MD5 Generator

1. What is MD5?
2. Is the MD5 algorithm secure?
3. Current applications

    What is MD5?

The MD5 hashing algorithm is a one-way cryptographic function, meaning that whatever goes through it cannot be reversed, unlike encryption and encoding functions. MD5 accepts as input a string (series of characters) of any length and produces a 128-bit fixed-length digest value. It was initially designed by Ronald Rivest in 1991-1992 with the intention to be used as a cryptographic hash function. However, it was later discovered to have extensive vulnerabilities, therefore nowadays its use should be limited to that of an integrity checksum. The MD5 checksum can verify data integrity, but only against non-malicious corruption and errors (see "Is the MD5 algorithm secure?").

MD5 was detailed in RFC 1321 and the abbreviation "MD" stands for "Message Digest.". It is a successor of an earlier version: MD4.

To get an idea of how an MD5 generator works, take a look at this sentence:

The quick brown fox jumps over the lazy dog

Its MD5 hash is 9e107d9d372bb6826bd81d3542a419d6. Now, let's check how good the hashing algorithm is. If it is a good algorithm, changing even just one character, or adding or subtracting one character, should result in completely different MD5 checksums. And it does:

MD5 examples

Input	Checksum
The quick brown fox jumps over the lazy dog	9e107d9d372bb6826bd81d3542a419d6
The quick brown fox jumps over tha lazy dog	cf666d3ade1a6952fcb1d4fc58dd0e95
The quick-brown fox jumps over the lazy dog	b601d727a8a5e934a99fe89a93ea3e7c
The quick brown fox jumps over the lazy dogg	706d49104c4390b5147037e127399092
The quick brown fox jumps over th lazy dog	4de8b1f33b5688c511ff89f62c682753

The table was produced using our md5 generator and it is easily seen that even the most trivial change results in vastly different hashes.

The security of the MD5 has been severely compromised, with its weaknesses having been exploited in the field, most infamously by the Flame malware in 2012. The CMU Software Engineering Institute considers MD5 essentially "cryptographically broken and unsuitable for further use".[4] Despite this known vulnerability, MD5 remains in use

    Is the MD5 algorithm secure?

MD5 has not been considered secure for many years now, due to vast amounts of evidence with regards to its poor collision resistance. It's usage for storing passwords, in digital signatures, in verification of the authenticity of a document etc. is strongly discouraged. It is very easy nowadays to produce two files that produce the same MD5 checksum, as demonstrated by Wang & Yu in their 2005 paper appropriately titled "How to Break MD5 and Other Hash Functions" ^[1].

In that paper they demonstrated an approach which results in the ability to easily produce a collusion, that is: given some string, to find a string different than the first one that results in the same hash. This practically means that you can quickly substitute any content if the verification used relies solely on the generated checksum.

Certification Authorities that issue website security certificates (TLS certificates) have now stopped issuing certificates based on MD5 and modern browsers will reject certificates signed with that function as unsecure.

    Current applications

Despite it being demonstrably broken for applications in cryptography, it is still used in older software and website systems that have not been updated through the years. For example, it may still be used for storing hashed passwords. It has a legitimate use only as a checksum to verify that a file has not been broken due to errors in transmission or compression/decompression. Some software providers would post the MD5 checksum alongside the download links on their website, so once downloaded a user can calculate the checksum on his own machine, or by using an online md5 generator like ours, and then check if it matches against the one posted on the site. If there is a match, the file was not corrupted due to errors. It should be strongly noted that this does not protect against attacks, hacks, virus infections of the file, etc., though it might help in some cases.