>> They can attack an encrypted communication and probably decrypt it No. If you do it right, nobody on earth can decrypt it. From Bruce Schneier: >> In fact,

>> They can attack an encrypted communication and probably decrypt it No. If you do it right, nobody on earth can decrypt it. From Bruce Schneier: >> In fact, we cannot even imagine a world where 256-bit brute force searches are possible. It requires some fundamental breakthroughs in physics and our understanding of the universe. For public-key cryptography, 2048-bit keys have same sort of property; longer is meaningless. and >> These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space. http://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html http://www.schneier.com/blog/archives/2009/09/the_doghouse_c... Also, from Bitcoin Talk: >> But what about very well funded entities such as the US National Security Agency (NSA)? Could they build a machine to crack a 256 bit key? Assume they could build a theoretical nanocomputer that executes 10^13 instructions per second (approximate rate of atomic vibrations) in a space of a cube with a side that is 5.43nm across (This is the approximate size of a silicon lattice10 atoms wide, or a crystal containing 1000 silicon atoms). Assume that it could calculate an attempt in 10 cycles. Such a computer the size of the earth would take more than 10^13 years (roughly 58 times the estimated age of the earth) to attack a 256 bit algorithm via brute force. https://bitcointalk.org/index.php?topic=360.15;wap2 https://bitcointalk.org/index.php?topic=360.15;wap2