SHA1 vs MD5

[brsy]

Note to Mod: I wasn't sure if this should go in Coders' Paradise as this is considered a debate. Please don't infract me if I am wrong.

There have been a few discussions about wether people should use SHA1 or MD5. I honestly think SHA1 is more secure because it has more characters which would be harder to crack. Although MD5 is very popular so there must be some good behind it. What do you think?

 

[HelloSkittle]

For some uses MD5 and SHA1 are very bad hash functions to use.

 

[brsy]

For some uses MD5 and SHA1 are very bad hash functions to use.

Those reasons are??

 

[HelloSkittle]

Those reasons are??

''If you were using MD5 someone malicious could generate two messages GOOD and EVIL, give you the good one to look up and later on pretend that you saw the EVIL message.''

Take for example password storage. The trouble with MD5 and SHA1 are that they are really fast, they are designed that way. A fast computer could hash millions of passwords a second.

 

[brsy]

''If you were using MD5 someone malicious could generate two messages GOOD and EVIL, give you the good one to look up and later on pretend that you saw the EVIL message.''

Take for example password storage. The trouble with MD5 and SHA1 are that they are really fast, they are designed that way. A fast computer could hash millions of passwords a second.

Wouldn't that be a good thing? You are making your website faster if more passwords can be hashed.

 

[Kryptos]

I'd recommend using

You must be registered for see links

for hashing a password.

What is BCrypt? Go to that URL or read these long blocks of text.

Blocks of text:

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• You must be registered for see links

So to answer your question...

Neither. You should use

bcrypt​

. The hashes you mention are all optimized to be quick and easy on hardware, and so cracking them share the same qualities. If you have no other choice, at least be sure to use a long salt and re-hash multiple times.​

 

[HelloSkittle]

Wouldn't that be a good thing? You are making your website faster if more passwords can be hashed.

Uhm no.
The problem is, that if an attacker gets a dump of the database, he can, quite effectively guess passwords using brute-force. Every combination he tries only takes a fraction of millisecond, and he can try out hundreds of thousands of passwords a second.

 

[Kryptos]

Wouldn't that be a good thing? You are making your website faster if more passwords can be hashed.

If you want security, that's a bad thing.

 

[Cablink]

For some uses MD5 and SHA1 are very bad hash functions to use.

That's your opinion. But my opinion is that, they actually are not.

 

[Markshall]

I personally prefer using MD5 because it's what I'm more familiar with. It's quick and doesn't take up much storage in a database -- MD5 ecryptions are ALWAYS 32 characters long, no matter what length of characters you choose to hash.

I may start creating my own salt functions when doing user systems from now on, though.

 

[langer6]

What about using both? Sha1 then Md5 the Sha1 encryption?

 

[Adil]

MD5 is a fast algorithm that can be cracked like that. Your best bet is a more secure encryption algorithm, such as bCrypt. You could also use RSA and whatnot, and if you were really clever, you could incorporate Euler's totient function (like sulake did), to protect your data.

 

[Sojobo]

SHA-512, wham bam, thankyou ma'am