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# BC - Bench Calculator

### 'bc' is a unix scripting tool that provides 'arbitary precision' mathematics.

It has a 'C' like syntax, supports recursion and allows variables and functions to be defined (although as the old bc only allowed single letter names I have carried on using this).

An example of bc in action can be seen in calculate pi with arbitary precision .

In this project it is used via php scripts, to provide the mathematical muscle to deal with the very large numbers handled in RSA implementations. It is still a little slow, and the cpu load will regularly hit 95% as it calculates large exponents. Very large values may even cause the page to take minutes to complete calculations. However, the numbers used in RSA are so large that double precision, or floating point, is woefully inadequate.

Link to unix bc man page converted to html.