1 files changed, 51 insertions, 0 deletions
diff --git a/libraries/spongycastle/pkix/src/main/java/org/spongycastle/operator/bc/BcAsymmetricKeyUnwrapper.java b/libraries/spongycastle/pkix/src/main/java/org/spongycastle/operator/bc/BcAsymmetricKeyUnwrapper.java
new file mode 100644
index 000000000..8fed9debe
--- /dev/null
+++ b/libraries/spongycastle/pkix/src/main/java/org/spongycastle/operator/bc/BcAsymmetricKeyUnwrapper.java
@@ -0,0 +1,51 @@
+package org.spongycastle.operator.bc;
+
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.asn1.pkcs.PKCSObjectIdentifiers;
+import org.spongycastle.asn1.x509.AlgorithmIdentifier;
+import org.spongycastle.crypto.AsymmetricBlockCipher;
+import org.spongycastle.crypto.InvalidCipherTextException;
+import org.spongycastle.crypto.params.AsymmetricKeyParameter;
+import org.spongycastle.operator.AsymmetricKeyUnwrapper;
+import org.spongycastle.operator.GenericKey;
+import org.spongycastle.operator.OperatorException;
+
+public abstract class BcAsymmetricKeyUnwrapper
+    extends AsymmetricKeyUnwrapper
+{
+    private AsymmetricKeyParameter privateKey;
+
+    public BcAsymmetricKeyUnwrapper(AlgorithmIdentifier encAlgId, AsymmetricKeyParameter privateKey)
+    {
+        super(encAlgId);
+
+        this.privateKey = privateKey;
+    }
+
+    public GenericKey generateUnwrappedKey(AlgorithmIdentifier encryptedKeyAlgorithm, byte[] encryptedKey)
+        throws OperatorException
+    {
+        AsymmetricBlockCipher keyCipher = createAsymmetricUnwrapper(this.getAlgorithmIdentifier().getAlgorithm());
+
+        keyCipher.init(false, privateKey);
+        try
+        {
+            byte[] key = keyCipher.processBlock(encryptedKey, 0, encryptedKey.length);
+
+            if (encryptedKeyAlgorithm.getAlgorithm().equals(PKCSObjectIdentifiers.des_EDE3_CBC))
+            {
+                return new GenericKey(encryptedKeyAlgorithm, key);
+            }
+            else
+            {
+                return new GenericKey(encryptedKeyAlgorithm, key);
+            }
+        }
+        catch (InvalidCipherTextException e)
+        {
+            throw new OperatorException("unable to recover secret key: " + e.getMessage(), e);
+        }
+    }
+
+    protected abstract AsymmetricBlockCipher createAsymmetricUnwrapper(ASN1ObjectIdentifier algorithm);
+}