# Gavin Andresen
# 2011-08-15 14:08:14
# https://bitcointalk.org/index.php?topic=37157.msg457384#msg457384

I'd say the short answer to "is it possible to accept them again in the near future" is no (where "near" is in the next six months). @p{par}

I agree with Maged@p{--} before enabling new opcodes, I'd like to see a peer-reviewed academic-style paper that works through the security implications of the existing set of opcodes and gives a nice framework for thinking about new (or disabled old) opcodes. Doing that is way outside my own personal level of expertise; I know only enough about designing secure algorithms to know that I  have no idea whether or not re-enabling OP_XOR would have security implications for bitcoin. @p{par}

Same goes for enabling nLockTime / transaction replacement, although I suspect that proving that transaction replacement doesn't open up any subtle attacks may be harder than proving security properties of opcodes. @p{brk}