Go-ethereum: how to check an eth address is valid ?

[xuzhiping7]

i haven't found the api to check an eth-address is valid ~

have the func like bitcoin-core of "bool ValidateAddress(address)" ?

[karalabe]

Ethereum addresses are plain 20 bytes, anything can be in them. Since it's hard to reason about them, programs represent them as 40 character long hex strings. So every 0x<40 hex character> is a valid Ethereum address.

[karalabe]

In the Geth 1.5 codebase if you create a common.Address form a hex string I'd imagine it would validate it's length.

[xuzhiping7]

ok ~ i see

[xuzhiping7]

hello karalabe ~

i sent some eth to an address of "0x4961aC1d43B6249bc998D611F33d42B54E31712E"

why it return me the error msg :

error":{"code":-32602,"message":"Invalid address length, expected 40 got 41 bytes"}}

i can check this address on chain:
https://etherchain.org/account/0x4961aC1d43B6249bc998D611F33d42B54E31712E%20

[karalabe]

The link you sent contains a space at the end (encoded %20). Perhaps you also inserted a space at the end of the address?

[xuzhiping7]

oh ~~ i know ~~thanks again .

i would have a try ~!

[qyvlik]

Use this ^0x[a-fA-F0-9]{40}$

please use the CRC to check the eth address: https://gist.github.com/adyliu/6c5ff4d41aa0177da55f4b8b1703f54a

thx @adyliu

[TriAnMan]

@xuzhiping7 you can validate an CRC for your address
https://github.com/ethereum/EIPs/blob/master/EIPS/eip-55.md

[raisty]

Nice module: https://github.com/cilphex/ethereum-address/blob/master/index.js

[adyliu]

Java checker of ethereum address
https://gist.github.com/adyliu/6c5ff4d41aa0177da55f4b8b1703f54a

[huahuayu]

hey you guys, do you have golang eip55 implement to check address? in the eip55 readme page, only list python js swift implement, no golang implement been found.

Then I search in go ethereum codebase only find below code which is to generate an eip55 compliant hex address but doesn't provide the method to verify the address.

// Hex returns an EIP55-compliant hex string representation of the address.
func (a Address) Hex() string {
    unchecksummed := hex.EncodeToString(a[:])
    sha := sha3.NewKeccak256()
    sha.Write([]byte(unchecksummed))
    hash := sha.Sum(nil)

    result := []byte(unchecksummed)
    for i := 0; i < len(result); i++ {
        hashByte := hash[i/2]
        if i%2 == 0 {
            hashByte = hashByte >> 4
        } else {
            hashByte &= 0xf
        }
        if result[i] > '9' && hashByte > 7 {
            result[i] -= 32
        }
    }
    return "0x" + string(result)
}

there's another code snippet in types.go which I think is as same as ^0x[a-fA-F0-9]{40}$

// IsHexAddress verifies whether a string can represent a valid hex-encoded
// Ethereum address or not.
func IsHexAddress(s string) bool {
    if hasHexPrefix(s) {
        s = s[2:]
    }
    return len(s) == 2*AddressLength && isHex(s)
}

@qyvlik @adyliu