From d36603c2ba876c519d823e48b3fc1f232f80c3c0 Mon Sep 17 00:00:00 2001
From: Andreas Schildbach <andreas.schildbach@bloq.com>
Date: Wed, 1 May 2019 19:12:02 +0200
Subject: [PATCH] Use Bouncy Castle's Scrypt implementation rather than the
 standalone library.

Amazingly, on a Pixel 2 this implementation is a bit quicker than Will Glozer/Colin Percival's native code.
---
 core/build.gradle                                        | 1 -
 .../main/java/org/bitcoinj/crypto/BIP38PrivateKey.java   | 9 +++++----
 .../main/java/org/bitcoinj/crypto/KeyCrypterScrypt.java  | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/core/build.gradle b/core/build.gradle
index d8fda868..7db94ac4 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -9,7 +9,6 @@ eclipse.project.name = 'bitcoinj-core'
 
 dependencies {
     compile 'org.bouncycastle:bcprov-jdk15on:1.60'
-    implementation 'com.lambdaworks:scrypt:1.4.0'
     implementation 'com.google.guava:guava:27.0.1-android'
     compile 'com.google.protobuf:protobuf-java:3.6.1'
     implementation 'com.squareup.okhttp3:okhttp:3.12.1'
diff --git a/core/src/main/java/org/bitcoinj/crypto/BIP38PrivateKey.java b/core/src/main/java/org/bitcoinj/crypto/BIP38PrivateKey.java
index 80748dae..45fcee64 100644
--- a/core/src/main/java/org/bitcoinj/crypto/BIP38PrivateKey.java
+++ b/core/src/main/java/org/bitcoinj/crypto/BIP38PrivateKey.java
@@ -17,8 +17,9 @@
 package org.bitcoinj.crypto;
 
 import org.bitcoinj.core.*;
+import org.bouncycastle.crypto.generators.SCrypt;
+
 import com.google.common.primitives.Bytes;
-import com.lambdaworks.crypto.SCrypt;
 
 import javax.crypto.Cipher;
 import javax.crypto.spec.SecretKeySpec;
@@ -126,7 +127,7 @@ public class BIP38PrivateKey extends PrefixedChecksummedBytes {
 
     private ECKey decryptNoEC(String normalizedPassphrase) {
         try {
-            byte[] derived = SCrypt.scrypt(normalizedPassphrase.getBytes(StandardCharsets.UTF_8), addressHash, 16384, 8, 8, 64);
+            byte[] derived = SCrypt.generate(normalizedPassphrase.getBytes(StandardCharsets.UTF_8), addressHash, 16384, 8, 8, 64);
             byte[] key = Arrays.copyOfRange(derived, 32, 64);
             SecretKeySpec keyspec = new SecretKeySpec(key, "AES");
 
@@ -148,7 +149,7 @@ public class BIP38PrivateKey extends PrefixedChecksummedBytes {
             byte[] ownerEntropy = Arrays.copyOfRange(content, 0, 8);
             byte[] ownerSalt = hasLotAndSequence ? Arrays.copyOfRange(ownerEntropy, 0, 4) : ownerEntropy;
 
-            byte[] passFactorBytes = SCrypt.scrypt(normalizedPassphrase.getBytes(StandardCharsets.UTF_8), ownerSalt, 16384, 8, 8, 32);
+            byte[] passFactorBytes = SCrypt.generate(normalizedPassphrase.getBytes(StandardCharsets.UTF_8), ownerSalt, 16384, 8, 8, 32);
             if (hasLotAndSequence) {
                 byte[] hashBytes = Bytes.concat(passFactorBytes, ownerEntropy);
                 checkState(hashBytes.length == 40);
@@ -159,7 +160,7 @@ public class BIP38PrivateKey extends PrefixedChecksummedBytes {
 
             byte[] salt = Bytes.concat(addressHash, ownerEntropy);
             checkState(salt.length == 12);
-            byte[] derived = SCrypt.scrypt(k.getPubKey(), salt, 1024, 1, 1, 64);
+            byte[] derived = SCrypt.generate(k.getPubKey(), salt, 1024, 1, 1, 64);
             byte[] aeskey = Arrays.copyOfRange(derived, 32, 64);
 
             SecretKeySpec keyspec = new SecretKeySpec(aeskey, "AES");
diff --git a/core/src/main/java/org/bitcoinj/crypto/KeyCrypterScrypt.java b/core/src/main/java/org/bitcoinj/crypto/KeyCrypterScrypt.java
index cff7e038..74d6a05d 100644
--- a/core/src/main/java/org/bitcoinj/crypto/KeyCrypterScrypt.java
+++ b/core/src/main/java/org/bitcoinj/crypto/KeyCrypterScrypt.java
@@ -20,12 +20,12 @@ package org.bitcoinj.crypto;
 import com.google.common.base.Objects;
 import com.google.common.base.Stopwatch;
 import com.google.protobuf.ByteString;
-import com.lambdaworks.crypto.SCrypt;
 import org.bitcoinj.core.Utils;
 import org.bitcoinj.wallet.Protos;
 import org.bitcoinj.wallet.Protos.ScryptParameters;
 import org.bitcoinj.wallet.Protos.Wallet.EncryptionType;
 import org.bouncycastle.crypto.engines.AESEngine;
+import org.bouncycastle.crypto.generators.SCrypt;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.bouncycastle.crypto.BufferedBlockCipher;
@@ -157,7 +157,7 @@ public class KeyCrypterScrypt implements KeyCrypter {
             }
 
             final Stopwatch watch = Stopwatch.createStarted();
-            byte[] keyBytes = SCrypt.scrypt(passwordBytes, salt, (int) scryptParameters.getN(), scryptParameters.getR(), scryptParameters.getP(), KEY_LENGTH);
+            byte[] keyBytes = SCrypt.generate(passwordBytes, salt, (int) scryptParameters.getN(), scryptParameters.getR(), scryptParameters.getP(), KEY_LENGTH);
             watch.stop();
             log.info("Deriving key took {} for {} scrypt iterations.", watch, scryptParameters.getN());
             return new KeyParameter(keyBytes);