HMAC MD5 Hash Generator

What is HMAC MD5?

HMAC MD5 is a cryptographic hashing technique that combines the MD5 hash function with a secret key to create a unique digital signature of a message. While MD5 alone is not secure for hashing passwords or storing sensitive data, using it in HMAC form is still viable for message verification where speed is important, and moderate security is acceptable.

How Does HMAC MD5 Work?

HMAC MD5 works by applying the HMAC construction to the MD5 algorithm:

1. Normalize the Secret Key:

   
   

   • If longer than 64 bytes, hash it.

   • If shorter, pad it with zeros.

   
   

2. Prepare Inner and Outer Padding:

   
   

   • ipad = 0x36 repeated

   • opad = 0x5C repeated

   
   

3. Apply Two-Step Hashing:

   
   
   

   inner = MD5((key ⊕ ipad) || message)
   final = MD5((key ⊕ opad) || inner)

   
   The output is a 128-bit (32-character hexadecimal) digest.

Use This Tool With Other Qodex Utilities:

• Base64 Encoder – Convert HMAC MD5 output to base64 for headers or URLs

• URL Encoder – Encode signed query parameters safely

• MD5 Hash Generator – Compare simple MD5 vs HMAC MD5

• HMAC SHA-256 Generator – For enhanced security when needed

Practical Examples

Example 1: Signing a REST API Request

Message:

action=delete-user&id=9841

Secret Key:

mySecretKey

Generated HMAC MD5:

a192c2cf8c2068c9f58c26b2d80bd3c3

This hash can be included in headers for signature verification on the server.

Example 2: Protecting Form Submission Data

You can hash form data (like username/email) along with a shared secret to ensure no one tampers with it between client and server.

Example 3: File Integrity Check

Generate an HMAC MD5 of file content with a known key. If the file is changed in any way, the hash won’t match when revalidated.

Sample Code – HMAC MD5 in Python

import hmac
import hashlib

def hmac_md5(key, message):
    return hmac.new(key.encode(), message.encode(), hashlib.md5).hexdigest()

print(hmac_md5("mySecretKey", "action=delete-user&id=9841"))

Why Use HMAC MD5?

Pro Tips

• Avoid using HMAC MD5 for password storage; use it only for integrity verification.

• Combine it with Base64 Encoder to transmit hashes in JSON or URLs.

• For more secure applications, consider HMAC SHA-1 or HMAC SHA-256.

• MD5 produces a 32-character digest, so always validate the length during implementation.

• Always keep your secret key securely stored (e.g., in environment variables, not front-end code).