dbfv

package
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Published: Aug 10, 2023 License: Apache-2.0 Imports: 6 Imported by: 0

Documentation

Overview

Package dbfv implements a distributed (or threshold) version of the BFV scheme that enables secure multiparty computation solutions with secret-shared secret keys.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func NewCKGProtocol

func NewCKGProtocol(params bfv.Parameters) *drlwe.CKGProtocol

NewCKGProtocol creates a new drlwe.CKGProtocol instance from the BFV parameters

func NewRKGProtocol

func NewRKGProtocol(params bfv.Parameters) *drlwe.RKGProtocol

NewRKGProtocol creates a new drlwe.RKGProtocol instance from the BFV parameters

func NewRTGProtocol

func NewRTGProtocol(params bfv.Parameters) *drlwe.RTGProtocol

NewRTGProtocol creates a new drlwe.RTGProtocol instance from the BFV parameters

Types

type CKSProtocol

type CKSProtocol struct {
	drlwe.CKSProtocol
	// contains filtered or unexported fields
}

CKSProtocol is a structure storing the parameters for the collective key-switching protocol.

func NewCKSProtocol

func NewCKSProtocol(params bfv.Parameters, sigmaSmudging float64) *CKSProtocol

NewCKSProtocol creates a new CKSProtocol that will be used to perform a collective key-switching on a ciphertext encrypted under a collective public-key, whose secret-shares are distributed among j parties, re-encrypting the ciphertext under another public-key, whose secret-shares are also known to the parties.

func (*CKSProtocol) AllocateShare

func (cks *CKSProtocol) AllocateShare() *drlwe.CKSShare

AllocateShare allocates the shares of one party in the CKS protocol for BFV.

func (*CKSProtocol) KeySwitch

func (cks *CKSProtocol) KeySwitch(ctIn *bfv.Ciphertext, combined *drlwe.CKSShare, ctOut *bfv.Ciphertext)

KeySwitch performs the actual keyswitching operation on a ciphertext ct and put the result in ctOut

func (*CKSProtocol) ShallowCopy

func (cks *CKSProtocol) ShallowCopy() *CKSProtocol

ShallowCopy creates a shallow copy of CKSProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned CKSProtocol can be used concurrently.

type E2SProtocol

type E2SProtocol struct {
	CKSProtocol
	// contains filtered or unexported fields
}

E2SProtocol is the structure storing the parameters and temporary buffers required by the encryption-to-shares protocol.

func NewE2SProtocol

func NewE2SProtocol(params bfv.Parameters, sigmaSmudging float64) *E2SProtocol

NewE2SProtocol creates a new E2SProtocol struct from the passed BFV parameters.

func (*E2SProtocol) GenShare

func (e2s *E2SProtocol) GenShare(sk *rlwe.SecretKey, ct1 *ring.Poly, secretShareOut *rlwe.AdditiveShare, publicShareOut *drlwe.CKSShare)

GenShare generates a party's share in the encryption-to-shares protocol. This share consist in the additive secret-share of the party which is written in secretShareOut and in the public masked-decryption share written in publicShareOut. ct1 is degree 1 element of a bfv.Ciphertext, i.e. bfv.Ciphertext.Value[1].

func (*E2SProtocol) GetShare

func (e2s *E2SProtocol) GetShare(secretShare *rlwe.AdditiveShare, aggregatePublicShare *drlwe.CKSShare, ct *bfv.Ciphertext, secretShareOut *rlwe.AdditiveShare)

GetShare is the final step of the encryption-to-share protocol. It performs the masked decryption of the target ciphertext followed by a the removal of the caller's secretShare as generated in the GenShare method. If the caller is not secret-key-share holder (i.e., didn't generate a decryption share), `secretShare` can be set to nil. Therefore, in order to obtain an additive sharing of the message, only one party should call this method, and the other parties should use the secretShareOut output of the GenShare method.

func (*E2SProtocol) ShallowCopy

func (e2s *E2SProtocol) ShallowCopy() *E2SProtocol

ShallowCopy creates a shallow copy of E2SProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned E2SProtocol can be used concurrently.

