base/lib/stellar/util/strkey.rb
module Stellar
module Util
require "base32"
require "digest/crc16_xmodem"
class StrKey
VERSION_BYTES = {
account_id: [6 << 3].pack("C"), # Base32-encodes to 'G...'
seed: [18 << 3].pack("C"), # Base32-encodes to 'S...'
pre_auth_tx: [19 << 3].pack("C"), # Base32-encodes to 'T...'
hash_x: [23 << 3].pack("C"), # Base32-encodes to 'X...'
muxed: [12 << 3].pack("C"), # Base32-encodes to 'M...'
signed_payload: [15 << 3].pack("C") # Base32-encodes to 'P...'
}
def self.check_encode(version, byte_str)
version_byte = VERSION_BYTES[version]
raise ArgumentError, "Invalid version: #{version}" if version_byte.blank?
payload = version_byte + byte_str.dup.force_encoding("BINARY")
check = checksum(payload)
# TODO: sort out, is it 100% safe to remove padding
# SEP-23 says yes, but shit happens
Base32.encode(payload + check).tr("=", "")
end
# Converts an Stellar::MuxedAccount to its string representation, forcing the ed25519 representation.
# @param muxed_account [Stellar::MuxedAccount] account
# @return [String] "G.."-like address
def self.encode_muxed_account(muxed_account)
if muxed_account.ed25519
check_encode(:account_id, muxed_account.ed25519)
else
check_encode(:muxed, muxed_account.med25519!.ed25519 + [muxed_account.med25519!.id].pack("Q>"))
end
end
# Returns a Stellar::MuxedAccount, forcing the ed25519 discriminant
#
# @param strkey [String] address string to decode
# @return [Stellar::MuxedAccount] MuxedAccount with ed25519 discriminant
def self.decode_muxed_account(strkey)
case strkey
when /^G[0-9A-Z]{55}$/
ed25519 = check_decode(:account_id, strkey)
Stellar::MuxedAccount.ed25519(ed25519)
when /^M[0-9A-Z]{68}$/
payload = check_decode(:muxed, strkey)
Stellar::MuxedAccount.med25519(ed25519: payload[0, 32], id: payload[32, 8].unpack1("Q>"))
else
raise "cannot decode MuxedAccount from #{strkey}"
end
end
# @param payload [Stellar::SignerKey::Ed25519SignedPayload]
# @return [String] "P.."-like address
def self.encode_signed_payload(payload)
check_encode(:signed_payload, payload.to_xdr)
end
# @param strkey [String] address string to decode
# @return [Stellar::SignerKey::Ed25519SignedPayload]
def self.decode_signed_payload(strkey)
raw = check_decode(:signed_payload, strkey)
Stellar::SignerKey::Ed25519SignedPayload.from_xdr(raw, :raw)
end
def self.check_decode(expected_version, str)
decoded = begin
Base32.decode(str)
rescue
raise ArgumentError, "Invalid base32 string"
end
version_byte = decoded[0]
payload = decoded[1...-2]
check = decoded[-2..-1]
version = VERSION_BYTES.key(version_byte)
raise ArgumentError, "invalid encoded string" if str != Base32.encode(decoded).tr("=", "")
raise ArgumentError, "Unexpected version: #{version.inspect}" if version != expected_version
raise ArgumentError, "Invalid checksum" if check != checksum(decoded[0...-2])
payload
end
# return the "XModem CRC16" (CCITT-like, but with 0-init and MSB first)
# packed into a string in little-endian order
def self.checksum(bytes)
crc = Digest::CRC16XModem.checksum(bytes)
[crc].pack("S<")
end
end
end
end