HADOOP-10891. Add EncryptedKeyVersion factory method to KeyProviderCryptoExtension. (wang)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1613332 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -189,6 +189,9 @@ Trunk (Unreleased)
     HADOOP-10720. KMS: Implement generateEncryptedKey and decryptEncryptedKey
     in the REST API. (asuresh via tucu)
 
+    HADOOP-10891. Add EncryptedKeyVersion factory method to
+    KeyProviderCryptoExtension. (wang)
+
   BUG FIXES
 
     HADOOP-9451. Fault single-layer config if node group topology is enabled.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderCryptoExtension.java

@@ -79,6 +79,30 @@ public class KeyProviderCryptoExtension extends
       this.encryptedKeyVersion = encryptedKeyVersion;
     }
 
+    /**
+     * Factory method to create a new EncryptedKeyVersion that can then be
+     * passed into {@link #decryptEncryptedKey}. Note that the fields of the
+     * returned EncryptedKeyVersion will only partially be populated; it is not
+     * necessarily suitable for operations besides decryption.
+     *
+     * @param encryptionKeyVersionName Version name of the encryption key used
+     *                                 to encrypt the encrypted key.
+     * @param encryptedKeyIv           Initialization vector of the encrypted
+     *                                 key. The IV of the encryption key used to
+     *                                 encrypt the encrypted key is derived from
+     *                                 this IV.
+     * @param encryptedKeyMaterial     Key material of the encrypted key.
+     * @return EncryptedKeyVersion suitable for decryption.
+     */
+    public static EncryptedKeyVersion createForDecryption(String
+        encryptionKeyVersionName, byte[] encryptedKeyIv,
+        byte[] encryptedKeyMaterial) {
+      KeyVersion encryptedKeyVersion = new KeyVersion(null, null,
+          encryptedKeyMaterial);
+      return new EncryptedKeyVersion(null, encryptionKeyVersionName,
+          encryptedKeyIv, encryptedKeyVersion);
+    }
+
     /**
      * @return Name of the encryption key used to encrypt the encrypted key.
      */