github #486 added bitLength check for GCD test

bcgit · Apr 4, 2019 · 522f6de · 522f6de
1 parent f72dd46
commit 522f6de
Showing 1 changed file with 7 additions and 3 deletions.
diff --git a/core/src/main/java/org/bouncycastle/util/BigIntegers.java b/core/src/main/java/org/bouncycastle/util/BigIntegers.java
@@ -148,6 +148,8 @@ public static BigInteger createRandomBigInteger(int bitLength, SecureRandom rand
             + "ce86165a978d719ebf647f362d33fca29cd179fb42401cbaf3df0c614056f9c8"
             + "f3cfd51e474afb6bc6974f78db8aba8e9e517fded658591ab7502bd41849462f",
         16);
+    private static final int SQR_MAX_SMALL = 20; // bitlength of 743 * 743
+
     /**
      * Return a prime number candidate of the specified bit length.
      *
@@ -181,10 +183,12 @@ public static BigInteger createRandomPrime(int bitLength, int certainty, SecureR
             base[base.length - 1] |= 0x01;
 
             rv = new BigInteger(1, base);
-
-            while (!rv.gcd(SMALL_PRIMES_PRODUCT).equals(ONE))
+            if (bitLength > SQR_MAX_SMALL)
             {
-                rv = rv.add(TWO);
+                while (!rv.gcd(SMALL_PRIMES_PRODUCT).equals(ONE))
+                {
+                    rv = rv.add(TWO);
+                }
             }
         }
         while (!rv.isProbablePrime(certainty));