type MaskedTransformFunc

type MaskedTransformFunc struct {
	Decode bool
	Func   func(coeffs []uint64)
	Encode bool
}

MaskedTransformFunc is struct containing user defined in-place function that can be applied to masked BFV plaintexts, as a part of the Masked Transform Protocol. Transform is a function called with a vector of integers modulo bfv.Parameters.T() of size bfv.Parameters.N() as input, and must write its output on the same buffer. Transform can be the identity. Decode: if true, then the masked BFV plaintext will be decoded before applying Transform. Recode: if true, then the masked BFV plaintext will be recoded after applying Transform. i.e. : Decode (true/false) -> Transform -> Recode (true/false).

type MaskedTransformProtocol

type MaskedTransformProtocol struct {
	// contains filtered or unexported fields
}

MaskedTransformProtocol is a struct storing the parameters for the MaskedTransformProtocol protocol.

func NewMaskedTransformProtocol

func NewMaskedTransformProtocol(paramsIn, paramsOut bfv.Parameters, sigmaSmudging float64) (rfp *MaskedTransformProtocol, err error)

NewMaskedTransformProtocol creates a new instance of the PermuteProtocol.

func (*MaskedTransformProtocol) AggregateShares

func (rfp *MaskedTransformProtocol) AggregateShares(share1, share2, shareOut *MaskedTransformShare)

AggregateShares sums share1 and share2 on shareOut.

func (*MaskedTransformProtocol) AllocateShare

func (rfp *MaskedTransformProtocol) AllocateShare() *MaskedTransformShare

AllocateShare allocates the shares of the PermuteProtocol.

func (*MaskedTransformProtocol) GenShare

func (rfp *MaskedTransformProtocol) GenShare(skIn, skOut *rlwe.SecretKey, c1 *ring.Poly, crs drlwe.CKSCRP, transform *MaskedTransformFunc, shareOut *MaskedTransformShare)

GenShare generates the shares of the PermuteProtocol. ct1 is the degree 1 element of a bfv.Ciphertext, i.e. bfv.Ciphertext.Value[1].

func (*MaskedTransformProtocol) SampleCRP

func (rfp *MaskedTransformProtocol) SampleCRP(level int, crs utils.PRNG) drlwe.CKSCRP

SampleCRP samples a common random polynomial to be used in the Masked-Transform protocol from the provided common reference string.

func (*MaskedTransformProtocol) ShallowCopy

ShallowCopy creates a shallow copy of MaskedTransformProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned MaskedTransformProtocol can be used concurrently.

func (*MaskedTransformProtocol) Transform

func (rfp *MaskedTransformProtocol) Transform(ciphertext *bfv.Ciphertext, transform *MaskedTransformFunc, crs drlwe.CKSCRP, share *MaskedTransformShare, ciphertextOut *bfv.Ciphertext)

Transform applies Decrypt, Recode and Recrypt on the input ciphertext.

type MaskedTransformShare

type MaskedTransformShare struct {
	// contains filtered or unexported fields
}

MaskedTransformShare is a struct storing the decryption and recryption shares.

func (*MaskedTransformShare) MarshalBinary

func (share *MaskedTransformShare) MarshalBinary() ([]byte, error)

MarshalBinary encodes a RefreshShare on a slice of bytes.

func (*MaskedTransformShare) UnmarshalBinary

func (share *MaskedTransformShare) UnmarshalBinary(data []byte) (err error)

UnmarshalBinary decodes a marshaled RefreshShare on the target RefreshShare.

type PCKSProtocol

type PCKSProtocol struct {
	drlwe.PCKSProtocol
	// contains filtered or unexported fields
}

PCKSProtocol is the structure storing the parameters for the collective public key-switching.

func NewPCKSProtocol

func NewPCKSProtocol(params bfv.Parameters, sigmaSmudging float64) *PCKSProtocol

NewPCKSProtocol creates a new PCKSProtocol object and will be used to re-encrypt a Ciphertext ctx encrypted under a secret-shared key among j parties under a new collective public-key.

func (*PCKSProtocol) AllocateShare

func (pcks *PCKSProtocol) AllocateShare() *drlwe.PCKSShare

AllocateShare allocates the shares of one party in the PCKS protocol for BFV.

