Editing Straddling checkerboard (section)

====Example====
The table below shows the conversion of string "ATTACK AT DAWN"<ref>[https://asecuritysite.com/coding/straddling?word=attackatdawn "Straddling Cipher"]</ref> into numbers using the straddling checkerboard setup above.
{| class="wikitable"
|-
|| Plaintext || A || T || T || A || C || K || A || T || D || A || W || N
|-
|| Numbers || 3&nbsp; || 1&nbsp; || 1&nbsp; || 3&nbsp; || 21 || 27 || 3&nbsp; || 1&nbsp; || 22 || 3&nbsp; || 65 || 5&nbsp;
|}
The resulting message, 3113212731223655 has to be secured by other means if the straddling checkerboard table is not scrambled. By passing digits through an additional [[transposition cipher|transposition]] or [[substitution cipher|substitution]] cipher stage can be used to secure message -- to whatever extent transposition or substitution can be considered secure.

For example, securing the message above using as a secret key digits "0452" -- digits of the secret key are repeated to get at least as many digits as there are digits in the message -- and [[Modular arithmetic|adding modulo]] 10 for transposition produces:
{| class="wikitable"
|-
| Message digits
| 3 || 1 || 1 || 3
| 2 || 1 || 2 || 7
| 3 || 1 || 2 || 2
| 3 || 6 || 5 || 5
|-
| Key digits
| 0 || 4 || 5 || 2
| 0 || 4 || 5 || 2
| 0 || 4 || 5 || 2
| 0 || 4 || 5 || 2
|-
| Cipher digits
| 3 || 5 || 6 || 5
| 2 || 5 || 7 || 9
| 3 || 5 || 7 || 4
| 3 || 0 || 0 || 7
|}
The message can also be ciphered with a substitution cipher using the same straddling checkerboard to convert the digits back to letters again:
{| class="wikitable"
|-
| Message numbers
| 3 || 5 || 65 || 25 || 7
| 9 || 3 || 5 || 7 || 4
| 3 || 0 || 0 || 7
|-
| Ciphertext
| A || N || W || H || R
| S || A || N || R || O
| A || E || E || R
|}

Deciphering is simply the reverse of these processes. Although the size of groups can vary, deciphering is unambiguous because whenever the next element to be deciphered starts with a 2 or a 6, it is a pair; otherwise, it is a singleton. If the letter decoded is the numerical escape character '/' then the next 1+ digits (depending on scheme) are to be interpreted as a digit.