RSA Encryption

[ypankaj]

Hi,

I want to encrypt a text using rsa encryption method. I did it using command openssl but i want it using my library api, the library api is as,

int rsa_calc (unsigned char * msg, unsigned char * mod, int count, int exp, unsigned char result);

I can't understand how i input public key (.pem file) and what will be the modulus (unsigned char * mod) and exponent (int exp) for any text.

Is there any kind of formula to calculate modulus and exponent of the text.

Please help on this.

[Kloschüssel]

unsigned char = 1 byte = 8 bit

you would probably cast it to unsigned int and do the encryption on the numeric. how the RSA encryption works on a numeric should be clear if you understood how RSA works / the mathematics behind it.

why use your api and not the openssl one? I ask because I don't trust the programming skills of software engineers and neither mine.

[ypankaj]

Thanks for your reply Kloschüssel.. I can't use openssl here since I am doing this encryption at POS device where I can't use openssl or can't install any package on the device as it does't give permissions to install any package..

I am trying with this API and hopefully will solve my problem.

Thanks