Hacking Secret Ciphers with Python

Chapter 24 – Public Key Cryptography and the RSA Cipher 377

Warning to Time Travelers:

Should you travel back to the early 1990’s with this book, the contents of Chapter 24 would be
illegal to possess in the United States. Strong crypto (that is, cryptography strong enough not to
be hacked) was regulated at the same level as tanks, missiles, and flamethrowers and the export of
encryption software would require State Department approval. They said that this was a matter of
national security.

Daniel J. Bernstein, a student at the University of California, Berkeley at the time, wanted to
publish an academic paper and associated source code on his “Snuffle” encryption system. He
was told by the U.S. government that he would first need to become a licensed arms dealer before
he could post his source code on the Internet. They also told him that they would deny him an
export license if he actually applied for one, because his technology was too secure.

The Electronic Frontier Foundation, in its second major case as a young digital civil liberties
organization, brought about the Bernstein v. United States court cases. The court ruled, for the
first time ever, that written software code is speech protected by the First Amendment, and that
the export control laws on encryption violated Bernstein’s First Amendment rights by prohibiting
his constitutionally protected speech.

Today, strong crypto is used to safeguard businesses and e-commerce used by millions of Internet
shoppers everyday. Cryptography is at the foundation of a large part of the global economy. But
in the 1990’s, spreading this knowledge freely (as this book does) would have landed you in
prison for arms trafficking.

A more detailed history of the legal battle for cryptography can be found in Steven Levy’s book,
Crypto: How the Code Rebels Beat the Government, Saving Privacy in the Digital Age.

The fears and predictions made by the “experts” of the intelligence community that encryption
software would become a grave national security threat turned out to be... less than well-founded.