paillier

Documentation

Index

• Constants
• Variables
• func GenerateKeyPair(ctx context.Context, rand io.Reader, modulusBitLen int, ...) (privateKey *PrivateKey, publicKey *PublicKey, err error)
• func GenerateXs(m int, k, N *big.Int, ecdsaPub *crypto2.ECPoint) []*big.Int
• func L(u, N *big.Int) *big.Int
• type PrivateKey
  • func (privateKey *PrivateKey) Decrypt(c *big.Int) (m *big.Int, err error)
  • func (privateKey *PrivateKey) Proof(k *big.Int, ecdsaPub *crypto2.ECPoint) (Proof, error)
• type Proof
  • func (pf Proof) Verify(pkN, k *big.Int, ecdsaPub *crypto2.ECPoint) (bool, error)
• type PublicKey
  • func (publicKey *PublicKey) AsInts() []*big.Int
  • func (publicKey *PublicKey) Encrypt(rand io.Reader, m *big.Int) (c *big.Int, err error)
  • func (publicKey *PublicKey) EncryptAndReturnRandomness(rand io.Reader, m *big.Int) (c *big.Int, x *big.Int, err error)
  • func (publicKey *PublicKey) Gamma() *big.Int
  • func (publicKey *PublicKey) HomoAdd(c1, c2 *big.Int) (*big.Int, error)
  • func (publicKey *PublicKey) HomoMult(m, c1 *big.Int) (*big.Int, error)
  • func (publicKey *PublicKey) NSquare() *big.Int

Constants

const (
	// ProofIters is the number of iterations used in the Paillier key correctness proof.
	ProofIters = 13
)

Variables

var (
	// ErrMessageTooLong is returned when the plaintext is negative or exceeds the modulus.
	ErrMessageTooLong = fmt.Errorf("the message is too large or < 0")
	// ErrMessageMalFormed is returned when the ciphertext is not coprime with N^2.
	ErrMessageMalFormed = fmt.Errorf("the message is mal-formed")
)

Functions

func GenerateKeyPair

func GenerateKeyPair(ctx context.Context, rand io.Reader, modulusBitLen int, optionalConcurrency ...int) (privateKey *PrivateKey, publicKey *PublicKey, err error)

len is the length of the modulus (each prime = len / 2)

func GenerateXs

func GenerateXs(m int, k, N *big.Int, ecdsaPub *crypto2.ECPoint) []*big.Int

GenerateXs generates the challenges used in Paillier key Proof

func L

func L(u, N *big.Int) *big.Int

L computes the Paillier L function: L(u) = (u - 1) / N.

Types

type PrivateKey

type PrivateKey struct {
	PublicKey
	LambdaN,
	PhiN *big.Int // (p-1) * (q-1)
	P, Q *big.Int
}

PrivateKey represents a Paillier private key containing the public key and the secret prime factors.

func (*PrivateKey) Decrypt

func (privateKey *PrivateKey) Decrypt(c *big.Int) (m *big.Int, err error)

Decrypt decrypts the ciphertext c using the Paillier private key and returns the plaintext.

func (*PrivateKey) Proof

func (privateKey *PrivateKey) Proof(k *big.Int, ecdsaPub *crypto2.ECPoint) (Proof, error)

type Proof

type Proof [ProofIters]*big.Int

Proof uses the new GenerateXs method in GG18Spec (6)

func (Proof) Verify

func (pf Proof) Verify(pkN, k *big.Int, ecdsaPub *crypto2.ECPoint) (bool, error)

Verify checks whether the Paillier key correctness proof is valid for the given public key N.

type PublicKey

type PublicKey struct {
	N *big.Int
}

PublicKey represents a Paillier public key containing the modulus N.

func (*PublicKey) AsInts

func (publicKey *PublicKey) AsInts() []*big.Int

AsInts returns the PublicKey serialised to a slice of *big.Int for hashing

func (*PublicKey) Encrypt

func (publicKey *PublicKey) Encrypt(rand io.Reader, m *big.Int) (c *big.Int, err error)

Encrypt encrypts the plaintext m under the Paillier public key and returns the ciphertext.

func (*PublicKey) EncryptAndReturnRandomness

func (publicKey *PublicKey) EncryptAndReturnRandomness(rand io.Reader, m *big.Int) (c *big.Int, x *big.Int, err error)

EncryptAndReturnRandomness encrypts the plaintext m and also returns the randomness used for the encryption.

func (*PublicKey) Gamma

func (publicKey *PublicKey) Gamma() *big.Int

Gamma returns N+1

func (*PublicKey) HomoAdd

func (publicKey *PublicKey) HomoAdd(c1, c2 *big.Int) (*big.Int, error)

HomoAdd homomorphically adds two ciphertexts, producing a ciphertext of the sum of the two plaintexts.

func (*PublicKey) HomoMult

func (publicKey *PublicKey) HomoMult(m, c1 *big.Int) (*big.Int, error)

HomoMult homomorphically multiplies a ciphertext c1 by a plaintext scalar m, equivalent to encrypting m * plaintext(c1).

func (*PublicKey) NSquare

func (publicKey *PublicKey) NSquare() *big.Int

NSquare returns N^2, used as the modulus for ciphertext operations.