How can I decrypt a password hash in PHP

Question

I need to decrypt a password  The password is encrypted with password hash function    password    examplepassword    crypted   password hash  password  PASSWORD DEFAULT     Now  let s assume that  crypted is stored in a database  there s a  users  table  with usernames  passwords  etc  and I need to do a login  I have to see if the password entered by the user matches the encrypted password stored in the database   This is the sql code      sql script    select   from USERS where username     username    and password     inputpassword           but  inputpassword is not encrypted  so it s not equal to what is stored in the password field of the table users     So  there s a function to decrypt after the use of password hash  Or should I change my encrypt method  Or what else

User · Answer

I need to decrypt a password  The password is crypted with   password hash function    password    examplepassword    crypted   password hash  password  PASSWORD DEFAULT      Its not clear to me if you need password verify  or you are trying to gain unauthorized access to the application or database  Other have talked about password verify  so here s how you could gain unauthorized access  Its what bad guys often do when they try to gain access to a system   First  create a list of plain text passwords  A plain text list can be found in a number of places due to the massive data breaches from companies like Adobe  Sort the list and then take the top 10 000 or 100 000 or so   Second  create a list of digested passwords  Simply encrypt or hash the password  Based on your code above  it does not look like a salt is being used  or its a fixed salt   This makes the attack very easy   Third  for each digested password in the list  perform a select in an attempt to find a user who is using the password    sql script    select   from USERS where password     digested password       Fourth  profit   So  rather than picking a user and trying to reverse their password  the bad guy picks a common password and tries to find a user who is using it  Odds are on the bad guy s side     Because the bad guy does these things  it would behove you to not let users choose common passwords  In this case  take a look at ProCheck  EnFilter or Hyppocrates  et al   They are filtering libraries that reject bad passwords  ProCheck achieves very high compression  and can digest multi-million word password lists into a 30KB data file

User · Answer

The passwords cannot be decrypted as will makes a vulnerability for users  So  you can simply use password verify   method to compare the passwords   if password verify  upass   userRow  user pass             code for redirecting to login screen     where   upass is password entered by user and  userRow  user pass   is user pass field in database which is encrypted by password hash   function

User · Answer

Use the password verify   function  if  password vertify  inputpassword   row  password         print  Logged in   else       print  Password Incorrect

User · Answer

it seems someone finally has created a script to decrypt password hash  checkout this one  https   pastebin com Sn19ShVX   lt  php error reporting 0      Coded by L0c4lh34rtz - IndoXploit     n - gt  linux    r n - gt  windows  list   explode   n   file get contents  argv 1       change  n to  r n if you re using windows   -------------------     hash     2y 10 BxO1iVD3HYjVO83NJ58VgeM4wNc7gd3gpggEV8OoHzB1dOCThBpb6     hash here  NB  use single quote       don t use double quote      if isset  argv 1          foreach  list as  wordlist            print         print  password verify  wordlist   hash       hash - gt   wordlist  OK  n      hash - gt   wordlist  SALAH  n           else       print  usage  php    argv 0    wordlist txt n       gt

User · Answer

Bcrypt is a one-way hashing algorithm  you can t decrypt hashes  Use password verify to check whether a password matches the stored hash   lt  php    See the password hash   example to see where this came from   hash     2y 07 BCryptRequires22Chrcte VlQH0piJtjXl 0t1XkA8pw9dMXTpOq    if  password verify  rasmuslerdorf    hash         echo  Password is valid      else       echo  Invalid password       In your case  run the SQL query using only the username   sql script    SELECT   FROM USERS WHERE username      And do the password validation in PHP using a code that is similar to the example above  The way you are constructing the query is very dangerous  If you don t parameterize the input properly  the code will be vulnerable to SQL injection attacks  See this Stack Overflow answer on how to prevent SQL injection

[php] How can I decrypt a password hash in PHP?

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