ASCII table with hex, decimal, octal and binary
Every codepoint from 0 to 127 with its decimal, hexadecimal, octal, and binary representation and control-character name.
Open in ctfpalThe table you end up wanting three times an hour. Beyond lookups, the structure of ASCII is itself useful: the relationships between ranges are exactly what several classes of challenge exploit.
It is worth treating as more than a lookup table because ASCII was designed, not accumulated. The ranges line up on bit boundaries deliberately, and several standard puzzle mechanics are just that design being exploited - which means the table doubles as a list of tricks.
Structure worth memorising
- Uppercase and lowercase differ by one bit - 0x20.
Ais 0x41,ais 0x61. XORing a letter with 0x20 toggles its case, which is why case-flipping appears so often in XOR challenges. - Digits start at 0x30 - so
'7' - '0'is 7, the conversion every parser performs. - Control characters are 0x00 to 0x1F - printable output containing these means you decoded with the wrong scheme.
- 0x7F is DEL - the odd one out at the end, not a printable character.
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