Skip to content

Latest commit

 

History

History
69 lines (43 loc) · 4.66 KB

md5_hash.md

File metadata and controls

69 lines (43 loc) · 4.66 KB
Raw

Cross-platform cryptography

MD-5 hash of a string

Hashing of data is one of the most function used when working with cryptographic.

What is a hash?

The hash of data is often described as "fingerprint" of the data as the result is a kind of "checksum" that is characteristic for the data. An other name for a hash is a trapdoor as there should be no way back meaning: with having a hash value it should not been able to get the data back or even think what data was used as input.

How secure is a hash?

Very import for hash function is it to change a lot of bytes even when just 1 byte of the plaintext changes. As hashes are very often used in combination with digital signatures it is most important that you cannot create a changed or second document that gets the same hash. This article describes the unsecure hash algorithm MD-5 - please don't use it ever! Visit the website https://natmchugh.blogspot.com/2015/02/create-your-own-md5-collisions.html and see the two pictures - one is a crashing plane and the other is the wrack of a sunken ship - both have the same MD-5 hash.

Why is MD-5 still in use?

In "old days" the AES-128 algorithm was used very often and needs a 128/8 = 16 bytes long key and initialization vector and the MD-5 algorithm has an output of 16 bytes - perfect for a "poor man's key derivation".

Is this password derivation secure?

Just a simple answer: no, MD-5 is BROKEN and UNSECURE.

What is a secure hash algorithm?

As date of writing a SHA-256 is secure enough but if possible you should change to the SHA-3-variants as they are more secure and faster.

⚠️ Security warning ⚠️

Please use this function only for migration and not for actual (new written) software projects as it is UNSECURE.

⚠️ Security warning ⚠️

This is a serious warning regarding the security of the programs shown in these article series. Always keep in mind my disclaimer regarding my programs: All programs are for educational purposes and are not intended to use in production or any other programs where a secure solution is needed. The programs do not have proper exceptional/error handling and in some cases they use insecure key lengths or other methods that are insecure. Never ever use the programs in real life unless checked by a qualified professional cryptographer.

The following links provide the solution in code and an online compiler that runs the code.

Language available Online-compiler
Java ✅ replit.com CpcJavaGenerateMd5#Main.java
PHP ✅ replit.com CspPhpGenerateMd5
C# ✅ replit.com CpcCsharpGenerateMd5#main.cs
Javascript CryptoJs ✅ replit.com CpcCryptoJsGenerateMd5
NodeJS Crypto ✅ replit.com CpcNodeJsGenerateMd5#index.js
NodeJS forge ✅ replit.com CpcNodeJsGenerateMd5#index.js
Python ✅ replit.com CpcPythonGenerateMd5#main.java
Go ✅ replit.com CpcGoGenerateMd5#main.java
Dart *1) ✅ no online compiler available

*1) you need the external library pointycastle version 3.1.1

This is an output:

Generate a MD5 hash

# # # SECURITY WARNING: This code is provided for achieve    # # #
# # # compatibility between different programming languages. # # #
# # # It is NOT SECURE - DO NOT USE THIS CODE ANY LONGER !   # # #
# # # The hash algorithm MD5 is BROKEN.                      # # #
# # # DO NOT USE THIS CODE IN PRODUCTION                     # # #

plaintext:                The quick brown fox jumps over the lazy dog
md5Value (hex) length: 16 data: 9e107d9d372bb6826bd81d3542a419d6

Last update: Oct. 18th 2021

Back to the main page: readme.md