Why Google’s Wi-Spy Argument Is Stronger Than It First Appears

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Category: Computer Law, Privacy Rights, Public
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Google Street View Car(This is Part 2 of 4 posts on the issue of whether the Wiretap Act bars interception of unencrypted wi-fi signals. See Part I.)

When we last tuned in I was explaining the arguments in the Google “Wi-Spy” case, involving Google’s Street View vehicles’ interception of home wireless network transmissions. Google argues that unencrypted wireless network transmissions are not protected by the Wiretap Act. Forget to set your wi-fi password? Then all of your network communications are free for the taking by your neighbor, local hacker, or multi-national conglomerate driving down the street. Sure, that sounds counter-intuitive, Google might admit, but the Wiretap Act is a counter-intuitive statute (they’ve got that part right, at least).

The plaintiffs argue that Google is simply engaged in lawyer games, willfully contorting the statute in order to save its bacon. There’s a provision in the Wiretap Act that (roughly speaking) defines unencrypted communications to be publicly accessible, but it only applies to radio communications. And, the plaintiffs argue, “radio communications . . . readily accessible to the general public” is only used in one place in the statute, a provision that talks only about “governmental, law enforcement, civil defense, private land mobile, or public safety communications system[s].” Home wireless routers clearly aren’t any of those. The exception that Google needs refers to “electronic communication[s] . . . readily accessible to the general public.” There’s no definition for that use of “readily accessible,” however, so the ordinary English reading will have to suffice.

The district court didn’t take quite the same tack as the plaintiffs. The district court noticed that “wire communications,” “electronic communications,” and “oral communications” cover the waterfront in terms of ways of communicating information to someone. All forms of communication — except perhaps for ESP — must fit into one of those three categories. Whatever “radio communications” are, then, they overlap with at least two of those categories — some “radio communications” are also “electronic communications,” and some are “wire communications.” So when Section 2511(2)(g)(i) talks about “electronic communication[s] . . . readily accessible to the general public,” and those electronic communications are sent by radio, then it would seem the definition of “readily accessible” in Section 2510(16) should apply.

Unless, that is, “radio communications” is much more limited than just any communication sent by radio. The district court concluded that the text and history of the Electronic Communications Privacy Act — the law that added all of this stuff about radio communications to the Wiretap Act — clearly show that “radio communications” means “traditional radio services,” by which the district court seemed to mean — well, you know, radio. Stuff like what you get when you turn the radio on. Sounds broadcast over radio for anyone to hear. Wi-fi is a transmission between a router or access point and a limited set of computers that have joined its network; it’s not Casey Kasem’s Top 40.

It doesn’t matter which of these interpretations you choose, however — the plaintiffs’ or the district court’s — they’re both difficult to squeeze into the language of the Act. We’ll start with the plaintiffs’ reading. According to the plaintiffs, Section 2510(16), with its requirement that radio communications be “scrambled or encrypted” (or fit into one of the other exceptions) to be protected, applies only to the phrase, a “radio communication . . . readily accessible to the general public.” But that phrase only occurs once in the Wiretap Act, in Section 2511(2)(g)(ii)(II), which makes it permissible “to intercept any radio communication which is transmitted . . . by any governmental, law enforcement, civil defense, private land mobile, or public safety communications system, including police and fire, readily accessible to the general public.”

The problem is that the definition in ยง 2510(16) of “readily accessible to the general public” makes little sense applied only to this one provision. Here is that definition again:

“[R]eadily accessible to the general public” means, with respect to a radio communication, that such communication is not —

(A) scrambled or encrypted;

(B) transmitted using modulation techniques whose essential parameters have been withheld from the public with the intention of preserving the privacy of such communication;

(C) carried on a subcarrier or other signal subsidiary to a radio transmission;

(D) transmitted over a communication system provided by a common carrier, unless the communication is a tone only paging system communication; or

(E) transmitted on frequencies allocated under part 25, subpart D, E, or F of part 74, or part 94 of the Rules of the Federal Communications Commission, unless, in the case of a communication transmitted on a frequency allocated under part 74 that is not exclusively allocated to broadcast auxiliary services, the communication is a two-way voice communication by radio . . . .

