Refactoring around SecureRandom

8 files changed, 41 insertions, 54 deletions

diff --git a/crypto/src/crypto/prng/SP800SecureRandom.cs b/crypto/src/crypto/prng/SP800SecureRandom.cs
index 30c838c1b..2e1484125 100644
--- a/crypto/src/crypto/prng/SP800SecureRandom.cs
+++ b/crypto/src/crypto/prng/SP800SecureRandom.cs
@@ -49,6 +49,11 @@ namespace Org.BouncyCastle.Crypto.Prng
 
         public override void NextBytes(byte[] bytes)
         {
+            NextBytes(bytes, 0, bytes.Length);
+        }
+
+        public override void NextBytes(byte[] buf, int off, int len)
+        {
             lock (this)
             {
                 if (mDrbg == null)
@@ -57,21 +62,14 @@ namespace Org.BouncyCastle.Crypto.Prng
                 }
 
                 // check if a reseed is required...
-                if (mDrbg.Generate(bytes, null, mPredictionResistant) < 0)
+                if (mDrbg.Generate(buf, off, len, null, mPredictionResistant) < 0)
                 {
                     mDrbg.Reseed(null);
-                    mDrbg.Generate(bytes, null, mPredictionResistant);
+                    mDrbg.Generate(buf, off, len, null, mPredictionResistant);
                 }
             }
         }
 
-        public override void NextBytes(byte[] buf, int off, int len)
-        {
-            byte[] bytes = new byte[len];
-            NextBytes(bytes);
-            Array.Copy(bytes, 0, buf, off, len);
-        }
-
         public override byte[] GenerateSeed(int numBytes)
         {
             return EntropyUtilities.GenerateSeed(mEntropySource, numBytes);
diff --git a/crypto/src/crypto/prng/X931Rng.cs b/crypto/src/crypto/prng/X931Rng.cs
index 2bd8e0c6b..53c982c25 100644
--- a/crypto/src/crypto/prng/X931Rng.cs
+++ b/crypto/src/crypto/prng/X931Rng.cs
@@ -46,14 +46,14 @@ namespace Org.BouncyCastle.Crypto.Prng
          *
          * @return number of bits generated, -1 if a reseed required.
          */
-        internal int Generate(byte[] output, bool predictionResistant)
+        internal int Generate(byte[] output, int outputOff, int outputLen,  bool predictionResistant)
         {
             if (mR.Length == 8) // 64 bit block size
             {
                 if (mReseedCounter > BLOCK64_RESEED_MAX)
                     return -1;
 
-                if (IsTooLarge(output, BLOCK64_MAX_BITS_REQUEST / 8))
+                if (outputLen > BLOCK64_MAX_BITS_REQUEST / 8)
                     throw new ArgumentException("Number of bits per request limited to " + BLOCK64_MAX_BITS_REQUEST, "output");
             }
             else
@@ -61,7 +61,7 @@ namespace Org.BouncyCastle.Crypto.Prng
                 if (mReseedCounter > BLOCK128_RESEED_MAX)
                     return -1;
 
-                if (IsTooLarge(output, BLOCK128_MAX_BITS_REQUEST / 8))
+                if (outputLen > BLOCK128_MAX_BITS_REQUEST / 8)
                     throw new ArgumentException("Number of bits per request limited to " + BLOCK128_MAX_BITS_REQUEST, "output");
             }
 
@@ -72,7 +72,7 @@ namespace Org.BouncyCastle.Crypto.Prng
                     throw new InvalidOperationException("Insufficient entropy returned");
             }
 
-            int m = output.Length / mR.Length;
+            int m = outputLen / mR.Length;
 
             for (int i = 0; i < m; i++)
             {
@@ -80,12 +80,12 @@ namespace Org.BouncyCastle.Crypto.Prng
                 Process(mR, mI, mV);
                 Process(mV, mR, mI);
 
-                Array.Copy(mR, 0, output, i * mR.Length, mR.Length);
+                Array.Copy(mR, 0, output, outputOff + i * mR.Length, mR.Length);
 
                 Increment(mDT);
             }
 
-            int bytesToCopy = (output.Length - m * mR.Length);
+            int bytesToCopy = (outputLen - m * mR.Length);
 
             if (bytesToCopy > 0)
             {
@@ -93,14 +93,14 @@ namespace Org.BouncyCastle.Crypto.Prng
                 Process(mR, mI, mV);
                 Process(mV, mR, mI);
 
-                Array.Copy(mR, 0, output, m * mR.Length, bytesToCopy);
+                Array.Copy(mR, 0, output, outputOff + m * mR.Length, bytesToCopy);
 
