sick let the user sign and check files in a simple and secure way. It uses the well-known ed25519 algorithm and simple asymetric keys format as a backend, using the library from rdeker/ed25519.

The process is simple. Bob generates two keys: a private and a public one:

$ sick -v -g bob
Creating private key bob.key
Creating public key
Bob must then give his public key to Alice, preferably in person, to ensure the public key she has is Bob's (yes, crypto involves paranoia). Bob can now sign a file, and mail it to Alice with the following command:
$ sick -v -s -f bob.key lolcat.png | mail
Signing stream (1337 bytes)
Alice can now safely retrieve her lolcat picture using her sick tool!
$ sick -v -f lolcat.png.signed > lolcat.png
Extracting signature from input
Verifying stream (1337 bytes)
Stream check OK
Alice can now be SURE that the cat she's looking at is the one sent by Bob! If it wasn't, lolcat.png would simply be an empty file.


git clone git://



safe is built using make (plan9's mk is also supported):

$ make
# make install



If you find any bug, please report them, or send a patch to dev AT z3bra DOT org.