Class MultipartyCKKSRNS

• Defined in File ckksrns-multiparty.h

Inheritance Relationships

Base Type

• public lbcrypto::MultipartyRNS (Class MultipartyRNS)

Class Documentation

class lbcrypto::MultipartyCKKSRNS : public lbcrypto::MultipartyRNS

Inheritence diagram for lbcrypto::MultipartyCKKSRNS:

Collaboration diagram for lbcrypto::MultipartyCKKSRNS:

Public Functions

virtual ~MultipartyCKKSRNS() = default

virtual DecryptResult MultipartyDecryptFusion(const std::vector<Ciphertext<DCRTPoly>> &ciphertextVec, Poly *plaintext) const override

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

Parameters

• &ciphertextVec – vector of “partial” decryptions.

• *plaintext – the plaintext output as a Poly.

Returns

the decoding result.

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

virtual Ciphertext<DCRTPoly> IntBootAdjustScale(ConstCiphertext<DCRTPoly> ciphertext) const override

Prepare a ciphertext for interactive bootstraping.

For the FIXEDMANUAL and FIXEDAUTO modes of CKKS, drops the the number of towers 2 and makes sure the scale is Delta (not a power of Delta). The input should have at least 2 towers.

For the FLEXIBLEAUTO mode of CKKS, the input ciphertext should have at least 3 towers. One tower will be used to adjust the scale to level 0.

Parameters

ciphertext – Input Ciphertext

Returns

: Resulting Ciphertext

virtual Ciphertext<DCRTPoly> IntMPBootAdjustScale(ConstCiphertext<DCRTPoly> ciphertext) const override

Threshold FHE: Prepare a ciphertext for Multi-Party Interactive Bootstrapping

Parameters

ciphertext – Input Ciphertext

Returns

: Resulting Ciphertext

virtual Ciphertext<DCRTPoly> IntMPBootRandomElementGen(std::shared_ptr<CryptoParametersCKKSRNS> params, const PublicKey<DCRTPoly> publicKey) const override

Threshold FHE: Generate a common random polynomial for Multi-Party Interactive Bootstrapping

Parameters

publicKey – the scheme public key (you can also provide the lead party’s public-key)

Returns

: Resulting ring element

virtual Ciphertext<DCRTPoly> IntMPBootRandomElementGen(std::shared_ptr<CryptoParametersCKKSRNS> params, ConstCiphertext<DCRTPoly> &ciphertext) const override

virtual std::vector<Ciphertext<DCRTPoly>> IntMPBootDecrypt(const PrivateKey<DCRTPoly> privateKey, ConstCiphertext<DCRTPoly> ciphertext, ConstCiphertext<DCRTPoly> a) const override

Threshold FHE: Does masked decryption as part of Multi-Party Interactive Bootstrapping. Each party calls this function as part of the protocol

Parameters

• privateKey – secret key share for party i

• ciphertext – input ciphertext

• a – input common random polynomial

Returns

: Resulting masked decryption

virtual std::vector<Ciphertext<DCRTPoly>> IntMPBootAdd(std::vector<std::vector<Ciphertext<DCRTPoly>>> &sharesPairVec) const override

Threshold FHE: Aggregates a vector of masked decryptions and re-encryotion shares, which is the second step of the interactive multiparty bootstrapping procedure.

Parameters

sharesPairVec – vector of pair of ciphertexts, each element of this vector contains (h_0i, h_1i) - the masked-decryption and encryption shares ofparty i

Returns

: aggregated pair of shares ((h_0, h_1)

virtual Ciphertext<DCRTPoly> IntMPBootEncrypt(const PublicKey<DCRTPoly> publicKey, const std::vector<Ciphertext<DCRTPoly>> &sharesPair, ConstCiphertext<DCRTPoly> a, ConstCiphertext<DCRTPoly> ciphertext) const override

Threshold FHE: Does public key encryption of lead party’s masked decryption as part of interactive multi-party bootstrapping, which increases the ciphertext modulus and enables future computations. This operation is done by the lead party as the final step of interactive multi-party bootstrapping.

Parameters

• publicKey – the lead party’s public key

• sharesPair – aggregated decryption and re-encryption shares

• a – common random ring element

• ciphertext – input ciphertext

Returns

: Resulting encryption

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

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

inline std::string SerializedObjectName() const