                 Increment(mDT);
             }
 
             mReseedCounter++;
 
-            return output.Length;
+            return outputLen * 8;
         }
 
         /**
@@ -137,10 +137,5 @@ namespace Org.BouncyCastle.Crypto.Prng
                     break;
             }
         }
-
-        private static bool IsTooLarge(byte[] bytes, int maxBytes)
-        {
-            return bytes != null && bytes.Length > maxBytes;
-        }
     }
 }
diff --git a/crypto/src/crypto/prng/X931SecureRandom.cs b/crypto/src/crypto/prng/X931SecureRandom.cs
index d2e4849c5..1402e5c31 100644
--- a/crypto/src/crypto/prng/X931SecureRandom.cs
+++ b/crypto/src/crypto/prng/X931SecureRandom.cs
@@ -44,24 +44,22 @@ namespace Org.BouncyCastle.Crypto.Prng
 
         public override void NextBytes(byte[] bytes)
         {
+            NextBytes(bytes, 0, bytes.Length);
+        }
+
+        public override void NextBytes(byte[] buf, int off, int len)
+        {
             lock (this)
             {
                 // check if a reseed is required...
-                if (mDrbg.Generate(bytes, mPredictionResistant) < 0)
+                if (mDrbg.Generate(buf, off, len, mPredictionResistant) < 0)
                 {
                     mDrbg.Reseed();
-                    mDrbg.Generate(bytes, mPredictionResistant);
+                    mDrbg.Generate(buf, off, len, mPredictionResistant);
                 }
             }
         }
 
-        public override void NextBytes(byte[] buf, int off, int len)
-        {
-            byte[] bytes = new byte[len];
-            NextBytes(bytes);
-            Array.Copy(bytes, 0, buf, off, len);
-        }
-
         public override byte[] GenerateSeed(int numBytes)
         {
             return EntropyUtilities.GenerateSeed(mDrbg.EntropySource, numBytes);
diff --git a/crypto/src/crypto/prng/drbg/CtrSP800Drbg.cs b/crypto/src/crypto/prng/drbg/CtrSP800Drbg.cs
index 5715a915e..a7b1326c3 100644
--- a/crypto/src/crypto/prng/drbg/CtrSP800Drbg.cs
+++ b/crypto/src/crypto/prng/drbg/CtrSP800Drbg.cs
@@ -331,14 +331,15 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	     *
 	     * @return number of bits generated, -1 if a reseed required.
 	     */
-	    public int Generate(byte[] output, byte[] additionalInput, bool predictionResistant)
+	    public int Generate(byte[] output, int outputOff, int outputLen, byte[] additionalInput,
+			bool predictionResistant)
 	    {
 	        if (mIsTdea)
 	        {
 	            if (mReseedCounter > TDEA_RESEED_MAX)
 	                return -1;
 
-                if (DrbgUtilities.IsTooLarge(output, TDEA_MAX_BITS_REQUEST / 8))
+                if (outputLen > TDEA_MAX_BITS_REQUEST / 8)
 	                throw new ArgumentException("Number of bits per request limited to " + TDEA_MAX_BITS_REQUEST, "output");
 	        }
 	        else
@@ -346,7 +347,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	            if (mReseedCounter > AES_RESEED_MAX)
 	                return -1;
 
-                if (DrbgUtilities.IsTooLarge(output, AES_MAX_BITS_REQUEST / 8))
+                if (outputLen > AES_MAX_BITS_REQUEST / 8)
 	                throw new ArgumentException("Number of bits per request limited to " + AES_MAX_BITS_REQUEST, "output");
 	        }
 
@@ -370,11 +371,9 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
             mEngine.Init(true, new KeyParameter(ExpandKey(mKey)));
 
-            for (int i = 0; i <= output.Length / tmp.Length; i++)
+            for (int i = 0, limit = outputLen / tmp.Length; i <= limit; i++)
 	        {
-				int bytesToCopy = ((output.Length - i * tmp.Length) > tmp.Length)
-					? tmp.Length
-	                : (output.Length - i * mV.Length);
+				int bytesToCopy = System.Math.Min(tmp.Length, outputLen - i * tmp.Length);
 
                 if (bytesToCopy != 0)
 	            {
@@ -382,7 +381,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
                     mEngine.ProcessBlock(mV, 0, tmp, 0);
 
-                    Array.Copy(tmp, 0, output, i * tmp.Length, bytesToCopy);
+                    Array.Copy(tmp, 0, output, outputOff + i * tmp.Length, bytesToCopy);
 	            }
 	        }
 
@@ -390,7 +389,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
             mReseedCounter++;
 
