refactoring.

16 files changed, 347 insertions, 344 deletions

diff --git a/src/main/java/org/bouncycastle/crypto/prng/DRBGProvider.java b/src/main/java/org/bouncycastle/crypto/prng/DRBGProvider.java
new file mode 100644
index 00000000..c39760c9
--- /dev/null
+++ b/src/main/java/org/bouncycastle/crypto/prng/DRBGProvider.java
@@ -0,0 +1,8 @@
+package org.bouncycastle.crypto.prng;
+
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
+
+interface DRBGProvider
+{
+    SP80090DRBG get(EntropySource entropySource);
+}
diff --git a/src/main/java/org/bouncycastle/crypto/random/SP800SecureRandom.java b/src/main/java/org/bouncycastle/crypto/prng/SP800SecureRandom.java
index 0b54ac54..e1ec6c28 100644
--- a/src/main/java/org/bouncycastle/crypto/random/SP800SecureRandom.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/SP800SecureRandom.java
@@ -1,9 +1,8 @@
-package org.bouncycastle.crypto.random;
+package org.bouncycastle.crypto.prng;
 
 import java.security.SecureRandom;
 
-import org.bouncycastle.crypto.prng.EntropySource;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 
 public class SP800SecureRandom
     extends SecureRandom
@@ -55,7 +54,12 @@ public class SP800SecureRandom
                 drbg = drbgProvider.get(entropySource);
             }
 
-            drbg.generate(bytes, null, predictionResistant);
+            // check if a reseed is required...
+            if (drbg.generate(bytes, null, predictionResistant) < 0)
+            {
+                drbg.reseed(entropySource.getEntropy());
+                drbg.generate(bytes, null, predictionResistant);
+            }
         }
     }
 
diff --git a/src/main/java/org/bouncycastle/crypto/random/SP800SecureRandomBuilder.java b/src/main/java/org/bouncycastle/crypto/prng/SP800SecureRandomBuilder.java
index 10bd3505..c5c5827a 100644
--- a/src/main/java/org/bouncycastle/crypto/random/SP800SecureRandomBuilder.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/SP800SecureRandomBuilder.java
@@ -1,18 +1,15 @@
-package org.bouncycastle.crypto.random;
+package org.bouncycastle.crypto.prng;
 
 import java.security.SecureRandom;
 
 import org.bouncycastle.crypto.BlockCipher;
 import org.bouncycastle.crypto.Digest;
 import org.bouncycastle.crypto.Mac;
-import org.bouncycastle.crypto.prng.BasicEntropySourceProvider;
-import org.bouncycastle.crypto.prng.CTRSP800DRBG;
-import org.bouncycastle.crypto.prng.DualECSP800DRBG;
-import org.bouncycastle.crypto.prng.EntropySource;
-import org.bouncycastle.crypto.prng.EntropySourceProvider;
-import org.bouncycastle.crypto.prng.HMacSP800DRBG;
-import org.bouncycastle.crypto.prng.HashSP800DRBG;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.CTRSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.DualECSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.HMacSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.HashSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 
 /**
  * Builder class for making SecureRandom objects based on SP 800-90A Deterministic Random Bit Generators (DRBG).
diff --git a/src/main/java/org/bouncycastle/crypto/prng/VMPCRandomGenerator.java b/src/main/java/org/bouncycastle/crypto/prng/VMPCRandomGenerator.java
index 9f9ff7b2..b882b796 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/VMPCRandomGenerator.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/VMPCRandomGenerator.java
@@ -124,5 +124,4 @@ public class VMPCRandomGenerator implements RandomGenerator
             }

         }

     }

-

 }

diff --git a/src/main/java/org/bouncycastle/crypto/prng/CTRSP800DRBG.java b/src/main/java/org/bouncycastle/crypto/prng/drbg/CTRSP800DRBG.java
index c3b33abb..50f70467 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/CTRSP800DRBG.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/drbg/CTRSP800DRBG.java
@@ -1,14 +1,15 @@
-package org.bouncycastle.crypto.prng;
+package org.bouncycastle.crypto.prng.drbg;
 
 import org.bouncycastle.crypto.BlockCipher;
 import org.bouncycastle.crypto.params.KeyParameter;
+import org.bouncycastle.crypto.prng.EntropySource;
 import org.bouncycastle.util.Arrays;
 import org.bouncycastle.util.encoders.Hex;
 
