Trust, but verify
Trust, but verify is a form of advice given which recommends that while a source of information might be considered reliable, one should perform additional research to verify that such information is accurate, or trustworthy. The original Russian proverb is a short rhyme which states, Доверяй, но проверяй (doveryai, no proveryai).
Suzanne Massie, a writer on Russia met with President Ronald Reagan many times between 1984 and 1987. She taught him the Russian Proverb, Doveryai no Proveryai (Trust but Verify) advising him that "The Russians like to talk in proverbs. It would be nice of you to know a few. You are an actor – you can learn them very quickly". The proverb was adopted as a signature phrase by Reagan, who subsequently used it frequently when discussing U.S. relations with the Soviet Union.
After Reagan used the phrase to emphasize "the extensive verification procedures that would enable both sides to monitor compliance with the treaty", at the signing of the INF Treaty, on 8 December 1987, [notes 1]his counterpart General Secretary Mikhail Gorbachev responded: "You repeat that at every meeting," to which Reagan answered "I like it."While Reagan quoted Russian proverbs, Mr. Gorbachev quoted Ralph Waldo Emerson. 
The National Infrastructure Protection Center (NIPC), a national critical infrastructure threat investigation and response entity, published a paper entitled "Trust but verify", in 2001 on how to protect yourself and your company from e-mail viruses. 
- The Intermediate Nuclear Force Treaty (INF) aimed to eliminate short and medium range nuclear weapons from their respective national arsenals (Watson 2011). Watson described it as a "written embodiment of Gorbachev’s policies and personality based on a life spent in and out of the Soviet Union."
- "The Reagan Years". Suzanne Massie.
- Suzanne Massie speaking on the 22nd Episode of the television documentary, Cold War (TV series).
- Shipler, David K. (9 December 1987). "Reagan and Gorbachev Sign Missile Treaty and Vow to Work for Greater Reductions". New York Times.
- "Remarks on Signing the Intermediate-Range Nuclear Forces Treaty", 1987-12-8. Retrieved on 2009-4-8.
- Watson, William D. (Fall 2011). "Trust, but Verify: Reagan, Gorbachev, and the INF Treaty". Hilltop Review (Western Michigan University) 5.
- "DoD News Briefing: Brigadier General Gregory G. Govan, USA, On-Site Inspection Agency". United States Department of Defense. February 22, 1995. Retrieved April 24, 2009.
- Lindgren, David T. (November 2000). Trust But Verify: Imagery Analysis in the Cold War. Annapolis, Md.: Naval Institute Press. pp. xiii+222.
- Day, Dwayne A. (October 2001). "Trust but Verify: Imagery Analysis in the Cold War (review)". Technology and Culture 42 (4): 822–823. doi:10.1353/tech.2001.0156.
- Trust but verify [electronic resource] : a guide to using e-mail correspondence (Report). Washington, D.C.: National Infrastructure Protection Center (U.S.). 2001.