Newbie help - password hash

[Aki Tuomi]

On Sun, Sep 13, 2009 at 11:52:42AM -0700, cc10 wrote:
> 
> Hi,
> 
> I am very new to libgcrypt. I am trying to write a simple system, where a
> user in order to login needs a password. I'd like to store this password
> hashed in md5 on the computer. This is what I did so far:
> 
> char userPass[16]; // password of the user (string)
> scanf("%s", &userPass);

This is dangerous, and wrong. 

scanf("%16s", userPass); is bit more correct.

> 
> char userPassHash[16]; // hash of the password
> gcry_md_hash_buffer(1, userPassHash, userPass, strlen(userPass));
> 

this is wrong, as well. You are supposed to say

gcry_md_hash_buffer(GCRY_MD_MD5, userPassHash, userPass, strlen(userPass));

> I was hoping that userPassHash would give me the hash of the password (which
> I then convert to hex for storage), but it is not the case. I am sure I am
> doing something stupid (my guess is that I cannot use the string as an input
> in the hash function, but I am not sure what type of input it needs to be).
> Can anyone help?
> 
> Thank you,
> Charles
> -- 



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