoted as /sigma in most publications. Community standards typically call for a value of 3 to 6. Lower values provide more room for computation while larger values provide more security.
assuranceMeasure	Assurance level, typically denoted as w in most applications. This is oftern perceived as a fudge factor in the literature, with a typical value of 9.
securityLevel	Security level as Root Hermite Factor. We use the Root Hermite Factor representation of the security level to better conform with US ITAR and EAR export regulations. This is typically represented as /delta in the literature. Typically a Root Hermite Factor of 1.006 or less provides reasonable security for RLWE crypto schemes.
relinWindow	The size of the relinearization window. This is relevant when using this scheme for proxy re-encryption, and the value is denoted as r in the literature.
delta	BFV-specific factor that is multiplied by the plaintext polynomial.
mode	mode for secret polynomial, defaults to RLWE.
bigModulus	modulus used in polynomial multiplications in EvalMult
bigRootOfUnity	root of unity for bigModulus
bigModulusArb	modulus used in polynomial multiplications in EvalMult (for arbitrary cyclotomics)
bigRootOfUnityArb	root of unity for bigModulus (for arbitrary cyclotomics)
depth	is the depth of computation circuit supported for these parameters (not used now; for future use).
maxDepth	the maximum power of secret key for which the relinearization key is generated

LPCryptoParametersBFV() [4/5]

template<class Element >

lbcrypto::LPCryptoParametersBFV< Element >::LPCryptoParametersBFV	(	shared_ptr< ParmType >	params,
		EncodingParams	encodingParams,
		float	distributionParameter,
		float	assuranceMeasure,
		float	securityLevel,
		usint	relinWindow,
		const IntType &	delta = IntType(0),
		MODE	mode = RLWE,
		const IntType &	bigModulus = IntType(0),
		const IntType &	bigRootOfUnity = IntType(0),
		const IntType &	bigModulusArb = IntType(0),
		const IntType &	bigRootOfUnityArb = IntType(0),
		int	depth = 1,
		int	maxDepth = 2
	)

Constructor that initializes values.

Parameters

&params	element parameters.
&encodingParams	plaintext space parameters.
distributionParameter	noise distribution parameter.
assuranceMeasure	assurance level. = BigInteger::ZERO
securityLevel	security level (root Hermite factor).
relinWindow	the size of the relinearization window.
delta	BFV-specific factor that is multiplied by the plaintext polynomial.
mode	mode for secret polynomial, defaults to RLWE.
bigModulus	modulus used in polynomial multiplications in EvalMult
bigRootOfUnity	root of unity for bigModulus
bigModulusArb	modulus used in polynomial multiplications in EvalMult (arbitrary cyclotomics)
bigRootOfUnityArb	root of unity for bigModulus (arbitrary cyclotomics)
depth	is the depth of computation circuit supported for these parameters (not used now; for future use).
maxDepth	the maximum power of secret key for which the relinearization key is generated

LPCryptoParametersBFV() [5/5]

template<class Element >

lbcrypto::LPCryptoParametersBFV< Element >::LPCryptoParametersBFV	(	shared_ptr< ParmType >	params,
		EncodingParams	encodingParams,
		float	distributionParameter,
		float	assuranceMeasure,
		SecurityLevel	securityLevel,
		usint	relinWindow,
		const IntType &	delta = IntType(0),
		MODE	mode = RLWE,
		const IntType &	bigModulus = IntType(0),
		const IntType &	bigRootOfUnity = IntType(0),
		const IntType &	bigModulusArb = IntType(0),
		const IntType &	bigRootOfUnityArb = IntType(0),
		int	depth = 1,
		int	maxDepth = 2
	)

Constructor that initializes values.

