How can I use RSA on a file?
 

I'm new to using RSA.

How can I use it for myself?

Is there an idot-proof program that does it?

You haven't actually said what you want to use it for, however, entering "using RSA" in your favorite search engine will get you a large number of discussions of the subject of "using RSA."

Regards,

yeah, express your questions as clearly as possible.

Do you mean "using RSA to encrypt files"? Get a Big Number library such as OpenSSL/MIRACL/FreeLip/Crypto++/GMP etc., and read its sample programs + docs.

Interesing is HIT library - HIT stands Huge Integer Tool - its really simple for use and well documented tool :)
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Regards.
Janus.

Also be sure to check www.cryptool.com for a great program on how it all works.
It also allows you to encrypt/decrypt a file if you want.

RSA is a big name
 

The RSA in large refers to either the three giants or the company from the three giants. Of course there are also may algorithms for cryptography from RSA, like those hash/digest MD# series, symmetric ciphers RC#, and the number theory based public key RSA ...

PGP from pgp.com/ might be a good example for idot-proof program, especially the PGPfreeware which is totally free of charge.

If what you mean by RSA is the cryptography, you may find more like DSA, ECC, etc, than the almost historical RSA ...

While we are on the topic, I have often found in the literature that RSA is NOT used to encrypt/decrypt large chunck of data, instead its used to encrypt the session key of the block cipher. I failed to understand why this is so ?? other than the speed constraint, what other reason could it possibly be ???

If you're really interested in finding out the ins and outs of RSA and cryptography in general, follow these simple steps:

1) go to http://www.google.com/

2) type rsa faq

3) click on I'm Feeling Lucky

4) read with gusto

Extra credit: check out http://mywebpage.netscape.com/cryptobench/

I decided upload some sources. It's on Dephi/Pascal,
but with samples/help and source code.
You can easy translate to C++.
Implemtation of DES, ECC, MD5, RIPE-MD, SHA included.
Good old TMS units.
Sorry, no RSA, but I hope it's be useful to somebody.
If I find RSA related, i share it on this forum.

I used MD5 instead of CRC, based on this sources. :)

lots of source code examples on h++p://www.planetsourcecode.com/ in many langs.

Look at _hxxp://triade.studentenweb.org/GInt/gint.html.

"FGInt is a package I wrote in Delphi & Free Pascal to handle Fast Gigantic Integers, the size of these integers is merely bounded by the available memory."

RSA, ElGamal, DSA, GOSTDSA, ECC ElGamal, ECDSA and Prime generation implementation. With sources.