def crypto_box(message, nonce, pk, sk):
"""
Encrypts and returns a message ``message`` using the secret key ``sk``,
public key ``pk``, and the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise exc.ValueError("Invalid nonce size")
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise exc.ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise exc.ValueError("Invalid secret key")
padded = (b"\x00" * crypto_box_ZEROBYTES) + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box(ciphertext, padded, len(padded), nonce, pk, sk)
ensure(rc == 0, 'Unexpected library error', raising=exc.RuntimeError)
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
def crypto_box(message, nonce, pk, sk):
"""
Encrypts and returns a message ``message`` using the secret key ``sk``,
public key ``pk``, and the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce size")
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
padded = (b"\x00" * crypto_box_ZEROBYTES) + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box(ciphertext, padded, len(padded), nonce, pk, sk)
assert rc == 0
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
