ARJ to RAR Converter

RAR (Roshal Archive) is a proprietary compressed archive format created by Russian software engineer Eugene Roshal in March 1993, distributed through the WinRAR archiver that became one of the most widely installed Windows applications worldwide. The format uses a sophisticated compression algorithm that has evolved through several major versions (RAR 1.3, 2.0, 3.0, 5.0), with each revision improving compression ratios and adding features. RAR5, the current version, employs a dictionary-based algorithm with dictionary sizes up to 1 GB and supports optional BLAKE2sp hashing for integrity verification. The format provides solid compression (treating multiple files as a continuous stream), multi-volume archive splitting, recovery records for repairing damaged archives, AES-256 encryption for both content and filenames, and Unicode filename support. One advantage is reliable error recovery — RAR's recovery record feature can reconstruct damaged archive portions, a capability that made it popular for distributing large files across unreliable connections and Usenet posts. Strong compression performance is another key strength: RAR consistently ranks among the top formats for general-purpose compression ratios, particularly on heterogeneous file collections. While the compression algorithm is proprietary and creating RAR archives requires licensed software, the decompression code is freely available, and extraction is supported by virtually every archiving tool across all platforms. RAR remains one of the most common archive formats encountered online.