Displaying Deterministic Username for a given Token

fe2-android/app/src/main/java/com/github/dedis/popstellar/model/objects/security/PublicKey.kt

@@ -1,6 +1,7 @@
 package com.github.dedis.popstellar.model.objects.security
 
 import com.github.dedis.popstellar.model.Immutable
+import com.github.dedis.popstellar.utility.GeneralUtils
 import com.google.crypto.tink.PublicKeyVerify
 import com.google.crypto.tink.subtle.Ed25519Verify
 import java.security.GeneralSecurityException
@@ -14,13 +15,16 @@ import timber.log.Timber
 @Immutable
 class PublicKey : Base64URLData {
   private val verifier: PublicKeyVerify
+  @Transient private var label: String
 
   constructor(data: ByteArray) : super(data) {
     verifier = Ed25519Verify(data)
+    label = GeneralUtils.generateUsernameFromBase64(this.encoded)
   }
 
   constructor(data: String) : super(data) {
     verifier = Ed25519Verify(this.data)
+    label = GeneralUtils.generateUsernameFromBase64(this.encoded)
   }
 
   fun verify(signature: Signature, data: Base64URLData): Boolean {
@@ -33,6 +37,14 @@ class PublicKey : Base64URLData {
     }
   }
 
+  /**
+   * Function that return the username of the public key The username is deterministic and is
+   * computed from the hash of the public key
+   */
+  fun getLabel(): String {
+    return label
+  }
+
   /**
    * Function that compute the hash of a public key
    *
@@ -52,5 +64,13 @@ class PublicKey : Base64URLData {
 
   companion object {
     private val TAG = PublicKey::class.java.simpleName
+
+    fun findPublicKeyFromUsername(
+        username: String,
+        publicKeys: List<PublicKey>,
+        default: PublicKey
+    ): PublicKey {
+      return publicKeys.firstOrNull { it.getLabel() == username } ?: default
+    }
   }
 }

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/DigitalCashIssueFragment.kt

@@ -10,6 +10,7 @@ import androidx.fragment.app.Fragment
 import com.github.dedis.popstellar.R
 import com.github.dedis.popstellar.databinding.DigitalCashIssueFragmentBinding
 import com.github.dedis.popstellar.model.objects.security.PublicKey
+import com.github.dedis.popstellar.model.objects.security.PublicKey.Companion.findPublicKeyFromUsername
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainDigitalCashViewModel
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainViewModel
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.setCurrentFragment
@@ -74,14 +75,19 @@ class DigitalCashIssueFragment : Fragment() {
   private fun issueCoins() {
     /*Take the amount entered by the user*/
     val currentAmount = binding.digitalCashIssueAmount.text.toString()
-    val currentPublicKeySelected = binding.digitalCashIssueSpinner.editText!!.text.toString()
+    val currentPublicKeySelected =
+        findPublicKeyFromUsername(
+            binding.digitalCashIssueSpinner.editText!!.text.toString(),
+            digitalCashViewModel.attendeesFromTheRollCallList,
+            digitalCashViewModel.validToken.publicKey)
     val radioGroup = binding.digitalCashIssueSelect.checkedRadioButtonId
 
     if (digitalCashViewModel.canPerformTransaction(
-        currentAmount, currentPublicKeySelected, radioGroup)) {
+        currentAmount, currentPublicKeySelected.encoded, radioGroup)) {
       try {
         val issueMap =
-            computeMapForPostTransaction(currentAmount, currentPublicKeySelected, radioGroup)
+            computeMapForPostTransaction(
+                currentAmount, currentPublicKeySelected.encoded, radioGroup)
         if (issueMap.isEmpty()) {
           displayToast(radioGroup)
         } else {
@@ -165,7 +171,7 @@ class DigitalCashIssueFragment : Fragment() {
     /* Roll Call attendees to which we can send*/
     var myArray: List<String>
     try {
-      myArray = digitalCashViewModel.attendeesFromTheRollCallList
+      myArray = digitalCashViewModel.attendeesFromTheRollCallList.map { it.getLabel() }
     } catch (e: NoRollCallException) {
       Timber.tag(TAG).e(getString(R.string.error_no_rollcall_closed_in_LAO))
       Toast.makeText(

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/DigitalCashReceiptFragment.kt

