1 files changed, 135 insertions, 0 deletions
diff --git a/libraries/spongycastle/pkix/src/main/java/org/spongycastle/cms/PasswordRecipientInformation.java b/libraries/spongycastle/pkix/src/main/java/org/spongycastle/cms/PasswordRecipientInformation.java
new file mode 100644
index 000000000..90b7c4996
--- /dev/null
+++ b/libraries/spongycastle/pkix/src/main/java/org/spongycastle/cms/PasswordRecipientInformation.java
@@ -0,0 +1,135 @@
+package org.spongycastle.cms;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.spongycastle.asn1.ASN1Encodable;
+import org.spongycastle.asn1.cms.PasswordRecipientInfo;
+import org.spongycastle.asn1.pkcs.PBKDF2Params;
+import org.spongycastle.asn1.x509.AlgorithmIdentifier;
+import org.spongycastle.crypto.PBEParametersGenerator;
+import org.spongycastle.crypto.generators.PKCS5S2ParametersGenerator;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.util.Integers;
+
+/**
+ * the RecipientInfo class for a recipient who has been sent a message
+ * encrypted using a password.
+ */
+public class PasswordRecipientInformation
+    extends RecipientInformation
+{
+    static Map KEYSIZES = new HashMap();
+    static Map BLOCKSIZES = new HashMap();
+
+    static
+    {
+        BLOCKSIZES.put(CMSAlgorithm.DES_EDE3_CBC, Integers.valueOf(8));
+        BLOCKSIZES.put(CMSAlgorithm.AES128_CBC, Integers.valueOf(16));
+        BLOCKSIZES.put(CMSAlgorithm.AES192_CBC, Integers.valueOf(16));
+        BLOCKSIZES.put(CMSAlgorithm.AES256_CBC, Integers.valueOf(16));
+
+        KEYSIZES.put(CMSAlgorithm.DES_EDE3_CBC, Integers.valueOf(192));
+        KEYSIZES.put(CMSAlgorithm.AES128_CBC, Integers.valueOf(128));
+        KEYSIZES.put(CMSAlgorithm.AES192_CBC, Integers.valueOf(192));
+        KEYSIZES.put(CMSAlgorithm.AES256_CBC, Integers.valueOf(256));
+    }
+
+    private PasswordRecipientInfo info;
+
+    PasswordRecipientInformation(
+        PasswordRecipientInfo   info,
+        AlgorithmIdentifier     messageAlgorithm,
+        CMSSecureReadable       secureReadable,
+        AuthAttributesProvider  additionalData)
+    {
+        super(info.getKeyEncryptionAlgorithm(), messageAlgorithm, secureReadable, additionalData);
+
+        this.info = info;
+        this.rid = new PasswordRecipientId();
+    }
+
+    /**
+     * return the object identifier for the key derivation algorithm, or null
+     * if there is none present.
+     *
+     * @return OID for key derivation algorithm, if present.
+     */
+    public String getKeyDerivationAlgOID()
+    {
+        if (info.getKeyDerivationAlgorithm() != null)
+        {
+            return info.getKeyDerivationAlgorithm().getAlgorithm().getId();
+        }
+
+        return null;
+    }
+
+    /**
+     * return the ASN.1 encoded key derivation algorithm parameters, or null if
+     * there aren't any.
+     * @return ASN.1 encoding of key derivation algorithm parameters.
+     */
+    public byte[] getKeyDerivationAlgParams()
+    {
+        try
+        {
+            if (info.getKeyDerivationAlgorithm() != null)
+            {
+                ASN1Encodable params = info.getKeyDerivationAlgorithm().getParameters();
+                if (params != null)
+                {
+                    return params.toASN1Primitive().getEncoded();
+                }
+            }
+
+            return null;
+        }
+        catch (Exception e)
+        {
+            throw new RuntimeException("exception getting encryption parameters " + e);
+        }
+    }
+
+    /**
+     * Return the key derivation algorithm details for the key in this recipient.
+     *
+     * @return AlgorithmIdentifier representing the key derivation algorithm.
+     */
+    public AlgorithmIdentifier getKeyDerivationAlgorithm()
+    {
+        return info.getKeyDerivationAlgorithm();
+    }
+
+    protected RecipientOperator getRecipientOperator(Recipient recipient)
+        throws CMSException, IOException
+    {
+        PasswordRecipient pbeRecipient = (PasswordRecipient)recipient;
+        AlgorithmIdentifier kekAlg = AlgorithmIdentifier.getInstance(info.getKeyEncryptionAlgorithm());
+        AlgorithmIdentifier kekAlgParams = AlgorithmIdentifier.getInstance(kekAlg.getParameters());
+
+        byte[] passwordBytes = getPasswordBytes(pbeRecipient.getPasswordConversionScheme(),
+            pbeRecipient.getPassword());
+        PBKDF2Params params = PBKDF2Params.getInstance(info.getKeyDerivationAlgorithm().getParameters());
+
+        PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator();
+        gen.init(passwordBytes, params.getSalt(), params.getIterationCount().intValue());
+
+        int keySize = ((Integer)KEYSIZES.get(kekAlgParams.getAlgorithm())).intValue();
+
+        byte[] derivedKey = ((KeyParameter)gen.generateDerivedParameters(keySize)).getKey();
+
+        return pbeRecipient.getRecipientOperator(kekAlgParams, messageAlgorithm, derivedKey, info.getEncryptedKey().getOctets());
+    }
+    
+    protected byte[] getPasswordBytes(int scheme, char[] password)
+    {
+        if (scheme == PasswordRecipient.PKCS5_SCHEME2)
+        {
+            return PBEParametersGenerator.PKCS5PasswordToBytes(password);
+        }
+
+        return PBEParametersGenerator.PKCS5PasswordToUTF8Bytes(password);
+    }
+}