What is MD5?
MD5 is a 128-bit cryptographic hash function from 1992 that is now considered broken for security purposes — practical collision attacks exist, meaning two different inputs can be crafted to produce the same hash. It is still used for non-security checksums (e.g. verifying a file was not corrupted in transit) but should never be used for passwords or signatures.
Example
MD5 of "hello" is 5d41402abc4b2a76b9719d911017c592.
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