Technologies are generally described for providing a signcryption scheme. In some examples, a method performed under control of a sender device may include calculating a public key of the sender device based on a system parameter, calculating a temporary public key of the sender device based on the system parameter, calculating a temporary common key of the sender device based on a temporary secret key of the sender device and a public key of a receiver device, calculating a ciphertext from a message based on the temporary common key and generating a signature of the sender device based on an intermediate parameter, the system parameter and the secret key of the sender device. The temporary secret key of the sender device, intermediate parameter and secret key of the sender device are engaged in a non-associative octonion ring.