Embodiments of the present invention relate to systems and methods to authenticate software licenses. One embodiment of the present invention comprises a method where a vendor creates a reversible hash from a known, predetermined seed value, encrypts the hash to generate a digital signature, and sends the digital signature to the customer. The customer enters the digital signature. The customer's client computer reverses the reversible hash to obtain a determined seed value. The client has access to the known seed value used by the vendor. The known seed value is compared to the determined seed value. If the seed values compare, the software license and the associated software is authenticate.