MD5 hash decryption. Hashing and decryption of MD5 hash code. What is hash encryption

In recent decades, problems of confidentiality and information security have become increasingly relevant. That is why attempts are constantly being made using the most modern algorithms. One such method is to use a hashing algorithm called MD5. How to decrypt an MD5 hash will now be discussed. True, you shouldn’t really hope to gain knowledge of hacking passwords or any other confidential information due to the difficulty of such a process and its illegality.

What is MD5 hash?

In general, hashing means converting any incoming data into a string of a certain length, represented on a 128-bit basis, using a special algorithm.

In other words, such a process cannot be called encryption. And in the same way, we cannot talk about decrypting an MD5 hash, since other methods of presenting information are used here. In addition, in this case a special calculation system is used, which nullifies all attempts at decryption.

How to decrypt an MD5 hash: general principles

At best, we can only talk about selecting the desired content using three main methods:

using a dictionary;
application of “rainbow tables”;
Brutus method.

The initial MDA5 hashing technology was developed under the direction of Professor Ronald L. Rivest. Since then, it has been widely used as a cryptography method for online keys, creating electronic signatures, verifying the integrity of file systems, creating web identities, etc. And it is believed that decrypting an MD5 hash using direct algorithmic methods is extremely difficult (although it is possible), because even changing one of the characters in the hexadecimal representation entails an automatic change in all the others. This leaves only the method commonly called brute (intervention using brute force). Nevertheless, the simplest combinations can be restored to their original form.

Use of online resources

If the need for decryption is ripe, first you can use the services of many Internet resources offering their services. In general terms, the principle of operation is that the user enters a combination to be decrypted in a special line on the website, after which he activates the selection process.

If the initial information was encoded using the PHP language, in some cases online services may use a combination of base_64 encode/base_64 decode commands. In any case, the technique only involves the selection of symbols, numbers or letters in the desired combination by comparison with databases that store examples of coded results.

How about yourself?

Some users try to decrypt the hash code on their own. But, as it turns out, doing this is quite problematic. To simplify this procedure, it is better to use narrowly focused utilities, among which the following programs clearly stand out:

PasswordPro.
John the Ripper.
Cain & Abel.
"Stirlitz" and others.

The first two programs are designed to calculate the simplest combinations by substituting elementary combinations like 1212121.

The third one seems to be able to decrypt the MD5 hash, but it does it too slowly. However, its advantage is that it comes with a table generator, although an uninitiated user is unlikely to understand this.

"Stirlitz" is a very interesting application, but it uses too limited a number of calculation algorithms, among which the most significant are BtoA, uuencode, base64, xxencode and binhex.

If it really comes down to it, you need to use the BarsWF brute utility, which is the fastest of all known and in most cases can decrypt an MD5 hash (the password, if any, can also be brought into the desired form), operating with billions of hash calculations per second . However, even with the use of all these software tools, one should also take into account the fact that, in addition to the main algorithm, MDA5 encoding can be performed simultaneously using MD4 or IM.

But even with all this, there are still many holes to be found in hashing. Many experts believe that the length of the code, even with a 128-bit base, is too small, and therefore with the development of software tools and the increase in the computing capabilities of modern processor systems, the decryption process is becoming less and less labor-intensive, which is why the further development and use of such tools already looks completely inappropriate.

Conclusion

It remains to add that you can decrypt an MD5 hash not only using the tools described above. If you scour the Internet thoroughly, you can find a lot of such programs. The question is: is it necessary to do such things? It seems that such knowledge is unlikely to be useful to an ordinary user of any computer system.

It happens that you forget the code for the front door, and you stand there, waiting for someone who has a better memory than you. Although scientists have the best memory. They still remember the times when their heels were burned with a hot iron for new knowledge. Otherwise, they would not have come up with such a terrible thing as MD5 decryption. And before that, they also managed to encrypt it!

What is MD5?

MD5 is one of the 128-bit hashing algorithms. Hashing means converting input data using a specific algorithm into a bit string of a certain length. In this case, the result obtained during the calculations is presented in hexadecimal notation. It is called a hash, hash sum or hash code.

