# Gavin Andresen
# 2011-02-04 18:33:36
# https://bitcointalk.org/index.php?topic=3092.msg44493#msg44493

@s{quotedtext}
@s{quotedtext}
 @p{brk}
Sure, every block has a unique hash. @p{par}

But I don't think that helps at all; you might see that transactions A B C D are in block #100,000 with hash H1, but after a block chain re-org block #100,000 might contain transactions A D (with block hash H2). @p{par}

The probability of that happening rapidly approaches zero as the block gets confirmed; after 6 confirmations you can safely assume it just won't happen. @p{par}