 public class CTRSP800DRBG
     implements SP80090DRBG
 {
-    private EntropySource         _entropySource;
+    private EntropySource _entropySource;
     private BlockCipher           _engine;
     private int                   _keySizeInBits;
     private int                   _seedLength;
diff --git a/src/main/java/org/bouncycastle/crypto/prng/DualECSP800DRBG.java b/src/main/java/org/bouncycastle/crypto/prng/drbg/DualECSP800DRBG.java
index caeac7a0..518ae04e 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/DualECSP800DRBG.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/drbg/DualECSP800DRBG.java
@@ -1,9 +1,10 @@
-package org.bouncycastle.crypto.prng;
+package org.bouncycastle.crypto.prng.drbg;
 
 import java.math.BigInteger;
 
 import org.bouncycastle.asn1.nist.NISTNamedCurves;
 import org.bouncycastle.crypto.Digest;
+import org.bouncycastle.crypto.prng.EntropySource;
 import org.bouncycastle.math.ec.ECCurve;
 import org.bouncycastle.math.ec.ECFieldElement;
 import org.bouncycastle.math.ec.ECPoint;
@@ -35,7 +36,7 @@ public class DualECSP800DRBG
 
     private Digest                 _digest;
     private int                    _reseedCounter;
-    private EntropySource          _entropySource;
+    private EntropySource _entropySource;
     private int                    _securityStrength;
     private int                    _seedlen;
     private int                    _outlen;
diff --git a/src/main/java/org/bouncycastle/crypto/prng/HMacSP800DRBG.java b/src/main/java/org/bouncycastle/crypto/prng/drbg/HMacSP800DRBG.java
index dd22f4c6..de448f7b 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/HMacSP800DRBG.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/drbg/HMacSP800DRBG.java
@@ -1,7 +1,8 @@
-package org.bouncycastle.crypto.prng;
+package org.bouncycastle.crypto.prng.drbg;
 
 import org.bouncycastle.crypto.Mac;
 import org.bouncycastle.crypto.params.KeyParameter;
+import org.bouncycastle.crypto.prng.EntropySource;
 import org.bouncycastle.util.Arrays;
 
 public class HMacSP800DRBG
diff --git a/src/main/java/org/bouncycastle/crypto/prng/HashSP800DRBG.java b/src/main/java/org/bouncycastle/crypto/prng/drbg/HashSP800DRBG.java
index c52dd917..489054b0 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/HashSP800DRBG.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/drbg/HashSP800DRBG.java
@@ -1,305 +1,306 @@
-package org.bouncycastle.crypto.prng;

-

-import java.util.Hashtable;

-

-import org.bouncycastle.crypto.Digest;

-import org.bouncycastle.util.Arrays;

-import org.bouncycastle.util.Integers;

-

-public class HashSP800DRBG implements SP80090DRBG

-{

-    private final static byte[]     ONE = { 0x01 };

-    private final static int        RESEED_MAX = 100000;

-    private final static Hashtable  seedlens = new Hashtable();

-

-    static

-    {

-        seedlens.put("SHA-1", Integers.valueOf(440));

-        seedlens.put("SHA-224", Integers.valueOf(440));

-        seedlens.put("SHA-256", Integers.valueOf(440));

-        seedlens.put("SHA-512/256", Integers.valueOf(440));

-        seedlens.put("SHA-512/224", Integers.valueOf(440));

-        seedlens.put("SHA-384", Integers.valueOf(888));

-        seedlens.put("SHA-512", Integers.valueOf(888));

-    }

-

-    private Digest                 _digest;

-    private byte[]                 _V;

-    private byte[]                 _C;

-    private int                    _reseedCounter;

-    private EntropySource          _entropySource;

-    private int                    _securityStrength;

-    private int _seedLength;

-

-    public HashSP800DRBG(Digest digest, EntropySource entropySource, byte[] nonce,

-                         byte[] personalisationString, int securityStrength)

-    {

-        if (securityStrength > digest.getDigestSize() * 8) // TODO: this may, or may not be correct, but it's good enough for now

-        {

-            throw new IllegalStateException(

-                    "Security strength is not supported by the derivation function");

-        }

-        

-        _digest = digest;

-        _entropySource = entropySource;

-        _securityStrength = securityStrength;

-        _seedLength = ((Integer)seedlens.get(digest.getAlgorithmName())).intValue();

-

-        // 1. seed_material = entropy_input || nonce || personalization_string.

-        // 2. seed = Hash_df (seed_material, seedlen).

-        // 3. V = seed.

-        // 4. C = Hash_df ((0x00 || V), seedlen). Comment: Preceed V with a byte

-        // of zeros.

-        // 5. reseed_counter = 1.

