Yet for the agreement to be credible, Iran must be willing to go even further and allow international inspectors to visit any sites deemed "suspicious", while answering the many questions the agency has asked about past and possibly continuing research on nuclear weapons.Disagreements over verification give opponents of the deal on both sides their best chance of undermining it.
He began trying to conceive of a zero-knowledge proof for nuclear-weapons verification, teaming up with his colleague Robert Goldston, a plasma physicist, and the computer scientist Boaz Barak, who at the time worked for Microsoft Research and is now a professor at Harvard.
At the moment, the United States and four of North Korea's neighbors -- Japan, South Korea, China and Russia -- are trying to bring North Korea back into negotiations over its nuclear weapons program, with safeguards for verification.
In 1956 he was invited by Columbia University to spend a year studying the legal issues involved in the control and verification of nuclear weapons, the subject of his first book, "Arms Control and Inspection in American Law" (1958).
The Bush administration is offering only to preserve some parts of the nuclear accord to guarantee inspections and verification of the nuclear weapons reductions it set in motion — but in a still undermined format far less formal than a major treaty.
Tactical nuclear weapons use dual-purpose vehicles, which makes verification much more complicated, and in the view of some, impossible.
At present the U.S. and Russia have the majority of the world's nuclear weapons and also have the deepest experience in verification.
Withdrawing all tactical nuclear weapons rather than only some of them would make verification much easier.
There are plenty of other deficiencies, from inadequate verification provisions to leaving Moscow's extensive tactical nuclear weapons capabilities unlimited.
For more than a year, the two largest stockpiles of nuclear weapons have been without the finely calibrated system of trust and verification which the original Start treaty from 1991 ensured.
By signing the treaty, the two nations that control 90% of the world's nuclear weapons agreed to historic cuts in their respective stockpiles and to unprecedented verification procedures.
