dbfv

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

• type CKGProtocol
  • func NewCKGProtocol(params bfv.Parameters) *CKGProtocol
• type CKSProtocol
  • func NewCKSProtocol(params bfv.Parameters, sigmaSmudging float64) *CKSProtocol
  • func (pcks *CKSProtocol) AllocateShareBFV() *drlwe.CKSShare
• type E2SProtocol
  • func NewE2SProtocol(params bfv.Parameters, sigmaSmudging float64) *E2SProtocol
  • func (e2s *E2SProtocol) GenShare(sk *rlwe.SecretKey, ct *bfv.Ciphertext, secretShareOut *rlwe.AdditiveShare, ...)
  • func (e2s *E2SProtocol) GetShare(secretShare *rlwe.AdditiveShare, aggregatePublicShare *drlwe.CKSShare, ...)
• type MaskedTransformFunc
• type MaskedTransformProtocol
  • func NewMaskedTransformProtocol(params bfv.Parameters, sigmaSmudging float64) (rfp *MaskedTransformProtocol)
  • func (rfp *MaskedTransformProtocol) Aggregate(share1, share2, shareOut *MaskedTransformShare)
  • func (rfp *MaskedTransformProtocol) AllocateShare() *MaskedTransformShare
  • func (rfp *MaskedTransformProtocol) GenShares(sk *rlwe.SecretKey, ciphertext *bfv.Ciphertext, crs *ring.Poly, ...)
  • func (rfp *MaskedTransformProtocol) Transform(ciphertext *bfv.Ciphertext, transform MaskedTransformFunc, crs *ring.Poly, ...)
• type MaskedTransformShare
  • func (share *MaskedTransformShare) MarshalBinary() ([]byte, error)
  • func (share *MaskedTransformShare) UnmarshalBinary(data []byte) error
• type PCKSProtocol
  • func NewPCKSProtocol(params bfv.Parameters, sigmaSmudging float64) *PCKSProtocol
  • func (pcks *PCKSProtocol) AllocateShareBFV() *drlwe.PCKSShare
• type RKGProtocol
  • func NewRKGProtocol(params bfv.Parameters) *RKGProtocol
• type RTGProtocol
  • func NewRotKGProtocol(params bfv.Parameters) (rtg *RTGProtocol)
• type RefreshProtocol
  • func NewRefreshProtocol(params bfv.Parameters, sigmaSmudging float64) (rfp *RefreshProtocol)
  • func (rfp *RefreshProtocol) Aggregate(share1, share2, shareOut *RefreshShare)
  • func (rfp *RefreshProtocol) AllocateShare() *RefreshShare
  • func (rfp *RefreshProtocol) Finalize(ciphertext *bfv.Ciphertext, crs *ring.Poly, share *RefreshShare, ...)
  • func (rfp *RefreshProtocol) GenShares(sk *rlwe.SecretKey, ciphertext *bfv.Ciphertext, crs *ring.Poly, ...)
• type RefreshShare
• type S2EProtocol
  • func NewS2EProtocol(params bfv.Parameters, sigmaSmudging float64) *S2EProtocol
  • func (s2e *S2EProtocol) GenShare(sk *rlwe.SecretKey, c1 *ring.Poly, secretShare *rlwe.AdditiveShare, ...)
  • func (s2e *S2EProtocol) GetEncryption(c0Agg *drlwe.CKSShare, c1 *ring.Poly, ctOut *bfv.Ciphertext)

Types

type CKGProtocol

type CKGProtocol struct {
	drlwe.CKGProtocol
}

CKGProtocol is the structure storing the parameters and state for a party in the collective key generation protocol.

func NewCKGProtocol

func NewCKGProtocol(params bfv.Parameters) *CKGProtocol

NewCKGProtocol creates a new CKGProtocol instance

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 operate 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) AllocateShareBFV

func (pcks *CKSProtocol) AllocateShareBFV() *drlwe.CKSShare

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

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, ct *bfv.Ciphertext, 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.

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.

type MaskedTransformFunc

type MaskedTransformFunc func(ptIn, ptOut bfv.PlaintextRingT)

MaskedTransformFunc is type of functions that can be operated on masked BFV plaintexts as a part of the Masked Transform Protocol.

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(params bfv.Parameters, sigmaSmudging float64) (rfp *MaskedTransformProtocol)

NewMaskedTransformProtocol creates a new instance of the PermuteProtocol.

func (*MaskedTransformProtocol) Aggregate

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

Aggregate sums share1 and share2 on shareOut.

func (*MaskedTransformProtocol) AllocateShare

func (rfp *MaskedTransformProtocol) AllocateShare() *MaskedTransformShare

AllocateShare allocates the shares of the PermuteProtocol

func (*MaskedTransformProtocol) GenShares

func (rfp *MaskedTransformProtocol) GenShares(sk *rlwe.SecretKey, ciphertext *bfv.Ciphertext, crs *ring.Poly, transform MaskedTransformFunc, shareOut *MaskedTransformShare)

GenShares generates the shares of the PermuteProtocol

func (*MaskedTransformProtocol) Transform

func (rfp *MaskedTransformProtocol) Transform(ciphertext *bfv.Ciphertext, transform MaskedTransformFunc, crs *ring.Poly, 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) 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) AllocateShareBFV

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

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

type RKGProtocol

type RKGProtocol struct {
	drlwe.RKGProtocol
}

RKGProtocol is the structure storing the parameters and state for a party in the collective relinearization key generation protocol.

func NewRKGProtocol

func NewRKGProtocol(params bfv.Parameters) *RKGProtocol

NewRKGProtocol creates a new RKGProtocol object that will be used to generate a collective evaluation-key among j parties in the given context with the given bit-decomposition.

type RTGProtocol

type RTGProtocol struct {
	drlwe.RTGProtocol
}

RTGProtocol is the structure storing the parameters for the collective rotation-keys generation.

func NewRotKGProtocol

func NewRotKGProtocol(params bfv.Parameters) (rtg *RTGProtocol)

NewRotKGProtocol creates a new rotkg object and will be used to generate collective rotation-keys from a shared secret-key among j parties.

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) Aggregate

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

Aggregate 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(ciphertext *bfv.Ciphertext, crs *ring.Poly, share *RefreshShare, ciphertextOut *bfv.Ciphertext)

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

func (*RefreshProtocol) GenShares

func (rfp *RefreshProtocol) GenShares(sk *rlwe.SecretKey, ciphertext *bfv.Ciphertext, crs *ring.Poly, shareOut *RefreshShare)

GenShares generates a share for the Refresh protocol.

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, c1 *ring.Poly, 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 `c1` and the party's secret share of the message.

func (*S2EProtocol) GetEncryption

func (s2e *S2EProtocol) GetEncryption(c0Agg *drlwe.CKSShare, c1 *ring.Poly, ctOut *bfv.Ciphertext)

GetEncryption computes the final encryption of the secret-shared message when provided with the aggregation `c0Agg` of the parties' share in the protocol and with the common, CRS-sampled polynomial `c1`.