-        // 6. Return V, C, and reseed_counter as the initial_working_state

-

-        byte[] entropy = entropySource.getEntropy();

-        byte[] seedMaterial = Arrays.concatenate(entropy, nonce, personalisationString);

-        byte[] seed = hash_df(seedMaterial, _seedLength);

-

-        _V = seed;

-        byte[] subV = new byte[_V.length + 1];

-        System.arraycopy(_V, 0, subV, 1, _V.length);

-        _C = hash_df(subV, _seedLength);

-        _reseedCounter = 1;

-        

-//        System.out.println("Constructor V: "+ new String(Hex.encode(_V)));

-//        System.out.println("Constructor C: "+ new String(Hex.encode(_C)));

-

-    }

-

-    // 1. If reseed_counter > reseed_interval, then return an indication that a

-    // reseed is required.

-    // 2. If (additional_input != Null), then do

-    // 2.1 w = Hash (0x02 || V || additional_input).

-    // 2.2 V = (V + w) mod 2^seedlen

-    // .

-    // 3. (returned_bits) = Hashgen (requested_number_of_bits, V).

-    // 4. H = Hash (0x03 || V).

-    // 5. V = (V + H + C + reseed_counter) mod 2^seedlen

-    // .

-    // 6. reseed_counter = reseed_counter + 1.

-    // 7. Return SUCCESS, returned_bits, and the new values of V, C, and

-    // reseed_counter for the new_working_state.

-    public int generate(byte[] output, byte[] additionalInput, boolean predictionResistant)

-    {

-        int numberOfBits = output.length*8;

-        

-        if (predictionResistant || _reseedCounter > RESEED_MAX) 

-        {   

-            reseed(additionalInput);

-            additionalInput = null;

-        }

-

-        // 2.

-        if (additionalInput != null)

-        {

-            byte[] newInput = new byte[1 + _V.length + additionalInput.length];

-            newInput[0] = 0x02;

-            System.arraycopy(_V, 0, newInput, 1, _V.length);

-            // TODO: inOff / inLength

-            System.arraycopy(additionalInput, 0, newInput, 1 + _V.length, additionalInput.length);

-            byte[] w = hash(newInput);

-

-            addTo(_V, w);

-        }

-        

-        // 3.

-        byte[] rv = hashgen(_V, numberOfBits);

-        

-        // 4.

-        byte[] subH = new byte[_V.length + 1];

-        System.arraycopy(_V, 0, subH, 1, _V.length);

-        subH[0] = 0x03;

-        

-        byte[] H = hash(subH);

-        

-        // 5.

-        addTo(_V, H);

-        addTo(_V, _C);

-        byte[] c = new byte[4];

-        c[0] = (byte)(_reseedCounter >> 24);

-        c[1] = (byte)(_reseedCounter >> 16);

-        c[2] = (byte)(_reseedCounter >> 8);

-        c[3] = (byte)_reseedCounter;

-        

-        addTo(_V, c);

-        _reseedCounter++;

-

-        System.arraycopy(rv, 0, output, 0, output.length);

-//        System.out.println("Generate V: "+ new String(Hex.encode(_V)));

-//        System.out.println("Generate C: "+ new String(Hex.encode(_C)));

-

-        return numberOfBits;

-    }

-

-    // this will always add the shorter length byte array mathematically to the

-    // longer length byte array.

-    // be careful....

-    private void addTo(byte[] longer, byte[] shorter)

-    {

-        int carry = 0;

-        for (int i=1;i <= shorter.length; i++) // warning

-        {

-            int res = (longer[longer.length-i] & 0xff) + (shorter[shorter.length-i] & 0xff) + carry;

-            carry = (res > 0xff) ? 1 : 0;

-            longer[longer.length-i] = (byte)res;

-        }

-        

-        for (int i=shorter.length+1;i <= longer.length; i++) // warning

-        {

-            int res = (longer[longer.length-i] & 0xff) + carry;

-            carry = (res > 0xff) ? 1 : 0;

-            longer[longer.length-i] = (byte)res;

-        }

-    }

-

-    // 1. seed_material = 0x01 || V || entropy_input || additional_input.

-    //

-    // 2. seed = Hash_df (seed_material, seedlen).

-    //

-    // 3. V = seed.

-    //

-    // 4. C = Hash_df ((0x00 || V), seedlen).

-    //

-    // 5. reseed_counter = 1.

-    //

-    // 6. Return V, C, and reseed_counter for the new_working_state.

-    //

-    // Comment: Precede with a byte of all zeros.

