MD5 conversion and MD5 reverse lookup
MD5 (Message Digest algorithm, 5th version) is an algorithm which converts a given sequence of characters into another unique sequence of characters, with a fixed length, called «hash». For instance, the MD5 hash of the word password is 5f4dcc3b5aa765d61d8327deb882cf99.
These hashes are mostly used to validate file integrity, to encrypt sensitive data (like passwords), and to generate unique identifiers.
Is it secure?
MD5 hashes are theoretically impossible to reverse directly, ie, it is not possible to retrieve the original string from a given hash using only mathematical operations.
Most web sites and applications store their user passwords into databases with MD5 encryption. This method appears to be safe as it seems impossible to retrieve original user passwords if, say, a hacker manages to have a look at the database content.
Unfortunately, there is a way to decrypt a MD5 hash, using a dictionary populated with strings and their MD5 counterpart. As most users use very simple passwords (like «123456», «password», «abc123», etc), MD5 dictionaries make them very easy to retrieve.
This website uses a MD5 reverse dictionary containing several millions of entries, which you can use with MD5 hashes from your application.
If some of the hashes you enter can be reversed, consider using another way of generating hashes, like using stronger algorithms (SHA-2, Whirlpool, etc), combining algorithms, and using a «salt».
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Md5 Decrypt & Encrypt
MD5 (or Message Digest 5), is a cryptographic function that allows you to create a 128-bits (32 characters in hexadecimal since you only need 4 bits to code hexadecimal) «hash» from any input up to 2^64 bits. This produces a digital fingerprint of the file or text and thus allows to sign it for security verifications. MD5 was created in 1991 as a replacement of MD4 algorithm, that, however being a 128-bits algorithm too, suffered from security breaches (collisions were found very early). In 1996 actual collisions were also found on MD5 which is considered as insecure since then, collisions were confirmed in 2004. You can find out more about collisions here.
Despite being insecure, MD5 is still widely used as a file fingerprint (such as SHA-1) and password storage by webmasters that are not well informed about security.
The hash produced by MD5 is supposed to be unique (it cannot be since 128-bits even if very large is finite), so for instance if you type the word «Password» with a capital, it will produce this hash :
Password : dc647eb65e6711e155375218212b3964
While the same word without the Capital «P» gives this hash :
password : 5f4dcc3b5aa765d61d8327deb882cf99
How to decrypt MD5 ?
Since MD5 in a hashing function, it is not reversible. Meaning that you cannot calculate the plaintext that was hashed only looking at the hash. It’s a one-way function. This is also why it is used to sign files and also to store passwords. Thanks to this, webmasters are not in capacity to know your plain password from their database. When you enter a password on a website it is (most of the time) stored as hash, then when you come back this hash is compared to the hash of password you enter, if they match the passwords were the same.
Now if MD5 is a one way function, how do we decrypt it ? We actually don’t «decrypt» MD5, we use this word because it’s easy to understand, but hashing function cannot be decrypted. It can be reversed. For this to happen, the only way is to compare a given hash with a database of couples password:hash. This is what we have on this website. We have billions hashes stored in our database, and more in our premium database. When you enter a hash in our search bar, we look into our database if we have a match. If so we provide you with the password. Now for premium search you’ll have to buy credits, but you can also enter hashes in the website search bar, you’ll be able to know if we have it/them in our premium database so you do not pay for nothing. Our database contains every dictionnary that we were able to find on the internet. We also made our own dictionnaries from statistical analysis of actual used passwords. We also bruteforce the unfound passwords every few weeks, so if your hash wasn’t found, you can come back later maybe we’ll have it cracked. If we are not able to crack it, you can still use paying bruteforce services such as hashes.com or onlinehascrack.com. Or if you have a good GPU, you can download hashcat and use it to crack MD5 hashes yourself.
Is MD5 secure ?
As stated before, MD5 isn’t considered as secure since collisions were found in 1996. Even though, it’s still widely used by webmasters. Plain MD5 is actually one of the worst and unsecure way to store passwords, just after plaintext of course. If you actually store MD5 on your database, and don’t want to recode your password scheme to use better password hashing techniques, you can add a salt. The salt is a random string that will be added to the user’s password. this will make online database (rainbow tables and hash tables) as ours useless because we would have to recalculate every password with the salt. You could for instance rehash every password entry in your database by adding the salt to the user’s password. For instance if your user’s MD5 password is the one we hashed before :
Password : dc647eb65e6711e155375218212b3964
You want to add a salt. For instance a 128-bits salt (which is a minimum) : 4*;df-A4+#1q:eD7
If we add this salt to the user’s MD5 on the database it gives us this hash :
4*;df-A4+#1q:eD7dc647eb65e6711e155375218212b3964 : 7ff41d989745f57784e50d3e1630490a
Now when an user wants to log on your website, you just have to hash its password, add your random salt to it, then re-hash the concatenate string, and check if it’s the same MD5 that you stored. You can also use a pepper, which is a database-wide string that you add on top of the salted password.