The hashing process is widely used in programming and the web industry. Mainly for creating unique values in associative arrays, identifiers.

Scope of hash codes:

Creation of electronic signatures;
Storing passwords in security system databases;
As part of modern cryptography to create unique keys online;
Verifying the authenticity and integrity of PC file system elements.

MD5 as a hashing standard was developed in 1991 to create a unique hash code from a given value and then verify its authenticity.

The md5sum utility, designed to hash the data of a given file using the MD5 algorithm, returns a string. It consists of 32 numbers in hexadecimal (016f8e458c8f89ef75fa7a78265a0025).

That is, the hash obtained from a function whose operation is based on this algorithm produces a string of 16 bytes (128) bits. And this string includes 16 hexadecimal numbers. In this case, changing at least one of its characters will lead to a subsequent irrevocable change in the values of all other bits of the string:

MD5 reliability issues

It would seem that such a characteristic of MD5 should provide a 100% guarantee of invulnerability and data preservation. But even this turned out to be not enough. In the course of their research, scientists identified a number of holes and vulnerabilities in this already widespread algorithm at that time. The main reason for the weak security of MD5 is the relatively easy detection of collisions during encryption.

Collision is understood as the possibility of obtaining the same result of hash function calculations for different input values.

Simply put, the greater the probability of finding collisions, the lower the reliability of the algorithm used. The probability of finding collisions when encrypting with more reliable hash functions is practically reduced to 0.

That is, the high probability of decrypting MD5 passwords is the main reason for refusing to use this algorithm. Many cryptologists ( data encryption specialists) attribute the low reliability of MD5 to the short length of the resulting hash code.

Scope of application of the hashing algorithm:

Checking the integrity of files received via the Internet - many software installation packages are equipped with a hash code. When an application is activated, its value is compared with the value located in the developer's database;
Searching for duplicate files in the file system - each file has its own hash code. A special application scans the computer's file system, comparing the hashes of all elements. If a match is detected, the utility notifies the user or deletes the duplicate. One such program is Duplifinder:

For password hashing - in the UNIX family of operating systems, each user of the system has his own unique password, which is protected using MD5-based hashing. Some Linux-based systems also use this password encryption method.

Overview of tools for decoding MD5 hash code

Sometimes when working with a computer or damaged databases, you need to decode an MD5-encrypted hash value.

It is most convenient to use specialized resources that provide the opportunity to do this online:

md5.web-max.ca – this service has a simple and intuitive interface. To get the decoded value, you need to enter the hash and fill out the verification captcha field:

md5decrypter.com – a similar service;
msurf.ru – this resource has a simple Russian-language interface. Its functionality allows you not only to decrypt hash code values, but also to create them:

If you look at the decoding values displayed in the figure shown above, it becomes clear that the decoding process produces almost no results. These resources are one or more interconnected databases that contain transcripts of the simplest words.

At the same time, MD5 hash decoding data for even such a common part of the password as “admin” was found in only one database. Therefore, password hashes consisting of more complex and longer combinations of characters are almost impossible to decrypt.

Generating an MD5 hash is a one-way process. Therefore, it does not imply reverse decoding of the original meaning.

Security Basics When Using MD5

This coding standard is one of the most common data protection methods not only in application programming, but also in web programming. Therefore, it will not be superfluous to protect your md5 hash from intentional hacking.

The main way to ensure the security of your password hash is to use a “salt”. It is based on adding a few random characters to the password and then hashing the result.

Many programming languages use special classes and functions for this. Server-side programming languages are no exception to the rule.

You can create an MD5 hash code in php using several functions:

md5() – takes the value “salt” as one of the parameters;
crypt() - unlike the previous one, this function completely automates the entire process, including generating the salt value.

Its syntax is:

string crypt (string $str [, string $salt ])

Usage example:

$hash = crypt("password")

When using the md5() function in PHP, random number generation methods are used to set the salt value. For example, rand() :

In addition to using the salt, several other methods have been developed to protect the MD5 hash.

