Fix rubocop offenses for contracthash

Author: elihaims

lib/bitcoin/contracthash.rb

@@ -1,76 +1,72 @@
-#
-# Ruby port of https://github.com/Blockstream/contracthashtool
-#
-
 module Bitcoin
+  # Ruby port of https://github.com/Blockstream/contracthashtool
   module ContractHash
-
-    HMAC_DIGEST = OpenSSL::Digest.new("SHA256")
-    EC_GROUP = OpenSSL::PKey::EC::Group.new("secp256k1")
+    HMAC_DIGEST = OpenSSL::Digest.new('SHA256')
+    EC_GROUP = OpenSSL::PKey::EC::Group.new('secp256k1')
 
     def self.hmac(pubkey, data)
       OpenSSL::HMAC.hexdigest(HMAC_DIGEST, pubkey, data)
     end
 
     # generate a contract address
-    def self.generate(redeem_script_hex, payee_address_or_ascii, nonce_hex=nil)
-      redeem_script = Bitcoin::Script.new([redeem_script_hex].pack("H*"))
-      raise "only multisig redeem scripts are currently supported" unless redeem_script.is_multisig?
+    def self.generate(redeem_script_hex, payee_address_or_ascii, nonce_hex = nil)
+      redeem_script = Bitcoin::Script.new([redeem_script_hex].pack('H*'))
+      raise 'only multisig redeem scripts are currently supported' unless redeem_script.is_multisig?
       nonce_hex, data = compute_data(payee_address_or_ascii, nonce_hex)
 
       derived_keys = []
       redeem_script.get_multisig_pubkeys.each do |pubkey|
         tweak = hmac(pubkey, data).to_i(16)
-        raise "order exceeded, pick a new nonce" if tweak >= EC_GROUP.order.to_i
+        raise 'order exceeded, pick a new nonce' if tweak >= EC_GROUP.order.to_i
         tweak = OpenSSL::BN.new(tweak.to_s)
 
-        key = Bitcoin::Key.new(nil, pubkey.unpack("H*")[0])
+        key = Bitcoin::Key.new(nil, pubkey.unpack('H*')[0])
         key = key.instance_variable_get(:@key)
         point = EC_GROUP.generator.mul(tweak).ec_add(key.public_key).to_bn.to_i
-        raise "infinity" if point == 1/0.0
+        raise 'infinity' if point == 1 / 0.0
 
         key = Bitcoin::Key.new(nil, point.to_s(16))
-        key.instance_eval{ @pubkey_compressed = true }
+        key.instance_eval { @pubkey_compressed = true }
         derived_keys << key.pub
       end
 
       m = redeem_script.get_signatures_required
       p2sh_script, redeem_script = Bitcoin::Script.to_p2sh_multisig_script(m, *derived_keys)
 
-      [ nonce_hex, redeem_script.unpack("H*")[0], Bitcoin::Script.new(p2sh_script).get_p2sh_address ]
+      [nonce_hex, redeem_script.unpack('H*')[0], Bitcoin::Script.new(p2sh_script).get_p2sh_address]
     end
 
     # claim a contract
     def self.claim(private_key_wif, payee_address_or_ascii, nonce_hex)
       key = Bitcoin::Key.from_base58(private_key_wif)
       data = compute_data(payee_address_or_ascii, nonce_hex)[1]
 
-      pubkey = [key.pub].pack("H*")
+      pubkey = [key.pub].pack('H*')
       tweak = hmac(pubkey, data).to_i(16)
-      raise "order exceeded, verify parameters" if tweak >= EC_GROUP.order.to_i
+      raise 'order exceeded, verify parameters' if tweak >= EC_GROUP.order.to_i
 
       derived_key = (tweak + key.priv.to_i(16)) % EC_GROUP.order.to_i
-      raise "zero" if derived_key == 0
+      raise 'zero' if derived_key.zero?
 
       Bitcoin::Key.new(derived_key.to_s(16))
     end
 
     # compute HMAC data
     def self.compute_data(address_or_ascii, nonce_hex)
-      nonce = nonce_hex ? [nonce_hex].pack("H32") : SecureRandom.random_bytes(16)
+      nonce = nonce_hex ? [nonce_hex].pack('H32') : SecureRandom.random_bytes(16)
       if Bitcoin.valid_address?(address_or_ascii)
         address_type = case Bitcoin.address_type(address_or_ascii)
-                       when :hash160;  'P2PH'
-                       when :p2sh;     'P2SH'
+                       when :hash160 then  'P2PH'
+                       when :p2sh then     'P2SH'
                        else
                          raise "unsupported address type #{address_type}"
                        end
-        contract_bytes = [ Bitcoin.hash160_from_address(address_or_ascii) ].pack("H*")
+        contract_bytes = [Bitcoin.hash160_from_address(address_or_ascii)].pack('H*')
       else
-        address_type = "TEXT"
+        address_type = 'TEXT'
         contract_bytes = address_or_ascii
       end
-      [ nonce.unpack("H*")[0], address_type + nonce + contract_bytes ]
+      [nonce.unpack('H*')[0], address_type + nonce + contract_bytes]
     end
   end
 end