Tiny C Documentation

Tiny Cipher 1.5 © David Gillies 1995-1998 The installer for Tiny Cipher 1.5 was created using Installer VISE from MindVision Software. For more information on Installer VISE, contact: MindVision Software 7201 North 7th Street Lincoln Nebraska 68521-8913 U.S.A. Voice: (+1) 402-477-3269 Fax: (+1) 402-477-1395 Internet: mindvision@mindvision.com http://www.mindvision.com Introduction Tiny Cipher is an encryption program. In other words, it takes a file that can be easily read by you (or a third party), and turns it into a new file (of approximately the same size) that is apparently random garbage. Needless to say, it can do the reverse operation to restore the file to its original state. It has been accelerated for Power Macintosh. Tiny Cipher is a fully-featured Macintosh application, with all the features you would expect in a modern program, such as the ability to drag and drop files and folders onto Tiny Cipher’s icon for processing. Tiny Cipher uses a fast and secure cryptographic algorithm, the Tiny Encryption Algorithm. This provides near-military grade security coupled with extremely fast processing. Tiny Cipher is about three times faster than good commercial implementations of the Data Encryption Standard while providing higher security. Short Cryptography Tutorial. I. Why do we need cryptography? Encryption becomes more and more necessary every day. Sensitive information of all kinds is now stored on computers, and there is often little defence against its being read by unauthorised persons. There are several ways to guard against this. The first, and most obvious, is to deny unauthorised persons physical access to the sensitive data. In other words, the computer and hard disk is in a locked room to which you have the only key. This is called physical security. It has a number of serious drawbacks, especially in an environment like an office where several people might require access to the same machine, but are not allowed access to all the files. The second method is common in multi–user operating systems like UNIX: everybody has a password, and is only allowed access to his or her own files and a restricted set of other files. This is fine for most purposes, but it is vulnerable to attack if the security of the system is not absolutely first–rate. UNIX is a notoriously insecure system, and with the growth of internetworking, systems are susceptible to attack from geographically distant quarters. The third method is to hide the file in such a way as to make it look like it is something else, or to make it impossible to find. This approach is called steganography, from the Greek for concealed writing, and if used carefully can be extremely effective. Unfortunately, most situations do not lend themselves well to this method. So we are left with the fourth method, cryptography, which is Greek for secret writing. A system which implements a cryptographic algorithm (or cipher) is known as a cryptosystem. Tiny Cipher is one such syst…