http://www.bouncycastle.org/jira/browse/BMA-82

- use SecureRandom to generate "arbitrary" values

4 files changed, 13 insertions, 7 deletions

diff --git a/crypto/src/math/BigInteger.cs b/crypto/src/math/BigInteger.cs
index f302f077e..f31e2d5f2 100644
--- a/crypto/src/math/BigInteger.cs
+++ b/crypto/src/math/BigInteger.cs
@@ -4,6 +4,7 @@ using System.Diagnostics;
 using System.Globalization;
 using System.Text;
 
+using Org.BouncyCastle.Security;
 using Org.BouncyCastle.Utilities;
 
 namespace Org.BouncyCastle.Math
@@ -179,7 +180,7 @@ namespace Org.BouncyCastle.Math
         private const int chunk2 = 1, chunk8 = 1, chunk10 = 19, chunk16 = 16;
         private static readonly BigInteger radix2, radix2E, radix8, radix8E, radix10, radix10E, radix16, radix16E;
 
-        private static readonly Random RandomSource = new Random();
+        private static readonly SecureRandom RandomSource = new SecureRandom();
 
         /*
          * These are the threshold bit-lengths (of an exponent) where we increase the window size.
@@ -246,6 +247,11 @@ namespace Org.BouncyCastle.Math
             return (nBits + BitsPerByte - 1) / BitsPerByte;
         }
 
+        internal static BigInteger Arbitrary(int sizeInBits)
+        {
+            return new BigInteger(sizeInBits, RandomSource);
+        }
+
         private BigInteger(
             int		signum,
             int[]	mag,
diff --git a/crypto/src/math/ec/ECCurve.cs b/crypto/src/math/ec/ECCurve.cs
index 40b46ce72..fa2c72570 100644
--- a/crypto/src/math/ec/ECCurve.cs
+++ b/crypto/src/math/ec/ECCurve.cs
@@ -760,10 +760,9 @@ namespace Org.BouncyCastle.Math.EC
             ECFieldElement gamma, z, zeroElement = FromBigInteger(BigInteger.Zero);
 
             int m = FieldSize;
-            Random rand = new Random();
             do
             {
-                ECFieldElement t = FromBigInteger(new BigInteger(m, rand));
+                ECFieldElement t = FromBigInteger(BigInteger.Arbitrary(m));
                 z = zeroElement;
                 ECFieldElement w = beta;
                 for (int i = 1; i < m; i++)
diff --git a/crypto/src/math/ec/ECFieldElement.cs b/crypto/src/math/ec/ECFieldElement.cs
index 4d4fb3e4d..d0e008aab 100644
--- a/crypto/src/math/ec/ECFieldElement.cs
+++ b/crypto/src/math/ec/ECFieldElement.cs
@@ -306,13 +306,12 @@ namespace Org.BouncyCastle.Math.EC
             BigInteger k = legendreExponent.Add(BigInteger.One), qMinusOne = q.Subtract(BigInteger.One);
 
             BigInteger U, V;
-            Random rand = new Random();
             do
             {
                 BigInteger P;
                 do
                 {
-                    P = new BigInteger(q.BitLength, rand);
+                    P = BigInteger.Arbitrary(q.BitLength);
                 }
                 while (P.CompareTo(q) >= 0
                     || !ModReduce(P.Multiply(P).Subtract(fourX)).ModPow(legendreExponent, q).Equals(qMinusOne));
diff --git a/crypto/src/math/raw/Mod.cs b/crypto/src/math/raw/Mod.cs
index 63467e668..8d9e8fd21 100644
--- a/crypto/src/math/raw/Mod.cs
+++ b/crypto/src/math/raw/Mod.cs
@@ -2,12 +2,15 @@
 using System.Diagnostics;
 
 using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Security;
 using Org.BouncyCastle.Utilities;
 
 namespace Org.BouncyCastle.Math.Raw
 {
     internal abstract class Mod
     {
+        private static readonly SecureRandom RandomSource = new SecureRandom();
+
         public static void Invert(uint[] p, uint[] x, uint[] z)
         {
             int len = p.Length;
@@ -77,7 +80,6 @@ namespace Org.BouncyCastle.Math.Raw
         public static uint[] Random(uint[] p)
         {
             int len = p.Length;
-            Random rand = new Random();
             uint[] s = Nat.Create(len);
 
             uint m = p[len - 1];
@@ -90,7 +92,7 @@ namespace Org.BouncyCastle.Math.Raw
             do
             {
                 byte[] bytes = new byte[len << 2];
-                rand.NextBytes(bytes);
+                RandomSource.NextBytes(bytes);
                 Pack.BE_To_UInt32(bytes, 0, s);
                 s[len - 1] &= m;
             }