The shift cipher in the ASCII table is a shift cipher (therefore by substitution), which, as its name suggests, will use the ASCII table as an alphabet.
How to encrypt using ASCII Shift cipher?
The ASCII table is composed of 128 characters, as for the Latin alphabet and the Caesar code, the ASCII shift cipher consists in shifting the characters of a rank N to obtain another character.
Encryption considers the ASCII alphabet to be cyclic (moving after the end of the alphabet returns to the beginning) and uses a N value called offset, ranging from 1 to 127 (negative numbers are possible, this amounts to an offset in the other direction).
Example:A (ASCII code65) shifted by N = 40 becomes the code 105 (65 + 40 = 105) so i (ASCII code105).
The ASCII code includes non-printable characters, which dCode prints ' ', use decimal or hexadecimal formats to avoid losing information on the display.
How to decrypt ASCII Shift cipher?
The decryption of an ASCII offset is identical to the encryption but with a shift in the other direction (the equivalent is an encryption with a negative offset).
Example: The encrypted message SeU[[qUaVW shifted from N = -18 decodes 'ASCII_CODE'
Frequency analysis should emphasize groups of characters more often (those corresponding to the letters of the plain message).
How to decipher ASCII Shift without knowing the shift?
dCode allows you to test the 127 offsets and displays the most probable results automatically.
What are the variants of the ASCII Shift cipher?
The shift ciphers are numerous, the most known is the Caesar cipher, but ROT-47 is probably the closest to ASCII shift as it is limited to printable characters and is reversible.
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Cite as source (bibliography): ASCII Shift Cipher on dCode.fr [online website], retrieved on 2022-10-05, https://www.dcode.fr/ascii-shift-cipher