def update(self, input):
i = OpenSSL.c_int(0)
buffer = OpenSSL.malloc(b"", len(input) + self.cipher.get_blocksize())
inp = OpenSSL.malloc(input, len(input))
if OpenSSL.EVP_CipherUpdate(self.ctx, OpenSSL.byref(buffer),
OpenSSL.byref(i), inp, len(input)) == 0:
raise Exception("[OpenSSL] EVP_CipherUpdate FAIL ...")
return buffer.raw[0:i.value]