A 128-bit hashing algorithm called MD5 (Message Digest 5) was developed in 1991. Its creator is Ronald L. Rivest, a professor at MIT (Massachusetts Institute of Technology, located in Cambridge, USA). The algorithm is used to check the authenticity of encrypted data. In this article I will tell you what MD5 is used for, and I will also look at the ways in which it can be decrypted online.

MD5 - data hashing algorithm

MD5 technology is used as one of the cryptographic methods, with the help of which not only various data is checked for integrity, but also:

online keys and passwords are stored;
web identifiers and digital signatures are created;
searches for duplicate files and much more.

MD5 is widely used for authorization on various sites. The information entered by users is read in the form of fingerprints and stored in the site database. Therefore, even if an attacker steals this database, he will not be able to use it directly. All passwords are encrypted and presented in digests. Next, I will talk about decrypting an MD5 file using online services.

It is precisely in order to avoid falling into the hands of fraudsters that many data on the network are transmitted in encrypted form. The information is assigned MD5 = (random combination of characters), for example MD5 =. This set of characters (after the “=”) is called the “MD5 hash,” or checksum result. This hash is used to check the integrity of the transmitted data.

How does this happen?

When transmitting an array of information whose integrity needs to be monitored, an initial hash is assigned, calculated using the MD5 algorithm;
the result is recorded;
during regular or unscheduled checks, the resulting checksum is compared with the original one;
the results are the same - there is no cause for concern, but if they differ, then this indicates outside interference and changes in the data.

Files with hash code

Hash properties

The hash function must be able to convert information of varying lengths into a code consisting of 32 hexadecimal characters. In addition, there are several points to protect the user from outside interference and changes in encrypted information:

if different input data are used, then the hash calculation results should be noticeably different;
the algorithm of the function must be open so that it can be examined for cryptographic strength;
The hash is encrypted unilaterally, that is, there is no way to calculate the original information from the result.

The hash function should use minimal computing resources.

Using MD5 on your own

There is one interesting point here - using this function, each user can independently check the integrity of a file downloaded from the Internet. To do this, you need to use special services, for example, HashTab. The utility is downloaded and built into the file properties as a separate tab. With HashTab, you can use several data hashing algorithms, and the service is freely available for users who use it for personal purposes.

HashTab at work

How to decrypt MD5 online

An arbitrary array of information is converted into a “digest” or “fingerprint” of a certain length. Later, when checking the file, the resulting code is compared with the original fingerprint and a conclusion is drawn about the integrity of the data. In general terms, it is impossible to decrypt a hash code, since it was created so that it cannot be cracked. Conventional decoding methods do not work in this case, because the information is presented somewhat differently. Therefore, although this is a little difficult, we can only try to find the information we are looking for, with which special services and programs can help us.

MD5 decoding online

How does the online service used for MD5 decoding work? It has a database, which it accesses when decrypting the hash code. For example, the MD5 Decrypter website.

In a special field, enter the hash code that we need to decrypt, the captcha values and click decrypt (“Decrypt!”, if the site has not been translated into Russian). Below will be the results: MD5 hash and its decoding, or information that the decryption is not in the database.

You can also use the online tool MSurf.ru. This service allows you to both encode information using MD5 and decrypt the hash code.

Encode and decode information on the website MSurf.ru

It's worth noting that the MD5 feature is being deprecated. Attackers gain access to databases and, with a certain degree of probability, to encrypted information. Therefore, due to its relative unreliability, software developers are recommended to use MD5 either in combination with other algorithms, or gradually replace it with the more modern SHA.

In contact with

MD5 is a peculiar one; it appeared quite a long time ago, back in 1991. It stands for Message-Digest algorithm, it was created by Professor R. L. Rivest. The essence of his work is that with its help any information is encrypted according to the 128-bit hash format, which is a checksum of certain data. At the same time, counterfeiting such an amount is a very complex process. Typically, this mechanism is used to verify the authenticity of data that is already encrypted. The tool presented here gives you the ability to quickly and without much knowledge encrypt absolutely any text. The work of this tool is based on the same. You just need to paste the text into the field and press the button, as a result you will get the hash sum of your text. Using our service you can encrypt any information that has a text expression. This can be absolutely any texts, correspondence, passwords, etc. The undoubted advantage is that this algorithm cannot be deciphered, since the developer simply did not provide such a function. Therefore, we can say with confidence that this method can really protect your information very well.