Parameters

&params	element parameters.
&encodingParams	plaintext space parameters.
distributionParameter	noise distribution parameter.
assuranceMeasure	assurance level. = BigInteger::ZERO
securityLevel	standard security level.
relinWindow	the size of the relinearization window.
delta	BFV-specific factor that is multiplied by the plaintext polynomial.
mode	mode for secret polynomial, defaults to RLWE.
bigModulus	modulus used in polynomial multiplications in EvalMult
bigRootOfUnity	root of unity for bigModulus
bigModulusArb	modulus used in polynomial multiplications in EvalMult (arbitrary cyclotomics)
bigRootOfUnityArb	root of unity for bigModulus (arbitrary cyclotomics)
depth	is the depth of computation circuit supported for these parameters (not used now; for future use).
maxDepth	the maximum power of secret key for which the relinearization key is generated

~LPCryptoParametersBFV()

template<class Element >

virtual lbcrypto::LPCryptoParametersBFV< Element >::~LPCryptoParametersBFV ( )

inlinevirtual

Destructor

Member Function Documentation

GetBigModulus()

template<class Element >

const IntType& lbcrypto::LPCryptoParametersBFV< Element >::GetBigModulus ( ) const

inline

Gets the modulus used for polynomial multiplications in EvalMult

Returns

the modulus value.

GetBigModulusArb()

template<class Element >

const IntType& lbcrypto::LPCryptoParametersBFV< Element >::GetBigModulusArb ( ) const

inline

Gets the modulus used for polynomial multiplications in EvalMult (arbitrary cyclotomics)

Returns

the modulus value.

GetBigRootOfUnity()

template<class Element >

const IntType& lbcrypto::LPCryptoParametersBFV< Element >::GetBigRootOfUnity ( ) const

inline

Gets the primitive root of unity used for polynomial multiplications in EvalMult

Returns

the primitive root of unity value.

GetBigRootOfUnityArb()

template<class Element >

const IntType& lbcrypto::LPCryptoParametersBFV< Element >::GetBigRootOfUnityArb ( ) const

inline

Gets the primitive root of unity used for polynomial multiplications in EvalMult (arbitrary cyclotomics)

Returns

the primitive root of unity value.

GetDelta()

template<class Element >

const IntType& lbcrypto::LPCryptoParametersBFV< Element >::GetDelta ( ) const

inline

Gets the value of the delta factor.

Returns

the delta factor. It is an BFV-specific factor that is multiplied by the plaintext polynomial.

operator==()

template<class Element >

bool lbcrypto::LPCryptoParametersBFV< Element >::operator== ( const LPCryptoParameters< Element > &  rhs ) const

inlinevirtual

== operator to compare to this instance of LPCryptoParametersBFV object.

Parameters

&rhs	LPCryptoParameters to check equality against.

Implements lbcrypto::LPCryptoParameters< Element >.

SetBigModulus()

template<class Element >

void lbcrypto::LPCryptoParametersBFV< Element >::SetBigModulus ( const IntType &  bigModulus )

inline

Sets the modulus used for polynomial multiplications in EvalMult

Parameters

&bigModulus

the modulus value.

SetBigModulusArb()

template<class Element >

void lbcrypto::LPCryptoParametersBFV< Element >::SetBigModulusArb ( const IntType &  bigModulusArb )

inline

Sets the modulus used for polynomial multiplications in EvalMult (arbitrary cyclotomics)

SetBigRootOfUnity()

template<class Element >

void lbcrypto::LPCryptoParametersBFV< Element >::SetBigRootOfUnity ( const IntType &  bigRootOfUnity )

inline

Sets primitive root of unity used for polynomial multiplications in EvalMult

Parameters

&bigRootOfUnity

is the root of unity used for EvalMult operations.

SetBigRootOfUnityArb()

template<class Element >

void lbcrypto::LPCryptoParametersBFV< Element >::SetBigRootOfUnityArb ( const IntType &  bigRootOfUnityArb )

inline

Sets primitive root of unity used for polynomial multiplications in EvalMult (arbitrary cyclotomics)

SetDelta()

template<class Element >

void lbcrypto::LPCryptoParametersBFV< Element >::SetDelta ( const IntType &  delta )

inline

Sets the value of the delta factor

Parameters

&delta

is the delta factor

---

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

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