/// <summary>Run Rotation13 on the string</summary>

/// <param name="input"></param>

/// <returns></returns>

public static string Rot13( this string input )

=> !string.IsNullOrEmpty(input) ? new string(input.ToCharArray().Rot13()) : input;

/// <summary>Run Rotation13 on the string</summary>

/// <param name="array"></param>

/// <returns></returns>

private static char[] Rot13( this IEnumerable<char> array )

=> array.Select(s => (char)(( s >= 97 && s <= 122 ) ? ( (s + 13 > 122 ) ? s - 13 : s + 13) : ( s >= 65 && s <= 90 ? (s + 13 > 90 ? s - 13 : s + 13) : s ))).ToArray();

public static string Base64Encode( this string encode )

=> encode.Base64Encode(Encoding.UTF8);

public static string Base64Encode( this string encode, Encoding encoding )

=> Convert.ToBase64String(encoding.GetBytes(encode));

public static string Base64Decode( this string decode )

=> decode.Base64Decode(Encoding.UTF8);

public static string Base64Decode( this string decode, Encoding encoding )

=> encoding.GetString(Convert.FromBase64String(decode));