Hashing Utilities
Cryptographic hashing functions used throughout Ethereum
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Cryptographic hashing functions used throughout Ethereum
Cryptographic hashing functions used throughout Ethereum.
The primary hash function used in Ethereum:
1import "github.com/ChefBingbong/viem-go/utils/hash"2
3// Hash bytes4h := hash.Keccak256([]byte("hello"))5fmt.Printf("0x%x\n", h)6// 0x1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8Standard SHA-256 hash:
1h := hash.Sha256([]byte("hello"))2fmt.Printf("0x%x\n", h)3// 0x2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824RIPEMD-160 hash (used in Bitcoin addresses):
h := hash.Ripemd160([]byte("hello"))
fmt.Printf("0x%x\n", h)
// 0x108f07b8382412612c048d07d13f814118445acd
Hash a message for EIP-191 personal sign:
1import "github.com/ChefBingbong/viem-go/utils/signature"2
3// This prepends "\x19Ethereum Signed Message:\n" + length4messageHash := signature.HashMessage("Hello, Ethereum!")5fmt.Printf("0x%x\n", messageHash)The message hash is computed as:
keccak256("\x19Ethereum Signed Message:\n" + len(message) + message)
Hash EIP-712 typed structured data:
1import "github.com/ChefBingbong/viem-go/utils/signature"2
3typedData := signature.TypedDataDefinition{4 Domain: signature.TypedDataDomain{5 Name: "My App",6 Version: "1",7 ChainId: big.NewInt(1),8 },9 Types: map[string][]signature.TypedDataField{10 "Message": {11 {Name: "content", Type: "string"},12 },13 },14 PrimaryType: "Message",15 Message: map[string]any{16 "content": "Hello!",17 },18}19
20hash, err := signature.HashTypedData(typedData)21fmt.Printf("0x%x\n", hash)Get the 4-byte function selector:
1selector := hash.ToFunctionSelector("transfer(address,uint256)")2fmt.Printf("0x%x\n", selector)3// 0xa9059cbbGet the event topic hash:
1topic := hash.ToEventSelector("Transfer(address,address,uint256)")2fmt.Printf("%s\n", topic.Hex())3// 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3efCheck if a value is a valid hash:
1valid := hash.IsHash("0x1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8")2fmt.Println(valid) // true3
4invalid := hash.IsHash("0x123") // Too short5fmt.Println(invalid) // false// Check if code exists at address
code, _ := client.GetCode(ctx, address)
codeHash := hash.Keccak256(code)
fmt.Printf("Code hash: 0x%x\n", codeHash)
// Create unique ID from components
id := hash.Keccak256(append(
address.Bytes(),
big.NewInt(timestamp).Bytes()...,
))
// Hash the message the same way it was signed
messageHash := signature.HashMessage(originalMessage)
// Recover the signer
recovered, _ := signature.RecoverAddress(messageHash, sig)
// Verify it matches expected signer
if recovered != expectedSigner {
return errors.New("invalid signature")
}