Add isStandard to Address (#4353)

core-test/src/test/scala/org/bitcoins/core/protocol/Bech32mTest.scala

@@ -210,6 +210,21 @@ class Bech32mTest extends BitcoinSUnitTest {
     }
   }
 
+  it must "validate addresses as non standard" in {
+    // Taproot address with invalid x-only pubkey
+    assert(
+      !Bech32mAddress
+        .fromString(
+          "bc1pvkpqgqe7g6sl4rxwhpqp8nlz6dmv5uk47k2nr9yhh9ds32ny49cqdcghmx")
+        .isStandard)
+
+    // segwit v2 address
+    assert(
+      !Bech32mAddress
+        .fromString("bc1zw508d6qejxtdg4y5r3zarvaryvaxxpcs")
+        .isStandard)
+  }
+
   @tailrec
   private def pickReplacementChar(oldChar: Char): Char = {
     val rand = Math.abs(Random.nextInt())

core/src/main/scala/org/bitcoins/core/protocol/Address.scala

@@ -36,6 +36,13 @@ sealed abstract class Address {
   override def toString: String = value
 
   def descriptor: String = s"addr($value)"
+
+  /** Checks if the address currently follows the standardness rules of bitcoin
+    * and will be relayed by network.
+    *
+    * Currently this just means verifying the address is not of a [[UnassignedWitnessScriptPubKey]]
+    */
+  def isStandard: Boolean
 }
 
 sealed abstract class BitcoinAddress extends Address
@@ -54,6 +61,7 @@ sealed abstract class P2PKHAddress extends BitcoinAddress {
 
   override def scriptPubKey: P2PKHScriptPubKey = P2PKHScriptPubKey(hash)
 
+  override def isStandard: Boolean = true
 }
 
 sealed abstract class P2SHAddress extends BitcoinAddress {
@@ -69,6 +77,8 @@ sealed abstract class P2SHAddress extends BitcoinAddress {
   override def scriptPubKey: P2SHScriptPubKey = P2SHScriptPubKey(hash)
 
   override def hash: Sha256Hash160Digest
+
+  override def isStandard: Boolean = true
 }
 
 /** https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
@@ -109,6 +119,8 @@ sealed abstract class Bech32Address extends BitcoinAddress {
   def verifyChecksum: Boolean = {
     Bech32.verifyChecksum(hrp.expand, data ++ checksum, Bech32Encoding.Bech32)
   }
+
+  override def isStandard: Boolean = true
 }
 
 object Bech32Address extends AddressFactory[Bech32Address] {
@@ -246,6 +258,14 @@ sealed abstract class Bech32mAddress extends BitcoinAddress {
   def verifyChecksum: Boolean = {
     Bech32.verifyChecksum(hrp.expand, data ++ checksum, Bech32Encoding.Bech32m)
   }
+
+  override def isStandard: Boolean = {
+    scriptPubKey match {
+      case _: WitnessScriptPubKeyV0         => false // shouldn't be possible
+      case _: TaprootScriptPubKey           => true
+      case _: UnassignedWitnessScriptPubKey => false
+    }
+  }
 }
 
 object Bech32mAddress extends AddressFactory[Bech32mAddress] {