@@ -8,6 +8,7 @@ import androidx.fragment.app.Fragment
 import com.github.dedis.popstellar.R
 import com.github.dedis.popstellar.SingleEvent
 import com.github.dedis.popstellar.databinding.DigitalCashReceiptFragmentBinding
+import com.github.dedis.popstellar.model.objects.security.PublicKey
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.addBackNavigationCallback
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainDigitalCashViewModel
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainViewModel
@@ -51,11 +52,12 @@ class DigitalCashReceiptFragment : Fragment() {
     }
 
     digitalCashViewModel.getUpdateReceiptAddressEvent().observe(viewLifecycleOwner) {
-        stringEvent: SingleEvent<String> ->
-      val address = stringEvent.contentIfNotHandled
-      if (address != null) {
+        stringEvent: SingleEvent<PublicKey> ->
+      val pk = stringEvent.contentIfNotHandled
+      if (pk != null) {
         binding.digitalCashReceiptBeneficiary.text =
-            String.format(resources.getString(R.string.digital_cash_beneficiary_address), address)
+            String.format(
+                resources.getString(R.string.digital_cash_beneficiary_address), pk.getLabel())
       }
     }
   }

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/DigitalCashReceiveFragment.kt

@@ -60,7 +60,7 @@ class DigitalCashReceiveFragment : Fragment() {
                   val token = digitalCashViewModel.validToken
                   val publicKey = token.publicKey
 
-                  binding.digitalCashReceiveAddress.text = publicKey.encoded
+                  binding.digitalCashReceiveAddress.text = publicKey.getLabel()
 
                   val tokenData = PopTokenData(token.publicKey)
                   val myBitmap =

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/DigitalCashSendFragment.kt

@@ -11,6 +11,7 @@ import com.github.dedis.popstellar.R
 import com.github.dedis.popstellar.SingleEvent
 import com.github.dedis.popstellar.databinding.DigitalCashSendFragmentBinding
 import com.github.dedis.popstellar.model.objects.security.PublicKey
+import com.github.dedis.popstellar.model.objects.security.PublicKey.Companion.findPublicKeyFromUsername
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainDigitalCashViewModel
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.obtainViewModel
 import com.github.dedis.popstellar.ui.lao.LaoActivity.Companion.setCurrentFragment
@@ -60,15 +61,20 @@ class DigitalCashSendFragment : Fragment() {
       val event = booleanEvent.contentIfNotHandled
       if (event != null) {
         val currentAmount = binding.digitalCashSendAmount.text.toString()
-        val currentPublicKeySelected = binding.digitalCashSendSpinner.editText?.text.toString()
+        val currentPublicKeySelected =
+            findPublicKeyFromUsername(
+                binding.digitalCashSendSpinner.editText?.text.toString(),
+                digitalCashViewModel.attendeesFromTheRollCallList,
+                digitalCashViewModel.validToken.publicKey)
 
         if (digitalCashViewModel.canPerformTransaction(
-            currentAmount, currentPublicKeySelected, -1)) {
+            currentAmount, currentPublicKeySelected.encoded, -1)) {
           try {
             val token = digitalCashViewModel.validToken
             if (canPostTransaction(token.publicKey, currentAmount.toInt())) {
               laoViewModel.addDisposable(
-                  postTransaction(Collections.singletonMap(currentPublicKeySelected, currentAmount))
+                  postTransaction(
+                          Collections.singletonMap(currentPublicKeySelected.encoded, currentAmount))
                       .subscribe(
                           {
                             digitalCashViewModel.updateReceiptAddressEvent(currentPublicKeySelected)
@@ -124,7 +130,8 @@ class DigitalCashSendFragment : Fragment() {
     /* Roll Call attendees to which we can send */
     var myArray: MutableList<String>
     try {
-      myArray = digitalCashViewModel.attendeesFromTheRollCallList.toMutableList()
+      myArray =
+          digitalCashViewModel.attendeesFromTheRollCallList.map { it.getLabel() }.toMutableList()
     } catch (e: NoRollCallException) {
       Timber.tag(TAG).d(e)
       Toast.makeText(
@@ -155,7 +162,7 @@ class DigitalCashSendFragment : Fragment() {
    */
   private fun removeOwnToken(members: MutableList<String>) {
     try {
-      members.remove(digitalCashViewModel.validToken.publicKey.encoded)
+      members.remove(digitalCashViewModel.validToken.publicKey.getLabel())
     } catch (e: KeyException) {
       Timber.tag(TAG).e(e, resources.getString(R.string.error_retrieve_own_token))
     }

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/DigitalCashViewModel.kt

@@ -40,7 +40,6 @@ import io.reactivex.Single
 import java.nio.charset.StandardCharsets
 import java.security.GeneralSecurityException
 import java.util.Collections
-import java.util.stream.Collectors
 import javax.inject.Inject
 import timber.log.Timber
 
@@ -69,7 +68,7 @@ constructor(
   private val postTransactionEvent = MutableLiveData<SingleEvent<Boolean>>()
 
