1) Compute the SHA-1 hash of the file /etc/passwd on the labak.fi.muni.cz
   computer.[2]
2) Create a program (in any programming language including shell scripts)
   that will generate a random (no particular requirements on quality of the
   randomness) 64-bit symmetric encryption key and output it in hexadecimal
   format.[4]
3) Send me a digitally signed email to zriha@fi.muni.cz. Any kind of digital
   signature format is accepted (PGP, X509 etc).[4]