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A comment on Chunking Attacks on File Backup Services Using Content-Defined Chunking [pdf].

Re:Chunking Attacks on File Backup Services Using Content-De... by amarshall on Friday March 21, 2025 @09:56PM (#43442594)
My reading is that the primary vector is based on the size of the chunks (due to deterministic chunking and length-preserving encryption). Would padding chunks with random-length data (prior to encryption) help mitigate this at the cost of additional storage (and complexity)?
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Re:Chunking Attacks on File Backup Services Using Content-De... by cperciva on Friday March 21, 2025 @10:35PM (#43442762)
Tarsnap 1.0.41 (released today) adds padding for exactly this reason.
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Re:Chunking Attacks on File Backup Services Using Content-De... by ThomasWaldmann on Saturday March 22, 2025 @04:09PM (#43448259)
borg supports the "obfuscate" pseudo compressor since 1.2.0 (since Feb 2022), that adds random extra length to the chunks, using one of 2 different algorithms to determine the extra length.
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