Paste text typed one key off and we'll find the shift. Also handles the QWERTY cipher.
Put your hands on the keyboard one key to the right of where they belong and type hello: you get jr;;p. Every character becomes its neighbour on the same row. As a cipher it's just as simple: shift every key one (or more) places left or right along its row, wrapping round at the ends. Capitals and shifted symbols move with their key, so ! follows 1.
Paste a message into the decoder and it tries one, two and three keys in each direction, ranking them by how English they read. It uses the standard US QWERTY layout, including the number row and punctuation.
A different keyboard trick: write the alphabet in order, then write the keyboard's letter keys in order underneath, top row first: QWERTYUIOP ASDFGHJKL ZXCVBNM. A is Q, B is W, C is E, and so on. It's a simple substitution with a key everyone has on their desk. Switch to “QWERTY cipher” to use it.
A keyboard shift leaves telltale punctuation in the middle of words, especially ; where an L was or [ where a P was, and words keep their length. A QWERTY cipher looks like any other substitution, but the cipher identifier tests for both.
Every character is replaced by the key next to it on the keyboard, as if you'd typed with your hands one key to the right. HELLO becomes JR;;P. It turns up in puzzles and in real typos.
A substitution where the alphabet is laid onto the keyboard in order: A is Q, B is W, C is E, and so on along the rows.
US QWERTY, including the number row and punctuation. Shifted symbols move with their key, so ! shifts the same way as 1.