SHA-256 Hash Generator
Generate SHA-256 hashes from text or hex input using the Web Crypto API. Compare SHA-256 with Keccak256 for Ethereum development.
Common Examples
About SHA-256
SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function from the SHA-2 family, designed by the NSA and published by NIST. It produces a fixed 256-bit (32-byte) hash from any input.
SHA-256 is widely used in security applications, TLS/SSL certificates, digital signatures, and blockchain technology. Bitcoin uses SHA-256 for its proof-of-work mining algorithm, while Ethereum uses Keccak256 (a different SHA-3 candidate).
This tool uses the native Web Crypto API (crypto.subtle.digest) for computation, which runs entirely in your browser. No data is sent to any server.
How to Use This SHA-256 Hash Generator
This tool computes SHA-256 cryptographic hashes instantly in your browser using the Web Crypto API. No data is sent to any server, ensuring complete privacy for sensitive inputs.
- Enter your input — type or paste the text you want to hash into the input field. You can also switch to hex mode to hash raw byte sequences.
- View the hash — the SHA-256 hash is computed in real time as you type. The output is displayed as a 64-character hexadecimal string.
- Copy the result — click the copy button to copy the hash to your clipboard for use in your application, terminal, or documentation.
The hash is deterministic: the same input always produces the same output. Even a single-character change in the input produces a completely different hash, which is the avalanche effect that makes SHA-256 useful for data integrity checks.
Common Use Cases
- File integrity verification — Compare SHA-256 checksums to verify that downloaded files have not been tampered with or corrupted during transfer.
- Bitcoin and blockchain — Understand how Bitcoin uses double-SHA-256 for proof-of-work mining, transaction IDs, and Merkle tree construction.
- Password hashing — SHA-256 is used as a building block in password hashing schemes like PBKDF2, which derives cryptographic keys from passwords.
- Digital signatures — Hash a document or message before signing it with RSA or ECDSA to create a fixed-length digest for efficient signature computation.
- Data deduplication — Generate content-based identifiers by hashing file contents to detect duplicates without comparing raw data.
Related Tools
Keccak-256 Hash Generator
Generate Keccak-256 hashes used in Ethereum for addresses, transaction hashes, and smart contract storage.
MD5 Hash Generator
Generate MD5 hashes for checksums, fingerprinting, and legacy system compatibility.
What Is Keccak-256? (Guide)
Learn how Keccak-256 works, why Ethereum chose it over SHA-256, and its role in the EVM.
Frequently Asked Questions
What is SHA-256?
SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that produces a fixed 256-bit (32-byte) hash value. It is part of the SHA-2 family designed by the NSA and is widely used in Bitcoin, SSL certificates, and data integrity verification.
What is the difference between SHA-256 and MD5?
SHA-256 produces a 256-bit hash while MD5 produces a 128-bit hash. SHA-256 is cryptographically secure and collision-resistant, whereas MD5 has known vulnerabilities and should not be used for security purposes. SHA-256 is slower but far more secure.
What is the difference between SHA-256 and Keccak-256?
Both produce 256-bit hashes, but they use different algorithms. SHA-256 is used in Bitcoin and TLS, while Keccak-256 is used in Ethereum for address generation, transaction hashing, and the EVM. Keccak-256 was selected as the basis for the SHA-3 standard.
Is SHA-256 secure?
Yes. SHA-256 is considered cryptographically secure as of today. No practical collision attacks or preimage attacks have been found. It is used to secure billions of dollars in Bitcoin and is recommended by NIST for sensitive applications.
How is SHA-256 used in Bitcoin?
Bitcoin uses double SHA-256 (SHA-256 applied twice) for block header hashing, proof-of-work mining, transaction IDs, and Merkle tree construction. Miners compete to find a hash below a target difficulty by varying the block nonce.
How long is a SHA-256 hash?
A SHA-256 hash is always 256 bits, which is 32 bytes. When represented as a hexadecimal string, it is exactly 64 characters long regardless of the input size.
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