Keccak256 Hasher

Generate Solidity-compatible keccak256 hash instantly. Supports UTF-8 text and hex string input modes.

Hash Input

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

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