feat: add legacy address handling

src/main/java/org/arkecosystem/crypto/identities/LegacyAddress.java

@@ -0,0 +1,50 @@
+package org.arkecosystem.crypto.identities;
+
+import java.io.ByteArrayOutputStream;
+import org.arkecosystem.crypto.encoding.Base58;
+import org.arkecosystem.crypto.encoding.Hex;
+import org.bitcoinj.core.ECKey;
+import org.bouncycastle.crypto.digests.RIPEMD160Digest;
+
+public class LegacyAddress {
+    public static String fromPassphrase(String passphrase, int pubKeyHash) {
+        ECKey privateKey = PrivateKey.fromPassphrase(passphrase);
+        return fromPrivateKey(privateKey, pubKeyHash);
+    }
+
+    public static String fromPublicKey(String publicKey, int pubKeyHash) {
+        byte[] ripemd160 = ripemd160(Hex.decode(publicKey));
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        outputStream.write(pubKeyHash);
+        outputStream.write(ripemd160, 0, ripemd160.length);
+
+        return Base58.encodeChecked(outputStream.toByteArray());
+    }
+
+    public static String fromPrivateKey(ECKey privateKey, int pubKeyHash) {
+        return fromPublicKey(Hex.encode(privateKey.getPubKey()), pubKeyHash);
+    }
+
+    public static boolean validate(String address, int pubKeyHash) {
+        try {
+            byte[] decoded = Base58.decodeChecked(address);
+
+            if (decoded.length != 21) {
+                return false;
+            }
+
+            return (decoded[0] & 0xFF) == pubKeyHash;
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    private static byte[] ripemd160(byte[] input) {
+        RIPEMD160Digest digest = new RIPEMD160Digest();
+        digest.update(input, 0, input.length);
+        byte[] output = new byte[digest.getDigestSize()];
+        digest.doFinal(output, 0);
+        return output;
+    }
+}

src/test/java/org/arkecosystem/crypto/identities/LegacyAddressTest.java

@@ -0,0 +1,56 @@
+package org.arkecosystem.crypto.identities;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.bitcoinj.core.ECKey;
+import org.junit.jupiter.api.Test;
+
+public class LegacyAddressTest {
+
+    private static final int PUB_KEY_HASH = 30;
+    private static final String PASSPHRASE =
+            "enact busy minimum fantasy endless shoot reduce few inject ostrich snow promote";
+    private static final String PUBLIC_KEY =
+            "02a7c5ca78f6abbced169cb883aec3ffc0a0950affc0de575fb211873b5846e668";
+    private static final String PRIVATE_KEY =
+            "c7a0df6e1c42268946af49af28c49c6da64419f0203fa970b6e9be9f85a44875";
+    private static final String ADDRESS = "D6WFwqYDRiFkSf4ezzWRt3jCsUp2sRmDMi";
+
+    @Test
+    public void fromPassphrase() {
+        assertEquals(ADDRESS, LegacyAddress.fromPassphrase(PASSPHRASE, PUB_KEY_HASH));
+    }
+
+    @Test
+    public void fromPublicKey() {
+        assertEquals(ADDRESS, LegacyAddress.fromPublicKey(PUBLIC_KEY, PUB_KEY_HASH));
+    }
+
+    @Test
+    public void fromPrivateKey() {
+        ECKey privateKey = PrivateKey.fromHex(PRIVATE_KEY);
+        assertEquals(ADDRESS, LegacyAddress.fromPrivateKey(privateKey, PUB_KEY_HASH));
+    }
+
+    @Test
+    public void validate() {
+        assertTrue(LegacyAddress.validate(ADDRESS, PUB_KEY_HASH));
+    }
+
+    @Test
+    public void validateFailsWithIncorrectPubKeyHash() {
+        assertFalse(LegacyAddress.validate(ADDRESS, 32));
+    }
+
+    @Test
+    public void validateFailsWithInvalidAddress() {
+        assertFalse(LegacyAddress.validate("D2WFnqYDRiFkSf4ezzWRt3jCsUp2sRmDMifwd", PUB_KEY_HASH));
+    }
+
+    @Test
+    public void validateFailsWithDecodingError() {
+        assertFalse(LegacyAddress.validate("invalid", PUB_KEY_HASH));
+    }
+}