Define String constants for AndroidKeyStore crypto.

This defines the String enum values based on JCA standard names for
key algorithm, block mode, padding schemes, and digests. This should
make it safer to interact with AndroidKeyStore code that uses JCA
strings. This was requested by API Council.

Bug: 18088752
Change-Id: I241d9225a13b85479d0a84e49d0a98cbc77e5817

1 files changed, 10 insertions, 7 deletions

diff --git a/keystore/java/android/security/KeyChain.java b/keystore/java/android/security/KeyChain.java
index e9c24ddc7afb..8e27dc39ae98 100644
--- a/keystore/java/android/security/KeyChain.java
+++ b/keystore/java/android/security/KeyChain.java
@@ -262,7 +262,8 @@ public final class KeyChain {
      *     unavailable.
      */
     public static void choosePrivateKeyAlias(Activity activity, KeyChainAliasCallback response,
-            String[] keyTypes, Principal[] issuers, String host, int port, String alias) {
+            @KeyStoreKeyProperties.AlgorithmEnum String[] keyTypes, Principal[] issuers,
+            String host, int port, String alias) {
         choosePrivateKeyAlias(activity, response, keyTypes, issuers, host, port, null, alias);
     }
 
@@ -306,9 +307,8 @@ public final class KeyChain {
      *     unavailable.
      */
     public static void choosePrivateKeyAlias(Activity activity, KeyChainAliasCallback response,
-                                             String[] keyTypes, Principal[] issuers,
-                                             String host, int port, String url,
-                                             String alias) {
+            @KeyStoreKeyProperties.AlgorithmEnum String[] keyTypes, Principal[] issuers,
+            String host, int port, String url, String alias) {
         /*
          * TODO currently keyTypes, issuers are unused. They are meant
          * to follow the semantics and purpose of X509KeyManager
@@ -431,9 +431,11 @@ public final class KeyChain {
      * specific {@code PrivateKey} type indicated by {@code algorithm} (e.g.,
      * "RSA").
      */
-    public static boolean isKeyAlgorithmSupported(String algorithm) {
+    public static boolean isKeyAlgorithmSupported(
+            @KeyStoreKeyProperties.AlgorithmEnum String algorithm) {
         final String algUpper = algorithm.toUpperCase(Locale.US);
-        return "EC".equals(algUpper) || "RSA".equals(algUpper);
+        return KeyStoreKeyProperties.Algorithm.EC.equals(algUpper)
+                || KeyStoreKeyProperties.Algorithm.RSA.equals(algUpper);
     }
 
     /**
@@ -443,7 +445,8 @@ public final class KeyChain {
      * hardware support that can be used to bind keys to the device in a way
      * that makes it non-exportable.
      */
-    public static boolean isBoundKeyAlgorithm(String algorithm) {
+    public static boolean isBoundKeyAlgorithm(
+            @KeyStoreKeyProperties.AlgorithmEnum String algorithm) {
         if (!isKeyAlgorithmSupported(algorithm)) {
             return false;
         }