Where else can the MD5 algorithm be used?

There is an opinion that the use of this algorithm makes it possible to create fairly secure identifiers for pieces of information. This feature has been widely used in various fields. For example, by comparing MD5 sums of files, it becomes possible to find duplicate files on a computer. In this case, the contents of the files themselves are not used, the amount is simply checked. A striking example of such use of this algorithm can be considered the dupliFinder program, which was very widespread both in Windows and under Linux. In addition, the MD5 algorithm is often used to check the integrity of downloaded files from the Internet. It works very simply. A person who posts a link to download his file on the Internet includes the MD5 amount of this file in the description. And the person who downloads it checks whether the declared amount matches the one he received after downloading.

Previously, many Linux-based operating systems used this algorithm to store user passwords in encrypted form. Thus, it turned out that only the user himself knew the password, and the system checked it using the MD5 amount. Although there are many new encryption methods now available, this one is still used in many systems. Our text tool uses the same method. Most security experts agree that a password encrypted using the MD5 algorithm cannot be decrypted in any way. And there is only one way to hack it - by simply searching for words.

It is often necessary to find out a password with only a hash in hand. You can use your computer to sort through the options, but it’s much faster to use an existing database. Even public databases contain tens of millions of hash-password pairs, and searching them through a cloud service takes a matter of seconds.

There are several zettabytes of digital data in the world, but not all of this information is unique: repetitions are scattered across billions of media and servers. Regardless of the type of data, working with it requires solving the same fundamental problems. This is a reduction in redundancy due to partial elimination of repetitions (deduplication), integrity checking, incremental backups and user authorization. Of course, the last aspect interests us most, but all these techniques are based on general data processing methods using hashing. There are cloud services that allow you to use this procedure faster - for well-known purposes.

At first glance, it seems strange that different tasks use a common procedure for calculating and comparing checksums or hashes - bit sequences of a fixed length. However, this method is truly universal. Checksums serve as a kind of digital fingerprints of files, keys, passwords and other data, called messages in cryptography. Hashes (or digests) allow you to compare them with each other, quickly detect any changes and secure access checks. For example, using hashes you can check the consistency of entered passwords without transmitting them in clear text.

Mathematically, this process is performed by one of the hashing algorithms - iterative transformation of data blocks into which the original message is divided. The input can be anything from a short password to a huge database. All blocks are padded cyclically with zeros or truncated to a given length until a fixed-size digest is obtained.

Hashes are usually written in hexadecimal. This makes it much more convenient to compare them visually, and the recording is four times shorter than the binary one. The shortest hashes are obtained using Adler-32, CRC32 and other algorithms with a digest length of 32 bits. The longest ones are for SHA-512. In addition to these, there are a dozen other popular hash functions, and most of them are capable of calculating digests of intermediate lengths: 160, 224, 256 and 384 bits. Attempts to create a function with a longer hash length continue, since the longer the digest, the more different variants the hash function can generate.

The maximum amount of input data that a hash function can process is determined by the form of its presentation in the algorithm. They are typically written as a 64-bit integer, so the typical limit is 264 bits minus one, or two exabytes. Such a limitation does not yet have practical significance even for very large data centers.

Uniqueness is the key to reliability

The uniqueness of a hash is one of its key properties, which determines the cryptographic strength of the encryption system. The fact is that the number of possible password options is theoretically infinite, but the number of hashes is always finite, albeit very large. The digests of any hash function will be unique only to a certain extent. Powers of two, to be precise. For example, the CRC32 algorithm produces a set of only 232 options, and it is difficult to avoid repetition. Most other functions use 128-bit or 160-bit digests, which dramatically increases the number of unique hashes to 2'28 and 2,160 respectively.

