Editing Blind Delegation of Quantum Digital Signature (section)

==Outline==

The Blind QDS Protocol consists of 5 stages: setup, key distribution, message blinding, signing and verification.
Each pair of participants share a unique key using Simon et al.'s QKD Algorithm.

====Setup====
There are 3 participants. The owner is the one who will transform the message into a matrix form and blind it.
The signer will sign it. The verifier is the one who checks if a signature matches a message. 

====Key Distribution====
All three pairs establish their pairwise quantum key matrices using the QKD protocol.

====Message Blinding====
The owner of the message now converts the message into matrix format.
Then (s)he blinds the message matrix using the key shared with the verifier by multiplying the matrices.
Now, (s)he encrypts the blind message with the key shared with the signer by multiplying the matrices.
Finally, (s)he sends the encrypted matrix and the determinant of the blinded matrix to the signer and only the determinant of the message matrix to the verifier.

====Signing====
The signer creates a signature for the blinded message which means that he does not know the message matrix.
He decrypts the encrypted message with his shared key to obtain the blinded message and checks its authenticity by comparing its determinant value with the received value.
He then creates the signature using the blinded message and the key shared with the verifier and sends it to the verifier.

====Verification====
The verifier decrypts the signature using his key shared with the signer.
Next, he un-blinds the blinded message using the key shared with the owner.
He verifies the message matrix by comparing its determinant value with the received value.