SkeinDigest
Implementation of the Skein parameterised hash function 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.
            
Optionally initialises the Skein digest with the provided parameters.