add Credentials.sign()

Author: tempofeng

etherspace-java/src/main/java/cc/etherspace/Credentials.kt

@@ -11,6 +11,7 @@ import java.nio.charset.Charset
 interface Credentials {
     val address: String
     fun signTransaction(transactionObject: Web3.TransactionObject): String
+    fun sign(messageHash: ByteArray): Web3.Signature
 }
 
 open class WalletCredentials : Credentials {
@@ -55,6 +56,15 @@ open class WalletCredentials : Credentials {
             value,
             data)
 
+    override fun sign(messageHash: ByteArray): Web3.Signature {
+        val prefixMsgHash = Web3.attachEthereumSignedMessage(messageHash)
+        val ecKeyPair = ECKeyPair.create(Numeric.toBigInt(privateKey))
+        val signatureData = Sign.signMessage(prefixMsgHash, ecKeyPair)
+        return Web3.Signature(signatureData.v,
+                signatureData.r,
+                signatureData.s)
+    }
+
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
         if (javaClass != other?.javaClass) return false

etherspace-java/src/main/java/cc/etherspace/Web3.kt

@@ -1,5 +1,6 @@
 package cc.etherspace
 
+import org.bouncycastle.pqc.math.linearalgebra.ByteUtils
 import org.web3j.tx.Contract
 import org.web3j.tx.ManagedTransaction
 import org.web3j.utils.Numeric
@@ -115,5 +116,11 @@ interface Web3 {
 
     companion object {
         private const val SIGNATURE_LENGTH = 65
+
+        fun attachEthereumSignedMessage(messageHash: ByteArray): ByteArray? {
+            val prefix = "\u0019Ethereum Signed Message:\n".toByteArray(Charsets.UTF_8)
+            val prefixSize = ByteUtils.concatenate(prefix, messageHash.size.toString().toByteArray(Charsets.UTF_8))
+            return ByteUtils.concatenate(prefixSize, messageHash)
+        }
     }
 }

etherspace-java/src/main/java/cc/etherspace/web3j/Web3jAdapter.kt

@@ -28,7 +28,7 @@ class Web3jAdapter(val web3j: Web3j) : Web3 {
 
     class Web3jPersonal : Web3.Personal {
         override fun ecRecover(dataThatWasSigned: ByteArray, signature: Web3.Signature): String {
-            val prefixMsgHash = attachEthereumSignedMessage(dataThatWasSigned)
+            val prefixMsgHash = Web3.attachEthereumSignedMessage(dataThatWasSigned)
             val publicKey = Sign.signedMessageToKey(prefixMsgHash,
                     Sign.SignatureData(signature.v, signature.r, signature.s))
             return Keys.toChecksumAddress(Numeric.prependHexPrefix(Keys.getAddress(publicKey)))
@@ -43,7 +43,7 @@ class Web3jAdapter(val web3j: Web3j) : Web3 {
          * from: https://github.com/EuroHsu/TestLibrary/blob/6883528dbcddb283f14955620f042b4ea3253624/src/main/java/com/example/testlibrary/cryptos/signer.java
          */
         override fun sign(messageHash: ByteArray, privateKey: String): Web3.Signature {
-            val prefixMsgHash = attachEthereumSignedMessage(messageHash)
+            val prefixMsgHash = Web3.attachEthereumSignedMessage(messageHash)
             val ecKeyPair = ECKeyPair.create(Numeric.toBigInt(privateKey))
             val signatureData = Sign.signMessage(prefixMsgHash, ecKeyPair)
             return Web3.Signature(signatureData.v,
@@ -205,11 +205,5 @@ class Web3jAdapter(val web3j: Web3j) : Web3 {
                 Web3j.build(httpService)
             }
         }
-
-        private fun attachEthereumSignedMessage(messageHash: ByteArray): ByteArray? {
-            val prefix = "\u0019Ethereum Signed Message:\n".toByteArray(Charsets.UTF_8)
-            val prefixSize = ByteUtils.concatenate(prefix, messageHash.size.toString().toByteArray(Charsets.UTF_8))
-            return ByteUtils.concatenate(prefixSize, messageHash)
-        }
     }
 }