ElixirWallet

Creation of mnemonic phrase

The mnemonic phrase is created following the BIP-0039

indexes = Aewallet.Indexes.generate_indexes()
Aewallet.Mnemonic.generate_phrase(indexes)

Encrypting the mnemonic

The mnemonic phrase is encrypted using the AES algorithm with the CBC cipher mode. In the following diagram you can see how the Cypher Block Chaining (CBC) mode is working. More info here

In code goes like follows

Aewallet.Cypher.encrypt(data_to_encrypt, "password")

Aewallet.Cypher.decrypt(encrypted_data, "password")

Creation of master public and private key

From Mnemonic to seed

To create a seed from an already generated mnemonic phrase use the following function.

seed = Aewallet.KeyPair.generate_seed(mnemonic)

If a passphrase is not present, an empty string "" is used instead.

But an user may decide to protect their mnemonic with a passphrase, to do so add the passphrase as the next parameter

seed = Aewallet.KeyPair.generate_seed(mnemonic, pass_phrase)

Creating HD Wallet from the Seed

Following the BIP-0032

HD wallets are created from a single root seed, which is a 128bit random number. Most commonly, this seed is generated from a mnemonic as detailed in the previous section.

Every key in the HD wallet is deterministically derived from this root seed, which makes it possible to re-create the entire HD wallet from that seed in any compatible HD wallet. This makes it easy to back up, restore, export, and import HD wallets containing thousands or even millions of keys by simply transferring only the mnemonic that the root seed is derived from.

Creating extended 'master' Private key from a root seed

After we have generated our seed we can use to generate the Master Private key use the following function

master_priv_key = Aewallet.KeyPair.generate_master_key(seed, network, opts)

For the network you could use the following atoms: For creating keys on Mainnet - :mainnet For creating keys on Testnet - :testnet

For opts you could use only the option :type and as for values: For Aeternity keys use - :ae For Bitcoin keys use - :btc

If you don't state options Aeternity keys will be created by default!

Creating extended Public key

After we have generated the extended private key we can convert it to public key using the following function:

extended_pub_key = Aewallet.KeyPair.to_public_key(extended_private_key)

If the private key has an Aeternity prefix, an Aeternity public key shall be created, otherwise a Bitcoin public key.

Creating the Address

Having already the Public key generated, we can derive the address as follows

address = Aewallet.KeyPair.generate_wallet_address(pub_key, network, opts)

For the network you could use the following atoms: For creating address on Mainnet - :mainnet For creating address on Testnet - :testnet

For opts you could use only the option :type and as for values: For Aeternity address use - :ae For Bitcoin address use - :btc

Deriving a child key

Once we have the master extended keys we can use them to derive children using the following functions:

If we want to derive child private key we will use lowercase m in the path

Aewallet.KeyPair.derive(extended_priv_key, "m/0'", network)

If we want to derive child public key we will use uppercase M in the path

Aewallet.KeyPair.derive(extended_priv_key, "M/0'", network)

For network use either :mainnet or :testnet

To derive hardned key use an apostrophe ' sign after the number and a slash / to go deeper in the hierarchy

Aeternity key and address formatting

For deriving a Private key the following prefix values should be used: mainnet = 0x9E850AC9 testnet = 0x9E850AC9

For deriving a Public key the following prefix values should be used: mainnet = 0x9E86B78E testnet = 0xF350DAF8

For the address use the following Network bytes: mainnet = 0x18 testnet = 0x42

Installation

Make sure you have installed the following packages to make sure that the dependency libsecp256k1 will work properly:

sudo apt-get install autoconf autogen
sudo apt-get install libtool
sudo apt-get install libgmp3-dev

If available in Hex, the package can be installed by adding aewallet to your list of dependencies in mix.exs:

def deps do
  [
    {:aewallet, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/elixir_wallet.