Scripthash from bitcoin address with Golang

Question

I broke my head looking for a solution.
I want use bitcoin address for electrumx

Take bitcoin address from docs example: 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
And i need convert to 8b01df4e368ea28f8dc0423bcf7a4923e3a12d307c875e47a0cfbf90b5c39161

Example from docs https://electrumx.readthedocs.io/en/latest/protocol-basics.html#script-hashes

For example, the legacy Bitcoin address from the genesis block:
1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa

has P2PKH script:
76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac

with SHA256 hash:
6191c3b590bfcfa0475e877c302da1e323497acf3b42c08d8fa28e364edf018b

which is sent to the server reversed as:
8b01df4e368ea28f8dc0423bcf7a4923e3a12d307c875e47a0cfbf90b5c39161

By subscribing to this hash you can find P2PKH payments to that address.

my code:

func AddressToScriptHex(addressStr string) string {
    address, err := btcutil.DecodeAddress(addressStr, &chaincfg.MainNetParams)
    if err != nil {
        return ""
    }
    script, err := txscript.PayToAddrScript(address)
    if err != nil {
        return ""
    }
    return fmt.Sprintf("%x", script)
}

func TestBtcUtil_AddressToScriptHex(t *testing.T) {
    addressStr := "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"
    scriptHex := "76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac"

    assert.Equal(t, AddressToScriptHex(addressStr), scriptHex)
}

func TestBtcUtil_ScriptHexToSHA256(t *testing.T) {
    scriptHex := "76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac"
    exampleHash := "6191c3b590bfcfa0475e877c302da1e323497acf3b42c08d8fa28e364edf018b"
    sha256 := sha256.New()
    sha256.Write([]byte(scriptHex))

    actual := fmt.Sprintf("%x", sha256.Sum(nil))

    assert.Equal(t, exampleHash, actual) // ERROR
}

why actual != example

---

i was find other question, but they use other language ScriptHash from bitcoin address with BitcoinJS

Help me please

Answer 1

Change

sha256.Write([]byte(scriptHex))

to

s, err := hex.DecodeString(scriptHex)
if err != nil {
    log.Fatal(err) // or t.Fatalf(...) in unit test 
}
sha256.Write(s)

You must hash the binary data, not the hex string representation of it

See https://go.dev/play/p/iKHNKy118zd