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License Awareness


Highly Reusable Software

By activity
Professions, Sciences, Humanities, Business, ...

User Interface
Text-based, GUI, Audio, Video, Keyboards, Mouse, Images,...

Text Strings
Conversions, tests, processing, manipulation,...

Math
Integer, Floating point, Matrix, Statistics, Boolean, ...

Processing
Algorithms, Memory, Process control, Debugging, ...

Stored Data
Data storage, Integrity, Encryption, Compression, ...

Communications
Networks, protocols, Interprocess, Remote, Client Server, ...

Hard World
Timing, Calendar and Clock, Audio, Video, Printer, Controls...

File System
Management, Filtering, File & Directory access, Viewers, ...


The Digitally Signed License Certificate provides subscribers with an individual assurance of license and a method for integrity checking.

The certificate includes the license text, the subscriber's name, and lists the md5 checksums of the software files. The certificate is digitally signed using public key cryptography. The signature can be verified using PGP or GnuPG, using the public key.

It is computationally infeasible to sign a document without knowing the private key. Therefore, a valid signature indicates that the md5 checksums were created by us using our master sources. The characteristics of the md5 checksum are that any change to the file on the website, in transit, or in local storage, will result in a different md5 checksum. It is considered to be computationally infeasible to produce a message having a prespecified md5 checksum.

There are utilities which automatically verify the md5 checksums of a list of files from the license certificate. <A HREF=http://rocketaware.com/data/integrity/>md5sum</A> (sometimes called gmd5sum) from the GNU project is an example.

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