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Cyclic redundancy checks are for quickly checking data integrity, mainly for detecting accidental data corruption. CRCs are not meant to be attacked, not even by your little brother, they are easily reversible, and have one application. Think of the CRC as functioning along the lines of a hand-held calculator. Cryptographic hashes can help protect national-...


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So what's the point then, if they both detect such small errors? What CRC* can't do and SHA* and some MD* can, is that the latter are usually strong enough to prevent any supercomputer from creating 2 different files with the hash digest, where as CRC* don't have such strength. CRC* are good at detecting "wire noise" errors, but otherwise lacking certain ...


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CRCs are OK to detect naturally-occurring errors. But in cryptography, we face intelligent adversaries, which can use the mathematical properties of CRCs in order to make an arbitrary alteration in a file without altering its CRC. This is easy, even for large CRCs. Hashes are designed to prevent that (called a second-preimage attack), and other attacks such ...


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