Added fuzzer for tbls routine

Makefile

@@ -24,4 +24,4 @@ coverage: tidy
 # target to run all the possible checks; it's a good habit to run it before
 # pushing code
 check: lint vet test
-	echo "check done"
+	echo "check done"

sign/tbls/tbls_test.go

@@ -10,22 +10,39 @@ import (
 )
 
 func TestTBLS(test *testing.T) {
-	var err error
-	msg := []byte("Hello threshold Boneh-Lynn-Shacham")
+	BLSRoutine(test, []byte("Hello threshold Boneh-Lynn-Shacham"), 10)
+}
+
+func FuzzBLS(f *testing.F) {
+	f.Fuzz(func(t *testing.T, msg []byte, n int) {
+		if (n < 1) || (n > 100) {
+			t.Skip("n must be between 1 and 100")
+		}
+		if (len(msg) < 1) || (len(msg) > 1000) {
+			t.Skip("msg must have byte length between 1 and 1000")
+		}
+		BLSRoutine(t, msg, n)
+	})
+}
+
+func BLSRoutine(test *testing.T, msg []byte, n int) {
 	suite := bn256.NewSuite()
-	n := 10
-	t := n/2 + 1
+	th := n/2 + 1
+
 	secret := suite.G1().Scalar().Pick(suite.RandomStream())
-	priPoly := share.NewPriPoly(suite.G2(), t, secret, suite.RandomStream())
+	priPoly := share.NewPriPoly(suite.G2(), th, secret, suite.RandomStream())
 	pubPoly := priPoly.Commit(suite.G2().Point().Base())
 	sigShares := make([][]byte, 0)
+
 	for _, x := range priPoly.Shares(n) {
 		sig, err := Sign(suite, x, msg)
 		require.Nil(test, err)
 		sigShares = append(sigShares, sig)
 	}
-	sig, err := Recover(suite, pubPoly, msg, sigShares, t, n)
+
+	sig, err := Recover(suite, pubPoly, msg, sigShares, th, n)
 	require.Nil(test, err)
+
 	err = bls.Verify(suite, pubPoly.Commit(), msg, sig)
 	require.Nil(test, err)
 }