Compressing encrypted data without the encryption key

C. Hazay (Inventor), A. Jagmohan (Inventor), D. Klinc (Inventor), H. M. Krawczyk (Inventor), T. Rabin (Inventor)

Research output: Patent


A method, system and computer program product are disclosed for compressing encrypted data, wherein the data is encrypted by using a block encryption algorithm in a chained mode of operation, and the encrypted data is comprised of a set of N encrypted blocks, C1 . . . CN. In one embodiment, the method comprises leaving block CN uncompressed, and compressing all of the blocks C1 . . . CN in a defined sequence using a Slepian-Wolf code. In an embodiment, the data is encrypted using an encryption key K, and the compressing includes compressing all of the blocks C1 . . . CN without using the encryption key. In one embodiment, the compressing includes outputting the blocks C1 . . . CN as a set of compressed blocks CmprC1 . . . CmprCN-1, and the method further comprises decrypting CN to generate a reconstructed block {tilde over (X)}n, and decrypting and decompressing the set of compressed blocks using {tilde over (X)}n.
Original languageAmerican English
Patent numberNo.20110103580
StatePublished - 2011


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