1 files changed, 120 insertions, 0 deletions
diff --git a/bcpkix/src/main/java/org/bouncycastle/cert/crmf/jcajce/JceAsymmetricValueDecryptorGenerator.java b/bcpkix/src/main/java/org/bouncycastle/cert/crmf/jcajce/JceAsymmetricValueDecryptorGenerator.java
new file mode 100644
index 0000000..ff1158e
--- /dev/null
+++ b/bcpkix/src/main/java/org/bouncycastle/cert/crmf/jcajce/JceAsymmetricValueDecryptorGenerator.java
@@ -0,0 +1,120 @@
+package org.bouncycastle.cert.crmf.jcajce;
+
+import java.io.InputStream;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.PrivateKey;
+import java.security.Provider;
+import java.security.ProviderException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.CipherInputStream;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
+import org.bouncycastle.cert.crmf.CRMFException;
+import org.bouncycastle.cert.crmf.ValueDecryptorGenerator;
+import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
+import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
+import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
+import org.bouncycastle.operator.InputDecryptor;
+
+public class JceAsymmetricValueDecryptorGenerator
+    implements ValueDecryptorGenerator
+{
+    private PrivateKey recipientKey;
+    private CRMFHelper helper = new CRMFHelper(new DefaultJcaJceHelper());
+
+    public JceAsymmetricValueDecryptorGenerator(PrivateKey recipientKey)
+    {
+        this.recipientKey = recipientKey;
+    }
+
+    public JceAsymmetricValueDecryptorGenerator setProvider(Provider provider)
+    {
+        this.helper = new CRMFHelper(new ProviderJcaJceHelper(provider));
+
+        return this;
+    }
+
+    public JceAsymmetricValueDecryptorGenerator setProvider(String providerName)
+    {
+        this.helper = new CRMFHelper(new NamedJcaJceHelper(providerName));
+
+        return this;
+    }
+
+    private Key extractSecretKey(AlgorithmIdentifier keyEncryptionAlgorithm, AlgorithmIdentifier contentEncryptionAlgorithm, byte[] encryptedContentEncryptionKey)
+        throws CRMFException
+    {
+        try
+        {
+            Key sKey = null;
+
+            Cipher keyCipher = helper.createCipher(keyEncryptionAlgorithm.getAlgorithm());
+
+            try
+            {
+                keyCipher.init(Cipher.UNWRAP_MODE, recipientKey);
+                sKey = keyCipher.unwrap(encryptedContentEncryptionKey, contentEncryptionAlgorithm.getAlgorithm().getId(), Cipher.SECRET_KEY);
+            }
+            catch (GeneralSecurityException e)
+            {
+            }
+            catch (IllegalStateException e)
+            {
+            }
+            catch (UnsupportedOperationException e)
+            {
+            }
+            catch (ProviderException e)
+            {
+            }
+
+            // some providers do not support UNWRAP (this appears to be only for asymmetric algorithms)
+            if (sKey == null)
+            {
+                keyCipher.init(Cipher.DECRYPT_MODE, recipientKey);
+                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedContentEncryptionKey), contentEncryptionAlgorithm.getAlgorithm().getId());
+            }
+
+            return sKey;
+        }
+        catch (InvalidKeyException e)
+        {
+            throw new CRMFException("key invalid in message.", e);
+        }
+        catch (IllegalBlockSizeException e)
+        {
+            throw new CRMFException("illegal blocksize in message.", e);
+        }
+        catch (BadPaddingException e)
+        {
+            throw new CRMFException("bad padding in message.", e);
+        }
+    }
+
+    public InputDecryptor getValueDecryptor(AlgorithmIdentifier keyEncryptionAlgorithm, final AlgorithmIdentifier contentEncryptionAlgorithm, byte[] encryptedContentEncryptionKey)
+        throws CRMFException
+    {
+        Key secretKey = extractSecretKey(keyEncryptionAlgorithm, contentEncryptionAlgorithm, encryptedContentEncryptionKey);
+
+        final Cipher dataCipher = helper.createContentCipher(secretKey, contentEncryptionAlgorithm);
+
+        return new InputDecryptor()
+        {
+            public AlgorithmIdentifier getAlgorithmIdentifier()
+            {
+                return contentEncryptionAlgorithm;
+            }
+
+            public InputStream getInputStream(InputStream dataIn)
+            {
+                return new CipherInputStream(dataIn, dataCipher);
+            }
+        };
+    }
+}