Merge pull request #32 from Yamaguchi/feature/signed_message

Implement TIP 0137

lib/tapyrus.rb

@@ -6,6 +6,7 @@
 require 'ecdsa'
 require 'securerandom'
 require 'json'
+require 'jwt'
 require 'ffi'
 require 'observer'
 require 'tmpdir'
@@ -52,6 +53,8 @@ module Tapyrus
   autoload :TxBuilder, 'tapyrus/tx_builder'
   autoload :BIP175, 'tapyrus/bip175'
   autoload :Contract, 'tapyrus/contract'
+  autoload :TIP0137, 'tapyrus/tip0137'
+  autoload :JWS, 'tapyrus/jws'
 
   require_relative 'tapyrus/constants'
   require_relative 'tapyrus/ext/ecdsa'

lib/tapyrus/jws.rb

@@ -0,0 +1,76 @@
+module Tapyrus
+  module JWS
+    module_function
+
+    class DecodeError < StandardError
+    end
+
+    ALGO = 'ES256K'
+    CURVE_NAME = 'secp256k1'
+
+    # Encode data as JWS format.
+    #
+    # @param payload [Object] The data to be encoded as JWS.
+    # @param private_key_hex [String] The private key as hex string
+    # @return [String] JWS signed with the specified private key
+    def encode(payload, private_key_hex)
+      parameters = { use: 'sig', alg: ALGO }
+
+      # see https://github.com/nov/json-jwt/blob/413848c/lib/json/jwk.rb#L162-L172
+      # see https://www.rfc-editor.org/rfc/rfc5915.html#page-6
+      sequence =
+        OpenSSL::ASN1.Sequence(
+          [
+            OpenSSL::ASN1.Integer(1),
+            OpenSSL::ASN1.OctetString(OpenSSL::BN.new(private_key_hex, 16).to_s(2)),
+            OpenSSL::ASN1.ObjectId(CURVE_NAME, 0, :EXPLICIT),
+            OpenSSL::ASN1.BitString(
+              ECDSA::Format::PointOctetString.encode(point_for(private_key_hex), compression: false),
+              1,
+              :EXPLICIT
+            )
+          ]
+        )
+      ec_key = OpenSSL::PKey::EC.new(sequence.to_der)
+      jwk = JWT::JWK.new(ec_key, parameters)
+      jwks_hash = JWT::JWK::Set.new(jwk).export(include_private: false)
+      JWT.encode(payload, jwk.signing_key, jwk[:alg], { typ: 'JWT', algo: ALGO, jwk: jwks_hash })
+    end
+
+    # Decode JWS to JSON object
+    #
+    # @param jws [String] The JWS formatted data to be decoded
+    # @return [Array[JSON]] JSON objects representing JWS header and payload.
+    # @raise [JWT::VerificationError] If the verification of the signature fails
+    # @raise [Tapyrus::JWS::DecodeError] If no jwk key found in header
+    # @raise [Tapyrus::JWS::DecodeError] If jwk kty header is not EC
+    # @raise [Tapyrus::JWS::DecodeError] If jwk crv header is not P-256K
+    # @raise [Tapyrus::JWS::DecodeError] If jwk use header is not sig
+    # @raise [Tapyrus::JWS::DecodeError] If jwk alg header is not ES256K
+    def decode(jws)
+      jwt_claims, header = JWT.decode(jws, nil, false, { algorithm: ALGO })
+      jwks_hash = header.dig('jwk', 'keys')
+      raise Tapyrus::JWS::DecodeError, 'No jwk key found in header' unless jwks_hash
+      validate_header!(jwks_hash)
+      jwks = JWT::JWK::Set.new(jwks_hash)
+      JWT.decode(jws, nil, true, { algorithm: ALGO, jwks: jwks, allow_nil_kid: true })
+    end
+
+    def validate_header!(jwks)
+      jwk = jwks.first
+      raise Tapyrus::JWS::DecodeError, 'No jwk key found in header' unless jwk
+      raise Tapyrus::JWS::DecodeError, 'kty must be "EC"' if jwk['kty'] && jwk['kty'] != 'EC'
+      raise Tapyrus::JWS::DecodeError, 'crv must be "P-256K"' if jwk['crv'] && jwk['crv'] != 'P-256K'
+      raise Tapyrus::JWS::DecodeError, 'use must be "sig"' if jwk['use'] && jwk['use'] != 'sig'
+      raise Tapyrus::JWS::DecodeError, 'alg must be "ES256K"' if jwk['alg'] && jwk['alg'] != 'ES256K'
+    end
+
+    # Return point object that represents rG
+    #
+    # @param r_hex [String] r value as hex string
+    # @return [ECDSA::Point] The point that represents r * G
+    def point_for(r_hex)
+      Tapyrus::Key.new(priv_key: r_hex).to_point
+    end
+  end
+end

