Encryption using the Cipher Feedback (CFB) mode.
Gwenda (PNG version), <a href="//commons.wikimedia.org/wiki/User:WhiteTimberwolf" title="User:WhiteTimberwolf">WhiteTimberwolf</a> (SVG version)
<a href="//commons.wikimedia.org/wiki/File:Cfb_encryption.png" title="File:Cfb encryption.png">PNG version</a>