The tcb package contains core components of our tcb suite implementing the alternative password shadowing scheme on Openwall GNU/*/Linux (Owl). It is being made available separately from Owl primarily for use by other distributions. For more information please refer to: https://www.openwall.com/tcb/ To compile and use this you either need recent libxcrypt (which adopted the password hashing API we had introduced in Owl) or our crypt_blowfish patched into glibc (which is how we had introduced that API originally). libxcrypt is available at: https://github.com/besser82/libxcrypt crypt_blowfish is available at: https://www.openwall.com/crypt/