Historical clue formulations

• Not allowed — 2025-02-03
• Not authorized — 2024-03-24
• Black-market, say — 2020-09-20
• Prohibited — 2015-03-19
• Unauthorized — 2002-02-07
• Backdoor — 1996-08-30
• Backdoor — 1995-05-28
• Shady — 1994-12-27
• Backdoor — 1994-03-23