SecureBlackbox 16: Why am I getting an "Input too long" error when trying to encrypt or decrypt the data?

Asymmetric (public-key) algorithms operate with relatively small chunks of data. The exact size depends on the key length and other factors.

For example, with an RSA 1024-bit key, the length of data that you can encrypt or decrypt is a bit more than 100 bytes. If you need to encrypt a larger block, use the session symmetric key to encrypt the data, then encrypt the session key using the asymmetric algorithm.