   /* Update the receipt after sending a transaction */
-  private val updateReceiptAddressEvent = MutableLiveData<SingleEvent<String>>()
+  private val updateReceiptAddressEvent = MutableLiveData<SingleEvent<PublicKey>>()
   private val updateReceiptAmountEvent = MutableLiveData<SingleEvent<String>>()
 
   fun getPostTransactionEvent(): LiveData<SingleEvent<Boolean>> {
@@ -80,11 +79,11 @@ constructor(
     postTransactionEvent.postValue(SingleEvent(true))
   }
 
-  fun getUpdateReceiptAddressEvent(): LiveData<SingleEvent<String>> {
+  fun getUpdateReceiptAddressEvent(): LiveData<SingleEvent<PublicKey>> {
     return updateReceiptAddressEvent
   }
 
-  fun updateReceiptAddressEvent(address: String?) {
+  fun updateReceiptAddressEvent(address: PublicKey?) {
     updateReceiptAddressEvent.postValue(SingleEvent(address))
   }
 
@@ -237,9 +236,8 @@ constructor(
     get() = lao.organizer
 
   @get:Throws(NoRollCallException::class)
-  val attendeesFromTheRollCallList: List<String>
-    get() =
-        attendeesFromLastRollCall.stream().map(Base64URLData::encoded).collect(Collectors.toList())
+  val attendeesFromTheRollCallList: List<PublicKey>
+    get() = attendeesFromLastRollCall.toList()
 
   @get:Throws(UnknownLaoException::class)
   val lao: LaoView

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/digitalcash/HistoryListAdapter.kt

@@ -51,7 +51,10 @@ class HistoryListAdapter(
     holder.transactionIdValue.text = transactionId
     holder.transactionProvenanceTitle.setText(
         if (element.isSender) R.string.digital_cash_to else R.string.digital_cash_from)
-    holder.transactionProvenanceValue.text = element.senderOrReceiver
+    holder.transactionProvenanceValue.text =
+        if (element.senderOrReceiver.encoded == viewModel.organizer.encoded)
+            element.senderOrReceiver.encoded + " (organizer)"
+        else element.senderOrReceiver.getLabel()
 
     val listener =
         View.OnClickListener {
@@ -96,7 +99,6 @@ class HistoryListAdapter(
       // To know if we are in input or not. We assume that no two different person
       val isSender = transactionObject.isSender(ownKey)
       val isIssuance = transactionObject.isCoinBaseTransaction
-
       transactionHistoryElements.addAll(
           transactionObject.outputs
               .stream() // If we are in input, we want all output except us. If we are not in input,
@@ -108,8 +110,11 @@ class HistoryListAdapter(
               }
               .map { outputObject: OutputObject ->
                 TransactionHistoryElement(
-                    if (isSender) outputObject.pubKeyHash
-                    else transactionObject.inputs[0].pubKey.encoded,
+                    // TODO : was previously outputObject.pubKeyHash, but was wrong (hash is smaller
+                    // than 32 bytes and is clearly not the receivers public key)
+                    // I set it to ownKey so that it works for now, but should actually show the
+                    // public key of the receiver | Maxime @Kaz-ookid 06.2025
+                    if (isSender) ownKey else PublicKey(transactionObject.inputs[0].pubKey.encoded),
                     outputObject.value.toString(),
                     transactionObject.transactionId,
                     !isIssuance && isSender)
@@ -125,9 +130,9 @@ class HistoryListAdapter(
     val transactionTypeTitle: TextView = itemView.findViewById(R.id.history_transaction_type_title)
     val transactionTypeValue: TextView = itemView.findViewById(R.id.history_transaction_type_value)
     val transactionProvenanceTitle: TextView =
-        itemView.findViewById(R.id.history_transaction_provenance_value)
-    val transactionProvenanceValue: TextView =
         itemView.findViewById(R.id.history_transaction_provenance_title)
+    val transactionProvenanceValue: TextView =
+        itemView.findViewById(R.id.history_transaction_provenance_value)
     val transactionIdValue: TextView =
         itemView.findViewById(R.id.history_transaction_transaction_id_value)
     val detailLayout: ConstraintLayout =
@@ -136,14 +141,14 @@ class HistoryListAdapter(
   }
 
   private class TransactionHistoryElement(
-      val senderOrReceiver: String,
+      val senderOrReceiver: PublicKey,
       val value: String,
       val id: String,
       val isSender: Boolean
   ) {
 
     override fun toString(): String {
-      return "TransactionHistoryElement{senderOrReceiver='$senderOrReceiver', value='$value', " +
+      return "TransactionHistoryElement{senderOrReceiverHash='${senderOrReceiver.encoded}', senderOrReceiverUsername='${senderOrReceiver.getLabel()}',value='$value', " +
           "id='$id', isSender=$isSender}"
     }
   }

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/event/rollcall/RollCallArrayAdapter.kt

