Hash Generator

What is a Hash Function?

A hash function is a mathematical algorithm that transforms any input data into a fixed-length string called a hash or digest. Hash functions are fundamental to modern computing, appearing in data integrity checks, cryptography, digital signatures, and password storage.

Key properties of a cryptographic hash function:

• Deterministic: The same input always produces the same output
• Fixed-length output: Regardless of input size, the output is always the same length
• One-way: It is computationally infeasible to reverse the hash back to the original input
• Avalanche effect: A small change in the input produces a completely different hash

MD5: Message Digest Algorithm 5

MD5 produces a 128-bit (32 hexadecimal characters) hash value. Developed by Ronald Rivest in 1991, MD5 was originally designed for cryptographic use. However, security vulnerabilities were discovered that make it unsuitable for cryptographic security.

Common uses of MD5 today: file integrity verification, detecting duplicate files, non-security-critical data fingerprinting, and legacy system compatibility.

SHA-256: Secure Hash Algorithm

SHA-256 is part of the SHA-2 family, producing a 256-bit (64 hexadecimal characters) hash. It is the industry standard for cryptographic security.

When to use SHA-256: password hashing, digital signatures, certificate fingerprinting, blockchain, and security-sensitive data integrity.

SHA-512 for Maximum Security

SHA-512 produces a 512-bit (128 hexadecimal characters) hash. It offers the highest security level among the supported algorithms.

File Integrity Checking

Hash generators are essential for verifying file integrity. When you download software, the developer publishes the expected hash. You can use this tool to hash the downloaded file and compare it with the published hash.

HMAC: Hash-based Message Authentication Code

HMAC combines a hash function with a secret key to provide both data integrity and authentication. Common uses: API authentication, JWT token generation, webhook signature verification.

Note: HMAC-MD5 is not supported in browsers because the Web Crypto API excludes MD5 from key operations.

Frequently Asked Questions

Is this hash generator private? Yes. All hash computation happens entirely in your browser using the Web Crypto API. No data is sent to any server.

What is the difference between MD5 and SHA-256? MD5 produces a 128-bit hash and is not cryptographically secure. SHA-256 produces a 256-bit hash and is cryptographically secure.

Can I reverse a hash? No. Hash functions are designed to be one-way. You cannot reverse a hash to get the original input.

Why does changing one character change the entire hash? This is the avalanche effect, a core property of good hash functions.