# Gavin Andresen
# 2012-02-01 14:37:51
# https://bitcointalk.org/index.php?topic=62181.msg725958#msg725958

I apologize for the shouting, it's been a hard couple of weeks.  And thanks for the support. @p{par}

Very quickly, the problem with any chain split is double spends.  An attacker can spend his bitcoins twice, once using CHECKSIGEX and some script instead of a public key.  They can wait for the coins to confirm on the "new" chain, and then they can spend the coins again, using CHECKSIG, on the old chain. @p{par}

The result would be massive confusion and chaos as those "old" users slowly upgraded and then found their wallets had NEGATIVE balances after the upgrade. @p{brk}