JonDo is a free, open-source and highly portable (Java-based) client software for accessing the JonDonym services. Its primary use is the anonymisation of web site requests against web site operators, internet providers and the anonymisation service Operators.
All requests of the web browser have to be processed by the JonDo program instead of accessing the internet directly. JonDo encrypts the data and sends it to the first Mix of a Mix Cascade. The first Mix then mixes the data with that of other users and sends it to the second mix station which passes it on to the third mix station which decrypts and sends the data through a cache proxy to the internet.
Each mix carries out cryptographic operations on the message so that the JonDo-encrypted data is only readable after having passed through the proper mixes in the proper order. This ensures that an eavesdropper either only receives unreadable (encrypted) data or can no longer determine the sender. In order for it to work correctly, only one mix in the cascade needs be trusted not to inform the eavesdropper about the method of message mixing. The more users that use the cascade, the harder it is for an observer to distinguish single users.