Skip to content


Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Pretty Curved Privacy
C Python C++ Perl Shell
branch: master

Fetching latest commit…

Cannot retrieve the latest commit at this time



Pretty Curved Privacy (pcp1) is a commandline utility which can be used to encrypt files. pcp1 uses eliptc curve cryptography for encryption (CURVE25519 by Dan J. Bernstein). While CURVE25519 is no worldwide accepted standard it hasn't been compromised by the NSA - which might be better, depending on your point of view.

Caution: since CURVE25519 is no accepted standard, pcp1 has to be considered as experimental software. In fact, I wrote it just to learn about the curve and see how it works.

Beside some differences it works like GNUPG. So, if you already know how to use gpg, you'll feel almost home.


Lets say, Alicia and Bobby want to exchange encrypted messages. Here's what the've got to do.

First, both have create a secret key:

 Alicia                             Bobby
 pcp1 -k                            pcp1 -k

After entering their name, email address and a passphrase to protect the key, it will be stored in their vault file (by default ~/.pcpvault).

Now, both of them have to export the public key, which has to be imported by the other one. With pcp you can export the public part of your primary key, but the better solution is to export a derived public key especially for the recipient:

 Alicia                             Bobby
 pcp1 -p -r Bobby -O     pcp1 -p -r Alicia -O

They've to exchange the public key somehow (which is not my problem at the moment, use ssh, encrypted mail, whatever). Once exchanged, they have to import it:

 Alicia                             Bobby
 pcp1 -K -I               pcp1 -K -I

They will see a response as this when done:

 key 0x29A323A2C295D391 added to .pcpvault.

Now, Alicia finally writes the secret message, encrypts it and sends it to Bobby, who in turn decrypts it:

 Alicia                             Bobby
 echo "Love you, honey" > letter
 pcp1 -e -r Bobby -I letter -O letter.asc
 cat letter.asc | mail

                                    pcp1 -d -I letter.asc | less

And that's it.

Please note the big difference to GPG though: both Alicia AND Bobby have to enter the passphrase for their secret key! That's the way CURVE25519 works: you encrypt a message using your secret key and the recipients public key and the recipient does the opposite, he uses his secret key and your public key to actually decrypt the message.

Oh - and if you're wondering why I named them Alicia and Bobby: I was just sick of Alice and Bob. We're running NSA-free, so we're using other sample names as well.


There are currently no packages available, so pcp has to be compiled from source. Follow these steps:

First, you will need libsodium:

 git clone git://
 cd libsodium
 ./configure && make check
 sudo make install
 sudo ldconfig
 cd ..

Next, pcp:

 git clone git://
 cd pcp
 sudo make install
 cd ..

Optionally, you might run the unit tests:

 make test


To learn how to use pcp, read the manpage:

 man pcp1


Copyright (c) 2013-2015 by T.v.Dein <tom AT vondein DOT org>


ZeroMQ Z85 encoding routine
 Copyright (c) 2007-2013 iMatix Corporation
 Copyright (c) 2009-2011 250bpm s.r.o.
 Copyright (c) 2010-2011 Miru Limited
 Copyright (c) 2011 VMware, Inc.
 Copyright (c) 2012 Spotify AB
Tarsnap readpass helpers
 Copyright 2009 Colin Percival
jen_hash() hash algorithm
 Bob Jenkins, Public Domain.
UTHASH hashing macros
 Copyright (c) 2003-2013, Troy D. Hanson
Random art image from OpenSSH keygen
 Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.

 Comitted by Alexander von Gernler in rev 1.7.

Every incorporated source code is opensource and licensed under the GPL as well.


T.v.Dein <tom AT vondein DOT org>


Licensed under the GNU GENERAL PUBLIC LICENSE version 3.


The homepage of Pretty Curved Privacy can be found on The source is on Github:

Something went wrong with that request. Please try again.