The Advanced Encryption Standard (AES) is used in order to protect data against unauthorised access and to encrypt this. The cryptographic process key of varying lengths is utilised for this purpose. This is designated AES-128, AES-192 or AES-256 depending on the length.

The process was originally introduced by the American National Institute of Standards and Technology and can be used in the USA to encrypt documents with a maximum security rating.

This method of encryption of any type of data is considered to be particularly secure and effective. It is used in numerous protocols and transmission technologies, for example the WPA2 protection of WiFi networks utilises the Advanced Encryption Standard and likewise the SSH or IPsec Standard. With Voice-over-IP technology (VoIP), the AES process is frequently used in order to protect user and signalling data.

Today, the Advanced Encryption Standard is permanently integrated into the hardware of many devices. This enables more rapid and effective encryption and decryption than would be possible with pure software solutions.

The AES enjoys huge popularity because the advantages speak for themselves. For example this encryption standard is freely usable, incurs no licence fees and is not subject to patent restrictions. Added to this come relatively low storage and hardware requirements. The encryption algorithm is uncomplicated and elegant in programming, and is simple to implement.

The Advanced Encryption Standard uses the Rijndael algorithm in combination with symmetrical block ciphers as its encryption method. The block lengths are fixed by definition and comprise 128 Bit. The same applies to the fixed key lengths; in addition to 128 Bit these can also comprise 192 or 256 Bit.