diff --git a/src/PhoneNumber.php b/src/PhoneNumber.php
new file mode 100644
index 0000000..ab25052
--- /dev/null
+++ b/src/PhoneNumber.php
@@ -0,0 +1,67 @@
+<?php
+
+/*
+ * PHP-Auth (https://github.com/delight-im/PHP-Auth)
+ * Copyright (c) delight.im (https://www.delight.im/)
+ * Licensed under the MIT License (https://opensource.org/licenses/MIT)
+ */
+
+namespace Delight\Auth;
+
+final class PhoneNumber {
+
+	/**
+	 * Returns a masked version of the given phone number that can be used for privacy reasons and data safety reasons
+	 *
+	 * @param string $phoneNumber
+	 * @return string
+	 */
+	public static function mask($phoneNumber) {
+		if (empty($phoneNumber)) {
+			return '';
+		}
+
+		$phoneNumber = \preg_replace('/[^0-9A-Za-z+]+/', '', $phoneNumber);
+
+		if (empty($phoneNumber)) {
+			return '';
+		}
+
+		$hasLeadingPlus = \mb_substr($phoneNumber, 0, 1) === '+';
+
+		if ($hasLeadingPlus) {
+			$phoneNumber = \mb_substr($phoneNumber, 1);
+		}
+
+		$significantCharsLength = \mb_strlen($phoneNumber);
+
+		if ($significantCharsLength >= 7) {
+			$phoneNumber = \mb_substr($phoneNumber, 0, 2) . '***' . \mb_substr($phoneNumber, -2);
+		}
+		elseif ($significantCharsLength === 6) {
+			$phoneNumber = \mb_substr($phoneNumber, 0, 2) . '**' . \mb_substr($phoneNumber, -2);
+		}
+		elseif ($significantCharsLength === 5) {
+			$phoneNumber = \mb_substr($phoneNumber, 0, 1) . '**' . \mb_substr($phoneNumber, -2);
+		}
+		elseif ($significantCharsLength === 4) {
+			$phoneNumber = \mb_substr($phoneNumber, 0, 1) . '**' . \mb_substr($phoneNumber, -1);
+		}
+		elseif ($significantCharsLength === 3) {
+			$phoneNumber = '**' . \mb_substr($phoneNumber, -1);
+		}
+		elseif ($significantCharsLength === 2) {
+			$phoneNumber = '**';
+		}
+		else {
+			$phoneNumber = '*';
+		}
+
+		if ($hasLeadingPlus) {
+			$phoneNumber = '+' . $phoneNumber;
+		}
+
+		return $phoneNumber;
+	}
+
+}