def crypto_box_afternm(message, nonce, k):
"""
Encrypts and returns the message ``message`` using the shared key ``k`` and
the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise exc.ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise exc.ValueError("Invalid shared key")
padded = b"\x00" * crypto_box_ZEROBYTES + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box_afternm(ciphertext, padded, len(padded), nonce, k)
ensure(rc == 0,
'Unexpected library error',
raising=exc.RuntimeError)
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
def crypto_box_afternm(message, nonce, k):
"""
Encrypts and returns the message ``message`` using the shared key ``k`` and
the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise exc.ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise exc.ValueError("Invalid shared key")
padded = b"\x00" * crypto_box_ZEROBYTES + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box_afternm(ciphertext, padded, len(padded), nonce, k)
ensure(rc == 0,
'Unexpected library error',
raising=exc.RuntimeError)
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
