HMAC uses a secret key to create authenticated hash signatures
SHA-256 is my go-to hashing algorithm when security actually matters—unlike MD5, it's still cryptographically secure and widely used in production systems. I use it daily for password hashing (combined with salt), generating API signatures, creating commit hashes in version control, and blockchain applications. Part of the SHA-2 family, SHA-256 produces a 256-bit (64-character hex) hash that's virtually collision-resistant with current computing power. It's the standard for TLS/SSL certificates, Bitcoin mining, and secure authentication systems. This tool generates SHA-256 hashes client-side, but remember: for password storage, you still need proper salting and stretching—use bcrypt, argon2, or PBKDF2, not raw SHA-256.
Use Cases in Engineering
- File integrity verification - verify downloaded files match official hashes
- API signing & security - OAuth PKCE, AWS Signature, webhook signatures
- Blockchain & Web3 - Bitcoin block hashing, Merkle tree, address generation
- Deduplication - compare files to check if they are identical
- Debugging & testing - quick hashing for API payloads or specific strings
How to Use This Tool
- Enter text in the input field - hash appears automatically
- Or upload a file - file hash appears automatically
- Select input or output encoding if needed
- Enable HMAC if you need key-based signatures
- Copy the hash result via the copy button
🔒 Privacy & Security
All processing is done entirely in your browser. No data is sent to the server. Your files and text remain completely private.
⚠️ Important Note
For password storage, use bcrypt, argon2, or PBKDF2 instead of raw SHA-256. SHA-256 alone is not suitable for password hashing without proper salting and key stretching.
SHA-256 is my go-to hashing algorithm when security actually matters—unlike MD5, it's still cryptographically secure and widely used in production systems. I use it daily for password hashing (combined with salt), generating API signatures, creating commit hashes in version control, and blockchain applications. Part of the SHA-2 family, SHA-256 produces a 256-bit (64-character hex) hash that's virtually collision-resistant with current computing power. It's the standard for TLS/SSL certificates, Bitcoin mining, and secure authentication systems. This tool generates SHA-256 hashes client-side, but remember: for password storage, you still need proper salting and stretching—use bcrypt, argon2, or PBKDF2, not raw SHA-256.
How to Use
Enter text or upload a file in the input panel. The tool instantly generates a 64-character hexadecimal SHA-256 hash. For text: useful when creating API request signatures, generating deterministic IDs from content, or hashing configuration data. For files: verify downloads by comparing generated hash with official checksums, detect file modifications, or create content-addressed storage keys. The hash is deterministic (same input = same output) and one-way (cannot reverse the hash to get original data). Performance: handles files up to ~100MB in browser; for larger files use command-line tools like shasum -a 256 (Mac/Linux) or certutil -hashfile [file] SHA256 (Windows).
Common Use Cases & Examples
**Download Verification**: Download software, generate SHA-256 hash, compare with vendor-published hash to ensure authenticity and detect tampering. **API Request Signing**: Create HMAC-SHA256 signatures for AWS, Stripe, or webhook authentication: hash(secret + request_body) proves request authenticity. **Git Commit Hashes**: Git uses SHA-256 (transitioning from SHA-1) to identify commits—understanding hashing helps debug merge conflicts. **Password Storage (with salt)**: Hash passwords with unique salt before storage: `SHA256(password + random_salt)` then store both hash and salt (but use bcrypt in production). **Blockchain/Cryptocurrency**: Bitcoin addresses and block hashes use SHA-256—useful for understanding crypto fundamentals. **Content Deduplication**: Hash file content to detect duplicates in storage systems without comparing entire files.
Limitations & Important Notes
While SHA-256 is cryptographically secure for integrity and signatures, **DO NOT use raw SHA-256 for password hashing** in production. It's too fast—attackers can compute billions of hashes per second with GPUs. Use purpose-built password hashing functions like bcrypt, argon2, or PBKDF2 which include salting and key stretching. For API signatures, always use HMAC-SHA256 (hash with secret key) not plain SHA-256. Browser performance: large files (>100MB) may cause slowdowns or memory issues—use command-line tools for batch processing. SHA-256 is deterministic and one-way: (1) same input always produces same output (good for caching, bad for password storage without salt), (2) cannot reverse hash to retrieve original data. For compliance: some regulations (e.g., FIPS 140-2) require specific hash implementations—verify your crypto library is certified if needed.
// Node.js SHA-256 example
const crypto = require('crypto');
// Generate SHA-256 hash
const hash = crypto.createHash('sha256')
.update('Hello World')
.digest('hex');
console.log(hash);
// Generate HMAC-SHA256
const hmac = crypto.createHmac('sha256', 'secret-key')
.update('Hello World')
.digest('hex');
console.log(hmac);