@@ -1,36 +1,64 @@
 package com.github.dedis.popstellar.ui.lao.event.rollcall
 
 import android.content.Context
+import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ArrayAdapter
 import android.widget.TextView
 import androidx.core.content.ContextCompat
 import com.github.dedis.popstellar.R
 import com.github.dedis.popstellar.model.objects.security.PoPToken
+import com.github.dedis.popstellar.model.objects.security.PublicKey
 
 class RollCallArrayAdapter(
     private val context: Context,
     private val layout: Int,
-    private val attendeesList: List<String>,
+    private val attendeesList: List<PublicKey>,
     private val myToken: PoPToken?,
     private val fragment: RollCallFragment
-) : ArrayAdapter<String>(context, layout, attendeesList) {
+) : ArrayAdapter<PublicKey>(context, layout, attendeesList) {
 
   init {
-    fragment.isAttendeeListSorted(attendeesList, context)
+    fragment.isAttendeeListSorted(attendeesList.map { it.encoded }, context)
   }
 
   override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
-    val view = super.getView(position, convertView, parent)
+    val view: View
+    val holder: ViewHolder
 
-    // highlights our token in the list
-    val currentToken = getItem(position)
-    if (myToken != null && currentToken == myToken.publicKey.encoded) {
-      val colorAccent = ContextCompat.getColor(context, R.color.colorAccent)
-      (view as TextView).setTextColor(colorAccent)
+    if (convertView == null) {
+      view = LayoutInflater.from(context).inflate(R.layout.list_item_attendee, parent, false)
+      holder = ViewHolder(view)
+      view.tag = holder
+    } else {
+      view = convertView
+      holder = view.tag as ViewHolder
+    }
+
+    val publicKey = getItem(position)
+    if (publicKey != null) {
+      holder.usernameTextView.text = publicKey.getLabel()
+      holder.hashTextView.text = publicKey.encoded
+
+      // Set the default color
+      val defaultColor = ContextCompat.getColor(context, R.color.textOnBackground)
+      holder.usernameTextView.setTextColor(defaultColor)
+      holder.hashTextView.setTextColor(defaultColor)
+
+      // highlights our token in the list
+      if (myToken != null && publicKey.encoded == myToken.publicKey.encoded) {
+        val colorAccent = ContextCompat.getColor(context, R.color.colorAccent)
+        holder.usernameTextView.setTextColor(colorAccent)
+        holder.hashTextView.setTextColor(colorAccent)
+      }
     }
 
     return view
   }
+
+  private class ViewHolder(view: View) {
+    val usernameTextView: TextView = view.findViewById(R.id.username_text_view)
+    val hashTextView: TextView = view.findViewById(R.id.hash_text_view)
+  }
 }

fe2-android/app/src/main/java/com/github/dedis/popstellar/ui/lao/event/rollcall/RollCallFragment.kt

@@ -248,16 +248,15 @@ class RollCallFragment : AbstractEventFragment {
     binding.rollCallAttendeesText.visibility = visibility
     binding.listViewAttendees.visibility = visibility
 
-    var attendeesList: List<String>? = null
+    var attendeesList: List<PublicKey>? = null
     if (isOrganizer && rollCall.isOpen) {
       // Show the list of all time scanned attendees if the roll call is opened
       // and the user is the organizer
       attendeesList =
           rollCallViewModel
               .getAttendees()
               .stream()
-              .map(PublicKey::encoded)
-              .sorted(compareBy(String::toString))
+              .sorted(compareBy { it.encoded })
               .collect(Collectors.toList())
 
       binding.rollCallAttendeesText.text =
@@ -266,7 +265,7 @@ class RollCallFragment : AbstractEventFragment {
               rollCallViewModel.getAttendees().size)
     } else if (rollCall.isClosed) {
       val orderedAttendees: MutableSet<PublicKey> = LinkedHashSet(rollCall.attendees)
-      attendeesList = orderedAttendees.stream().map(PublicKey::encoded).collect(Collectors.toList())
+      attendeesList = orderedAttendees.stream().collect(Collectors.toList())
 
       // Show the list of attendees if the roll call has ended
       binding.rollCallAttendeesText.text =
@@ -295,10 +294,12 @@ class RollCallFragment : AbstractEventFragment {
   private fun retrieveAndDisplayPublicKey() {
     val popToken = popToken ?: return
     val pk = popToken.publicKey.encoded
+    val pkUsername = popToken.publicKey.getLabel()
     Timber.tag(TAG).d("key displayed is %s", pk)
 
     // Set the QR visible only if the rollcall is opened and the user isn't the organizer
     if (rollCall.isOpen) {
+      binding.rollCallPopTokenUsername.text = pkUsername
       binding.rollCallPopTokenText.text = pk
       binding.rollCallPkQrCode.visibility = View.VISIBLE
       binding.rollCallPopTokenText.visibility = View.VISIBLE