My limited mind induces me to think that a certificate become subject to timing attacks on the RSA private signing key. This appears to meet the main critieria of fixed data (for instance, a bank's certificate in/on ecash), processed widely by a small group of machines (eg a subset of customers) on inherently untrusted machines (home PC's) which may or may not have the right software/operating system parts. Certificates in general, do not appear to lend themselves to "blinding". In this case, certificate verification processes seem flawed and highly unreliable. eg a merchant gets lots of data containing a bank(s) certificate, and probably encrypted data. Is this the death knell for STT/SEPP and ecash/echeque systems ??? Some ramblings and thoughts. lyal