-    public void reseed(byte[] additionalInput)

-    {

-        if (additionalInput == null) 

-        {

-            additionalInput = new byte[0];

-        }

-

-        byte[] entropy = _entropySource.getEntropy();

-        

-//        System.out.println("Reseed Entropy: "+ new String(Hex.encode(entropy)));

-        

-        byte[] seedMaterial = Arrays.concatenate(ONE, _V, entropy, additionalInput);

-

-//        System.out.println("Reseed SeedMaterial: "+ new String(Hex.encode(seedMaterial)));

-

-        byte[] seed = hash_df(seedMaterial, _seedLength);

-        

-//        System.out.println("Reseed Seed: "+ new String(Hex.encode(seed)));

-

-        _V = seed;

-        byte[] subV = new byte[_V.length + 1];

-        subV[0] = 0x00;

-        System.arraycopy(_V, 0, subV, 1, _V.length);

-        _C = hash_df(subV, _seedLength);

-        _reseedCounter = 1;

-        

-//        System.out.println("Reseed V: "+ new String(Hex.encode(_V)));

-//        System.out.println("Reseed C: "+ new String(Hex.encode(_C)));

-    }

-    

-    

-    // ---- Internal manipulation --- 

-    // ---- Migrating from the external HashDF class --

-    

-

-    // 1. temp = the Null string.

-    // 2. .

-    // 3. counter = an 8-bit binary value representing the integer "1".

-    // 4. For i = 1 to len do

-    // Comment : In step 4.1, no_of_bits_to_return

-    // is used as a 32-bit string.

-    // 4.1 temp = temp || Hash (counter || no_of_bits_to_return ||

-    // input_string).

-    // 4.2 counter = counter + 1.

-    // 5. requested_bits = Leftmost (no_of_bits_to_return) of temp.

-    // 6. Return SUCCESS and requested_bits.

-    private byte[] hash_df(byte[] seedMaterial, int seedLength)

-    {

-        byte[] temp = new byte[seedLength / 8];

-

-        int len = temp.length / _digest.getDigestSize();

-        int counter = 1;

-

-        byte[] dig = new byte[_digest.getDigestSize()];

-

-        for (int i = 0; i <= len; i++)

-        {

-            _digest.update((byte)counter);

-

-            _digest.update((byte)(seedLength >> 24));

-            _digest.update((byte)(seedLength >> 16));

-            _digest.update((byte)(seedLength >> 8));

-            _digest.update((byte)seedLength);

-

-            _digest.update(seedMaterial, 0, seedMaterial.length);

-

-            _digest.doFinal(dig, 0);

-

-            int bytesToCopy = ((temp.length - i * dig.length) > dig.length)

-                    ? dig.length

-                    : (temp.length - i * dig.length);

-            System.arraycopy(dig, 0, temp, i * dig.length, bytesToCopy);

-

-            counter++;

-        }

-

-        // do a left shift to get rid of excess bits.

-        if (seedLength % 8 != 0)

-        {

-            int shift = 8 - (seedLength % 8);

-            int carry = 0;

-

-            for (int i = 0; i != temp.length; i++)

-            {

-                int b = temp[i] & 0xff;

-                temp[i] = (byte)((b >>> shift) | (carry << (8 - shift)));

-                carry = b;

-            }

-        }

-

-        return temp;

-    }

-    

-    private byte[] hash(byte[] input)

-    {

-        _digest.update(input, 0, input.length);

-        byte[] hash = new byte[_digest.getDigestSize()];

-        _digest.doFinal(hash, 0);

-        return hash;

-    }

-    

-    // 1. m = [requested_number_of_bits / outlen]

-    // 2. data = V.

-    // 3. W = the Null string.

-    // 4. For i = 1 to m

-    // 4.1 wi = Hash (data).

-    // 4.2 W = W || wi.

-    // 4.3 data = (data + 1) mod 2^seedlen

-    // .

-    // 5. returned_bits = Leftmost (requested_no_of_bits) bits of W.

-    private byte[] hashgen(byte[] input, int lengthInBits)

-    {

-        int digestSize = _digest.getDigestSize();

-        int m = (lengthInBits / 8) / digestSize;

-

-        byte[] data = new byte[input.length];

-        System.arraycopy(input, 0, data, 0, input.length);

-

-        byte[] W = new byte[lengthInBits / 8];

-

-        byte[] dig;

-        for (int i = 0; i <= m; i++)

-        {

-            dig = hash(data);

-

-            int bytesToCopy = ((W.length - i * dig.length) > dig.length)

-                    ? dig.length

-                    : (W.length - i * dig.length);

-            System.arraycopy(dig, 0, W, i * dig.length, bytesToCopy);

-

-            addTo(data, ONE);

