---
name: "rekey"
section: "1"
platform: "linux"
package: "kaya"
version: "0.2.0-6"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/rekey"
---

# rekey(1)

Binary key regeneration for kaya web applications

## NAME

rekey - Binary key regeneration for kaya web applications

## SYNOPSIS

**rekey** *FILE1 \[FILE2 \[...\]\]*

## DESCRIPTION

**rekey** gives all Kaya binaries specified on the command line a new application secret key

The application secret key makes webapps and webprogs secure, by encrypting the state transfers. If you receive a webapp or webprog binary from someone else, or you believe someone untrusted has had read access to your binary, you can use the rekey application to generate a new application secret key without needing a recompile.

Binary distributors of Kaya applications are strongly recommended to use 'rekey' as part of the installation process.

## OBTAINING

The latest release of Kaya can be obtained from \<http://compsoc.dur.ac.uk/kaya/download.php\>

Development versions can be obtained using **[darcs(1)](/darcs/1.md)** from \<http://compsoc.dur.ac.uk/kaya/darcs/\>

## SECURITY

**rekey** will use /dev/random to generate the new key if possible. If /dev/random is unavailable (Windows without MinGW, for example), the new key will be generated pseudo-randomly. This may allow an attacker to easily guess the new key. In environments where security is a concern, therefore, we strongly recommend recompiling with **[kayac(1)](/kayac/1.md)** rather than using **rekey** if /dev/random is unavailable.

**rekey** will give a warning when rekeying if /dev/random is unavailable.

## BUGS

Please report bugs in rekey to \<kaya-devel@compsoc.dur.ac.uk\>

**rekey** cannot rekey Kaya binaries generated with a compiler older than the switch to AES256 encryption (0.2.0 final version)

In rare cases,  **rekey** may not be able to successfully rekey a file and will print an error instead. You must recompile in this case to get a new application key.

## LICENSE

**rekey** is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (version 2) as published by the Free Software Foundation.

## SEE ALSO

**[kayac(1)](/kayac/1.md)**