Encryption using the Counter (CTR) mode.
<a href="//commons.wikimedia.org/wiki/User:WhiteTimberwolf" title="User:WhiteTimberwolf">WhiteTimberwolf</a> (SVG version)
Gwenda (PNG version), <a href="//commons.wikimedia.org/wiki/File:Ctr_encryption.png" title="File:Ctr encryption.png">PNG version</a>