func (*PCKSProtocol) KeySwitch

func (pcks *PCKSProtocol) KeySwitch(ctIn *bfv.Ciphertext, combined *drlwe.PCKSShare, ctOut *bfv.Ciphertext)

KeySwitch performs the actual keyswitching operation on a ciphertext ct and put the result in ctOut.

func (*PCKSProtocol) ShallowCopy

func (pcks *PCKSProtocol) ShallowCopy() *PCKSProtocol

ShallowCopy creates a shallow copy of PCKSProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned PCKSProtocol can be used concurrently.

type RefreshProtocol

type RefreshProtocol struct {
	MaskedTransformProtocol
}

RefreshProtocol is a struct storing the relevant parameters for the Refresh protocol.

func NewRefreshProtocol

func NewRefreshProtocol(params bfv.Parameters, sigmaSmudging float64) (rfp *RefreshProtocol)

NewRefreshProtocol creates a new Refresh protocol instance.

func (*RefreshProtocol) AggregateShares

func (rfp *RefreshProtocol) AggregateShares(share1, share2, shareOut *RefreshShare)

AggregateShares aggregates two parties' shares in the Refresh protocol.

func (*RefreshProtocol) AllocateShare

func (rfp *RefreshProtocol) AllocateShare() *RefreshShare

AllocateShare allocates the shares of the PermuteProtocol

func (*RefreshProtocol) Finalize

func (rfp *RefreshProtocol) Finalize(ctIn *bfv.Ciphertext, crp drlwe.CKSCRP, share *RefreshShare, ctOut *bfv.Ciphertext)

Finalize applies Decrypt, Recode and Recrypt on the input ciphertext.

func (*RefreshProtocol) GenShare

func (rfp *RefreshProtocol) GenShare(sk *rlwe.SecretKey, ct1 *ring.Poly, crp drlwe.CKSCRP, shareOut *RefreshShare)

GenShare generates a share for the Refresh protocol. ct1 is degree 1 element of a bfv.Ciphertext, i.e. bfv.Ciphertext.Value[1].

func (*RefreshProtocol) ShallowCopy

func (rfp *RefreshProtocol) ShallowCopy() *RefreshProtocol

ShallowCopy creates a shallow copy of RefreshProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned RefreshProtocol can be used concurrently.

type RefreshShare

type RefreshShare struct {
	MaskedTransformShare
}

RefreshShare is a struct storing a party's share in the Refresh protocol.

type S2EProtocol

type S2EProtocol struct {
	CKSProtocol
	// contains filtered or unexported fields
}

S2EProtocol is the structure storing the parameters and temporary buffers required by the shares-to-encryption protocol.

func NewS2EProtocol

func NewS2EProtocol(params bfv.Parameters, sigmaSmudging float64) *S2EProtocol

NewS2EProtocol creates a new S2EProtocol struct from the passed BFV parameters.

func (*S2EProtocol) GenShare

func (s2e *S2EProtocol) GenShare(sk *rlwe.SecretKey, crp drlwe.CKSCRP, secretShare *rlwe.AdditiveShare, c0ShareOut *drlwe.CKSShare)

GenShare generates a party's in the shares-to-encryption protocol given the party's secret-key share `sk`, a common polynomial sampled from the CRS `crp` and the party's secret share of the message.

func (*S2EProtocol) GetEncryption

func (s2e *S2EProtocol) GetEncryption(c0Agg *drlwe.CKSShare, crp drlwe.CKSCRP, ctOut *bfv.Ciphertext)

GetEncryption computes the final encryption of the secret-shared message when provided with the aggregation `c0Agg` of the parties' shares in the protocol and with the common, CRS-sampled polynomial `crp`.

func (*S2EProtocol) ShallowCopy

func (s2e *S2EProtocol) ShallowCopy() *S2EProtocol

ShallowCopy creates a shallow copy of S2EProtocol in which all the read-only data-structures are shared with the receiver and the temporary buffers are reallocated. The receiver and the returned S2EProtocol can be used concurrently.

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