SHA-256 is the most widely used cryptographic hash algorithm in the world: digital signatures, TLS certificates, Bitcoin blockchain, file integrity verification and password storage (combined with bcrypt or argon2). Generating a SHA-256 hash online is useful for testing, verifying or learning.
SHA-256 (Secure Hash Algorithm 256 bits) is a cryptographic hash function that transforms any input into a 256-bit (32-byte) fingerprint, represented in hexadecimal as 64 characters. The function is one-way (irreversible), deterministic (same input = same hash) and collision-resistant (two different inputs produce different hashes with astronomical probability).
📐 Formula
SHA-256(message) → 64-character hexadecimal fingerprint
📊 Reference table
| Input | SHA-256 hash (64 hex characters) |
|---|---|
| "hello" | 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 |
| "Hello" | 185f8db32921bd46d35cc2e58658cf4f0c80a6b1b2f3ff6f5a8c4b5a2e8a6735 |
| "" (empty) | e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 |
| "ToolSmartly" | unique 64-character hash |
💡 Practical examples
Example 1: verify the integrity of a downloaded file
Download sites publish the SHA-256 of the file. Download the file, calculate its hash with the tool and compare: if identical, the file has not been altered.
Example 2: hash a password for testing
SHA-256("mypassword") always produces the same hash. Useful for testing a password verification implementation or an authentication system.
Example 3: create a unique identifier
SHA-256 of a combination of timestamp + userId + randomSalt generates a unique and unpredictable transaction identifier for your APIs.