# Gavin Andresen
# 2012-03-06 13:34:16
# https://bitcointalk.org/index.php?topic=67508.msg786207#msg786207

@s{quotedtext}
@s{quotedtext}
 @p{brk}
I was thinking of a kind of replay attack: @p{par}

+ Control the TPM's view of the world (e.g. make it seem like it is Jan 1, 2010) @p{brk}
+ Get the TPM to sign a small transaction, shut it down. @p{brk}
+ Increment time, get it to sign another transaction @p{brk}
+ Repeat. @p{par}

Replace "time" with "blockchain" and you've got the same problem: can the TPM know that it's view of the external world is correct?  If it sends a nonce (to prevent replay attacks) to some external service that adds a timestamp and signs it with a public key known to the TPM code... then we're back to using two different servers. @p{brk}