Cryptographic tamper evidence

We propose a new notion of cryptographic tamper evidence. A tamper-evident signature scheme provides an additional procedure Div which detects tampering: given two signatures, Div can determine whether one of them was generated by the forger. Surprisingly, this is possible even after the adversary has inconspicuously learned (exposed1 ) some — or even all — the secrets in the system. In this case, it might be impossible to tell which signature is generated by the legitimate signer and which by the forger, but at least the fact of the tampering will be made evident. We define several variants of tamper-evidence, differing in their power to detect tampering. In all of these, we assume an equally powerful adversary: she adaptively controls all the inputs to the legitimate signer (i.e., all messages to be signed and their timing), and observes all his outputs; she can also adaptively expose all the secrets at arbitrary times. We provide tamper-evident schemes for all the variants. S...

• Type: Conference
• Year: 2003
• Where: CCS
• Authors: Gene Itkis
• Keywords: CCS 2003, Legitimate Signer, Security Privacy, Signature Schemes, Tamper-evident Signature Scheme