How do I use the Keccak256 hasher?

Enter your input as UTF-8 text or a hex string. The tool will instantly generate the Keccak256 hash, compatible with Solidity's keccak256() function.

Is my input data stored or sent to a server?

No. All hashing is performed locally in your browser for maximum privacy and security.

What is the difference between UTF-8 and Hex input modes?

UTF-8 mode hashes plain text directly. Hex mode expects hex-encoded data (starting with 0x). The hash output depends on the encoding.

When should I use the Keccak256 hasher?

Use it to compute Solidity-compatible hashes for event topics, function selectors, or any keccak256 value during development or debugging.

Why does my hash differ from Solidity?

Ensure input encoding matches: Solidity's keccak256(abi.encodePacked(...)) may differ from raw UTF-8 or hex. Use the same encoding as in your contract.

Keccak256 Hasher

Generate keccak256 hash online instantly. Solidity compatible hashing for Ethereum smart contract development. UTF-8 text and hex input modes.

Read the guide

Hash Input

Hashing is performed using keccak256 (SHA-3 variant used in Solidity).

Input Mode

Enter text to hash

Auto-hash on typing (debounced 300ms)

What is Keccak256?

Keccak256 is a cryptographic hash function that's part of the SHA-3 family. It's the standard hash algorithm used in Ethereum smart contracts via Solidity's keccak256() function. It produces a 256-bit (32-byte) hash output regardless of input size.

Why Keccak256?

•Ethereum Standard: Official hashing algorithm for Solidity contracts
•Deterministic: Same input always produces identical hash
•One-way: Impossible to reverse engineer input from hash
•Collision Resistant: Extremely unlikely two inputs produce same hash

Common Use Cases

•Creating unique identifiers in smart contracts
•Verifying data integrity and authenticity
•Implementing commit-reveal schemes
•Generating merkle trees for efficient verification
•Storing passwords securely (though bcrypt is better)

Solidity Example

Here's how keccak256 is commonly used in smart contracts:

// Hash a single value
bytes32 hash = keccak256(abi.encodePacked("hello"));

// Hash multiple values
bytes32 hash = keccak256(abi.encodePacked(
  address(0x123...),
  uint256(42),
  string("data")
));

// Commit-reveal pattern
bytes32 commitment = keccak256(abi.encodePacked(secret, nonce));

Keccak256 vs SHA-256

While both are 256-bit hash functions, Keccak256 is Ethereum's choice for smart contract development, while SHA-256 is used in Bitcoin and general cryptography.

Keccak256 offers superior security properties under certain conditions and better aligns with Ethereum's design goals.

Input Modes

UTF-8 Text: Hash plain text directly (e.g., "hello")

Hex String: Hash hex-encoded data (e.g., 0x68656c6c6f for "hello")

Frequently Asked Questions

Keccak256 is a cryptographic hash function used in Ethereum for hashing data, generating unique identifiers, and ensuring data integrity in smart contracts.

Related Tools

// Hash a single value bytes32 hash = keccak256(abi.encodePacked("hello")); // Hash multiple values bytes32 hash = keccak256(abi.encodePacked( address(0x123...), uint256(42), string("data") )); // Commit-reveal pattern bytes32 commitment = keccak256(abi.encodePacked(secret, nonce));

Frequently Asked Questions

Keccak256 is a cryptographic hash function used in Ethereum for hashing data, generating unique identifiers, and ensuring data integrity in smart contracts.