var result = String.Concat("ESı!BJCŝPM".Zip("DUŝJXL@HġT", (a, b) => --a + "" + ++b));

var encode = "DERVİŞ KAYIMBAŜIOĢLU"
    .Select((x, i) => new {Group = i % 2, Ch = i % 2 == 0 ? ++x : --x})
    .GroupBy(item => item.Group == 1)
    .Select(gr => string.Concat(gr.Select(item => item.Ch)))
    .ToArray();

var decode = String.Concat(encode[0].Zip(encode[1], (a, b) => --a + "" + ++b));

if (result.Equals(decode))
    Console.WriteLine("That's Me!");