tarmill 0.50

tarmill project is a tar file compression/encryption program.

This is a program to compress and encrypt tar archives. Each archive member is handled separately, so damage in the middle of the archive does not render the rest of the archive unusable - it will be possible to resume at the next readable member header. Compressed and encrypted
archives are still valid tar files, any well-behaved tar should be able to list (but not extract) them.

tarmill acts as a filter, it takes a tar archive on standard input and produces a tar archive on standard output. Use it in backup scripts in conjunction with tar, like in this definition for the "tob" package:

BACKUPCMD=tar -c -S -T $FILELIST -f - |
tarmill -F1500 -m8M -C6M zip 3 list encrypt /etc/tob/key >$BACKUPDEV
RESTORECMD=tarmill decrypt /etc/tob/key unzip list <$BACKUPDEV |
tar -x -f - "$FILESPEC"

tarmill was written to work with GNU tar 1.12, it uses exactly the same archive format (to the extent possible).

Encryption is done via the "ARC4" algorithm implemented in tarmill, see README.ARC4 for details. Compression is done via zlib.

tarmill is written in C++, but does not use any C++ libraries. It also does not use "advanced" C++ features. It should be fairly portable, only the compiler specifics in the Makefile have to be adapted. The Makefile is set up to produce a binary which depends only on the shared C library, so it should be easy to use this in emergency
restore situations.