DIGITAL SIGNATURE SYSTEM BASED ON A CLOUD OF DEDICATED LOCAL DEVICES

Method and apparatus are disclosed for attack tolerant implementations of public key digital signatures based on a cloud of dedicated local devices. A system includes a first security device, a second security device, and a computing device remote from the first and second security devices. The first security device stores a first private key and, in response to receiving a message, generates a first signature based on a message received from the computing device and the first private key. The second security device stores a second private key that is independent from the first private key and, in response to receiving a message, generates a second signature based on a message received from the computing device and the first private key. The computing device generates a composite cryptographic signature based on the first signature and the second signature.