companyzero/sntrup4591761

Streamlined NTRU Prime 4591^761 in Go

sntrup4591761

Streamlined NTRU Prime 4591^761

sntrup4591761 is a Go library implementing the Streamlined NTRU Prime 4591⁷⁶¹ cryptosystem. Most of the code consists of a port of the reference C implementation.

Constants

• PublicKeySize

The size of an encoded public key.

• PrivateKeySize

The size of an encoded private key.

• CiphertextSize

The size of a ciphertext encapsulating a shared key.

• SharedKeySize

The size of a shared key.

Functions

• GenerateKey(s io.Reader) (*[PublicKeySize]byte, *[PrivateKeySize]byte, error)

GenerateKey returns a new a public/private key pair with randomness from s. GenerateKey will fail if randomness cannot be obtained from s.

• Encapsulate(s io.Reader, publicKey *[PublicKeySize]byte) (*[CiphertextSize]byte, *[SharedKeySize]byte, error)

Encapsulate generates a random shared key and encrypts it with the given public key. The shared key and its corresponding ciphertext are returned. Encapsulate will fail if randomness cannot be obtained from s.

• Decapsulate(ciphertext *[CiphertextSize]byte, privateKey *[PrivateKeySize]byte) (*[SharedKeySize]byte, int)

Decapsulate uses a private key to decrypt a ciphertext, returning an encapsulated shared key. Decapsulate will return zero if the ciphertext is invalid.

Examples

The library is accompanied by three small standalone applications demonstrating its use: keygen, encap, and decap. A test script is provided to exercise these applications comprehensively.

To build the bundled applications, ensure that the repository lies in your GOPATH and run make. Once built, the auxiliary test script can be triggered by invoking ./test.

Sage tests

A set of 128 different instances of NTRU Prime were simulated in Sage and their data compiled in testdata/sage128.gz. The TestSage Go test contrasts the results obtained by the library with those from the Sage implementation. Please note that this test can take seconds to complete.

Running the tests

To run the Sage tests and other tests, ensure that the repository lies in your GOPATH and run go test -v.

License

sntrup4591761 is licensed under the copyfree ISC License.

sntrup4591761's Issues

add exported function to derive public key from private key

func (sk *PrivateKey) Public() *PublicKey {
	pk := new(PublicKey)
	copy(pk[:], sk[382:])
	return pk
}

Regenerate sage128.gz?

It looks like the sage script used may have been older than the latest released sage script ( https://ntruprime.cr.yp.to/ntruprime-20200930.sage ).

Is there already a program that generates a fresh testdata/sage128.gz or would such a program be a useful contribution?

Other NTRUPrime systems?

• sntrup653
• ntrulpr653
• sntrup761
• sntrup4591761
• ntrulpr761
• ntrulpr4591761
• sntrup857
• ntrulpr857