A good code phrase is easy to say and hard to guess.
Five Rules
- Keep it short.
- Make it strange but not suspicious.
- Agree the meaning in advance.
- Tie it to one clear action.
- Never explain it where others can hear.
Learn From The Masters
John has a long mustache is five words.
It paints a picture and draws no attention.
The chair is against the wall is six words and a mystery.
Try It
The Code Room has a phrase generator that produces new ones in the same spirit.
The Signal Discipline page explains the habits behind them.