SkeinEngine
Implementation of the Skein family of parameterised hash functions in 256, 512 and 1024 bit block
            sizes, based on the  ThreefishEngineThreefish tweakable block cipher.
            
                
1024 bit block size - Skein-1024
            
256 bit block size - Skein-256
            
512 bit block size - Skein-512
            
Constructs a Skein digest with an internal state size and output size.
            
Creates a SkeinEngine as an exact copy of an existing instance.
            
Initialises the Skein engine with the provided parameters. See  SkeinParameters for
            details on the parameterisation of the Skein hash function.
            
Reset the engine to the initial state (with the key and any pre-message parameters , ready to
            accept message input.