1 files changed, 75 insertions, 0 deletions
diff --git a/pkix/src/main/java/org/spongycastle/cms/bc/BcPasswordRecipient.java b/pkix/src/main/java/org/spongycastle/cms/bc/BcPasswordRecipient.java
new file mode 100644
index 00000000..679f4144
--- /dev/null
+++ b/pkix/src/main/java/org/spongycastle/cms/bc/BcPasswordRecipient.java
@@ -0,0 +1,75 @@
+package org.spongycastle.cms.bc;
+
+import org.spongycastle.asn1.ASN1OctetString;
+import org.spongycastle.asn1.pkcs.PBKDF2Params;
+import org.spongycastle.asn1.x509.AlgorithmIdentifier;
+import org.spongycastle.cms.CMSException;
+import org.spongycastle.cms.PasswordRecipient;
+import org.spongycastle.crypto.InvalidCipherTextException;
+import org.spongycastle.crypto.Wrapper;
+import org.spongycastle.crypto.generators.PKCS5S2ParametersGenerator;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.crypto.params.ParametersWithIV;
+
+/**
+ * the RecipientInfo class for a recipient who has been sent a message
+ * encrypted using a password.
+ */
+public abstract class BcPasswordRecipient
+    implements PasswordRecipient
+{
+    private int schemeID = PasswordRecipient.PKCS5_SCHEME2_UTF8;
+    private char[] password;
+
+    BcPasswordRecipient(
+        char[] password)
+    {
+        this.password = password;
+    }
+
+    public BcPasswordRecipient setPasswordConversionScheme(int schemeID)
+    {
+        this.schemeID = schemeID;
+
+        return this;
+    }
+
+    protected KeyParameter extractSecretKey(AlgorithmIdentifier keyEncryptionAlgorithm, AlgorithmIdentifier contentEncryptionAlgorithm, byte[] derivedKey, byte[] encryptedContentEncryptionKey)
+        throws CMSException
+    {
+        Wrapper keyEncryptionCipher = EnvelopedDataHelper.createRFC3211Wrapper(keyEncryptionAlgorithm.getAlgorithm());
+
+        keyEncryptionCipher.init(false, new ParametersWithIV(new KeyParameter(derivedKey), ASN1OctetString.getInstance(keyEncryptionAlgorithm.getParameters()).getOctets()));
+
+        try
+        {
+            return new KeyParameter(keyEncryptionCipher.unwrap(encryptedContentEncryptionKey, 0, encryptedContentEncryptionKey.length));
+        }
+        catch (InvalidCipherTextException e)
+        {
+            throw new CMSException("unable to unwrap key: " + e.getMessage(), e);
+        }
+    }
+
+    public byte[] calculateDerivedKey(byte[] encodedPassword, AlgorithmIdentifier derivationAlgorithm, int keySize)
+        throws CMSException
+    {
+        PBKDF2Params params = PBKDF2Params.getInstance(derivationAlgorithm.getParameters());
+
+        PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator();
+
+        gen.init(encodedPassword, params.getSalt(), params.getIterationCount().intValue());
+
+        return ((KeyParameter)gen.generateDerivedParameters(keySize)).getKey();
+    }
+
+    public int getPasswordConversionScheme()
+    {
+        return schemeID;
+    }
+
+    public char[] getPassword()
+    {
+        return password;
+    }
+}