1 files changed, 1 insertions, 1 deletions
diff --git a/src/bignum.h b/src/bignum.h
index 6e8d3cb8ab..641ebf4b05 100644
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -300,7 +300,7 @@ public:
         while (isxdigit(*psz))
         {
             *this <<= 4;
-            int n = phexdigit[*psz++];
+            int n = phexdigit[(unsigned char)*psz++];
             *this += n;
         }
         if (fNegative)