-        }

-

-        return W;

-    }    

-}

+package org.bouncycastle.crypto.prng.drbg;
+
+import java.util.Hashtable;
+
+import org.bouncycastle.crypto.Digest;
+import org.bouncycastle.crypto.prng.EntropySource;
+import org.bouncycastle.util.Arrays;
+import org.bouncycastle.util.Integers;
+
+public class HashSP800DRBG implements SP80090DRBG
+{
+    private final static byte[]     ONE = { 0x01 };
+    private final static int        RESEED_MAX = 100000;
+    private final static Hashtable  seedlens = new Hashtable();
+
+    static
+    {
+        seedlens.put("SHA-1", Integers.valueOf(440));
+        seedlens.put("SHA-224", Integers.valueOf(440));
+        seedlens.put("SHA-256", Integers.valueOf(440));
+        seedlens.put("SHA-512/256", Integers.valueOf(440));
+        seedlens.put("SHA-512/224", Integers.valueOf(440));
+        seedlens.put("SHA-384", Integers.valueOf(888));
+        seedlens.put("SHA-512", Integers.valueOf(888));
+    }
+
+    private Digest                 _digest;
+    private byte[]                 _V;
+    private byte[]                 _C;
+    private int                    _reseedCounter;
+    private EntropySource _entropySource;
+    private int                    _securityStrength;
+    private int _seedLength;
+
+    public HashSP800DRBG(Digest digest, EntropySource entropySource, byte[] nonce,
+                         byte[] personalisationString, int securityStrength)
+    {
+        if (securityStrength > digest.getDigestSize() * 8) // TODO: this may, or may not be correct, but it's good enough for now
+        {
+            throw new IllegalStateException(
+                    "Security strength is not supported by the derivation function");
+        }
+        
+        _digest = digest;
+        _entropySource = entropySource;
+        _securityStrength = securityStrength;
+        _seedLength = ((Integer)seedlens.get(digest.getAlgorithmName())).intValue();
+
+        // 1. seed_material = entropy_input || nonce || personalization_string.
+        // 2. seed = Hash_df (seed_material, seedlen).
+        // 3. V = seed.
+        // 4. C = Hash_df ((0x00 || V), seedlen). Comment: Preceed V with a byte
+        // of zeros.
+        // 5. reseed_counter = 1.
+        // 6. Return V, C, and reseed_counter as the initial_working_state
+
+        byte[] entropy = entropySource.getEntropy();
+        byte[] seedMaterial = Arrays.concatenate(entropy, nonce, personalisationString);
+        byte[] seed = hash_df(seedMaterial, _seedLength);
+
+        _V = seed;
+        byte[] subV = new byte[_V.length + 1];
+        System.arraycopy(_V, 0, subV, 1, _V.length);
+        _C = hash_df(subV, _seedLength);
+        _reseedCounter = 1;
+        
+//        System.out.println("Constructor V: "+ new String(Hex.encode(_V)));
+//        System.out.println("Constructor C: "+ new String(Hex.encode(_C)));
+
+    }
+
+    // 1. If reseed_counter > reseed_interval, then return an indication that a
+    // reseed is required.
+    // 2. If (additional_input != Null), then do
+    // 2.1 w = Hash (0x02 || V || additional_input).
+    // 2.2 V = (V + w) mod 2^seedlen
+    // .
+    // 3. (returned_bits) = Hashgen (requested_number_of_bits, V).
+    // 4. H = Hash (0x03 || V).
+    // 5. V = (V + H + C + reseed_counter) mod 2^seedlen
+    // .
+    // 6. reseed_counter = reseed_counter + 1.
+    // 7. Return SUCCESS, returned_bits, and the new values of V, C, and
+    // reseed_counter for the new_working_state.
+    public int generate(byte[] output, byte[] additionalInput, boolean predictionResistant)
+    {
+        int numberOfBits = output.length*8;
+        
+        if (predictionResistant || _reseedCounter > RESEED_MAX) 
+        {   
+            reseed(additionalInput);
+            additionalInput = null;
+        }
+
+        // 2.
+        if (additionalInput != null)
+        {
+            byte[] newInput = new byte[1 + _V.length + additionalInput.length];
+            newInput[0] = 0x02;
+            System.arraycopy(_V, 0, newInput, 1, _V.length);
+            // TODO: inOff / inLength
+            System.arraycopy(additionalInput, 0, newInput, 1 + _V.length, additionalInput.length);
+            byte[] w = hash(newInput);
+
+            addTo(_V, w);
+        }
+        
+        // 3.
+        byte[] rv = hashgen(_V, numberOfBits);
+        
+        // 4.
+        byte[] subH = new byte[_V.length + 1];
+        System.arraycopy(_V, 0, subH, 1, _V.length);
+        subH[0] = 0x03;
+        
+        byte[] H = hash(subH);
+        
+        // 5.
+        addTo(_V, H);
+        addTo(_V, _C);
+        byte[] c = new byte[4];
+        c[0] = (byte)(_reseedCounter >> 24);
+        c[1] = (byte)(_reseedCounter >> 16);
+        c[2] = (byte)(_reseedCounter >> 8);
+        c[3] = (byte)_reseedCounter;
+        
+        addTo(_V, c);
+        _reseedCounter++;
+
+        System.arraycopy(rv, 0, output, 0, output.length);
+//        System.out.println("Generate V: "+ new String(Hex.encode(_V)));
+//        System.out.println("Generate C: "+ new String(Hex.encode(_C)));
+
+        return numberOfBits;
+    }
+
+    // this will always add the shorter length byte array mathematically to the
+    // longer length byte array.
+    // be careful....
+    private void addTo(byte[] longer, byte[] shorter)
+    {
+        int carry = 0;
+        for (int i=1;i <= shorter.length; i++) // warning
+        {
+            int res = (longer[longer.length-i] & 0xff) + (shorter[shorter.length-i] & 0xff) + carry;
