Keccak-256 Hash Generator
Compute Keccak-256 hashes for text or hex data, with function selector and address extraction
⚠️ Keccak-256 vs SHA-3-256
Keccak-256 is NOT the same as SHA-3-256 (NIST standard). Ethereum uses the original Keccak-256 algorithm. The final step padding differs: Keccak uses 0x01, while SHA-3 uses 0x06. Always use Keccak-256 for Ethereum.
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What is this tool?
The Keccak-256 Hash Generator computes Ethereum-compatible Keccak-256 hashes from arbitrary text or hex input. It also extracts the 4-byte function selector (first 4 bytes of the hash) and formats the hash as an Ethereum address. Essential for smart contract development, function signature identification, and blockchain data verification.
How to use
- 1
Enter input text or hex
Type plain text (e.g., a function signature) or paste hex data to hash.
- 2
View hash output
See the full Keccak-256 hash, 4-byte function selector, and formatted Ethereum address.
- 3
View results
Review the output.
Frequently Asked Questions
Is Keccak-256 the same as SHA-3?
No—Ethereum uses the original Keccak algorithm, not the NIST-standardized SHA-3. They differ in the padding scheme. Always use Keccak-256 for Ethereum-related hashing.
What is a 4-byte selector used for?
The first 4 bytes of a Keccak-256 hash of a function signature serve as the function selector in smart contract calls. For example, transfer(address,uint256) has selector 0xa9059cbb.
Can I reverse a hash?
No—hash functions are one-way by design. You cannot derive the original input from the hash output. This one-way property is fundamental to blockchain security.