Tahoe-LAFS (Least Authority File System) is a decentralized data store. It distributes your filesystem across multiple servers, and even if some of the servers fail or are taken over by an attacker, the entire filesystem continues to work correctly and to preserve your privacy and security.
zfec is a fast, portable, and programmable implementation of erasure coding. It includes a C library, a Python library, and a command-line tool. Erasure coding is also known as "forward error correction", which is the generation of redundant blocks of information such that if some blocks are lost then the original data can be recovered from the remaining blocks. The RAID-5 algorithm is an erasure code, but while RAID-5 can recover from the loss of any one element, zfec can be parameterized to choose in advance the number of elements whose loss it can tolerate.
The Enhanced File Crypt/eXtended File Stealth System (EFC/XFSS) makes your uploaded files safe on the server so that no one can read them without knowing a few details to decipher the files. It generates different obfuscated names and encrypted files so no one will know what the original format or name was.
cfv is a utility to both test and create .sfv (Simple File Verify), .csv, .crc, .md5(sfv style), md5sum, BSD md5, sha1sum, and .torrent checksum verification files. It also includes test-only support for .par and .par2 files. These files are commonly used to ensure the correct retrieval or storage of data.