Signcryption: Signing and Encrypting
Normally, when we digitally sign something, we have to create a hash of the data, and then use the public key of the receipitant to encrypt it. So can we sign something at the same time as we encrypt it? Well, we can, and one of the first papers to define this was created by Yuliang Zheng [here]:
One interesting method was created by John Malone-Lee [here][1]:
The method basically uses crypto pairing, and uses crypto pairing mapping of:
And where we use a mapping of one elliptic curve, to another, and then to produce another elliptic curve.
Method
With Signcryption, we can use the Malone-Lee signcryption method [here]. In this case we have a PKG (Private Key Generator), and which generate the private key for Bob and Alice. Bob will have an ID of IDb and Alice will have an ID of IDa.
For the key generation part, the PKG computes the private key of dID and is able to send this to Bob and Alice. Now Alice wants to send a…