Updated on 2026-08-14

.idea/gradle.xml

@@ -11,6 +11,7 @@
           <set>
             <option value="$PROJECT_DIR$" />
             <option value="$PROJECT_DIR$/app" />
+            <option value="$PROJECT_DIR$/blockchain" />
             <option value="$PROJECT_DIR$/server-android" />
             <option value="$PROJECT_DIR$/tangem-card-old" />
             <option value="$PROJECT_DIR$/tangem-core" />

blockchain/src/main/java/com/tangem/blockchain/common/Wallet.kt

@@ -21,7 +21,7 @@ data class Amount(
         val currencySymbol: String,
         val value: BigDecimal?,
         val address: String,
-        val decimals: Int,
+        val decimals: Byte,
         val type: AmountType = AmountType.Coin
         )
 

blockchain/src/main/java/com/tangem/blockchain/eth/EthereumAddress.kt

@@ -4,6 +4,7 @@ import org.kethereum.crypto.toAddress
 import org.kethereum.functions.isValid
 import org.kethereum.model.Address
 import org.kethereum.model.PublicKey
+import org.kethereum.wallet.model.WalletCrypto
 
 object EthereumAddressFactory {
     fun makeAddress(cardPublicKey: ByteArray, testNet: Boolean = false): String =

blockchain/src/main/java/com/tangem/blockchain/eth/EthereumWalletManager.kt

@@ -3,13 +3,22 @@ package com.tangem.blockchain.eth
 import com.tangem.blockchain.common.*
 import com.tangem.blockchain.wallets.CurrencyWallet
 import com.tangem.tasks.TaskEvent
+import org.kethereum.DEFAULT_GAS_LIMIT
+import org.kethereum.ETH_IN_WEI
+import org.kethereum.crypto.api.ec.ECDSASignature
+import org.kethereum.crypto.determineRecId
+import org.kethereum.crypto.impl.ec.canonicalise
+import org.kethereum.functions.encodeRLP
+import org.kethereum.keccakshortcut.keccak
+import org.kethereum.model.*
+import java.math.BigInteger
 
 class EthereumWalletManager(
         private val cardId: String,
         private val walletPublicKey: ByteArray,
+        private val isTestNet: Boolean,
         walletConfig: WalletConfig
 ) : WalletManager,
-        TransactionEstimator,
         TransactionSender,
         FeeProvider {
 
@@ -17,39 +26,104 @@ class EthereumWalletManager(
     private val address = blockchain.makeAddress(walletPublicKey)
     override var wallet: Wallet = CurrencyWallet(walletConfig, address)
 
+
     override fun update() {
 
     }
 
-    override fun getEstimateSize(transactionData: TransactionData): Int {
-
-    }
-
     override fun send(transactionData: TransactionData, signer: TransactionSigner) {
         val builder = EthereumTransactionBuilder()
         val hashes = builder.buildToSign(transactionData, walletPublicKey)
         signer.sign(hashes.toTypedArray(), cardId) {
             when (it) {
-                is TaskEvent.Event -> builder.buildToSend(transactionData, it.data.signature)
+                is TaskEvent.Event -> builder.buildToSend(it.data.signature, walletPublicKey)
             }
         }
     }
 
     override fun getFee(amount: Amount, source: String, destination: String): List<Amount> {
+        val gasPrices: List<Long> = getEthGasPrices()
+        val gasLimit = getGasLimit(amount).value
 
+        val fees = mutableListOf<Amount>()
+        for (gasPrice in gasPrices) {
+            val feeValue = (gasPrice * gasLimit).toBigDecimal().divide(ETH_IN_WEI.toBigDecimal())
+            fees.add(Amount(blockchain.currency, feeValue, address, blockchain.decimals))
+        }
     }
 
 }
 
 
-class EthereumTransactionBuilder {
-
+private class EthereumTransactionBuilder {
+    var nonce: BigInteger? = null
+    var transaction: Transaction? = null
+    var hashToSign: ByteArray? = null
 
     fun buildToSign(transactionData: TransactionData, publicKey: ByteArray): List<ByteArray> {
+        val from = Address(transactionData.sourceAddress)
+        val to = Address(transactionData.destinationAddress)
+        val value = transactionData.amount.value!!
+                .movePointRight(transactionData.amount.decimals.toInt()).toBigInteger()
+        val fee = transactionData.fee!!.value!!
+                .movePointRight(transactionData.fee.decimals.toInt()).toBigInteger()
+        val gasPrice = fee.divide(DEFAULT_GAS_LIMIT)
 
+        transaction = createTransactionWithDefaults(
+                from = from,
+                to = to,
+                value = value,
+                gasPrice = gasPrice,
+                gasLimit = DEFAULT_GAS_LIMIT,
+                nonce = nonce,
+                chain = ChainId(Chain.Mainnet.id)
+        )
+
+        val transactionToSign = transaction!!
+                .encodeRLP(SignatureData().apply { v = transaction!!.chain!! })
+        hashToSign = transactionToSign.keccak()
+
+        return listOf(hashToSign!!)
     }
 
-    fun buildToSend(transactionData: TransactionData, signature: ByteArray) {
+    fun buildToSend(signature: ByteArray, walletPublicKey: ByteArray): ByteArray {
+        val r = BigInteger(1, signature.copyOfRange(0, 32))
+        var s = BigInteger(1, signature.copyOfRange(32, 64))
 
+        val ecdsaSignature = ECDSASignature(r, s).canonicalise()
+
+        val recId = ecdsaSignature.determineRecId(hashToSign!!, PublicKey(walletPublicKey))
+        val v = (recId + 27 + Chain.Mainnet.id).toBigInteger() // TODO: where to put chainId?
+        val signatureData = SignatureData(ecdsaSignature.r, ecdsaSignature.s, v)
+
+        return transaction!!.encodeRLP(signatureData)
+    }
+}
+
+private enum class Chain(val id: Long) {
+    Mainnet(1),
+    Morden(2),
+    Ropsten(3),
+    Rinkeby(4),
+    Rootstock_mainnet(30),
+    Rootstock_testnet(31),
+    Kovan(42),
+    Ethereum_Classic_mainnet(61),
+    Ethereum_Classic_testnet(62),
+    Geth_private_chains(1337),
+    Matic_Testnet(8995);
+}
+
+private enum class GasLimit(val value: Long) {
+    Default(210000),
+    Token(60000),
+    High(300000)
+}
+
+private fun getGasLimit(amount: Amount): GasLimit {
+    return when (amount.currencySymbol) {
+        "ETH" -> GasLimit.Default
+        "DGX" -> GasLimit.High
+        else -> GasLimit.Token
     }
 }