Re: PHP 5.1.0 - sha256() and sha256_file() support

Roman Ivanov wrote:

Ilia Alshanetsky wrote:

You cannot give it an md5 and have it generate you a string with the same md5 hash, so md5 is still relatively safe.

http://www.google.com/search?q=md5+hash+lookup&start=0&start=0&ie=utf-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-US:official

I'd take that link with a grain of salt. :) Dictionary attack is dangerous regardless of which hash function you use. That is when you don't use a salt. But md5 safeness depends on the purpose. It's use as a one way function hasn't been compromised (yet), but the ability to generate collisions means that it cannot be used to generate a fingerprint to detect malicious tampering. In my country we have legally binding digital signatures that currently use sha-1 to generate the fingerprint to sign and the weakening of sha-1's collision generation resistance is a bit unnerving. Fortunately the attacks are still too expensive to be useful, but I'm currently lobbying to have better hashes implemented. It would be nice to have the default PHP install be able to atleast verifiy digitally signed files. Ants Aasma