For debugging, i wish to compare several objects, and create some unique ID for each them, and according its contents and structure, the ID should be equal. Is there any existing function for doing this?
For example if an object is an structure:
S: S.a1 = 1 S.a2 = 2 S.b1 = 3 S.b11 = 4 S.b12 = 5 S.c1 = 6My current choice is copying it to the disk and calculate a MD5 64-bit checksum.
function d=checksum(x)%% Create unique identifier for variablesave('~$hashid.ini',x);d=md5('~$hashid.ini');delete('~$hashid.ini');Which is totally out of the way, wanting to do it for several objects and for debugging. But do not work because of the date of update of the file....
I accidentally stopped hashing passwords before they were stored, so now my database has a mix of MD5 Passwords and unhashed passwords.
I want to loop through and hash the ones that are not MD5. Is it possible to check if a string is an MD5 hash?
I'm trying to create a certain modular code using OpenSSL's EVP API for MD5 by passing the EVP_MD object within functions as shown below.
#include <stdio.h>#include <string.h>#include <openssl/evp.h>EVP_MD* md5_digest_init() { OpenSSL_add_all_digests(); EVP_MD *md = EVP_get_digestbyname("MD5"); if(!md) { printf("Unable to init MD5 digest\n"); exit(1); } return md;}unsigned char *md5_digest_process(EVP_MD* md, unsigned char *input_text) { EVP_MD_CTX mdctx; unsigned char hash[EVP_MAX_MD_SIZE]; int hash_len; EVP_MD_CTX_init(&mdctx); EVP_DigestInit_ex(&mdctx, md, NULL); EVP_DigestUpdate(&mdctx, input_text, strlen(input_text)+1); EVP_DigestFinal_ex(&mdctx, hash, &hash_len); EVP_MD_CTX_cleanup(&mdctx); return hash;}int main() { EVP_MD *md; md = md5_digest_init(); unsigned char* res; res = md5_digest_process(md, "foobar"); printf("%02x", res); return 0;}The problem is that on executing the code every time, I obtain a different hash value for the same text.
Such as
585c64a0554454a05f75a4a0, etcMD5 is deterministic and such an issue should not exist. Any reason why such as error exists? Also, the passing of the EVP_MD object within functions is important to me.
EDIT:
Replacing the final printf with the following code
for(int i = 0; i < 16; ++i) printf("%02x", res[i]);I get the following output.
b4000000000000000100000000000000However, this stays the same for all executions. But I'm guessing that this hash isn't right.
I wonder how reliable the adler32 checksum is, compared to e.g. md5 checksums? It was told on wikipedia that adler32 is "much less reliable" than md5, so I wonder how much, and in which way?
More specifically, I'm wondering if it is reliable enough as a consistency check for long-time archiving of (tar) files of size 20GB+?
hi there I am trying to make password recovery mechanism for my website using php and md5 hashing . what happens that I am hashing the user id with specific number using this
$hashed=md5(1290*13+$id);and send it to the user email when user hit the link which contains this hash
the following code runs
enter code here<title> Password recovery </title></head><body> <form method="post" action="./resetter.php"> <label> password </label> <input type="password" name="pwd"/> <br> <label> password confirm </label> <input type="password" name="pwdc"/> <br> <button type="submit" name="submit"> reset password </button> </form> <?php if(isset($_POST['submit'])){ if(!empty($_POST['pwd'])&&!empty($_POST['pwdc'])){ $pwd=$_POST['pwd']; $pwdc=$_POST['pwdc']; if($pwd===$pwdc){ $hashid=$_GET['idv']; $sql = "SELECT id FROM users where MD5(1290*13+id)='".$hashid."'"; $result=mysqli_query($conn,$sql); $rows = mysqli_fetch_array($result); if(count($rows)>=1){ $md5pwd=md5($pwd); $id=$rows['id']; $sql="update users set password=$md5pwd where id=$id"; mysqli_query($conn,$sql); echo "password has been resetted"; }else { echo "invalid link"; } }else { echo "password and confirmation does not match"; } }else { echo " please enter password and password confirm"; } } ?> </body>but when I type new password this always appears
"invalid link"
which mean that the query didn't worked well and returned nothing
this is the query and how i call it
$sql = "SELECT id FROM users where MD5(1290*13+id)='".$hashid."'"; $result=mysqli_query($conn,$sql); $rows = mysqli_fetch_assoc($result);any suggestions thanks :)
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