I don't think it's ethical. I clearly identified myself as a competitor and we were ahead of them technology wise so he had an incentive to talk to me and I shared a lot of our implementation details (not to give enough leverage, but enough to support an interesting conversation between hackers). I return he told me quite a lot about their implementation, but I don't think it's OK to share. I don't expect him to share what I told him as well. The dialogue was clearly off the record.

Or you're interested in our implementation?