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# How to check md5 hash via Total Commander + MD5 File Checker instruction

MD5 (Message Digest 5) is a 128-bit hash algorithm developed by Professor Ronald L. Rivest of the Massachusetts Institute of Technology (MIT) in 1991. Designed to create “fingerprints” or message digests of arbitrary length and subsequent verification of their authenticity.

The MD5 algorithm is vulnerable to some attacks, for example, it is possible to create two messages with the same hash sum, so its use is not recommended. An alternative is the SHA-2 family of algorithms.

## MD5 algorithm workflow

The input data stream, the hash of which must be found, is input to the algorithm. The message length can be any (including zero). Write the message length in L. This number is integer and non-negative. Multiplicity to any numbers is optional. After the data is received, the process of preparing the stream for calculations is in progress.

## Comparison of MD5 and MD4

The MD5 algorithm comes from MD4. Another round was added to the new algorithm, now there are 4 instead of 3 in MD4. We added a new constant in order to minimize the impact of the input message, in each round at each step and each time the constant is different, it is summed with the result F and the data block. The function G = XZ v (Y not (Z)) has been changed instead of (XY v XZ v YZ). The result of each step is added to the result of the previous step, because of this there is a more rapid change in the result. The procedure for working with input words in rounds 2 and 3 has changed.

## MD5 hashes

A hash contains 128 bits (16 bytes) and is usually represented as a sequence of 32 hexadecimal digits.

A few hash examples: `MD5("md5") = 1bc29b36f623ba82aaf6724fd3b16718`

Even a small change in the input message (in our case by one bit: the ASCII character “5” with the code 0x35 16 = 00011010 1 2 is replaced by the character “4” with the code 0x34 16 = 00011010 0 2 ) leads to a complete change in the hash. This property of the algorithm is called the avalanche effect.

`MD5("md4") = c93d3bf7a7c4afe94b64e30c2ce39f4f`

An example of an MD5 hash for a null string:

`MD5("") = d41d8cd98f00b204e9800998ecf8427e`

## How to check md5 Total Commander

The scope of the application of md5 hashing is quite wide, and here we will not breed blah blah on this topic, because we just want to know How to check md5 - the checksum and compare it.

If there is no way to use the utility, I think everyone has a total commander.

Select the necessary file for verification, then go File -> Calculate CRC amounts (SFV, MD5 format) ...

This window will pop up, check MD5, ok

Next to your file will be created another one with the same name and extension md5.

Select it and open it with the F3 key, we see the checksum. This is how you can test md5 with Total Commander.

## Brief instructions for working with the MD5 File Checker program

To make sure that the downloaded file is identical to the file on the server, you need to compare their checksums. For this purpose, you can use the md5 checksum calculation algorithm.

When you add a cartoon to the server, this very checksum is calculated, you can see it on the cartoon information page.

To calculate this checksum for the downloaded file on your computer, use the special MD5 File Checker program.

The program does not require installation. For users of the operating systems Linux, Unix, MacOS and others - see similar programs directly as part of your OS.

Run the program. On the page with any cartoon in the cartoon information block, we find the field with the md5 checksum and copy it to the clipboard.

• We insert in the field for verification No. 2.
• Select the file that we want to check in field No. 1.
• Click the "Check" button.
• As a result, we get a message with the result of the program.

For example, "MD5 file sum matches the checksum - everything is OK.

File is not damaged "or" MD5 file sum does not match checksum. The file may be corrupted. "We draw conclusions.

An additional feature of the program is the calculation of the md5 checksum for an arbitrary file and its output to the user.