The coincidence of hashes from different source data (including passwords) is called a collision. It can be random (found on large amounts of data) or pseudo-random - used for attack purposes. The collision effect is the basis for hacking various cryptographic systems - in particular, authorization protocols. All of them first calculate the hash of the entered password or key, and then transmit this digest for comparison, often mixing it with a portion of pseudo-random data at some stage, or use additional encryption algorithms to enhance security. The passwords themselves are not stored anywhere: only their digests are transmitted and compared. The important thing here is that after hashing absolutely any passwords with the same function, the output will always be a digest of the same and previously known size.

Pseudo-reverse

It is in principle impossible to carry out the reverse conversion and obtain the password directly from the hash, even if you clear it of salt, since hashing is a one-way function. Looking at the resulting digest, one cannot understand either the volume of the original data or its type. However, you can solve a similar problem: generate a password with the same hash. Due to the collision effect, the task is simplified: you may never find out the real password, but you will find a completely different one, which, after hashing using the same algorithm, gives the required digest.

Methods for optimizing calculations appear literally every year. They are carried out by teams from HashClash, Distributed Rainbow Table Generator and other international cryptographic computing projects. As a result, for every short combination of printable characters or variant from the list of typical passwords, hashes have already been calculated. They can be quickly compared with the intercepted one until a complete match is found.

Previously, this required weeks or months of processor time, which in recent years has been reduced to several hours thanks to multi-core processors and brute force in programs that support CUDA and OpenCL. Administrators load servers with table calculations during downtime, and someone rents a virtual cluster in Amazon EC2.

Google hash search

Not all services are ready to provide the service of searching passwords using hashes for free. Somewhere registration is required and a ton of advertising is running, and on many sites you can also find advertisements for a paid hacking service. Some of them actually use powerful clusters and load them, putting the sent hashes into the job queue, but there are also ordinary scoundrels. They perform free searches for money, taking advantage of the ignorance of potential clients.

Instead of advertising honest services here, I will suggest using a different approach - finding hash-password pairs in popular search engines. Their spider robots comb the web every day and collect new data, including the latest entries from rainbow tables.

So to get started, just write the hash in the Google search bar. If some dictionary password corresponds to it, then it will (as a rule) be displayed among the search results already on the first page. Single hashes can be Googled manually, but large lists will be more conveniently processed using the BozoCrack script

Search XOR calculate

Popular hashing algorithms work so fast that to date it has been possible to create hash-password pairs for almost all possible variants of short digest functions. In parallel, functions with a hash length of 128 bits or more have flaws in the algorithm itself or its specific implementations, which greatly simplifies hacking.

In the nineties, the MD5 algorithm, written by Ronald Rivest, became extremely popular. It has become widely used when authorizing users on websites and when connecting to client application servers. However, its further study showed that the algorithm is not reliable enough. In particular, it is vulnerable to pseudo-random collision attacks. In other words, it is possible to deliberately create another data sequence whose hash will exactly match the known one.

Since message digests are widely used in cryptography, in practice the use of the MD5 algorithm today leads to serious problems. For example, using such an attack, you can fake an x.509 digital certificate. It is also possible to forge an SSL certificate, allowing an attacker to pass off his fake as a trusted root certificate (CA). Moreover, in most sets of trusted certificates it is easy to find those that still use the MD5 algorithm for signing. Therefore, the entire public key infrastructure (PKI) is vulnerable to such attacks.

A grueling brute-force attack will only have to be carried out in the case of really complex passwords (consisting of a large set of random characters) and for hash functions with long digests (from 160 bits), which have not yet been found to have serious flaws. Today, a huge mass of short and dictionary passwords can be opened in a couple of seconds using online services.

Hash decryption online

So far, not all hash-password pairs can be found using online services and rainbow tables. However, short digest functions have already been defeated, and short and dictionary passwords are easy to detect even using SHA-160 hashes. Particularly impressive is the instant search for passwords using their digests using Google. This is the simplest, fastest and completely free option.