[Cryptography] XOR linked list & crypto

[John Levine]

In Article <E1Auysi-0007Kq-0O at Elasmtp-Kukur.Atl.Sa.Earthlink.Net> You Write:
>A Famous Xor Hack (Knuth??) Enables Traversing A List In Either Direction:
>
>Https://En.Wikipedia.Org/Wiki/Xor_Linked_List

Knuth Described It, But It Was Well Known When He Did.  It Probably Dates
>From The 1950S, When We Really Cared About Saving Bits.

>Q: Have These Features/Drawbacks Been Used In Any Encryption Scheme?
>
>Thanks For Any Pointers(!) Or References(!) To Published Work.

Sounds a lot like Pcbc.

R'S,
John