1 files changed, 1 insertions, 1 deletions
diff --git a/crypto/src/asn1/DerBitString.cs b/crypto/src/asn1/DerBitString.cs
index 2b1ff3354..8aab88353 100644
--- a/crypto/src/asn1/DerBitString.cs
+++ b/crypto/src/asn1/DerBitString.cs
@@ -125,7 +125,7 @@ namespace Org.BouncyCastle.Asn1
                 return;
             }
 
-            int bits = BigInteger.BitLen(namedBits);
+            int bits = 32 - Integers.NumberOfLeadingZeros(namedBits);
             int bytes = (bits + 7) / 8;
             Debug.Assert(0 < bytes && bytes <= 4);