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.In some examples, a method performed under control of a receiver device may include calculating a public key of the receiver device based on a system parameter, calculating a temporary common key of the receiver device based on a temporary public key of the sender device and a secret key of a receiver device, deciphering the ciphertext based on the temporary common keys of receiver device, determining whether the digital signature received is generated by sender device. A temporary public key of the sender device, the secret key of the receiver device and the temporary common keys of the receiver device are engaged in a non-associative octonion ring.