1 files changed, 4 insertions, 3 deletions
diff --git a/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Field.java b/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Field.java
index 5a066d81..1e04f4b9 100644
--- a/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Field.java
+++ b/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP256R1Field.java
@@ -112,9 +112,10 @@ public class SecP256R1Field
         long t4 = xx12 + xx13;
         long t5 = xx13 + xx14;
         long t6 = xx14 + xx15;
+        long t7 = t5 - t0;
 
         long cc = 0;
-        cc += (xx[0] & M) + t0 - t3 - t5;
+        cc += (xx[0] & M) - t3 - t7;
         z[0] = (int)cc;
         cc >>= 32;
         cc += (xx[1] & M) + t1 - t4 - t6;
@@ -123,7 +124,7 @@ public class SecP256R1Field
         cc += (xx[2] & M) + t2 - t5;
         z[2] = (int)cc;
         cc >>= 32;
-        cc += (xx[3] & M) + (t3 << 1) + xx13 - xx15 - t0;
+        cc += (xx[3] & M) + (t3 << 1) + t7 - t6;
         z[3] = (int)cc;
         cc >>= 32;
         cc += (xx[4] & M) + (t4 << 1) + xx14 - t1;
@@ -132,7 +133,7 @@ public class SecP256R1Field
         cc += (xx[5] & M) + (t5 << 1) - t2;
         z[5] = (int)cc;
         cc >>= 32;
-        cc += (xx[6] & M) + (t6 << 1) + t5 - t0;
+        cc += (xx[6] & M) + (t6 << 1) + t7;
         z[6] = (int)cc;
         cc >>= 32;
         cc += (xx[7] & M) + (xx15 << 1) + xx08 - t2 - t4;