Area58check
What is Area58?
Area58 is a library to encode and decode base58check. Base58check is used in Bitcoin whenever there is a need for a user to read or transcribe a number, such a bitcoin adresses, encrypted key, private key, or script hash.
What is NOT Area58?
This can’t be used to generate bitcoin address from a private key. It’s only a base58check encoder/decoder. But it’s easy to generate a bitcoin address from the private key.
Example: If you want to generate a (uncompressed) bitcoin address using this library you can…
iex> privkey = "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |> Base.decode16!()
iex> {uncompressed_pubkey, _priv_key} = :crypto.generate_key(:ecdh, :crypto.ec_curve(:secp256k1), privkey)
iex> uncompressed_pubkey = :crypto.hash(:ripemd160, :crypto.hash(:sha256, uncompressed_pubkey))
iex> Area58check.encode(uncompressed_pubkey, version: <<0>>)
%{encoded: "1CLrrRUwXswyF2EVAtuXyqdk4qb8DSUHCX",
version: :p2pkh,
version_bin: <<0>>}
or you can use another library that does all that for you.
What is base58check?
Encoding
Base58 charset is based on easy to trancribe characters, upper and
lower case letters and numbers excluding 0
, O
, l
, I
.
Bitcoin version prefixes
Usually there is a version (binary number) to signal what kind of string is being encoded. list of bitcoin prefixes
Example: for standard bitcoin address, is used the hexadecimal number 0x00, for compressed WIF (allows to import a private key in bitcoin) is used 0x80, etc.
Checksum
When a string is encoded, 4 bytes (or 32bits), are added to the end by
Area58check.encode
function as a checksum to make sure that no
characters were wrongly transcribed. This checksum is not meant to allow
to fix a wrong transcribed string, but it allows to verify if string is
correct or not.
Usage
Encoding
Encode a private key into WIF (Wallet Import Format):
iex> privkey = "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |> Base.decode16!()
iex> Area58check.encode(privkey, version: :wif )
%{encoded: "5HpneLQNKrcznVCQpzodYwAmZ4AoHeyjuRf9iAHAa498rP5kuWb",
version: :wif,
version_bin: <<128>>}
iex> Area58check.encode(privkey, version: [128] )
%{encoded: "5HpneLQNKrcznVCQpzodYwAmZ4AoHeyjuRf9iAHAa498rP5kuWb",
version: :wif,
version_bin: <<128>>}
iex> Area58check.encode(privkey, version: <<128>>)
%{encoded: "5HpneLQNKrcznVCQpzodYwAmZ4AoHeyjuRf9iAHAa498rP5kuWb",
version: :wif,
version_bin: <<128>>}
iex> Area58check.encode(privkey, version: 0x80)
%{encoded: "5HpneLQNKrcznVCQpzodYwAmZ4AoHeyjuRf9iAHAa498rP5kuWb",
version: :wif,
version_bin: <<128>>}
Encode a public key into an address:
iex> {uncompressed_pubkey, _priv_key} = :crypto.generate_key(:ecdh, :crypto.ec_curve(:secp256k1), privkey)
iex> derived_uncomp_pubkey = :crypto.hash(:ripemd160, :crypto.hash(:sha256, uncompressed_pubkey))
iex> Area58check.encode(derived_uncomp_pubkey, version: 0x00)
%{encoded: "1CLrrRUwXswyF2EVAtuXyqdk4qb8DSUHCX",
version: :p2pkh,
version_bin: <<0>>}
Error when version is unknown:
iex> Area58check.encode(privkey, version: :jhkdsfajhkfdasjhkfd)
** (ArgumentError) :jhkdsfajhkfdasjhkfd is not a recognized version.
You can either pass a charlist (ex: [4, 136, 178, 30]), number (ex:
70617039), hexadecimal (ex: 0x043587CF), binary version (ex: <<4,
136, 178, 30>>), or a recognized atom like any of: :bip32_privkey,
:bip32_pubkey, :p2pkh, :p2sh, :tesnet_bip32_privkey,
:tesnet_bip32_pubkey, :tesnet_p2pkh, :tesnet_p2sh, :tesnet_wif, :wif
Decoding
Decoding strings encoded with base58check:
iex> Area58check.decode("1CLrrRUwXswyF2EVAtuXyqdk4qb8DSUHCX")
{:ok,
%{decoded: <<124, 106, 230, 190, 9, 150, 81, 133, 169, 75, 13, 161, 139, 201,
42, 157, 252, 238, 97, 23>>,
version: :p2pkh,
version_bin: <<0>>}}
iex> Area58check.decode("5HpneLQNKrcznVCQpzodYwAmZ4AoHeyjuRf9iAHAa498rP5kuWb")
{:ok,
%{decoded: <<1, 35, 69, 103, 137, 171, 205, 239, 1, 35, 69, 103, 137, 171, 205,
239, 1, 35, 69, 103, 137, 171, 205, 239, 1, 35, 69, 103, 137, 171, 205,
239>>,
version: :wif,
version_bin: <<0>>}}
If checksum is not valid returns error:
iex> Area58check.decode("1CheckSumError")
{:error, :checksum_incorrect}
If contains a non valid character like 0
, O
, l
, I
, returns
error:
iex> Area58check.decode("ContainsInvalidCharacter0")
{:error, :incorrect_base58}
Installation
If available in Hex, the package can be installed
by adding area58check
to your list of dependencies in mix.exs
:
def deps do
[
{:area58check, "~> 0.1.0"},
]
end
The docs can be found at https://hexdocs.pm/area58.