On Sun, Apr 7, 2013 at 5:34 PM, Pieter Wuille <pieter.wuille@gmail.com> wrote:

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.

Without significant effort, I don't think we're going to be able to get that number down. I'd like to stress that without making these non-standard encodings effectively invalid on the network, pretty much every full node implementation needs to depend on OpenSSL to guarantee compatibility (and that is hoping OpenSSL doesn't change its supported encodings), or make assumptions about which deviations are allowed.

The next question, I guess, is at which transaction frequency it's acceptable to move forward with this? The first step is definitely just not accepting them into memory pools, but leaving them valid inside blocks. Actual network rules will need to come later. However, even just not accepting them into memory pools will it make very hard (if not impossible) for the buggy clients that create transactions to get any confirmations. I'm not sure... 0.6% isn't much, but 9600 transactions is.

Pieter