-            return output.Length * 8;
+            return outputLen * 8;
 	    }
 
 	    /**
diff --git a/crypto/src/crypto/prng/drbg/DrbgUtilities.cs b/crypto/src/crypto/prng/drbg/DrbgUtilities.cs
index b1f2f29be..58baaf5d9 100644
--- a/crypto/src/crypto/prng/drbg/DrbgUtilities.cs
+++ b/crypto/src/crypto/prng/drbg/DrbgUtilities.cs
@@ -95,10 +95,5 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
             return temp;
 	    }
-
-        internal static bool IsTooLarge(byte[] bytes, int maxBytes)
-	    {
-	        return bytes != null && bytes.Length > maxBytes;
-	    }
 	}
 }
diff --git a/crypto/src/crypto/prng/drbg/HMacSP800Drbg.cs b/crypto/src/crypto/prng/drbg/HMacSP800Drbg.cs
index 78331705e..0ec0e8b71 100644
--- a/crypto/src/crypto/prng/drbg/HMacSP800Drbg.cs
+++ b/crypto/src/crypto/prng/drbg/HMacSP800Drbg.cs
@@ -104,9 +104,10 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	     *
 	     * @return number of bits generated, -1 if a reseed required.
 	     */
-	    public int Generate(byte[] output, byte[] additionalInput, bool predictionResistant)
+	    public int Generate(byte[] output, int outputOff, int outputLen, byte[] additionalInput,
+			bool predictionResistant)
 	    {
-	        int numberOfBits = output.Length * 8;
+	        int numberOfBits = outputLen * 8;
 
             if (numberOfBits > MAX_BITS_REQUEST)
 	            throw new ArgumentException("Number of bits per request limited to " + MAX_BITS_REQUEST, "output");
@@ -129,9 +130,9 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	        }
 
             // 3.
-	        byte[] rv = new byte[output.Length];
+	        byte[] rv = new byte[outputLen];
 
-            int m = output.Length / mV.Length;
+            int m = outputLen / mV.Length;
 
             mHMac.Init(new KeyParameter(mK));
 
@@ -155,7 +156,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
 	        mReseedCounter++;
 
-	        Array.Copy(rv, 0, output, 0, output.Length);
+	        Array.Copy(rv, 0, output, outputOff, outputLen);
 
             return numberOfBits;
 	    }
diff --git a/crypto/src/crypto/prng/drbg/HashSP800Drbg.cs b/crypto/src/crypto/prng/drbg/HashSP800Drbg.cs
index 506517aae..accc65ec3 100644
--- a/crypto/src/crypto/prng/drbg/HashSP800Drbg.cs
+++ b/crypto/src/crypto/prng/drbg/HashSP800Drbg.cs
@@ -101,7 +101,8 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	     *
 	     * @return number of bits generated, -1 if a reseed required.
 	     */
-	    public int Generate(byte[] output, byte[] additionalInput, bool predictionResistant)
+	    public int Generate(byte[] output, int outputOff, int outputLen, byte[] additionalInput,
+			bool predictionResistant)
 	    {
 	        // 1. If reseed_counter > reseed_interval, then return an indication that a
 	        // reseed is required.
@@ -116,7 +117,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	        // 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.
-	        int numberOfBits = output.Length * 8;
+	        int numberOfBits = outputLen * 8;
 
 	        if (numberOfBits > MAX_BITS_REQUEST)
 	            throw new ArgumentException("Number of bits per request limited to " + MAX_BITS_REQUEST, "output");
@@ -166,7 +167,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 
 	        mReseedCounter++;
 
-	        Array.Copy(rv, 0, output, 0, output.Length);
+	        Array.Copy(rv, 0, output, outputOff, outputLen);
 
 	        return numberOfBits;
 	    }
diff --git a/crypto/src/crypto/prng/drbg/ISP80090Drbg.cs b/crypto/src/crypto/prng/drbg/ISP80090Drbg.cs
index 0e398209e..78cbcd92f 100644
--- a/crypto/src/crypto/prng/drbg/ISP80090Drbg.cs
+++ b/crypto/src/crypto/prng/drbg/ISP80090Drbg.cs
@@ -23,7 +23,7 @@ namespace Org.BouncyCastle.Crypto.Prng.Drbg
 	     *
 	     * @return number of bits generated, -1 if a reseed required.
 	     */
-	    int Generate(byte[] output, byte[] additionalInput, bool predictionResistant);
+	    int Generate(byte[] output, int outputOff, int outputLen, byte[] additionalInput, bool predictionResistant);
 
 	    /**
 	     * Reseed the DRBG.