🔒 Hash Generator
A hash function is a one-way cryptographic algorithm that converts any input (text, file, etc.) into a fixed-length string of characters called a "hash" or "digest." The same input always produces the same hash, but even a tiny change creates a completely different hash.
Key Properties:
- Deterministic: Same input always produces the same hash
- One-way: Cannot reverse a hash to get the original input
- Avalanche Effect: Small input change = completely different hash
- Fixed Length: Output is always the same length regardless of input size
- Collision Resistant: Nearly impossible to find two inputs with the same hash
📚 Hash Algorithms Explained
MD5 (Message Digest 5): Produces a 128-bit (32 character) hash. Fast but cryptographically broken—not secure for passwords or security purposes. Still used for checksums and non-security applications.
SHA-1 (Secure Hash Algorithm 1): Produces a 160-bit (40 character) hash. Deprecated for security use due to collision vulnerabilities. Being phased out across the industry.
SHA-256 (SHA-2 family): Produces a 256-bit (64 character) hash. Currently secure and widely used for digital signatures, SSL certificates, blockchain, and password storage (with salt).
SHA-512 (SHA-2 family): Produces a 512-bit (128 character) hash. Even more secure than SHA-256, used for high-security applications and longer-term data protection.
- Don't use MD5 or SHA-1 for security: These are cryptographically broken
- Hashing ≠ Encryption: Hashes cannot be reversed (that's the point!)
- Password Storage: Always add a unique "salt" before hashing passwords
- Use Purpose-Built Functions: For passwords, use bcrypt, scrypt, or Argon2 instead of plain SHA
Input Length: 0 characters
💡 Common Use Cases
- File Integrity: Verify downloaded files haven't been tampered with
- Password Storage: Store password hashes instead of plaintext (with proper salting)
- Digital Signatures: Verify authenticity of documents and software
- Blockchain: Link blocks together and ensure immutability
- Data Deduplication: Identify duplicate files without comparing entire contents
- Checksums: Detect accidental data corruption during transmission
🔬 Try It Yourself
Experiment: Hash the word "hello" then hash "Hello" (capital H). Notice how one character change creates a completely different hash!
Fun Fact: Bitcoin uses SHA-256 hashing. Miners compete to find a hash that starts with a certain number of zeros—requiring trillions of attempts!