From 61ae2f908c3e8aaa3cbba90ea5fbbf6f239a0a1a Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Fri, 23 Feb 2024 18:57:44 +0000
Subject: Remove unused methods from android.security.KeyStore

Remove methods from android.security.KeyStore that have no real callers.

The methods with @UnsupportedAppUsage could be called via reflection by
apps targeting an old SDK level.  But since there is no valid use case
for these and they were already replaced with stubs in Android 12,
removing them is allowed by the non-SDK interface policy.

Bug: 326508120
Test: presubmit
Change-Id: Id742604786e71a212244f7800b9c245cea193057
---
 keystore/java/android/security/KeyStore.java | 63 +++-------------------------
 1 file changed, 6 insertions(+), 57 deletions(-)

diff --git a/keystore/java/android/security/KeyStore.java b/keystore/java/android/security/KeyStore.java
index 11b827117aa3..bd9abec22325 100644
--- a/keystore/java/android/security/KeyStore.java
+++ b/keystore/java/android/security/KeyStore.java
@@ -21,12 +21,14 @@ import android.os.Build;
 import android.os.StrictMode;
 
 /**
- * @hide This should not be made public in its present form because it
- * assumes that private and secret key bytes are available and would
- * preclude the use of hardware crypto.
+ * This class provides some constants and helper methods related to Android's Keystore service.
+ * This class was originally much larger, but its functionality was superseded by other classes.
+ * It now just contains a few remaining pieces for which the users haven't been updated yet.
+ * You may be looking for {@link java.security.KeyStore} instead.
+ *
+ * @hide
  */
 public class KeyStore {
-    private static final String TAG = "KeyStore";
 
     // ResponseCodes - see system/security/keystore/include/keystore/keystore.h
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -42,50 +44,6 @@ public class KeyStore {
         return KEY_STORE;
     }
 
-    /** @hide */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
-    public byte[] get(String key) {
-        return null;
-    }
-
-    /** @hide */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
-    public boolean delete(String key) {
-        return false;
-    }
-
-    /**
-     * List uids of all keys that are auth bound to the current user.
-     * Only system is allowed to call this method.
-     * @hide
-     * @deprecated This function always returns null.
-     */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
-    public int[] listUidsOfAuthBoundKeys() {
-        return null;
-    }
-
-
-    /**
-     * @hide
-     * @deprecated This function has no effect.
-     */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
-    public boolean unlock(String password) {
-        return false;
-    }
-
-    /**
-     *
-     * @return
-     * @deprecated This function always returns true.
-     * @hide
-     */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
-    public boolean isEmpty() {
-        return true;
-    }
-
     /**
      * Add an authentication record to the keystore authorization table.
      *
@@ -105,13 +63,4 @@ public class KeyStore {
     public void onDeviceOffBody() {
         AndroidKeyStoreMaintenance.onDeviceOffBody();
     }
-
-    /**
-     * Returns a {@link KeyStoreException} corresponding to the provided keystore/keymaster error
-     * code.
-     */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
-    public static KeyStoreException getKeyStoreException(int errorCode) {
-        return new KeyStoreException(-10000, "Should not be called.");
-    }
 }
-- 
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