+            carry = (res > 0xff) ? 1 : 0;
+            longer[longer.length-i] = (byte)res;
+        }
+        
+        for (int i=shorter.length+1;i <= longer.length; i++) // warning
+        {
+            int res = (longer[longer.length-i] & 0xff) + carry;
+            carry = (res > 0xff) ? 1 : 0;
+            longer[longer.length-i] = (byte)res;
+        }
+    }
+
+    // 1. seed_material = 0x01 || V || entropy_input || additional_input.
+    //
+    // 2. seed = Hash_df (seed_material, seedlen).
+    //
+    // 3. V = seed.
+    //
+    // 4. C = Hash_df ((0x00 || V), seedlen).
+    //
+    // 5. reseed_counter = 1.
+    //
+    // 6. Return V, C, and reseed_counter for the new_working_state.
+    //
+    // Comment: Precede with a byte of all zeros.
+    public void reseed(byte[] additionalInput)
+    {
+        if (additionalInput == null) 
+        {
+            additionalInput = new byte[0];
+        }
+
+        byte[] entropy = _entropySource.getEntropy();
+        
+//        System.out.println("Reseed Entropy: "+ new String(Hex.encode(entropy)));
+        
+        byte[] seedMaterial = Arrays.concatenate(ONE, _V, entropy, additionalInput);
+
+//        System.out.println("Reseed SeedMaterial: "+ new String(Hex.encode(seedMaterial)));
+
+        byte[] seed = hash_df(seedMaterial, _seedLength);
+        
+//        System.out.println("Reseed Seed: "+ new String(Hex.encode(seed)));
+
+        _V = seed;
+        byte[] subV = new byte[_V.length + 1];
+        subV[0] = 0x00;
+        System.arraycopy(_V, 0, subV, 1, _V.length);
+        _C = hash_df(subV, _seedLength);
+        _reseedCounter = 1;
+        
+//        System.out.println("Reseed V: "+ new String(Hex.encode(_V)));
+//        System.out.println("Reseed C: "+ new String(Hex.encode(_C)));
+    }
+    
+    
+    // ---- Internal manipulation --- 
+    // ---- Migrating from the external HashDF class --
+    
+
+    // 1. temp = the Null string.
+    // 2. .
+    // 3. counter = an 8-bit binary value representing the integer "1".
+    // 4. For i = 1 to len do
+    // Comment : In step 4.1, no_of_bits_to_return
+    // is used as a 32-bit string.
+    // 4.1 temp = temp || Hash (counter || no_of_bits_to_return ||
+    // input_string).
+    // 4.2 counter = counter + 1.
+    // 5. requested_bits = Leftmost (no_of_bits_to_return) of temp.
+    // 6. Return SUCCESS and requested_bits.
+    private byte[] hash_df(byte[] seedMaterial, int seedLength)
+    {
+        byte[] temp = new byte[seedLength / 8];
+
+        int len = temp.length / _digest.getDigestSize();
+        int counter = 1;
+
+        byte[] dig = new byte[_digest.getDigestSize()];
+
+        for (int i = 0; i <= len; i++)
+        {
+            _digest.update((byte)counter);
+
+            _digest.update((byte)(seedLength >> 24));
+            _digest.update((byte)(seedLength >> 16));
+            _digest.update((byte)(seedLength >> 8));
+            _digest.update((byte)seedLength);
+
+            _digest.update(seedMaterial, 0, seedMaterial.length);
+
+            _digest.doFinal(dig, 0);
+
+            int bytesToCopy = ((temp.length - i * dig.length) > dig.length)
+                    ? dig.length
+                    : (temp.length - i * dig.length);
+            System.arraycopy(dig, 0, temp, i * dig.length, bytesToCopy);
+
+            counter++;
+        }
+
+        // do a left shift to get rid of excess bits.
+        if (seedLength % 8 != 0)
+        {
+            int shift = 8 - (seedLength % 8);
+            int carry = 0;
+
+            for (int i = 0; i != temp.length; i++)
+            {
+                int b = temp[i] & 0xff;
+                temp[i] = (byte)((b >>> shift) | (carry << (8 - shift)));
+                carry = b;
+            }
+        }
+
+        return temp;
+    }
+    
+    private byte[] hash(byte[] input)
+    {
+        _digest.update(input, 0, input.length);
+        byte[] hash = new byte[_digest.getDigestSize()];
+        _digest.doFinal(hash, 0);
+        return hash;
+    }
+    
+    // 1. m = [requested_number_of_bits / outlen]
+    // 2. data = V.
+    // 3. W = the Null string.
+    // 4. For i = 1 to m
+    // 4.1 wi = Hash (data).
+    // 4.2 W = W || wi.
+    // 4.3 data = (data + 1) mod 2^seedlen
+    // .
+    // 5. returned_bits = Leftmost (requested_no_of_bits) bits of W.
+    private byte[] hashgen(byte[] input, int lengthInBits)
+    {
+        int digestSize = _digest.getDigestSize();
+        int m = (lengthInBits / 8) / digestSize;
+
+        byte[] data = new byte[input.length];
+        System.arraycopy(input, 0, data, 0, input.length);
+
+        byte[] W = new byte[lengthInBits / 8];
+
+        byte[] dig;
+        for (int i = 0; i <= m; i++)
+        {
+            dig = hash(data);
+
+            int bytesToCopy = ((W.length - i * dig.length) > dig.length)
+                    ? dig.length
+                    : (W.length - i * dig.length);
+            System.arraycopy(dig, 0, W, i * dig.length, bytesToCopy);
+
+            addTo(data, ONE);
+        }
+
+        return W;
+    }    
+}
diff --git a/src/main/java/org/bouncycastle/crypto/prng/SP80090DRBG.java b/src/main/java/org/bouncycastle/crypto/prng/drbg/SP80090DRBG.java
index 9fbd88f7..c93eb54c 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/SP80090DRBG.java
+++ b/src/main/java/org/bouncycastle/crypto/prng/drbg/SP80090DRBG.java
@@ -1,4 +1,4 @@
-package org.bouncycastle.crypto.prng;
+package org.bouncycastle.crypto.prng.drbg;
 
