Daemon mode:

1) create fifo:
	mkfifo fifo 
	
2) run:
./chainsign --daemon

3) write command to fifo:
START
CMD1
CMD2
<cmd2-argument>
CMD3
<cmd3-argument>
CMD4
CMD5
(...)
QUIT

example:
echo "START" > fifo
echo "SIGN-NEXTKEY" > fifo
echo "file1" > fifo
echo "QUIT" > fifo

comands in daemon mode:
SIGN-NEXTKEY - next command in fifo is name of file, sign one file
QUIT - close program


=== TODO ===

Optimize the verification:
loop should be in the program:
1. loop over all keys, find where keychain ends
2. loop over all files, check if they are signed properly, and are they signed with the pubkeys, and are the signing keys < the last good keychain key