Some Math behind RSA Algorithm -II
n,c,d are 512 bits; p,q are 256 bits; e could be small (3 or 65537); m must be less than or equal to bit length of n
lengths are doubled in recent implementations
As encoding is time consuming, we only use RSA for small messages anyway. However as in secret key methods, one must in general break longer messages into smaller sizes
- Deployed schemes use secret key methods (with key exchanged using public key method) for large amounts of data
PKCS (Public Key Encryption Standard) is a standard from RSA for encoding the information to be signed or encrypted through RSA. It incorporates “know-how” to make RSA work reliably.
Diffie-Hellman, El Gamal and DSS (Digital Signature Standard) are RSA like approaches aimed at digital signatures