 public interface SP80090DRBG
 {
diff --git a/src/main/java/org/bouncycastle/crypto/prng/package.html b/src/main/java/org/bouncycastle/crypto/prng/package.html
index 99525fbf..bb583abd 100644
--- a/src/main/java/org/bouncycastle/crypto/prng/package.html
+++ b/src/main/java/org/bouncycastle/crypto/prng/package.html
@@ -1,5 +1,5 @@
 <html>
 <body bgcolor="#ffffff">
-Lightweight psuedo-random number generators.
+Lightweight psuedo-random number generators and SecureRandom builders.
 </body>
 </html>
diff --git a/src/main/java/org/bouncycastle/crypto/random/DRBGProvider.java b/src/main/java/org/bouncycastle/crypto/random/DRBGProvider.java
deleted file mode 100644
index f1ef83b2..00000000
--- a/src/main/java/org/bouncycastle/crypto/random/DRBGProvider.java
+++ /dev/null
@@ -1,9 +0,0 @@
-package org.bouncycastle.crypto.random;
-
-import org.bouncycastle.crypto.prng.SP80090DRBG;
-import org.bouncycastle.crypto.prng.EntropySource;
-
-interface DRBGProvider
-{
-    SP80090DRBG get(EntropySource entropySource);
-}
diff --git a/src/test/java/org/bouncycastle/crypto/random/test/SP800RandomTest.java b/src/test/java/org/bouncycastle/crypto/random/test/SP800RandomTest.java
index c84b5744..5a7ad692 100644
--- a/src/test/java/org/bouncycastle/crypto/random/test/SP800RandomTest.java
+++ b/src/test/java/org/bouncycastle/crypto/random/test/SP800RandomTest.java
@@ -6,7 +6,7 @@ import org.bouncycastle.crypto.digests.SHA1Digest;
 import org.bouncycastle.crypto.digests.SHA256Digest;
 import org.bouncycastle.crypto.engines.DESedeEngine;
 import org.bouncycastle.crypto.macs.HMac;
-import org.bouncycastle.crypto.random.SP800SecureRandomBuilder;
+import org.bouncycastle.crypto.prng.SP800SecureRandomBuilder;
 import org.bouncycastle.crypto.test.DRBGTestVector;
 import org.bouncycastle.crypto.test.TestEntropySourceProvider;
 import org.bouncycastle.util.Arrays;
diff --git a/src/test/java/org/bouncycastle/crypto/test/CTRDRBGTest.java b/src/test/java/org/bouncycastle/crypto/test/CTRDRBGTest.java
index 813bbed3..59d2177b 100644
--- a/src/test/java/org/bouncycastle/crypto/test/CTRDRBGTest.java
+++ b/src/test/java/org/bouncycastle/crypto/test/CTRDRBGTest.java
@@ -2,8 +2,8 @@ package org.bouncycastle.crypto.test;
 
