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class noise.state.CipherState(noise_protocol)[source]

Implemented as per Noise Protocol specification - paragraph 5.1.

The initialize_key() function takes additional required argument - noise_protocol.

This class holds an instance of Cipher wrapper. It manages initialisation of underlying cipher function with appropriate key in initialize_key() and rekey() methods.

decrypt_with_ad(ad: bytes, ciphertext: bytes) → bytes[source]

If k is non-empty returns DECRYPT(k, n++, ad, ciphertext). Otherwise returns ciphertext. If an authentication failure occurs in DECRYPT() then n is not incremented and an error is signaled to the caller.

Parameters:
  • ad – bytes sequence
  • ciphertext – bytes sequence
Returns:

plaintext bytes sequence
encrypt_with_ad(ad: bytes, plaintext: bytes) → bytes[source]

If k is non-empty returns ENCRYPT(k, n++, ad, plaintext). Otherwise returns plaintext.

Parameters:
  • ad – bytes sequence
  • plaintext – bytes sequence
Returns:

ciphertext bytes sequence
has_key()[source]
Returns:True if self.k is not an instance of Empty
initialize_key(key)[source]
Parameters:key – Key to set within CipherState
class noise.state.HandshakeState[source]

Implemented as per Noise Protocol specification - paragraph 5.3.

The initialize() function takes different required argument - noise_protocol, which contains handshake_pattern.

classmethod initialize(noise_protocol: NoiseProtocol, initiator: bool, prologue: bytes = b'', s: _KeyPair = None, e: _KeyPair = None, rs: _KeyPair = None, re: _KeyPair = None) → HandshakeState[source]

Constructor method. Comments below are mostly copied from specification. Instead of taking handshake_pattern as an argument, we take full NoiseProtocol object, that way we have access to protocol name and crypto functions

Parameters:
  • noise_protocol – a valid NoiseProtocol instance
  • initiator – boolean indicating the initiator or responder role
  • prologue – byte sequence which may be zero-length, or which may contain context information that both parties want to confirm is identical
  • s – local static key pair
  • e – local ephemeral key pair
  • rs – remote party’s static public key
  • re – remote party’s ephemeral public key
Returns:

initialized HandshakeState instance
read_message(message: Union[bytes, bytearray], payload_buffer: bytearray)[source]

Comments below are mostly copied from specification.

Parameters:
  • message – byte sequence containing a Noise handshake message
  • payload_buffer – buffer-like object
Returns:

None or result of SymmetricState.split() - tuple (CipherState, CipherState)
write_message(payload: Union[bytes, bytearray], message_buffer: bytearray)[source]

Comments below are mostly copied from specification.

Parameters:
  • payload – byte sequence which may be zero-length
  • message_buffer – buffer-like object
Returns:

None or result of SymmetricState.split() - tuple (CipherState, CipherState)
class noise.state.SymmetricState[source]

Implemented as per Noise Protocol specification - paragraph 5.2.

The initialize_symmetric function takes different required argument - noise_protocol, which contains protocol_name.

decrypt_and_hash(ciphertext: bytes) → bytes[source]

Sets plaintext = DecryptWithAd(h, ciphertext), calls MixHash(ciphertext), and returns plaintext. Note that if k is empty, the DecryptWithAd() call will set plaintext equal to ciphertext.

Parameters:ciphertext – bytes sequence
Returns:plaintext bytes sequence
encrypt_and_hash(plaintext: bytes) → bytes[source]

Sets ciphertext = EncryptWithAd(h, plaintext), calls MixHash(ciphertext), and returns ciphertext. Note that if k is empty, the EncryptWithAd() call will set ciphertext equal to plaintext.

Parameters:plaintext – bytes sequence
Returns:ciphertext bytes sequence
classmethod initialize_symmetric(noise_protocol: NoiseProtocol) → SymmetricState[source]

Instead of taking protocol_name as an argument, we take full NoiseProtocol object, that way we have access to protocol name and crypto functions

Comments below are mostly copied from specification.

Parameters:noise_protocol – a valid NoiseProtocol instance
Returns:initialised SymmetricState instance
mix_hash(data: bytes)[source]

Sets h = HASH(h + data).

Parameters:data – bytes sequence
mix_key(input_key_material: bytes)[source]
Parameters:input_key_material –
Returns:
split()[source]

Returns a pair of CipherState objects for encrypting/decrypting transport messages.

Returns:tuple (CipherState, CipherState)

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