JarSigner and JarUnsigner | 2 Mb
Mandatory are file to be signed (To be signed)
and the two keys: publicKey and private key,
you can easy generate public key from private key
using "From PrivKey" button of PublicKey section,
there is no way in hell you can get private key from public key,
RSA 1024 is commonly used and sometimes (not often) even RSA 2048.
Rest of informations are optional and will be filled with some default values.