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, 11 insertions, 10 deletions

diff --git a/keystore/java/android/security/AndroidKeyPairGenerator.java b/keystore/java/android/security/AndroidKeyPairGenerator.java
index 3b25ba66b9c3..3f29c6ab83b6 100644
--- a/keystore/java/android/security/AndroidKeyPairGenerator.java
+++ b/keystore/java/android/security/AndroidKeyPairGenerator.java
@@ -54,13 +54,13 @@ public abstract class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
 
     public static class RSA extends AndroidKeyPairGenerator {
         public RSA() {
-            super("RSA");
+            super(KeyStoreKeyProperties.Algorithm.RSA);
         }
     }
 
     public static class EC extends AndroidKeyPairGenerator {
         public EC() {
-            super("EC");
+            super(KeyStoreKeyProperties.Algorithm.EC);
         }
     }
 
@@ -83,15 +83,15 @@ public abstract class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
     private android.security.KeyStore mKeyStore;
 
     private KeyPairGeneratorSpec mSpec;
-    private String mKeyAlgorithm;
+    private @KeyStoreKeyProperties.AlgorithmEnum String mKeyAlgorithm;
     private int mKeyType;
     private int mKeySize;
 
-    protected AndroidKeyPairGenerator(String algorithm) {
+    protected AndroidKeyPairGenerator(@KeyStoreKeyProperties.AlgorithmEnum String algorithm) {
         mAlgorithm = algorithm;
     }
 
-    public String getAlgorithm() {
+    public @KeyStoreKeyProperties.AlgorithmEnum String getAlgorithm() {
         return mAlgorithm;
     }
 
@@ -197,7 +197,7 @@ public abstract class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
         return certGen.generate(privateKey);
     }
 
-    private String getKeyAlgorithm(KeyPairGeneratorSpec spec) {
+    private @KeyStoreKeyProperties.AlgorithmEnum String getKeyAlgorithm(KeyPairGeneratorSpec spec) {
         String result = spec.getKeyType();
         if (result != null) {
             return result;
@@ -248,10 +248,11 @@ public abstract class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
         }
     }
 
-    private static String getDefaultSignatureAlgorithmForKeyAlgorithm(String algorithm) {
-        if ("RSA".equalsIgnoreCase(algorithm)) {
+    private static String getDefaultSignatureAlgorithmForKeyAlgorithm(
+            @KeyStoreKeyProperties.AlgorithmEnum String algorithm) {
+        if (KeyStoreKeyProperties.Algorithm.RSA.equalsIgnoreCase(algorithm)) {
             return "sha256WithRSA";
-        } else if ("EC".equalsIgnoreCase(algorithm)) {
+        } else if (KeyStoreKeyProperties.Algorithm.EC.equalsIgnoreCase(algorithm)) {
             return "sha256WithECDSA";
         } else {
             throw new IllegalArgumentException("Unsupported key type " + algorithm);
@@ -287,7 +288,7 @@ public abstract class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
         }
 
         KeyPairGeneratorSpec spec = (KeyPairGeneratorSpec) params;
-        String keyAlgorithm = getKeyAlgorithm(spec);
+        @KeyStoreKeyProperties.AlgorithmEnum String keyAlgorithm = getKeyAlgorithm(spec);
         int keyType = KeyStore.getKeyTypeForAlgorithm(keyAlgorithm);
         if (keyType == -1) {
             throw new InvalidAlgorithmParameterException(