1 files changed, 119 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/PKCS5S1ParametersGenerator.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/PKCS5S1ParametersGenerator.java
new file mode 100644
index 000000000..3a6415f25
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/PKCS5S1ParametersGenerator.java
@@ -0,0 +1,119 @@
+package org.spongycastle.crypto.generators;
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.crypto.Digest;
+import org.spongycastle.crypto.PBEParametersGenerator;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.crypto.params.ParametersWithIV;
+
+/**
+ * Generator for PBE derived keys and ivs as defined by PKCS 5 V2.0 Scheme 1.
+ * Note this generator is limited to the size of the hash produced by the
+ * digest used to drive it.
+ * <p>
+ * The document this implementation is based on can be found at
+ * <a href=http://www.rsasecurity.com/rsalabs/pkcs/pkcs-5/index.html>
+ * RSA's PKCS5 Page</a>
+ */
+public class PKCS5S1ParametersGenerator
+    extends PBEParametersGenerator
+{
+    private Digest  digest;
+
+    /**
+     * Construct a PKCS 5 Scheme 1 Parameters generator. 
+     *
+     * @param digest the digest to be used as the source of derived keys.
+     */
+    public PKCS5S1ParametersGenerator(
+        Digest  digest)
+    {
+        this.digest = digest;
+    }
+
+    /**
+     * the derived key function, the ith hash of the password and the salt.
+     */
+    private byte[] generateDerivedKey()
+    {
+        byte[] digestBytes = new byte[digest.getDigestSize()];
+
+        digest.update(password, 0, password.length);
+        digest.update(salt, 0, salt.length);
+
+        digest.doFinal(digestBytes, 0);
+        for (int i = 1; i < iterationCount; i++)
+        {
+            digest.update(digestBytes, 0, digestBytes.length);
+            digest.doFinal(digestBytes, 0);
+        }
+
+        return digestBytes;
+    }
+
+    /**
+     * Generate a key parameter derived from the password, salt, and iteration
+     * count we are currently initialised with.
+     *
+     * @param keySize the size of the key we want (in bits)
+     * @return a KeyParameter object.
+     * @exception IllegalArgumentException if the key length larger than the base hash size.
+     */
+    public CipherParameters generateDerivedParameters(
+        int keySize)
+    {
+        keySize = keySize / 8;
+
+        if (keySize > digest.getDigestSize())
+        {
+            throw new IllegalArgumentException(
+                   "Can't generate a derived key " + keySize + " bytes long.");
+        }
+
+        byte[]  dKey = generateDerivedKey();
+
+        return new KeyParameter(dKey, 0, keySize);
+    }
+
+    /**
+     * Generate a key with initialisation vector parameter derived from
+     * the password, salt, and iteration count we are currently initialised
+     * with.
+     *
+     * @param keySize the size of the key we want (in bits)
+     * @param ivSize the size of the iv we want (in bits)
+     * @return a ParametersWithIV object.
+     * @exception IllegalArgumentException if keySize + ivSize is larger than the base hash size.
+     */
+    public CipherParameters generateDerivedParameters(
+        int     keySize,
+        int     ivSize)
+    {
+        keySize = keySize / 8;
+        ivSize = ivSize / 8;
+
+        if ((keySize + ivSize) > digest.getDigestSize())
+        {
+            throw new IllegalArgumentException(
+                   "Can't generate a derived key " + (keySize + ivSize) + " bytes long.");
+        }
+
+        byte[]  dKey = generateDerivedKey();
+
+        return new ParametersWithIV(new KeyParameter(dKey, 0, keySize), dKey, keySize, ivSize);
+    }
+
+    /**
+     * Generate a key parameter for use with a MAC derived from the password,
+     * salt, and iteration count we are currently initialised with.
+     *
+     * @param keySize the size of the key we want (in bits)
+     * @return a KeyParameter object.
+     * @exception IllegalArgumentException if the key length larger than the base hash size.
+     */
+    public CipherParameters generateDerivedMacParameters(
+        int keySize)
+    {
+        return generateDerivedParameters(keySize);
+    }
+}