1 files changed, 131 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/OpenSSLPBEParametersGenerator.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/OpenSSLPBEParametersGenerator.java
new file mode 100644
index 000000000..70e35927d
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/OpenSSLPBEParametersGenerator.java
@@ -0,0 +1,131 @@
+package org.spongycastle.crypto.generators;
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.crypto.Digest;
+import org.spongycastle.crypto.PBEParametersGenerator;
+import org.spongycastle.crypto.digests.MD5Digest;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.crypto.params.ParametersWithIV;
+
+/**
+ * Generator for PBE derived keys and ivs as usd by OpenSSL.
+ * <p>
+ * The scheme is a simple extension of PKCS 5 V2.0 Scheme 1 using MD5 with an
+ * iteration count of 1.
+ * <p>
+ */
+public class OpenSSLPBEParametersGenerator
+    extends PBEParametersGenerator
+{
+    private Digest  digest = new MD5Digest();
+
+    /**
+     * Construct a OpenSSL Parameters generator. 
+     */
+    public OpenSSLPBEParametersGenerator()
+    {
+    }
+
+    /**
+     * Initialise - note the iteration count for this algorithm is fixed at 1.
+     * 
+     * @param password password to use.
+     * @param salt salt to use.
+     */
+    public void init(
+       byte[] password,
+       byte[] salt)
+    {
+        super.init(password, salt, 1);
+    }
+    
+    /**
+     * the derived key function, the ith hash of the password and the salt.
+     */
+    private byte[] generateDerivedKey(
+        int bytesNeeded)
+    {
+        byte[]  buf = new byte[digest.getDigestSize()];
+        byte[]  key = new byte[bytesNeeded];
+        int     offset = 0;
+        
+        for (;;)
+        {
+            digest.update(password, 0, password.length);
+            digest.update(salt, 0, salt.length);
+
+            digest.doFinal(buf, 0);
+            
+            int len = (bytesNeeded > buf.length) ? buf.length : bytesNeeded;
+            System.arraycopy(buf, 0, key, offset, len);
+            offset += len;
+
+            // check if we need any more
+            bytesNeeded -= len;
+            if (bytesNeeded == 0)
+            {
+                break;
+            }
+
+            // do another round
+            digest.reset();
+            digest.update(buf, 0, buf.length);
+        }
+        
+        return key;
+    }
+
+    /**
+     * 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;
+
+        byte[]  dKey = generateDerivedKey(keySize);
+
+        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;
+
+        byte[]  dKey = generateDerivedKey(keySize + ivSize);
+
+        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);
+    }
+}