> On 02/10/13 at 08:51am, Florian Weimer wrote: >> There is widespread belief that compressing before encrypting makes >> cryptanalysis harder, so compression is assumed to be beneficial.
> Any academic references? Applied Cryptography (2nd edition) contains this: | 10.6 Compression, Encoding, And Encryption | | Using a data compression algorithm together with an encryption | algorithm makes sense for two reasons: | | Cryptanalysis relies on exploiting redundancies in the plaintext; | compressing a file brfore encryption reduces these redundancies. | | Encryption is time-consuming; compressing a file before encryption | speeds up the process. | | The important thing to remember is to compress before encryption. […] Schneier doesn't cite any references for these claims, unfortunately. Bergen and Hogan, "A Chosen Plaintext Attack on an Adapative Arithmetic Coding Compression Algorithm" (2002) cite Witten and Cleary, "On the privacy afforded by Adaptive Text Compression" (1988) and Jones, "An efficient coding system for long source sequences" (1981). Neither paper appears to be available on the public Internet. _______________________________________________ cryptography mailing list cryptography@randombit.net http://lists.randombit.net/mailman/listinfo/cryptography
