diff --git a/lib/crypto/poly1305.js b/lib/crypto/poly1305.js
index a3b96cf7..d6a3d632 100644
--- a/lib/crypto/poly1305.js
+++ b/lib/crypto/poly1305.js
@@ -109,7 +109,7 @@ Poly1305.prototype.blocks = function blocks(data, bytes, m) {
         if (j <= i)
           d[i] += this.r[i - j];
         else
-          d[i] += 5 * this.r[i + 10 - j]);
+          d[i] += 5 * this.r[i + 10 - j];
 
         // Sum(h[i] * r[i] * 5) will overflow slightly
         // above 6 products with an unclamped r, so