Updated on 2026-08-14

libs/crypto/src/main/java/com/tangem/lib/crypto/derivation/AccountNodeRecognizer.kt

@@ -0,0 +1,46 @@
+package com.tangem.lib.crypto.derivation
+
+import com.tangem.blockchain.common.Blockchain
+import com.tangem.blockchain.common.isUTXO
+import com.tangem.crypto.hdWallet.DerivationPath
+
+/**
+ * Utility class to recognize the account node in a derivation path based on the blockchain type.
+ * Derivation path schema: [ m / purpose' / coin_type' / account' / change / address_index ].
+ *
+ * @param blockchain the blockchain for which the account node is to be recognized
+ *
+[REDACTED_AUTHOR]
+ */
+class AccountNodeRecognizer(blockchain: Blockchain) {
+
+    /** Index of the account node in the derivation path */
+    val accountNodeIndex: Int = if (blockchain.isUTXO) {
+        UTXO_BLOCKCHAIN_NODE_INDEX
+    } else {
+        NON_UTXO_BLOCKCHAIN_NODE_INDEX
+    }
+
+    /** Recognizes the account node value from the given derivation path string [derivationPathValue] */
+    fun recognize(derivationPathValue: String): Long? {
+        return runCatching {
+            recognize(derivationPath = DerivationPath(rawPath = derivationPathValue))
+        }
+            .getOrNull()
+    }
+
+    /** Recognizes the account node value from the given [derivationPath] */
+    fun recognize(derivationPath: DerivationPath): Long? {
+        return runCatching {
+            val accountNode = derivationPath.nodes.getOrNull(accountNodeIndex)
+
+            accountNode?.getIndex(includeHardened = false)
+        }
+            .getOrNull()
+    }
+
+    private companion object {
+        const val UTXO_BLOCKCHAIN_NODE_INDEX = 2
+        const val NON_UTXO_BLOCKCHAIN_NODE_INDEX = 4
+    }
+}

libs/crypto/src/main/java/com/tangem/lib/crypto/derivation/MutableDerivationPath.kt

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+package com.tangem.lib.crypto.derivation
+
+import com.tangem.blockchain.common.Blockchain
+import com.tangem.crypto.hdWallet.DerivationNode
+import com.tangem.crypto.hdWallet.DerivationPath
+import timber.log.Timber
+
+/** Extension function to convert a [DerivationPath] into a [MutableDerivationPath] */
+fun DerivationPath.toMutable(): MutableDerivationPath = MutableDerivationPath(value = this)
+
+/**
+ * A mutable representation of a derivation path, allowing modifications to specific nodes
+ *
+ * @property value the initial derivationPath to be used
+ */
+class MutableDerivationPath internal constructor(val value: DerivationPath) {
+
+    /**
+     * Replaces the account node in the derivation path with a new value
+     *
+     * @param value      the new index to set for the account node
+     * @param blockchain the blockchain used to determine the account node index
+     */
+    fun replaceAccountNode(value: Long, blockchain: Blockchain): MutableDerivationPath {
+        val mutableNodes = this@MutableDerivationPath.value.nodes.toMutableList()
+
+        val accountNodeIndex = AccountNodeRecognizer(blockchain).accountNodeIndex
+        val accountNode = mutableNodes.getOrNull(accountNodeIndex)
+
+        if (accountNode != null) {
+            mutableNodes[accountNodeIndex] = when (accountNode) {
+                is DerivationNode.Hardened -> DerivationNode.Hardened(value)
+                is DerivationNode.NonHardened -> DerivationNode.NonHardened(value)
+            }
+        } else {
+            Timber.e("Account node not found in the derivation path: ${this@MutableDerivationPath.value}")
+        }
+
+        return DerivationPath(path = mutableNodes).toMutable()
+    }
+
+    /** Applies the changes and returns it as an immutable [DerivationPath] */
+    fun apply(): DerivationPath = value
+}