The better way though to store passwords nowadays is through slow hashing algorithm such as Bcrypt or Blowfish which were created to slow down bruteforce techniques as you can set the number of iterations. Also there’s an automatic salt that is added to the password.
How to create a strong password ?
As you can see on this website, password cracking has never been easier, with online database and bruteforce using stronger and strogner GPUs. So how can you create a password that would be really strong, and easy to remember. Because random strings are strong but very hard to remember (which means that you would need a password manager), we advise users to create passphrases. A passphrase is easy to remember, and its length makes it very hard to break by plain bruteforce. A good wordlist with the right rules could break bad shaped passphrases though. When you create a passphrase, you should mix alpha-numeric with special characters, and don’t shape the phrase like a real life phrase. Put some Leetspeak characters for instance, double some letters, inverse some words, etc.
For instance a passphrase like [W0w,IcantBel13veStronghowisthisPa55phr4s3!] would take centuries to be bruteforced, even with the fastest GPU.
MD5 Encrypt/Decrypt
MD5 is a hashing algorithm. There is no direct method for MD5 decryption. MD5 is decrypted by using Trial & Error methodology. It may take some time if either the text that will be decrypted or the character set that will be used for decryption is long.
Similar Coding Tools
What is Online MD5 Encrypt/Decrypt?
MD5 Encrypt/Decrypt is a free online tool for generating MD5 hashes from strings and decrypting MD5 hashes to strings. In other words, this tool is a combination of MD5 hash generator and MD5 decrypter. MD5 is a hashing function that creates a unique 128-bit hash with 32 characters long for every string. No matter how long the input string is, it generates a unique output. MD5 stands for «Message-Digest algorithm 5». It is an irreversible function, that means, you can create an MD5 hash with a function directly, but you can’t reverse it, in other words, you can’t decrypt it with a function.
MD5 is created for cryptographic purposes in 1991. In recent years, SHA256 or SHA512 are used instead of MD5 since it has vulnerabilities and some issues about collusion that means 2 different inputs creates the same hash. Also, with the advances in computer technology and hardware, it becomes easier to crack MD5 hashes. Even MD5 has such vulnerabilities, it is still used widely. One usage purpose is to be used as checksum for data integrity. Most developers still used it in their databases to store sensitive information like passwords or user information, but it can be cracked easily. If the text that is decrypted is a common phrase or a short string, it takes only seconds to decrypt it. If it is a complex one, it may be still cracked with super computers with trial and error.
The following image shows how MD5 works; it produces a unique hash with same length for different strings that has different lengths. The origin of the idea is to produce unique hashes, but it is proved that it has collusions which makes it vulnerable.
MD5 is a cryptographic hash function, which means that it is a mathematical algorithm that takes an input of any size and produces a fixed-size output. This output is known as a «hash» and is typically represented as a string of hexadecimal numbers. It is called a «cryptographic» hash function because it has certain properties that make it suitable for use in cryptography.
One of the key properties of a cryptographic hash function is that it is one-way, which means that it is very easy to compute the hash of a given input, but it is extremely difficult to figure out the original input from the hash. This is what makes it useful for ensuring the integrity of data, since even a small change in the input will result in a completely different hash.
Because of this one-way property, it is not possible to «decrypt» an MD5 hash in the traditional sense. You cannot take an MD5 hash and «reverse» it to get the original input. The best you can do is to use a technique known as «hash cracking» to try to determine the original input by guessing possible inputs and then computing the hash of each guess to see if it matches the target hash. This can be a very time-consuming process, especially if the original input was a long and complex password.
As described before, there isn’t a function that automatically converts MD5 hash to string. It is impossible to functionally decrypt a MD5 hash. Most popular ways to decrypt MD5 is either to use a database that stores popular hashes with their string equivalents or to use trial and error method. This tool uses both methods. Since MD5 is mostly used to store passwords, it checks most common 100k password for MD5 decryption. If it could not be decrypted, you can use trial and error method by using decryption settings. You have to define character sets and it iterates all possible combinations within these characters to find the related hash. Because of this two-way decryption, this tool is the most advanced online MD5 decrypter you can use.
In summary, the process of «decrypting» an MD5 hash involves guessing possible inputs and then computing the hash of each guess to see if it matches the target hash. This can be a very time-consuming process, and it is not always possible to find the original input, especially if it was a long and complex password.
How to use Online MD5 Encrypt/Decrypt?
You can encyrpt or decrypt MD5 by following these steps.
- MD5 encryption is straightforward. Enter the string in input field and click «Encrypt» button.
- For MD5 decryption, enter the MD5 to input field and click «Decrypt». It checks most common 100K passwords as default for decryption. If it does not work, you can extend your search by using «Decryption Settings» button. Here you can include the characters for your trial-and-error iteration.
- Be careful, if you add too many characters for decryption, the time needed for decryption may be long. Be patient and wait for the process.
Some Art
Digital art created by AI is getting more and more popular. Here is a digital art created by AI about decripting MD5 hashes.