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MichaelsPlayground · Apr 7, 2023 · ed04ba8 · ed04ba8
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diff --git a/app/src/main/java/de/androidcrypto/talktoyourcreditcard/MainActivity.java b/app/src/main/java/de/androidcrypto/talktoyourcreditcard/MainActivity.java
@@ -140,7 +140,23 @@ public void onTagDiscovered(Tag tag) {
                      * step 1 code start
                      */
 
-
+                    printStepHeader(1, "select PPSE");
+                    byte[] PPSE = "2PAY.SYS.DDF01".getBytes(StandardCharsets.UTF_8); // PPSE
+                    byte[] selectPpseCommand = selectApdu(PPSE);
+                    byte[] selectPpseResponse = nfc.transceive(selectPpseCommand);
+                    writeToUiAppend("01 select PPSE command  length " + selectPpseCommand.length + " data: " + bytesToHexNpe(selectPpseCommand));
+                    writeToUiAppend("01 select PPSE response length " + selectPpseResponse.length + " data: " + bytesToHexNpe(selectPpseResponse));
+                    writeToUiAppend(etData, "01 select PPSE completed");
+                    writeToUiAppend(prettyPrintDataToString(selectPpseResponse));
+
+                    byte[] selectPpseResponseOk = checkResponse(selectPpseResponse);
+                    // proceed only when te do have a positive read result = 0x'9000' at the end of response data
+                    if (selectPpseResponseOk != null) {
+
+                    } else {
+                    // if (isoDepInTechList) {
+                    writeToUiAppend("The discovered NFC tag does not have an IsoDep interface.");
+                }
 
                     /**
                      * step 1 code end
@@ -173,6 +189,31 @@ public void onTagDiscovered(Tag tag) {
      * section for emv reading
      */
 
+    /**
+     * step 1 code start
+     */
+
+    /**
+     * build a select apdu command
+     *
+     * @param data
+     * @return
+     */
+    private byte[] selectApdu(@NonNull byte[] data) {
+        byte[] commandApdu = new byte[6 + data.length];
+        commandApdu[0] = (byte) 0x00;  // CLA
+        commandApdu[1] = (byte) 0xA4;  // INS
+        commandApdu[2] = (byte) 0x04;  // P1
+        commandApdu[3] = (byte) 0x00;  // P2
+        commandApdu[4] = (byte) (data.length & 0x0FF);       // Lc
+        System.arraycopy(data, 0, commandApdu, 5, data.length);
+        commandApdu[commandApdu.length - 1] = (byte) 0x00;  // Le
+        return commandApdu;
+    }
+
+    /**
+     * step 1 code end
+     */
 
     /**
      * add blanks to a string on right side up to a length of len

diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
@@ -21,7 +21,7 @@
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:padding="10dp"
-        android:text="Talk to your CreditCard part 0"
+        android:text="Talk to your CreditCard part 1"
         android:textAlignment="center"
         android:textSize="20sp"
         android:textStyle="bold" />

diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
@@ -2,5 +2,5 @@
     <string name="app_name">Talk to your Credit Card</string>
     <string name="action_licenses">Used libraries and their licenses</string>
     <string name="copy_right" translatable="false">Copyrights © %1$d</string>
-    <string name="app_description">This is the basic app (part 0) for the \"Talk to your Credit Card\" application.\n\nThe full app reads your Credit Card and retrieves the card number and expiration date.</string>
+    <string name="app_description">This is the first app (part 1) for the \"Talk to your Credit Card\" application.\n\nThe full app reads your Credit Card and retrieves the card number and expiration date.</string>
 </resources>
diff --git a/docs/app00.png b/docs/app00.png
diff --git a/docs/app01.png b/docs/app01.png
diff --git a/docs/full/app00.png b/docs/full/app00.png
diff --git a/docs/full/app01.png b/docs/full/app01.png
diff --git a/logfile.md b/logfile.md
@@ -2,7 +2,7 @@
 
 ```plaintext
 NFC tag discovered
-TagId: 0585921afb9100
+TagId: 028eedb17074b0
 TechList found with these entries:
 android.nfc.tech.IsoDep
 android.nfc.tech.NfcA
@@ -16,6 +16,31 @@ increase IsoDep timeout for long lasting reading
 timeout old: 2000 ms
 timeout new: 10000 ms
 
+*********************************
+************ step 01 ************
+* select PPSE                   *
+*********************************
+01 select PPSE command  length 20 data: 00a404000e325041592e5359532e444446303100
+01 select PPSE response length 64 data: 6f3c840e325041592e5359532e4444463031a52abf0c2761254f07a000000004101050104465626974204d6173746572436172648701019f0a04000101019000
+------------------------------------
+6F 3C -- File Control Information (FCI) Template
+      84 0E -- Dedicated File (DF) Name
+            32 50 41 59 2E 53 59 53 2E 44 44 46 30 31 (BINARY)
+      A5 2A -- File Control Information (FCI) Proprietary Template
+            BF 0C 27 -- File Control Information (FCI) Issuer Discretionary Data
+                     61 25 -- Application Template
+                           4F 07 -- Application Identifier (AID) - card
+                                 A0 00 00 00 04 10 10 (BINARY)
+                           50 10 -- Application Label
+                                 44 65 62 69 74 20 4D 61 73 74 65 72 43 61 72 64 (=Debit MasterCard)
+                           87 01 -- Application Priority Indicator
+                                 01 (BINARY)
+                           9F 0A 04 -- [UNKNOWN TAG]
+                                    00 01 01 01 (BINARY)
+90 00 -- Command successfully executed (OK)
+------------------------------------
+
+
 *********************************
 ************ step 99 ************
 * our journey ends              *

diff --git a/readme.md b/readme.md
@@ -1,4 +1,4 @@
-# Talk to your Credit Card part 0
+# Talk to your Credit Card part 1
 
 This app shows how to talk with a Credit Card and get information's like the Credit Card number, 
 the card's expiration date and some other data.
@@ -18,8 +18,7 @@ The app uses the NFC **ReaderMode** to get access to the card.
 
 There are apps available for each step in my GitHub repository - the naming shows the step that has the code including this step.
 
-This is the app for the general overview, means it is the basic app that has a very limited functionality: it detects the presence of a Credit Card 
-near the device's NFC reader: **TalkToYourCreditCardPart0**.
+This is the app for the first step 1: **select the Paypass Payment System Environment (PPSE)** in **TalkToYourCreditCardPart1**.
 
 The app is tested on real Android devices running Android versions 5.0.1, 8.0 and 13.
 
@@ -32,7 +31,7 @@ These are the steps to read a payment card, it is a kind of "question & answer"
 - read all files given in the AFL list and find the file where there are the elements "Application Primary Account Number" and "Application Expiration Date"
 - print out the "Application Primary Account Number" ("PAN") = card number and "Application Expiration Date" = expiration date of the card.
 
-![step 0: after reading a Credit Card](docs/app00.png?raw=true)
+![step 1: after reading a Credit Card](docs/app01.png?raw=true)
 
 In AndroidManifest.xml grant these permissions:
 ```plaintext