Change the weighted distribution algorithm be uniform.

The old way was biasted towards the earlier values.  Thanks to asn for
pointing this out and suggesting an alternative.

As an additional tweak, do not reuse the drbg seed when calculating the
IAT distribution, but instead run the seed through SHA256 first, for
extra tinfoil goodness.

1 files changed, 6 insertions, 1 deletions

diff --git a/csrand/csrand.go b/csrand/csrand.go
index 721fb1e..a3299aa 100644
--- a/csrand/csrand.go
+++ b/csrand/csrand.go
@@ -68,7 +68,12 @@ func (r csRandSource) Seed(seed int64) {
 	// No-op.
 }
 
-// Float64 returns, as a float 64, a pesudo random number in [0.0,1.0).
+// Int63n returns, as a int64, a pseudo random number in [0, n).
+func Int63n(n int64) int64 {
+	return CsRand.Int63n(n)
+}
+
+// Float64 returns, as a float64, a pesudo random number in [0.0,1.0).
 func Float64() float64 {
 	return CsRand.Float64()
 }