How many of these could realistically apply to government, law enforcement, civil defense, private land mobile, or public safety communications systems? (Private land mobile systems employ hand-held or car radios to allow local governments and businesses to communicate with employees in the field.) It’s time to walk through this list. It’s certainly possible that government or other systems on the list might use encryption or scrambling, in which case exception “G2″ would not apply. Government, law enforcement, etc. might also use special “modulation techniques” in their radio transmissions. Essentially what (B) is getting at, according to the legislative history, is spread-spectrum techniques, which are now used in cell phones and cordless phones. Spread-spectrum modulation moves the information signal around within a wider band of frequencies, which has several advantages, one of which is to make it somewhat harder for someone to intercept the signal with an ordinary scanner. In 1985, the FCC approved the use of spread-spectrum techniques by unlicensed consumer and state and local government devices, such as those used by law enforcement and public safety organizations. While these uses do not seem to have been widely implemented in 1986, the legislative history cites the FCC order. Spread-spectrum techniques were first used by cell phones in about 1989 or so, and by cordless phones in about 1995. (B) therefore has some application to government, law enforcement, and public safety conversations on modern cordless phones and some government communications systems. (It would probably not exclude government cell phone conversations from the definition of “readily accessible,” because 2511(2)(g)(ii)(II) applies only to systems run by the entities named, and I don’t believe any government, law enforcement agency, etc. runs their own cell phone network.)

That brings us to (C). A “subcarrier” is a separate signal associated with another signal that typically carries related information. FM stereo radio and analog color television broadcasts both make use of subcarriers. The subcarrier carries the information necessary to separate the right and left audio in the case of FM, and the additional color information to add to the main carrier’s black and white picture, in the case of analog television. (The reason it was done this way was backward-compatibility; older or simpler devices could receive just the main signal.) Subcarriers also carry closed-captioning and other information related to the broadcast on the main carrier. Of course, all of these uses are hardly private, and the legislative history indicates that they are all subject to the exemption in 2511(2)(g)(i)(I) for transmissions “for the use of the general public.”

So what sorts of subcarriers was Congress intending to protect? The legislative history, oddly, does not give a single example of one, but according to Wikipedia and the FCC, subcarriers were also used to transmit subscription radio broadcasts (e.g., Muzak), Off-Track Betting race results, traffic control switching, meter reading, utility load management, and telemetry and other information to allow broadcasters to remotely monitor and control their transmission towers. (C) is probably aimed at keeping these latter uses off-limits to interception. All of these subcarrier uses are transmitted only by broadcasters, however. Do “governmental, law enforcement, civil defense, private land mobile, or public safety communications system[s]” engage in any of them? It seems unlikely. If 2510(16) applied only to 2511(2)(g)(ii)(II), that would make (C) pointless.

The same goes for (D). (D) excludes transmissions over a system provided by a common carrier — i.e., a telephone company — from the definition of “readily accessible.” 2511(2)(g)(ii)(II) applies only to “governmental, [etc.] communications system[s]” — that is, systems run by the government, law enforcement, civil defense, private land mobile operators, or public safety organizations. Either the system is provided by a common carrier or it is provided by someone else, but it seems like it can’t be both.

(E) is no better. (E) exempts from “readily accessible” communications “transmitted on frequencies allocated under” 3 parts of the FCC regulations, Parts 25, 74 (subparts D, E, and F), and 94. None of those sorts of transmissions are likely to be made by “governmental, law enforcement, civil defense, private land mobile, or public safety communications system[s].” Part 25 applies to satellite broadcasts. Part 74, subparts D, E, and F, governs two types of transmissions used by broadcasters: remote pickups and studio-to-transmitter feeds. Unless law enforcement personnel are reporting live on location this seems unlikely to apply to them, or anyone else in the 2511(2)(g)(ii)(II) list. Part 94 has now been moved to Part 101, but it used to address private operational-fixed microwave services — using microwave signals to “operate unattended equipment; open and close switches or valves; record data like pressure, temperature, or speed of machines; telemeter voltage and current in power lines; and perform other control or monitoring functions.” Possibly there are some public safety systems using private operational-fixed microwave services, but other than that none of the other systems seems to fit. (Private land mobile systems are governed under a different part of the rules, Part 90.)

The bottom line for the plaintiffs is that if you read “radio communication[s] . . . readily accessible to the general public” as applying only to Section 2511(2)(g)(ii)(II), more than half of the definition of “readily accessible” in Section 2510(16) — specifically subsections (C), (D), and (E) — seems to have little point to it, and (B) would have been superfluous in 1986 (since cordless phones were exempted from the Act’s coverage and cell phones were covered under a different provision).

