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Phil Zimmermann

Phil Zimmermann is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Phil Zimmermann rather than just read about it. In short: Philip R. Zimmermann (born 1954) is an American computer scientist and cryptographer.

Phil Zimmermann — main illustration
Phil Zimmermann — illustration

Key takeaways

  • Phil Zimmermann belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Phil Zimmermann to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Phil Zimmermann from memory before moving on to harder problems.

Reference excerpt

Philip R. Zimmermann (born 1954) is an American computer scientist and cryptographer. He is the creator of Pretty Good Privacy (PGP), the most widely used email encryption software in the world. He is also known for his work in VoIP encryption protocols, notably ZRTP and Zfone. Zimmermann is co-founder and Chief Scientist of the global encrypted communications firm Silent Circle.

Background Zimmermann was born in Camden, New Jersey. He received a B.S. degree in computer science from Florida Atlantic University in Boca Raton, Florida, in 1978. In the 1980s, he worked in Boulder, Colorado, as a software engineer on the Nuclear Weapons Freeze Campaign as a military policy analyst. From 2016 to 2021, he worked at Delft University of Technology as an associate professor in the Cybersecurity section at the Faculty of Electrical Engineering, Mathematics, and Computer Science.

PGP In 1991, he wrote the popular Pretty Good Privacy (PGP) program, and made it available (together with its source code) through public FTP for download, the first widely available program implementing public-key cryptography. Shortly thereafter, it became available overseas via the Internet, though Zimmermann has said he had no part in its distribution outside the United States. The very first version of PGP included an encryption algorithm, BassOmatic, developed by Zimmermann. PGP was made to democratize software and digital privacy. But Zimmerman sold PGP to Network Associates (now McAfee) in 1997, for around 10 million dollars, and let them put the software behind a paywall.

Arms Export Control Act investigation After a report from RSA Security, who were in a licensing dispute with regard to the use of the RSA algorithm in PGP, the United States Customs Service started a criminal investigation of Zimmermann, for allegedly violating the Arms Export Control Act. The United States Government had long regarded cryptographic software as a munition, and thus subject to arms trafficking export controls. At that time, PGP was considered to be impermissible ("high-strength") for export from the United States. The maximum strength allowed for legal export has since been raised and now allows PGP to be exported. The investigation lasted three years, but was finally dropped without filing charges after MIT Press published the source code of PGP. In 1995, Zimmermann published the book PGP Source Code and Internals as a way to bypass limitations on exporting digital code. Zimmermann's introduction says the book contains "all of the C source code to a software package called PGP" and that the unusual publication in book form of the complete source code for a computer program was a direct response to the U.S. government's criminal investigation of Zimmermann for violations of U.S. export restrictions as a result of the international spread of PGP's use. After the government dropped its case without indictment in early 1996, Zimmermann founded PGP Inc. and released an updated version of PGP and some additional related products. That company was acquired by Network Associates (NAI) in December 1997, and Zimmermann stayed on for three years as a Senior Fellow. NAI decided to drop the product line and in 2002, PGP was acquired from NAI by a new company called PGP Corporation. Zimmermann served as a special advisor and consultant to that firm until Symantec acquired PGP Corporation in 2010. Zimmermann is also a fellow at the Stanford Law School's Center for Internet and Society. He was a principal designer of the cryptographic key agreement protocol (the "association model") for the Wireless USB standard.

Silent Circle Along with Mike Janke and Jon Callas, in 2012 he co-founded Silent Circle, a secure hardware and subscription based software security company.

Dark Mail Alliance In October 2013, Zimmermann, along with other key employees from Silent Circle, teamed up with Lavabit founder Ladar Levison to create the Dark Mail Alliance. The goal of the organization is to work on a new protocol to replace PGP that will encrypt email metadata, among other things that PGP is not capable of.

Okuna Zimmermann was also involved in the social network Okuna, formerly Openbook, which aimed to be an ethical and privacy-friendly alternative to existing social networks, especially Facebook. He sees today's established social media platforms as a threat to democracy and privacy, because of their profit-oriented revenue models that "are all about exploiting our personal information" and "[deepen] the political divides in our culture", and hoped Okuna would help solve these problems.

Zimmermann's Law In 2013, an article on "Zimmermann's Law" quoted Phil Zimmermann as saying "The natural flow of technology tends to move in the direction of making surveillance easier", and "the ability of computers to track us doubles every eighteen months", in reference to Moore's law.

Awards and other recognition Zimmermann has received numerous technical and humanitarian awards for his pioneering work in cryptography:

… excerpt ends here. Continue reading the full article.

Illustrations

Phil Zimmermann illustration

Worked examples

Example 1 — a first encounter with Phil Zimmermann

Start with the simplest possible case. Write down what Phil Zimmermann claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Phil Zimmermann before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Phil Zimmermann ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Phil Zimmermann

In research
Phil Zimmermann appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Phil Zimmermann in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Phil Zimmermann is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1954 births, American cryptographers, American human rights activists, so understanding it makes those chapters shorter.
In everyday life
Look for Phil Zimmermann outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Phil Zimmermann in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Phil Zimmermann means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Phil Zimmermann out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Phil Zimmermann in simple terms?

Philip R. Zimmermann (born 1954) is an American computer scientist and cryptographer.

Why does Phil Zimmermann matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Phil Zimmermann?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Phil Zimmermann.

Tags

  • 1954 births
  • American cryptographers
  • American human rights activists
  • American people of German descent
  • American technology company founders
  • Cypherpunks
  • Florida Atlantic University alumni
  • Living people
  • People from Camden, New Jersey
  • Privacy activists
  • Public-key cryptographers

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