Updated on 2026-08-14

tangem-core/src/main/java/com/tangem/CardSession.kt

@@ -48,6 +48,7 @@ class CardSession(
         private val initialMessage: Message? = null
 ) {
 
+    private val tag = this.javaClass.simpleName
     /**
      * True if some operation is still in progress.
      */
@@ -164,7 +165,10 @@ class CardSession(
         } else {
             error.localizedMessage
         }
-        if (error !is SessionError.UserCancelled) viewDelegate.onError(errorMessage)
+        if (error !is SessionError.UserCancelled) {
+            Log.e("tag", "Finishing with error: $errorMessage")
+            viewDelegate.onError(errorMessage)
+        }
     }
 
     fun send(apdu: CommandApdu, callback: (result: CompletionResult<ResponseApdu>) -> Unit) {
@@ -176,6 +180,7 @@ class CardSession(
 
         when (error) {
             is SessionError.NeedEncryption -> {
+                Log.i(tag, "Establishing encryption")
                 when (environment.encryptionMode) {
                     EncryptionMode.NONE -> {
                         environment.encryptionKey = null
@@ -186,7 +191,7 @@ class CardSession(
                         environment.encryptionMode = EncryptionMode.STRONG
                     }
                     EncryptionMode.STRONG -> {
-                        Log.e(this::class.simpleName!!, "Encryption doesn't work")
+                        Log.e(tag, "Encryption doesn't work")
                         callback(CompletionResult.Failure(SessionError.NeedEncryption()))
                     }
                 }

tangem-core/src/main/java/com/tangem/commands/Command.kt

@@ -38,6 +38,7 @@ abstract class Command<T : CommandResponse> : CardSessionRunnable<T> {
     abstract fun deserialize(environment: SessionEnvironment, apdu: ResponseApdu): T
 
     override fun run(session: CardSession, callback: (result: CompletionResult<T>) -> Unit) {
+        Log.i("Command", "Sending ${this::class.java.simpleName}")
         transceive(session, callback)
     }
 

tangem-core/src/main/java/com/tangem/common/tlv/Tlv.kt

@@ -1,6 +1,7 @@
 package com.tangem.common.tlv
 
 import com.tangem.Log
+import com.tangem.common.extensions.toHexString
 import java.io.ByteArrayInputStream
 import java.io.IOException
 
@@ -71,6 +72,10 @@ class Tlv {
         }
     }
 
+    override fun toString(): String {
+        return "${this.tag} ($tagRaw): ${value.toHexString()}"
+    }
+
 }
 
 fun List<Tlv>.serialize(): ByteArray =

tangem-core/src/main/java/com/tangem/common/tlv/TlvBuilder.kt

@@ -1,5 +1,7 @@
 package com.tangem.common.tlv
 
+import com.tangem.Log
+
 class TlvBuilder {
     private val tlvs = mutableListOf<Tlv>()
     private val encoder = TlvEncoder()
@@ -10,6 +12,10 @@ class TlvBuilder {
         tlvs.add(encoder.encode(tag, value))
     }
 
-    fun serialize(): ByteArray = tlvs.serialize()
+    fun serialize(): ByteArray {
+        Log.v("TLV",
+                "List of TLV that are being sent to a card:\n${tlvs.joinToString("\n")}")
+        return tlvs.serialize()
+    }
 
 }

tangem-core/src/main/java/com/tangem/common/tlv/TlvDecoder.kt

@@ -18,6 +18,11 @@ import java.util.*
  */
 class TlvDecoder(val tlvList: List<Tlv>) {
 
+    init {
+        Log.v("TLV",
+                "List of TLV received from card:\n${tlvList.joinToString("\n")}")
+    }
+
     /**
      * Finds [Tlv] by its [TlvTag].
      * Returns null if [Tlv] is not found, otherwise converts its value to [T].