Compression and encryption algorithms

Compression algorithms

Easy Compression Library (ECL) provides 3 main compression algorithms:

• ZLIB algorithm (modified by Davide Moretti dave@rimini.com)
• BZIP algorithm (by Julian Seward, jseward@acm.org.)
• PPM algorithm, variant G (by Dmitry Shkarin, shkarin@arstel.ru)

 

ECL has 3 levels for each of above algorithms: Fastest, Normal and Max.

Level	Meaning
eclNone	No compression
zlibFastest	ZLib algorithm, Fastest compression
zlibNormal	ZLib algorithm, Normal balance between speed and compression rate
zlibMax	ZLib algorithm, Maximum compression, rather slow speed
ppmFastest	PPM algorithm, Fastest compression
ppmNormal	PPM algorithm, Normal balance between speed and compression rate
ppmMax	PPM algorithm, Maximum compression, rather slow speed
bzipFastest	BZIP algorithm, Fastest compression
bzipNormal	BZIP algorithm, Normal balance between speed and compression rate
bzipMax	BZIP algorithm, Maximum compression, rather slow speed

 

Typically ZLib is the fastest algorithm, BZIP is fast and has a good rate, PPM provides the maximum rate with rather low speed.

But it also depends on compression level: i.e. for some files bzipNormal could give you both better compression rate and higher speed than zlibMax.

So we strongly recommend you to test the above compression levels with your application data, to make an optimal choice.

 

The most advanced users of ECL editions with source code could also tune the parameters of compression algorithms to achieve the best result for their specific tasks.

 

Encryption algorithm

Password protection is provided by the Rijndael encryption algorithm (AES), 128/256 bit key.Hash algorithm is RipeMD-128 / RipeMD-256.

Implementation of encryption routines is provided by well-known cryptography expert Hagen Reddmann (HaReddmann@AOL.COM), DEC Part I.

Users of the Pro version can switch between a 128-bit and 256-bit key encryption.

See Tuning ECL for more details.