Provider Class - Abstract class (Extend from properties class) - Properties class (Extend from HashMap class) Engine Class An engine class provides the interface to a specific type of cryptographic service. cryptographic operations (encryption, etc.) generators or converters of cryptographic material (keys and algorithm parameters), or objects (keystores or certificates) that encapsulate the cryptographic data and can be used at higher layers of abstraction. The following engine classes are available: SecureRandom: used to generate random or pseudo-random numbers. MessageDigest: used to calculate the message digest (hash) of specified data. Signature: initialized with keys, these are used to sign data and verify digital signatures. Cipher: initialized with keys, these are used for encrypting/decrypting data. There are various types of algorithms: symmetric bulk encryption (e.g. AES), asymmetric encryption (e.g. RSA), and password-based encryption (e.g. PBE). Mess...