diff --git a/4dev/tests/Create/CoreLibsCreateRandomKeyTest.php b/4dev/tests/Create/CoreLibsCreateRandomKeyTest.php
index 3662aa65..508f7ff9 100644
--- a/4dev/tests/Create/CoreLibsCreateRandomKeyTest.php
+++ b/4dev/tests/Create/CoreLibsCreateRandomKeyTest.php
@@ -200,6 +200,47 @@ final class CoreLibsCreateRandomKeyTest extends TestCase
 			\CoreLibs\Create\RandomKey::getRandomKeyLength()
 		);
 	}
+
+	/**
+	 * 1
+	 *
+	 * @return array
+	 */
+	public function setRandomKeyCharactersProvider(): array
+	{
+		return [
+			'lower case characters' => [
+				0 => "/^[a-z]+$/",
+				1 => ["a", "z"],
+			],
+			'lower case and upper case' => [
+				0 => "/^[A-Za-z]+$/",
+				1 => ["A", "Z"],
+				1 => ["a", "z"],
+			],
+			'alphanumeric' => [
+				0 => "/^[A-Za-z0-9]+$/",
+				1 => ["A", "Z"],
+				1 => ["a", "z"],
+				1 => ["0", "9"],
+			]
+		];
+	}
+
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::setRandomKeyCharacters
+	 * @dataProvider setRandomKeyCharactersProvider
+	 * @testdox check setRandomKeyCharacters [$_dataName]
+	 *
+	 * @return void
+	 */
+	public function testSetRandomKeyCharacters(string $expected_regex, array ...$random_keys): void
+	{
+
+	}
 }
 
 // __END__
diff --git a/www/admin/class_test.randomkey.php b/www/admin/class_test.randomkey.php
index 4416b63d..c6c11daf 100644
--- a/www/admin/class_test.randomkey.php
+++ b/www/admin/class_test.randomkey.php
@@ -43,8 +43,10 @@ print "S::RANDOMKEYGEN($key_length): " . RandomKey::randomKeyGen() . "<br>";
 print "S::RANDOMKEYGEN($key_length_b): " . RandomKey::randomKeyGen($key_length_b) . "<br>";
 print "S::RANDOMKEYGEN($key_length): " . RandomKey::randomKeyGen() . "<br>";
 print "S::RANDOMKEYGEN($key_lenght_long): " . RandomKey::randomKeyGen($key_lenght_long) . "<br>";
-$_array = new CoreLibs\Create\RandomKey();
-print "C->RANDOMKEYGEN(auto): " . $_array->randomKeyGen() . "<br>";
+$random_key = new CoreLibs\Create\RandomKey();
+print "C->RANDOMKEYGEN(auto): " . $random_key->randomKeyGen() . "<br>";
+$random_key->setRandomKeyCharacters(['a', 'z']);
+print "C->RANDOMKEYGEN(Fixed set): " . $random_key->randomKeyGen() . "<br>";
 
 print "</body></html>";
 
diff --git a/www/lib/CoreLibs/Create/RandomKey.php b/www/lib/CoreLibs/Create/RandomKey.php
index 6d57f754..ed405fe4 100644
--- a/www/lib/CoreLibs/Create/RandomKey.php
+++ b/www/lib/CoreLibs/Create/RandomKey.php
@@ -61,6 +61,32 @@ class RandomKey
 		}
 	}
 
+	/**
+	 * sets a different character range
+	 *
+	 * @param  array<array{0:string,1:string}> $ranges
+	 * @return bool
+	 */
+	public static function setRandomKeyCharacters(array ...$ranges): bool
+	{
+		// each range must be an arary of start end range
+		$character_range = [];
+		foreach ($ranges as $range) {
+			if (count($range) != 2) {
+				throw new \ArgumentCountError(__FUNCTION__ . ' array must have two range entries');
+			}
+			$character_range = array_merge($character_range, range($range[0], $range[1]));
+		}
+		self::$key_range = join('', $character_range);
+		self::$one_key_length = strlen(self::$key_range);
+		if (
+			self::$one_key_length == 0
+		) {
+			return false;
+		}
+		return true;
+	}
+
 	/**
 	 * sets the key length and checks that they key given is valid
 	 * if failed it will not change the default key length and return false