Digital signatures are growing in importance as a legal standing with traditional handwritten signatures, most secure web transactions today are already dependent on digital signatures, which are included as part of the digital certificates a server presents to a client identify. The digital certificates bind a key exchange algorithm with an identity and enable a receiver to verify the sender's digital signature, or as case when setting up a secure connection with a web server, enable a client to encrypt information.
This paper, describes the quantum computing with the representation of quantum bit, then this paper explains the proposed algorithm which is serving digital signature under unsecure communication channel by applying the quantum key exchange algorithm which is more complex in degree of computational complexity in data security of client than the classical key exchange algorithm.