feat: bls public key validation (#190)

Author: alfonsobries

build.gradle

@@ -27,6 +27,7 @@ dependencies {
     implementation 'org.bouncycastle:bcprov-jdk15on:1.70'
     implementation 'org.web3j:core:4.8.7'
     implementation 'com.google.code.gson:gson:2.11.0'
+    implementation 'foundation.icon:blst-java:0.3.2'
 
     // Test dependencies
     testImplementation 'org.hamcrest:hamcrest-library:3.0'

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

@@ -0,0 +1,31 @@
+package org.arkecosystem.crypto.identities;
+
+import org.arkecosystem.crypto.encoding.Hex;
+import supranational.blst.P1_Affine;
+
+public class BlsPublicKey {
+
+    public static boolean validate(String publicKeyHex) {
+        try {
+            if (publicKeyHex == null) {
+                return false;
+            }
+
+            if (publicKeyHex.startsWith("0x")) {
+                publicKeyHex = publicKeyHex.substring(2);
+            }
+
+            if (publicKeyHex.length() != 96) {
+                return false;
+            }
+
+            byte[] publicKeyBytes = Hex.decode(publicKeyHex);
+
+            P1_Affine point = new P1_Affine(publicKeyBytes);
+
+            return point.in_group();
+        } catch (Exception e) {
+            return false;
+        }
+    }
+}

src/main/java/org/arkecosystem/crypto/transactions/builder/ValidatorRegistrationBuilder.java

@@ -1,11 +1,16 @@
 package org.arkecosystem.crypto.transactions.builder;
 
+import org.arkecosystem.crypto.identities.BlsPublicKey;
 import org.arkecosystem.crypto.transactions.types.AbstractTransaction;
 import org.arkecosystem.crypto.transactions.types.ValidatorRegistration;
 
 public class ValidatorRegistrationBuilder
         extends AbstractTransactionBuilder<ValidatorRegistrationBuilder> {
     public ValidatorRegistrationBuilder validatorPublicKey(String validatorPublicKey) {
+        if (!BlsPublicKey.validate(validatorPublicKey)) {
+            throw new IllegalArgumentException("Invalid BLS public key");
+        }
+
         this.transaction.validatorPublicKey = validatorPublicKey;
 
         this.transaction.refreshPayloadData();

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

@@ -0,0 +1,118 @@
+package org.arkecosystem.crypto.identities;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class BlsPublicKeyTest {
+
+    @Test
+    public void validBlsPublicKeyFromMnemonic() {
+        assertTrue(
+                BlsPublicKey.validate(
+                        "b4865127896c3c5286296a7b26e7c8002586a3ecf5832bfb59e689336f1f4c75e10491b9dfaed8dfb2c2fbe22d11fa93"));
+    }
+
+    @Test
+    public void validG1GeneratorPoint() {
+        assertTrue(
+                BlsPublicKey.validate(
+                        "97f1d3a73197d7942695638c4fa9ac0fc3688c4f9774b905a14e3a3f171bac586c55e83ff97a1aeffb3af00adb22c6bb"));
+    }
+
+    @Test
+    public void validSecondBlsPublicKey() {
+        assertTrue(
+                BlsPublicKey.validate(
+                        "95af988701a6fb60e09da41d2ca1a9e0b49e43501bda4255b3ca01073f490c34102b6bbcafde6333185e9980745d72cb"));
+    }
+
+    @Test
+    public void validBlsPublicKeyWith0xPrefix() {
+        assertTrue(
+                BlsPublicKey.validate(
+                        "0xb4865127896c3c5286296a7b26e7c8002586a3ecf5832bfb59e689336f1f4c75e10491b9dfaed8dfb2c2fbe22d11fa93"));
+    }
+
+    @Test
+    public void emptyString() {
+        assertFalse(BlsPublicKey.validate(""));
+    }
+
+    @Test
+    public void singleCharacter() {
+        assertFalse(BlsPublicKey.validate("0"));
+    }
+
+    @Test
+    public void nonHexString() {
+        assertFalse(BlsPublicKey.validate("NOT A VALID PUBLICKEY"));
+    }
+
+    @Test
+    public void invalidHexCharactersMixedWithValid() {
+        assertFalse(BlsPublicKey.validate("02b5Gf"));
+    }
+
+    @Test
+    public void tooShort33BytesZeroPadded() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "000000000000000000000000000000000000000000000000000000000000000000"));
+    }
+
+    @Test
+    public void secp256k1CompressedPublicKeyPrefix02() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "02e0f7449c5588f24492c338f2bc8f7865f755b958d48edb0f2d0056e50c3fd5b7"));
+    }
+
+    @Test
+    public void secp256k1CompressedPublicKeyPrefix03() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "038c14b793cb19137e323a6d2e2a870bca2e7a493ec1153b3a95feb8a4873f8d08"));
+    }
+
+    @Test
+    public void secp256k1CompressedKeyWithInvalidHex() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "02b5Gf00d9de5a3ace28913fe78a15afcfe242926e94d9b517d06d2705b261f992"));
+    }
+
+    @Test
+    public void secp256k1UncompressedLengthKeyPrefix32() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "32337416a26d8d49ec27059bd0589c49bb474029c3627715380f4df83fb431aece"));
+    }
+
+    @Test
+    public void secp256k1UncompressedLengthKeyPrefix22() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "22337416a26d8d49ec27059bd0589c49bb474029c3627715380f4df83fb431aece"));
+    }
+
+    @Test
+    public void correctLengthButInvalidPoint() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001"));
+    }
+
+    @Test
+    public void tooLongBy1Byte() {
+        assertFalse(
+                BlsPublicKey.validate(
+                        "b4865127896c3c5286296a7b26e7c8002586a3ecf5832bfb59e689336f1f4c75e10491b9dfaed8dfb2c2fbe22d11fa9300"));
+    }
+
+    @Test
+    public void nullInput() {
+        assertFalse(BlsPublicKey.validate(null));
+    }
+}

src/test/java/org/arkecosystem/crypto/transactions/builder/ValidatorRegistrationBuilderTest.java

@@ -33,4 +33,13 @@ public void it_should_sign_it_with_a_passphrase() throws Exception {
         assertEquals(data.get("id"), builder.transaction.getId());
         assertTrue(builder.verify());
     }
+
+    @Test
+    public void it_should_throw_on_invalid_bls_public_key() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> {
+                    new ValidatorRegistrationBuilder().validatorPublicKey("invalid-bls-key");
+                });
+    }
 }