Judge Ware, the district court judge, had a slightly different reading of the text. Under his reading, “radio communication[s] . . . . readily accessible to the general public” has application outside of Section 2511(2)(g)(ii)(II). It also defines when an electronic communication is “readily accessible to the general public” under Section 2511(2)(g)(i), when that electronic communication is a radio communication. But Judge Ware concluded that “radio communication” means only traditional radio broadcasts.

The exceptions to “readily accessible” in Section 2510(16) don’t work well with Judge Ware’s reading either. Based on the same legislative history that Judge Ware based his “traditional radio services” reading on, Congress evidently intended “radio communications” to apply beyond ordinary AM, FM, and television broadcasts. Take Section 2510(16)(A), which excludes “scrambled or encrypted” signals from being “readily accessible.” A television or radio broadcast signal could in theory be scrambled or encrypted, for example to make it available only to paying subscribers, but it was never done, as far as I know. The one obvious case of encrypted or scrambled broadcasts is satellite signals for satellite or pay television services. Those are questionable examples of “traditional radio services.” But even worse, it’s clear that Congress intended (A) to apply far beyond “traditional radio services.” “Encryption” is described in the House and Senate reports as meaning “to convert plaintext into unintelligible form.” The reference to “plaintext” seems to envision data being encrypted, rather than just sound waves — particularly given that the report was written in 1986, long before digital recordings were common. (.WAV files, for example, were invented in 1991.)

(B) — proprietary modulation techniques — doesn’t have much to do with traditional radio services. As noted above, in the ECPA’s legislative history Congress cited the FCC’s order the prior year, 50 F.R. 25,234 (June 18, 1985), permitting the use of spread-spectrum techniques in communications. That approval, however, was not for traditional radio or television broadcasters, but for unlicensed communications devices under Parts 15 and 90 of the FCC regulations — cordless phones, walkie-talkies, wireless networks, and various police and public safety systems. (Yes, I mentioned wireless networks. What the text and legislative history giveth to Google’s argument, they also taketh away. More on that later.)

(C) — subcarriers — is also weak evidence of a focus on “traditional radio services.” Although the legislative history notes several common uses of subcarriers that seem to fall within traditional broadcasts, they are all public uses outside the exception. At least some of the nonpublic uses of subcarriers at the time of the ECPA would have been to carry data, however, such as traffic control switching, meter reading, utility load management, and remote control of broadcast transmission towers.

(D) — common carrier communications — also is not intuitively within the scope of “traditional radio services.” Common carriers are basically telephone and telegraph companies offering point-to-point communications services — the sort of communications that Judge Ware thought were the opposite of widely broadcast “traditional radio services.” If radio communications meant only broadcasts, there would be no need to exclude common carriers. The district court opinion makes a lot of hay out of the argument that if Google’s interpretation is correct, then cell phone signals would be “readily accessible” under the Wiretap Act, which Congress plainly did not intend. But that argument ignores the effect of Section 2510(16)(D), which excludes cell phone communications from the “readily accessible” definition altogether, even if they are radio communications.

Finally, (E) — satellite, remote and studio feeds, and private operational-fixed microwave services — likewise indicates that radio communications extend beyond “traditional radio services.” Part 25 governs all satellite communications, not simply satellite television and radio broadcasts; but even if Part 25 is “primarily” for television and radio, as the district court opinion puts it, Part 94 certainly was not. The primary uses for private operational-fixed microwave all seem to involve transmission of data, not audio or audiovisual communications, back and forth between a human operator and automated equipment. That doesn’t sound like “traditional radio services” to me.

Judge Ware’s reading of “radio communications” is not any more consistent with the exceptions to “readily accessible” in Section 2510(16) than the plaintiffs’ interpretation. (B), (D), and part of (E) make little sense, and (A) and (C) appeared to contemplate uses outside of “traditional radio services.” The better reading seems to be Google’s: “radio communications” are any wire or electronic communications that are being transmitted by radio.

This extended walk through the statute leads to two questions: what, exactly, then, is the distinction between “electronic communications . . . readily accessible to the general public” and “radio communications . . . readily accessible to the general public” in Section 2511(2)(g)(i) and (ii), and why is “readily accessible” defined for some electronic communications but not all of them? Did Congress really mean to exempt interception of wireless network communications, which although not widely used in 1986, were at least foreseen? That’s the first question. And second, does all this mean that Google should win in its appeal? I’ll take those on in the next two parts.

[Cross-posted at Madisonian.net.]

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