Randall Smith wrote: > Chunks of data (about 2MB) are to be stored on machines using a > peer-to-peer protocol. The recipient of these chunks can't assume that > the payload is benign. While the data senders are supposed to encrypt > data, that's not guaranteed, and I'd like to protect the recipient > against exposure to nefarious data by mangling or encrypting the data > before it is written to disk. > > My original idea was for the recipient to encrypt using AES. But I want > to keep this software pure Python "batteries included" and not require > installation of other platform-dependent software. Pure Python AES and > even DES are just way too slow. I don't know that I really need > encryption here, but some type of fast mangling algorithm where a bad > actor sending a payload can't guess the output ahead of time. > > Any ideas are appreciated. Thanks.
Would it be sufficient to prepend the chunk with one block, say, of random data? To unmangle you'd just strip off that block. BLOCK = os.urandom(BLOCKSIZE) def mangle(source, dest): dest.write(BLOCK) shutil.copyfileobj(source, dest) def unmangle(source, dest): source.read(BLOCKSIZE) shutil.copyfileobj(source, dest) Disclaimer: I did not follow the ongoing discussion. -- https://mail.python.org/mailman/listinfo/python-list