 import org.bouncycastle.crypto.engines.AESFastEngine;
 import org.bouncycastle.crypto.engines.DESedeEngine;
-import org.bouncycastle.crypto.prng.CTRSP800DRBG;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.CTRSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 import org.bouncycastle.util.encoders.Hex;
 import org.bouncycastle.util.test.SimpleTest;
 
diff --git a/src/test/java/org/bouncycastle/crypto/test/DualECDRBGTest.java b/src/test/java/org/bouncycastle/crypto/test/DualECDRBGTest.java
index 9161e6e5..8764b694 100644
--- a/src/test/java/org/bouncycastle/crypto/test/DualECDRBGTest.java
+++ b/src/test/java/org/bouncycastle/crypto/test/DualECDRBGTest.java
@@ -3,8 +3,8 @@ package org.bouncycastle.crypto.test;
 import org.bouncycastle.crypto.digests.SHA256Digest;
 import org.bouncycastle.crypto.digests.SHA384Digest;
 import org.bouncycastle.crypto.digests.SHA512Digest;
-import org.bouncycastle.crypto.prng.DualECSP800DRBG;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.DualECSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 import org.bouncycastle.util.encoders.Hex;
 import org.bouncycastle.util.test.SimpleTest;
 
diff --git a/src/test/java/org/bouncycastle/crypto/test/HMacDRBGTest.java b/src/test/java/org/bouncycastle/crypto/test/HMacDRBGTest.java
index e98d770c..06f2b25b 100644
--- a/src/test/java/org/bouncycastle/crypto/test/HMacDRBGTest.java
+++ b/src/test/java/org/bouncycastle/crypto/test/HMacDRBGTest.java
@@ -5,8 +5,8 @@ import org.bouncycastle.crypto.digests.SHA256Digest;
 import org.bouncycastle.crypto.digests.SHA384Digest;
 import org.bouncycastle.crypto.digests.SHA512Digest;
 import org.bouncycastle.crypto.macs.HMac;
-import org.bouncycastle.crypto.prng.HMacSP800DRBG;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.HMacSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 import org.bouncycastle.util.encoders.Hex;
 import org.bouncycastle.util.test.SimpleTest;
 
diff --git a/src/test/java/org/bouncycastle/crypto/test/HashDRBGTest.java b/src/test/java/org/bouncycastle/crypto/test/HashDRBGTest.java
index 06304d72..93920d64 100644
--- a/src/test/java/org/bouncycastle/crypto/test/HashDRBGTest.java
+++ b/src/test/java/org/bouncycastle/crypto/test/HashDRBGTest.java
@@ -4,8 +4,8 @@ import org.bouncycastle.crypto.digests.SHA1Digest;
 import org.bouncycastle.crypto.digests.SHA256Digest;
 import org.bouncycastle.crypto.digests.SHA384Digest;
 import org.bouncycastle.crypto.digests.SHA512Digest;
-import org.bouncycastle.crypto.prng.HashSP800DRBG;
-import org.bouncycastle.crypto.prng.SP80090DRBG;
+import org.bouncycastle.crypto.prng.drbg.HashSP800DRBG;
+import org.bouncycastle.crypto.prng.drbg.SP80090DRBG;
 import org.bouncycastle.util.encoders.Hex;
 import org.bouncycastle.util.test.SimpleTest;