Pcompress updated to 1.1

I just put out a new release that implements proper HMAC computation as described in my previous post. I added a bunch of new tests that test error conditions and error handling for out of range parameters and corrupted archives. These tests caused problems to show up that went unnoticed earlier. These were mostly improper error handling situations. As you see testing may be boring but is absolutely necessary.

I also optimized the use of Zlib by switching to raw Zlib streams. Normal Zlib puts a header and computes an Adler32 checksum among other things. However Pcompress adds its own headers and computes cryptographic checksums like SHA and SKEIN which are light years ahead of the simple Adler32 in terms of data integrity verification. So the Adler32 computation overhead was unnecessary.

I had also tweaked the rolling hash used for deduplication while doing the chunking analysis. This produces better results and improved identity dedupe reduction. Finally I also added header checksums in plain non-crypto mode.

 

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