THE METAPHOR IS THE KEY: CRYPTOGRAPHY, THE CLIPPER CHIP, AND THE CONSTITUTION A. MICHAEL FROOMKINt TABLE OF CONTENTS INTRODUCTION .................................. 712 I. MODERN CRYPTOGRAPHY: PRIVATE SECURITY, GOVERNMENT INSECURITY .................................. 718 A. Who Needs Cryptography?....................... 718 1. Banks, ATM-Users, Electronic Transactors ..... .719 2. Businesses with Commercial and Trade Secrets . 722 3. Professionals ............................ 724 4. National ID Cards and Data Authentication .... 725 5. Criminals ............................... 727 6. Users of Telephones, Electronic Mail, Faxes, or Computers .......................... 728 a. Cellular Telephones ..................... 728 b. Standard Telephones .................... 729 c. Faxes ............................... 729 d. E-mail ............................. 729 e. PersonalRecords ....................... 730 t © A. Michael Froomkin, 1995. Associate Professor, University of Miami School of Law. B.A. 1982, Yale College; M.Phil. 1984, Cambridge University;J.D. 1987, Yale Law School. Internet: [email protected] (PGP 2.6.2 public key appears infra note 787). Research for this article was supported by the University of Miami School of Law Summer Research Grant Fund. SueAnn Campbell, Nora de ]a Garza, YolandaJones, and Brian Williams provided superb library support, Rosalia Lliraldi provided secretarial support, andJulie Owen provided indefatigable research assistance. I am grateful to Abe Abraham, Stewart Baker, Tom Baker, Ken Bass, Caroline Bradley, Dorothy Denning, John Ely, Steve Fishbein,John Gilmore, Lance Hoffman, Mark Lemly, Larry Lessig, Charles C. Marson, George Mundstock, David Post,Jonathan Simon, Miles Smid, David Sobel, Cleveland Thorton, Lee Tien, Eugene Volokh, Stephen F. Williams, Steve Winter, two anonymous bureaucrats, and the participants in a University of Miami faculty seminar for their comments, corrections, and suggestions. I first encountered several of the issues discussed in this Article in the Cypherpunks and Cyberia-L mailing lists, and on the misc.legal.moderated newsgroup. For an earlier version of portions of Part III of this Article, see A. Michael Froomkin, The Constitutionality of Mandatory Key Escrow-A First Look, in BUILDING IN BIG BROTHER: THE CRYPTOGRAPHIC POLICY DEBATE (Lance Hoffman ed., forthcoming Mar. 1995) (manuscript at 413) [hereinafter BUILDING IN BIG BROTHER]. Unless otherwise specified, this Article reflects legal and technical developments occurring on or before January 1, 1995. (709) 710 UNIVERSITY OF PENNSYLVANIA LAW REVIEW [Vol. 143: 709 7. Dissidents and Others .................... 730 B. The U.S. DataEncryption Standard(DES) Is Increasingly Vulnerable ................................ 735 1. How DES Became a Standard ............... 735 2. DES Is Vulnerable to Attack ................ 738 3. How to Achieve Better Security ............. 740 C. The Escrowed Encryption Standard (EES) ........... 742 1. Why the Government Wants EES to Replace DES ................................... 743 a. Domestic Law Enforcement ................ 744 b. Intelligence Gathering ................... 747 c. Failure of Laws Designed to Prevent the Spread of Strong Cryptography ............. 748 i. Export Control: The ITAR ........... 748 ii. "Classified at Birth".................. 751 2. How Clipper Works ...................... 752 a. A Tale of Three Keys .................... 753 b. The Escrow Agents' CriticalRole ............ 759 c. Limited Recoursefor Improper Key Disclosure ... 762 II. THE ESCROWED ENCRYPTION PROPOSAL-LEGAL, POLICY, AND TECHNICAL PROBLEMS .......................... 764 A. EES: The Un-Rule Rule ....................... 764 1. FIPS 185: A Strange Standard .............. 764 2. An End-Run Around Accountability .......... 767 3. Did NIST's Cooperation with the NSA over FIPS 185 Violate the Computer Security Act of 1987? ........................... 776 4. Who Should Hold the Keys? ................ 782 B. Unresolved Issues ............................. 786 1. Requests from Foreign Governments ......... 787 2. Clipper Abroad? ........................ 788 3. What Level of Protection Do LEAFs Have Under the Electronic Communications Privacy Act? ............................. 789 C. Voluntary EES Is Constitutional ................. 793 D. Voluntary EES Is Unlikely to Displace Un-Escrowed Cryptography................................ 796 1. Why EES Worries People .................. 798 a. Preserving the Status Quo Prevents a Return to the Status Quo Ante ............. 798 b. EES Does Not Preserve the Status Quo ........ 800 c. The Status Quo May Not Be Stable .......... 802 1995] THE METAPHOR IS THE KEY- THE CLIPPER CHIP 711 2. Spoofing EES: The LEAF-Blower ............ 