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Board Service Announcements
Re: [ANN] bitaddress.org Safe JavaScript Bitcoin address/private key
by
casascius
on 30/01/2013, 03:45:02 UTC
I might throw up a bounty to do an "intermediate code generator" as well.  (this won't be hard - just another simple recipe using scrypt,sha256,base58)

Here is what I imagine... another tab that says "Encrypted Wallets"

On the tab there would be two functions: generate intermediate code, and decrypt encrypted wallet

THe intermediate code takes a passphrase and makes a code (or series of codes) out of it.  The code can be used by someone else to generate bip38-encrypted paper wallets without knowing the passphrase.  Intermediate code generator takes a passphrase as input, and outputs a string that simply encodes 4 bytes of salt, 4 bytes of a combined "batch" and "sequence" number, and one compressed EC point.  The EC point is G * sha256(scrypt(passphrase, salt, 16384, 8, 8 ) + batch+sequence bytes) or something substantially similar.  The sequence number can be incremented to create more intermediate codes from the same passphrase without repeating the scrypt.