MAKEKEY(8) MAKEKEY(8) NAME makekey - generate encryption key SYNOPSIS /usr/lib/makekey DESCRIPTION _M_a_k_e_k_e_y improves the usefulness of encryption schemes depending on a key by increasing the amount of time required to search the key space. It reads 10 bytes from its standard input, and writes 13 bytes on its standard output. The output depends on the input in a way intended to be difficult to compute (that is, to require a substantial fraction of a second). The first eight input bytes (the _i_n_p_u_t _k_e_y) can be arbitrary ASCII characters. The last two (the _s_a_l_t) are best chosen from the set of digits, upper- and lower-case letters, and ‘.’ and ‘/’. The salt char‐ acters are repeated as the first two characters of the output. The remaining 11 output characters are chosen from the same set as the salt and constitute the _o_u_t_p_u_t _k_e_y_. The transformation performed is essentially the following: the salt is used to select one of 4096 cryptographic machines all based on the National Bureau of Standards DES algorithm, but modified in 4096 dif‐ ferent ways. Using the input key as key, a constant string is fed into the machine and recirculated a number of times. The 64 bits that come out are distributed into the 66 useful key bits in the result. _M_a_k_e_k_e_y is intended for programs that perform encryption (for instance, _e_d and _c_r_y_p_t(1)). Usually makekey’s input and output will be pipes. SEE ALSO crypt(1), ed(1) 7th Edition April 27, 1985 MAKEKEY(8)