RE: documentation about key encryption:
See the comment at the top of crypter.h:
Private key encryption is done based on a CMasterKey,
which holds a salt and random encryption key.
CMasterKeys are encrypted using AES-256-CBC using a key
derived using derivation method nDerivationMethod
(0 == EVP_sha512()) and derivation iterations nDeriveIterations.
vchOtherDerivationParameters is provided for alternative algorithms
which may require more parameters (such as scrypt).
Wallet Private Keys are then encrypted using AES-256-CBC
with the double-sha256 of the public key as the IV, and the
master key's key as the encryption key (see keystore.[ch]).
The way I think of it: Take the passphrase and salt and SHA512-hash them nDerivationIterations times. That gets you an encryption key and initialization vector.
Use those to AES-256-decrypt the encrypted_key master key.
Now you can AES-256-decrypt the private keys, using the master key as the key and the (double-sha256-hash) PUBLIC part of the keypair as the initialization vector.
The "SHA-512-hash them a bunch of times" is actually done by the OpenSSL EVP_BytesToKey routine-- documentation for that is here:
http://www.openssl.org/docs/crypto/EVP_BytesToKey.htmlI'd been wondering about this for awhile. Thanks for the info.
Glad to see you are working on this again jackjack. Once I can retire one of my old wallets, I'll send you a donation.