Кратко: Fast compression and high-ratio compression toolkit with strong encryption.
ActiveX Easy Compression Library - high-performance and easy-to-use compression/encryption library. It has the all you need to compress and encrypt files, memory buffers and strings.
-Wide range of compression algorithms and modes
-Extremely fast modes
-Better rate than Rar, Zip, BZip
-Strong encryption - AES Rijndael
-One stream for transparent compression/decompression for write/read
-Forward and backward seeks in stream
-Read and write any portion of data