keydecode

Decodes PS/2 USB HID scan codes into human-readable characters. Useful for forensics and security research — e.g. replaying keystroke capture logs.

Build

gcc -o ds-decoder ds-decoder.c

Usage

Pass scan codes as hex arguments (prefix 0x or bare hex):

./ds-decoder 0x1E 0x30 0x2E    # → abc
./ds-decoder 0x2A 0x1E          # → A  (Shift + a)
./ds-decoder 0x3A 0x1E          # → A  (CapsLock then a)

Supported keys

• Full A–Z / a–z (with Shift and CapsLock state)
• Digits 0–9 and common symbols (-, =, `)
• Special keys: [Esc], [Shift], [CapsLk]

Unknown scan codes are printed as [Unknown:0xNN].

Scan code reference

Uses standard Set 1 (XT) PC scan codes. See OSDev Wiki — Keyboard Scan Codes for a full table.