806 E. What Happens If EES Fails? .................... 808 III. WOULD MANDATORY KEY ESCROW BE CONSTITUTIONAL? . 810 A. First Amendment Issues ........................ 812 1. Compelled Speech ......................... 813 2. Chilling Effect on Speech .................. 815 3. Anonymity and the Freedom of Association .... 817 4. The Parallel to Antimask Laws .............. 821 B. Fourth Amendment Issues ....................... 823 1. The Fourth Amendment Does Not Give the Government an Affirmative Right to an Effective Search .......................... 826 2. Mandatory Escrow of a Key Is a "Search or Seizure"................................ 827 3. Mandatory Key Escrow as a "Regulatory Search". ............................... 830 C. Fifth Amendment Issues ....................... 833 1. The Chip Key as a Private Paper .............. 834 2. Is a Chip Key or a Session Key "Incriminating"? . 836 D. Privacy Issues ............................... 838 1. The Right to Autonomous Choice Regarding Nonintimate Matters ..................... 838 2. The Right to Be Left Alone ................ 839 3. The Right to Autonomous Choice Regarding Intimate Matters ........................ 840 E. What Next? ................................. 843 IV. IDEAS ARE WEAPONS ........................... 843 A. Caught Between Archetypes ...................... 846 1. Big Brother ............................ 847 2. The Conspirator ........................ 850 a. Panics over Plotters ..................... 851 b. Modem Incarnations: The Drug Kingpin and the Terrorist ...................... 856 B. Mediating the Clash: A Metaphoric Menu ........... 859 1. Focus on Communication .................... 862 a. "Car"--How Messages Travel ............... 863 b. "Language"............................ 865 2. Focus on Exclusion ...................... 870 a. "Safe"............................... 871 b. "House"-Where Messages Come from ......... 874 C. The Power to Choose .......................... 879 CONCLUSION .................................... 882 712 UNIVERSITY OF PENNSYLVANIA LAW REVIEW [Vol. 143: 709 TECHNICAL APPENDIX: BRUTE-FORCE CRYPTANALYSIS, PUBLIC-KEY ENCRYPTION, AND DIGITAL SIGNATURES ....... 885 A. Brute-Force Cryptanalysis ...................... 887 B. Public-Key Cryptography ......................... 890 C. Digital Signatures ........................... 895 INTRODUCTION Without the ability to keep secrets, individuals lose the capacity to distinguish themselves from others, to maintain independent lives, to be complete and autonomous persons.... This does not mean that a person actually has to keep secrets to be autonomous, just that she must possess the ability to do so. The ability to keep secrets implies the ability to disclose secrets selectively, and so the capacity for selective disclosure at one's own discretion is impor- tant to individual autonomy as well.' Secrecy is a form of power.2 The ability to protect a secret, to preserve one's privacy, is a form of power.' The ability to pene- trate secrets, to learn them, to use them, is also a form of power. Secrecy empowers, secrecy protects, secrecy hurts. The ability to learn a person's secrets without her knowledge-to pierce a person's privacy in secret-is a greater power still. People keep secrets for good reasons and for evil ones. Learning either type of secret gives an intruder power over another. Depending on the people compromised and the secrets learned, this power may be deployed for good (preventing a planned harm) or ill (blackmail, intimidation). This Article is about the clash between two types of power: the individual's power to keep a secret from the state and others, and the state's power to penetrate that secret.' It focuses on new 'KIM L. SCHEPPELE, LEGAL SECRETS 302 (1988) (footnote omitted). 2 "Secrecy" refers to the intentional concealment of information so as to prevent others from "possessing it, making use of it, or revealing it" to third parties. SISSELA BOK, SECRETS: ON THE ETHICS OF CONCEALMENT AND REVELATION 6 (1982). It also refers to "the methods used to conceal [information], such as codes or disguises." Id. 3 Privacy is "that portion of human experience for which secrecy is regarded as most indispensable." Id. at 7. Secrecy and privacy are not identical, however. See id. at 10. Privacy is "the condition of being protected from unwanted access by others-either physical access, personal information, or attention. Claims to privacy are claims to control access to what one takes... to be one's personal domain." Id. at 10-11. ' In this sense, "the right to privacy has everything to do with delineating the legitimate limits of governmental power." Jed Rubenfeld, The Right of Privacy, 102 1995] THE METAPHOR IS THE KEY- THE CLIPPER CHIP 713 conflicts between the perennial desire