as some may know, Bitcoin uses DER-encoded signatures in its transactions. However, OpenSSL (which is used to verify them) accepts more than just the strict DER specification (it allows negative numbers, extra zero padding, extra bytes at the end, and perhaps more). As we don't like the de-facto specification of the Bitcoin block validity rules to depend on OpenSSL, we're trying to introduce a rule to make such non-standard signatures invalid. Obviously, that can't be done as long as any significant amount of clients on the network is creating these.

I've monitored all transactions the past weeks (1.4M transactions), and it seems 9641 of them contain at least one non-standard signature. See https://bitcointalk.org/index.php?topic=169620.0 for a list of the top addresses that had coins used as inputs in such transactions. If you recognize any of these addresses, or have an idea of who owns them or what software they are using, please let me know.

Thanks!