O'Reilly logo

Modern Cryptography: Theory and Practice by Wenbo Mao

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 19. Returning to “Coin Flipping Over Telephone”

The first cryptographic protocol of this book, “Coin Flipping Over Telephone” (Prot 1.1), is specified using a “magic function” f. Let us recap two properties of this function (Property 1.1):

  1. For every integer x, it is easy to compute f(x) from x while given any value f(x) it is impossible to find any information about a pre-image x, e.g., whether x is an odd or even number.

  2. It impossible to find a pair of integers (x, y) satisfying x ≠ y and f(x) = f(y).

So far, this “magic function” remains magic. No supporting evidence for the two uses of the word “impossible” has been provided, let alone the provision of a concrete realization of the function (and hence of Prot 1.1).

In fact, in ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required