lib/tapyrus/tip0137.rb

@@ -0,0 +1,201 @@
+module Tapyrus
+  module TIP0137
+    # @param key [Tapyrus::Key] A private key
+    # @param txid [String] A transaction id string in hexadecimal format (64 characters long)
+    # @param index [Integer] Index of the transaction output, a non-negative integer less than 2^32
+    # @param color_id [Tapyrus::Color::ColorIdentifier] A valid instance of Tapyrus::Color::ColorIdentifier
+    # @param value [Integer] A non-negative integer less than 2^64 representing the value of the transaction output
+    # @param script_pubkey [Tapyrus::Script] A script pubkey in the transaction output
+    # @param address [String] A valid Tapyrus address string for the transaction output
+    # @param message [String] A hexadecimal formatted string
+    # @param client [Tapyrus::RPC::TapyrusCoreClient] The RPC client instance. If the client is specified, verify that the transaction associated with the txid and index exists on the blockchain and that a valid script_pubkey exists in the transaction.
+    # @return [String] Returns the message signed in JWS Format
+    # @raise [ArgumentError] If the txid is not a 64-character hexadecimal string
+    # @raise [ArgumentError] If the index is not a non-negative integer less than 2^32
+    # @raise [ArgumentError] If the color_id is not a valid Tapyrus::Color::ColorIdentifier object
+    # @raise [ArgumentError] If the value is not a non-negative integer less than 2^64
+    # @raise [ArgumentError] If the script_pubkey is not a valid Tapyrus::Script object
+    # @raise [ArgumentError] If the provided Tapyrus address is invalid
+    # @raise [ArgumentError] If the message is not a hexadecimal string
+    # @raise [ArgumentError] If the transaction with the given txid and index is not found in the blockchain
+    # @raise [ArgumentError] If the script and value do not correspond with those in the blockchain
+    # @raise [Tapyrus::RPC::Error] If RPC access fails
+    def sign_message!(
+      key,
+      txid:,
+      index:,
+      value:,
+      script_pubkey:,
+      color_id: nil,
+      address: nil,
+      message: nil,
+      client: nil
+    )
+      validate_payload!(
+        key: key,
+        txid: txid,
+        index: index,
+        color_id: color_id,
+        value: value,
+        script_pubkey: script_pubkey,
+        address: address,
+        message: message
+      )
+      if client
+        validate_on_blockchain!(
+          client: client,
+          txid: txid,
+          index: index,
+          color_id: color_id,
+          value: value,
+          script_pubkey: script_pubkey
+        )
+      end
+      data = {
+        txid: txid,
+        index: index,
+        color_id: color_id&.to_hex,
+        value: value,
+        script_pubkey: script_pubkey&.to_hex,
+        address: address,
+        message: message
+      }
+      Tapyrus::JWS.encode(data, key.priv_key)
+    end
+
+    # @param jws [String] JWS (JSON Web Signature)
+    # @param client [Tapyrus::RPC::TapyrusCoreClient] The RPC client instance. If the client is specified, verify that the transaction associated with the txid and index exists on the blockchain and that a valid script_pubkey exists in the transaction.
+    # @return A decoded JSON Object
+    # @raise [ArgumentError] If the decoded txid is not a 64-character hexadecimal string
+    # @raise [ArgumentError] If the decoded index is not a non-negative integer less than 2^32
+    # @raise [ArgumentError] If the decoded color_id is an invalid Tapyrus::Color::ColorIdentifier object
+    # @raise [ArgumentError] If the decoded value is not a non-negative integer less than 2^64
+    # @raise [ArgumentError] If the decoded script_pubkey is an invalid Tapyrus::Script object
+    # @raise [ArgumentError] If the decoded address is an invalid Tapyrus address
+    # @raise [ArgumentError] If the decoded message is not a hexadecimal string
+    # @raise [ArgumentError] If a transaction is not found with the decoded txid and index in the blockchain
+    # @raise [ArgumentError] If the decoded script and value do not match the ones in the blockchain
+    # @raise [JWT::DecodeError] If JWS decoding fails
+    # @raise [Tapyus::JWS::DecodeError] If the JWK key is invalid
+    # @raise [JWT::VerificationError] If the verification of the signature fails
+    # @raise [Tapyrus::RPC::Error] If RPC access fails
+    def verify_message!(jws, client: nil)
+      Tapyrus::JWS
+        .decode(jws)
+        .tap do |decoded|
+          header = decoded[1]
+          validate_header!(header)
+          jwk = header.dig('jwk', 'keys', 0)
