HardGuard25
Generate human-friendly unique IDs using a 25-character alphabet designed to exclude common visual confusables.
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Possible combinations
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Bits of entropy
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Generated this session
Codes will appear here
Standard alphanumeric codes use 36 characters (0-9, A-Z). That creates problems when humans read, transcribe, or dictate codes aloud. HardGuard25 keeps all 10 digits and 15 carefully chosen letters, removing 11 sources of confusion. When a letter and a digit compete for the same visual slot, the digit always wins.
0 1 2 3 4 5 6 7 8 9 A C D F G H J K M N P R U W Y
| Removed | Reason |
|---|---|
| O | Looks like 0 (zero) |
| I | Looks like 1 (one) or l (lowercase L) |
| L | Looks like 1 (one) or I (uppercase i) |
| B | Looks like 8; dyslexia mirror pair with D |
| S | Looks like 5 |
| Z | Looks like 2 |
| E | Looks like 3 for dyslexic readers; digits take priority |
| Q | Looks like O in some typefaces; dyslexia mirror pair with P |
| V | Easily confused with U |
| T | Resembles a plus sign in some contexts |
| X | Collides with multiplication operator; varies by locale |
Read the full specification on GitHub.
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HardGuard25 by Sam Rogers,
Snap Synapse LLC
Original article
· GitHub
· Specification