diff --git a/random_119.go b/random_119.go
deleted file mode 100644
index 98d761c..0000000
--- a/random_119.go
+++ /dev/null
@@ -1,32 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build !go1.20
-// +build !go1.20
-
-package mail
-
-import (
-	"math/rand"
-	"time"
-)
-
-// randNum returns a random number with a maximum value of maxval.
-//
-// This function generates a random integer between 0 and maxval (exclusive). It seeds the
-// random number generator with the current time in nanoseconds to ensure different results
-// each time the function is called.
-//
-// Parameters:
-//   - maxval: The upper bound for the random number generation (exclusive).
-//
-// Returns:
-//   - A random integer between 0 and maxval. If maxval is less than or equal to 0, it returns 0.
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	rand.Seed(time.Now().UnixNano())
-	return rand.Intn(maxval)
-}
diff --git a/random_121.go b/random_121.go
deleted file mode 100644
index ea1e399..0000000
--- a/random_121.go
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build go1.20 && !go1.22
-// +build go1.20,!go1.22
-
-package mail
-
-import (
-	"math/rand"
-)
-
-// randNum returns a random number with a maximum value of maxval.
-//
-// This function generates a random integer between 0 and maxval (exclusive). If maxval is less
-// than or equal to 0, it returns 0. The random number generator uses the default seed provided
-// by the rand package.
-//
-// Parameters:
-//   - maxval: The upper bound for the random number generation (exclusive).
-//
-// Returns:
-//   - A random integer between 0 and maxval. If maxval is less than or equal to 0, it returns 0.
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	return rand.Intn(maxval)
-}
diff --git a/random_122.go b/random_122.go
deleted file mode 100644
index 27ded3d..0000000
--- a/random_122.go
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
-//
-// SPDX-License-Identifier: MIT
-
-//go:build go1.22
-// +build go1.22
-
-package mail
-
-import (
-	"math/rand/v2"
-)
-
-// randNum returns a random number with a maximum value of maxval.
-//
-// This function generates a random integer between 0 and maxval (exclusive). It utilizes
-// the math/rand/v2 interface for Go 1.22+ and will default to math/rand for older Go versions.
-// If maxval is less than or equal to 0, it returns 0.
-//
-// Parameters:
-//   - maxval: The upper bound for the random number generation (exclusive).
-//
-// Returns:
-//   - A random integer between 0 and maxval. If maxval is less than or equal to 0, it returns 0.
-func randNum(maxval int) int {
-	if maxval <= 0 {
-		return 0
-	}
-	return rand.IntN(maxval)
-}
diff --git a/random_test.go b/random_test.go
index e69b4e7..a608c2a 100644
--- a/random_test.go
+++ b/random_test.go
@@ -38,34 +38,12 @@ func TestRandomStringSecure(t *testing.T) {
 	}
 }
 
-// TestRandomNum tests the randomNum method
-func TestRandomNum(t *testing.T) {
-	tt := []struct {
-		testName string
-		max      int
-	}{
-		{"Max: 1", 1},
-		{"Max: 20", 20},
-		{"Max: 50", 50},
-		{"Max: 100", 100},
-		{"Max: 1000", 1000},
-		{"Max: 10000", 10000},
-		{"Max: 100000000", 100000000},
-	}
-
-	for _, tc := range tt {
-		t.Run(tc.testName, func(t *testing.T) {
-			rn := randNum(tc.max)
-			if rn > tc.max {
-				t.Errorf("random number generation failed: %d is bigger than given value %d", rn, tc.max)
-			}
-		})
-	}
-}
-
-func TestRandomNumZero(t *testing.T) {
-	rn := randNum(0)
-	if rn != 0 {
-		t.Errorf("random number generation failed: %d is not zero", rn)
+func BenchmarkGenerator_RandomStringSecure(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, err := randomStringSecure(22)
+		if err != nil {
+			b.Errorf("RandomStringFromCharRange() failed: %s", err)
+		}
 	}
 }