+          key = to_tapyrus_key(jwk)
+          payload = decoded[0]
+          color_id =
+            begin
+              Tapyrus::Color::ColorIdentifier.parse_from_payload(payload['color_id']&.htb) if payload['color_id']
+            rescue => _e
+              raise ArgumentError, 'color_id is invalid'
+            end
+          script_pubkey =
+            begin
+              Tapyrus::Script.parse_from_payload(payload['script_pubkey']&.htb)
+            rescue => _e
+              raise ArgumentError, 'script_pubkey is invalid'
+            end
+          validate_payload!(
+            key: key,
+            txid: payload['txid'],
+            index: payload['index'],
+            color_id: color_id,
+            value: payload['value'],
+            script_pubkey: script_pubkey,
+            address: payload['address'],
+            message: payload['message']
+          )
+          if client
+            validate_on_blockchain!(
+              client: client,
+              txid: payload['txid'],
+              index: payload['index'],
+              color_id: color_id,
+              value: payload['value'],
+              script_pubkey: script_pubkey
+            )
+          end
+        end
+    end
+
+    # @param jws [String] JWS (JSON Web Signature)
+    # @param client [Tapyrus::RPC::TapyrusCoreClient]  The RPC client instance
+    # @return [Boolean] true if JWT and decoded object is valid.
+    def verify_message(jws, client: nil)
+      verify_message!(jws, client: client)
+      true
+    rescue ArgumentError, JWT::DecodeError, JWT::VerificationError
+      return false
+    end
+
+    def validate_header!(header)
+      raise ArgumentError, 'type must be "JWT"' if header['typ'] && header['typ'] != 'JWT'
+      raise ArgumentError, 'alg must be "ES256K"' if header['alg'] && header['alg'] != Tapyrus::JWS::ALGO
+    end
+
+    def validate_payload!(key:, txid:, index:, value:, script_pubkey:, color_id: nil, address: nil, message: nil)
+      raise ArgumentError, 'txid is invalid' if !txid || !/^[0-9a-fA-F]{64}$/.match(txid)
+      raise ArgumentError, 'index is invalid' if !index || !/^\d+$/.match(index.to_s) || index < 0 || index >= 2**32
+
+      raise ArgumentError, 'value is invalid' if !value || !/^\d+$/.match(value.to_s) || value < 0 || value >= 2**64
+      if !script_pubkey || !script_pubkey.is_a?(Tapyrus::Script) || !(script_pubkey.p2pkh? || script_pubkey.cp2pkh?)
+        raise ArgumentError,
+              'script_pubkey is invalid. scirpt_pubkey must be a hex string and its type must be p2pkh or cp2pkh'
+      end
+
+      if color_id
+        if !color_id.is_a?(Tapyrus::Color::ColorIdentifier) || !color_id.valid?
+          raise ArgumentError, 'color_id is invalid'
+        end
+
+        raise ArgumentError, 'color_id should be equal to colorId in scriptPubkey' if color_id != script_pubkey.color_id
+      end
+
+      begin
+        address && Base58.decode(address)
+      rescue ArgumentError => e
+        raise ArgumentError, 'address is invalid'
+      end
+
+      if address && script_pubkey.to_addr != address
+        raise ArgumentError, 'address is invalid. An address should be derived from scriptPubkey'
+      end
+
+      if (script_pubkey.p2pkh? && key.to_p2pkh != script_pubkey.to_addr) ||
+           (script_pubkey.cp2pkh? && key.to_p2pkh != script_pubkey.remove_color.to_addr)
+        raise ArgumentError, 'key is invalid'
+      end
+
+      if message && !/^([0-9a-fA-F]{2})+$/.match(message)
+        raise ArgumentError, 'message is invalid. message must be a hex string'
+      end
+    end
+
+    def validate_on_blockchain!(client: nil, txid: nil, index: nil, color_id: nil, value: nil, script_pubkey: nil)
+      raw_tx = client.getrawtransaction(txid)
+      tx = Tapyrus::Tx.parse_from_payload(raw_tx.htb)
+      output = tx.outputs[index]
+      raise ArgumentError, 'output not found in blockchain' unless output
+      if color_id != output.color_id
+        raise ArgumentError, 'color_id of transaction in blockchain is not match to one in the signed message'
+      end
+      if value != output.value
+        raise ArgumentError, 'value of transaction in blockchain is not match to one in the signed message'
+      end
+      if script_pubkey != output.script_pubkey
+        raise ArgumentError, 'script_pubkey of transaction in blockchain is not match to one in the signed message'
+      end
+    end
+
+    def to_tapyrus_key(jwk)
+      vefiry_key = JWT::JWK.new(jwk).verify_key
+      pubkey = vefiry_key.public_key.to_octet_string(:compressed)
+      Tapyrus::Key.new(pubkey: pubkey.bth)
+    end
+  end
+end