Scrambling

This article deals with the term scrambling in electronic data processing, for the term freedom of word order from linguistics see scrambling (linguistics)

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The term scrambling (from English "swap") describes in electronic data processing:

• In the sense of “replace”, the exchange of bit sequences when data is stored or transmitted by those that are better adapted to the properties of the transmission channel
• In the sense of "weakly encrypt", the replacement of plain text with cipher

Those, mostly electronic assemblies that carry out the scrambling are called scramblers and consist of substitution tables or use linear feedback shift registers .

Signal transmission / storage

During scrambling, the bit sequences that are to be transmitted or stored are rearranged in such a way that certain requirements for the transmission channel , such as, for example, almost no DC components, are guaranteed.

Weak encryption

If you want to make a text incomprehensible, you can swap letters in blocks. By z. For example, if every 1st and 4th letter is swapped, a text becomes incomprehensible. This weak encryption can be significantly enhanced by other methods. B. carries out an exclusive-or link with a value generated by a pseudo- random generator .

Text: "Hello world !!"

Scrambling: "lalHe Wo! T! L"

Many symmetrical encryption algorithms have integrated steps with interchanging bit groups in their process, e.g. B. DES and AES . However, these methods use scramblers as only one component of several, which is why the encryption per se is not weak.