def crypto_box_beforenm(pk, sk):
"""
Computes and returns the shared key for the public key ``pk`` and the
secret key ``sk``. This can be used to speed up operations where the same
set of keys is going to be used multiple times.
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise exc.ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise exc.ValueError("Invalid secret key")
k = ffi.new("unsigned char[]", crypto_box_BEFORENMBYTES)
rc = lib.crypto_box_beforenm(k, pk, sk)
ensure(rc == 0, 'Unexpected library error', raising=exc.RuntimeError)
return ffi.buffer(k, crypto_box_BEFORENMBYTES)[:]
def crypto_box_beforenm(pk, sk):
"""
Computes and returns the shared key for the public key ``pk`` and the
secret key ``sk``. This can be used to speed up operations where the same
set of keys is going to be used multiple times.
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
k = ffi.new("unsigned char[]", crypto_box_BEFORENMBYTES)
rc = lib.crypto_box_beforenm(k, pk, sk)
assert rc == 0
return ffi.buffer(k, crypto_box_BEFORENMBYTES)[:]
