Tim May said:

Suppose encryption is allowed, but only with key escrow? [...] And it might pass constitutional muster (for the same reasons the FCC jurisdiction over airwaves and the ban on encryption by ham operators, got approval.

The restriction on using encryption on the ham bands is an outgrowth of the world-wide spectrum allocation process. Spectrum's allocated by the International Telecommunications Union (ITU); every four years, the World Amateur Radio Council (WARC) meets to go over existing allocations. Sometimes hams lose (as when the 220MHz band went away) and sometimes they win. The ITU accords were originally signed around WW I, when use of encryption on the radio bands was of great concern. The whole licensing system is based on the concept of an Amateur Radio _Service_, whose operators are licensed by the FCC to use a "public" resource. Said use is restricted by international treaties to which the US is a signatory. The difference here is that the courts have upheld government restrictions on broadcast spectrum because it's a scarce resource. In the special case of encryption on ham bands, no one's ever even challenged the restriction AFAIK. As Duncan Frissell has preached here many times, bandwidth is no longer as scarce, so I think a constitutional challenge to an encryption ban would probably be workable. -Paul