Introduction To Public Key Cryptography

[Ehtyar]

A nice introduction to public key cryptography, focusing on RSA.

Cryptography, the art of concealing the meaning of messages, has been practiced for at least 3000 years. In the past few centuries, it has become an indispensable tool in the military affairs, diplomacy, and commerce of most major nations. During that time there have been many innovations, and cryptography has changed and grown to accommodate the increasingly complex needs of its users. Present techniques are very sophisticated and provide excellent message protection. Current developments in computer technology and information theory, however, are on the verge of revolutionizing cryptography. New kinds of cryptographic systems are emerging that have incredible properties, which appear to eliminate completely some problems that have plagued cryptography users for centuries. One of these new systems is public key cryptography.

In public key systems, as in most forms of cryptography, a piece of information called a key is used to transform a message into cryptic form. In conventional cryptography this key must be kept secret, for it can also be used to decrypt the message. In public key cryptography, however, a message remains secure even if its encryption key is publicly revealed. This unique feature gives public key systems great advantages over conventional systems.

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Ehtyar.

[Shades]

For the interested...download the (Windows version of) OpenVPN software. It contains all software to make your own complete PKI (Public Key Infrastructure) based on RSA. All for free.

Truly interested should also download: abylon READER (Windows only). This is an excellent tool which amongst other things will give you a clear insight into the way certificates are used in your system.

[Ehtyar]

Is there a reason these are better than OpenSSL? OpenSSL contains several pke algorithms, and is debatably the most common way to implement cross platform crypto.

Ehtyar.

[Shades]

True, and AFAIK OpenVPN (and the included 'Easy-RSA' certificate creation scripts) makes use of OpenSSL.

Although Abylon reader has the ability to create its own certificates, I have never used it for that purpose. The reader helps you find out the where/which/when about the certificates in your system more quickly and clearly than the certificate MMC console from Windows.

Plus the reader comes with extra tools for the perfect price, free.

[Deozaan]

The article is from 1983. That's 25 years ago. Actually, it's 2 months shy of 26 years ago.

Oh how technology has changed in just the past 25-26 years!

[Ehtyar]

Hardly. RSA is still the most common PKE algorithm.

Ehtyar.