Bitcoin: A Peer-to-Peer Electronic Cash System @davidshares
| outpace any competing chains. To modify a past block, an attacker would have to
redo the proof-of-work of the block and all blocks after it and then catch up with and surpass @davidshares
| attacker catching up from a given deficit is analogous to a Gambler's
Ruin problem. Suppose a gambler with unlimited credit starts at a deficit and plays potentially an
| Sequences II: Methods in Communication, Security and Computer Science, pages 329-334, 1993.
 S. Haber, W.S. Stornetta, "Secure names for bit-strings," In Proceedings of the 4th @davidshares
| 365 = 4.2MB per year. With computer systems
typically selling with 2GB of RAM as of 2008, and Moore's Law predicting current growth of
1.2GB per year, storage should not be a problem @davidshares
transactions, which necessarily reveal that their inputs were owned by the same owner. The risk
is that if the owner of a key is revealed, linking could reveal other @davidshares
| to Adam Back's Hashcash , rather than newspaper or Usenet posts.
The proof-of-work involves scanning for a value that when hashed, such as with SHA-256, the
hash begins with a @davidshares
The receiver generates a new key pair and gives the public key to the sender shortly before
signing. This prevents the sender from preparing a chain of blocks ahead of time by @davidshares
| every transaction having to go through them, just like a bank.
We need a way for the payee to know that the previous owners did not sign any earlier
transactions. For our purposes, @davidshares