bitcoin-s

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Torkel Rogstad 4bdc7966d0 Add notion of address types in wallet In this commit we 1) Add the notion of address types in the wallet, and remove the emphasis on account types. Users now just request a segwit/nested-segwit/legacy address, and we take care of querying for the correct account 2) Fix a bug where a wallet could only get addresses for its default address type. This was a pretty minor bug, where a few values that should have been dynamic was hard coded.	2019-07-16 12:36:38 +02:00
..
src/main/scala/org/bitcoins/wallet	Add notion of address types in wallet	2019-07-16 12:36:38 +02:00
README.md	Process outgoing transactions (#555 )	2019-07-09 06:25:24 -05:00

Torkel Rogstad 4bdc7966d0 Add notion of address types in wallet

In this commit we
1) Add the notion of address types in the wallet, and remove
    the emphasis on account types. Users now just request
    a segwit/nested-segwit/legacy address, and we take care
    of querying for the correct account
2) Fix a bug where a wallet could only get addresses for
    its default address type. This was a pretty minor bug,
    where a few values that should have been dynamic was
    hard coded.

2019-07-16 12:36:38 +02:00

src/main/scala/org/bitcoins/wallet

Add notion of address types in wallet

2019-07-16 12:36:38 +02:00

README.md

Process outgoing transactions (#555 )

2019-07-09 06:25:24 -05:00

README.md

wallet

This is meant to be a stand alone project that can be used as a cold storage wallet and hot wallet.

Features

utxo storage
key storage
key generation
coin selection
transaction building
fee calculation

Design choices

Private key material is just stored once, as the mnemonic code used to initialize the wallet
Addresses we hand out to users are stored with their BIP44/BIP49/BIP84 paths and script types, so that everything we need for spending the money sent to an address is derivable.
The wallet is a "dumb" wallet that acts mostly as a database of UTXOs, transactions and addresses, with associated operations on these. The wallet module does very little verification of incoming data about transactions, UTXOs and reorgs. We're aiming to write small, self contained modules, that can be composed together into more fully fledged systems. That means the chain and node modules does the actual verification of data we receive, and wallet just blindly acts on this. This results in a design where you can swap out node for a Bitcoin Core full node, use it with hardware wallets, or something else entirely. However, that also means that users of wallet that doesn't want to use the other modules we provide have to make sure that the data they are feeding the wallet is correct.

Database structure

We store information in the following tables:

TXOs - Contains both the information needed to spent it as well as information related to wallet state (confirmations, spent/unspent etc)
Addresses - must reference the account it belongs to
Accounts

Mnemonic encryption

The mnemonic seed to the Bitcoin-S wallet is written to disk, encrypted. The file name is $HOME/.bitcoin-s/$NETWORK/encrypted_bitcoin-s_seed.json. We store it in a JSON object that looks like this:

{
  "iv": "initializationVector",
  "cipherText": "encryptedCipherText",
  "salt": "saltUsedInEncryption"
}

The parts that's relevant to this part of the wallet is WalletStorage.scala (where we handle the actual reading from and writing to disk), EncryptedMnemonic.scala (where we convert an encrypted mnemonic to a cleartext mnemonic) and AesCrypt.scala (where do the actual encryption/decryption).

We use AES encryption for this, block cipher mode and PKCS5 padding. The wallet password is fed into the PBKDF2 key stretching function, using SHA512 as the HMAC function. This happens in PBKDF2.scala.