def encrypt_with_ad(self, ad: bytes, plaintext: bytes) -> bytes:
"""
If k is non-empty returns ENCRYPT(k, n++, ad, plaintext). Otherwise returns plaintext.
:param ad: bytes sequence
:param plaintext: bytes sequence
:return: ciphertext bytes sequence
"""
if self.n == MAX_NONCE:
raise NoiseMaxNonceError('Nonce has depleted!')
if not self.has_key():
return plaintext
ciphertext = self.cipher.encrypt(self.k, self.n, ad, plaintext)
self.n = self.n + 1
return ciphertext
def decrypt_with_ad(self, ad: bytes, ciphertext: bytes) -> bytes:
"""
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.
:param ad: bytes sequence
:param ciphertext: bytes sequence
:return: plaintext bytes sequence
"""
if self.n == MAX_NONCE:
raise NoiseMaxNonceError('Nonce has depleted!')
if not self.has_key():
return ciphertext
plaintext = self.cipher.decrypt(self.k, self.n, ad, ciphertext)
self.n = self.n + 1
return plaintext