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How to query fio.address tables using a hash

Getting FIO addresses or names from the address tables using an i128 hash


The hash is a truncated sha1 hash, in big-endian order, as a hex-string.

  1. calculate the sha1 sum of the address
  2. take the first 16 bytes
  3. reverse the byte order
  4. convert to a hexadecimal string, and prepend "0x"

Example for "test@fiotestnet"

  • sha1 hash: 58df646ca7a4c9be1e1436b9ae1608eb62e653a0
  • first 16 bytes: 58df646ca7a4c9be1e1436b9ae1608eb
  • reverse byte order (big endian): eb0816aeb936141ebec9a4a76c64df58
  • prepend 0x

Examples of generating the hash


function nameHash(name) {
    const hash = require('crypto').createHash('sha1')
    return '0x' + hash.update(name).digest().slice(0,16).reverse().toString("hex")

// outputs: 0xeb0816aeb936141ebec9a4a76c64df58
console.log( nameHash('test@fiotestnet') )

browser-friendly javascript

const encoded = new TextEncoder().encode("test@fiotestnet")
// get a sha-1 hash of the value
crypto.subtle.digest("SHA-1", encoded).then( hash => {

  // take the first 16 bytes of the hash, and convert to big-endian
  const hashArray = Array.from(new Uint8Array(hash)).slice(0,16).reverse()

  // convert to a string with '0x' prefix
  const hashHex = '0x' + => b.toString(16).padStart(2, '0')).join('')

  // outputs: 0xeb0816aeb936141ebec9a4a76c64df58


An example that could work from a shell script. Note: this requires xxd which may not be installed on some systems, it is usually part of the vim package.

HASH="0x$(echo -n ${DOMAIN}| openssl sha1 -binary | LC_ALL=C rev |xxd -p | cut -c 9-40)"

# prints: 0xeb0816aeb936141ebec9a4a76c64df58
echo "${HASH}"


package main

import (
	"crypto/sha1" // #nosec

// I128Hash hashes a string to an i128 database value, often used as an index for a string in a table.
// It is the most-significant 16 bytes in big-endian of a sha1 hash of the provided string, returned as a hex-string
func I128Hash(s string) string {
	sha := sha1.New() // #nosec
	_, err := sha.Write([]byte(s))
	if err != nil {
		return ""

	// reverse byte order
	b := sha.Sum(nil)
	for i, j := 0, len(b)-1; i < j; i, j = i+1, j-1 {
		b[i], b[j] = b[j], b[i]

	// last 16 bytes of sha1-sum, as big-endian
	return "0x" + hex.EncodeToString(b)[8:]

func main() {
	// outputs: 0xeb0816aeb936141ebec9a4a76c64df58

Sending the query


Then to query the address table, specify index 5, with a type of i128, using the hash as the upper and lower bounds.

curl -s -d '{
  "code": "fio.address",
  "scope": "fio.address",
  "table": "fionames",
  "lower_bound": "0xeb0816aeb936141ebec9a4a76c64df58",
  "upper_bound": "0xeb0816aeb936141ebec9a4a76c64df58",
  "key_type": "i128",
  "index_position": "5",
  "json": true
}' | jq .


  "rows": [
      "id": 7523,
      "name": "test@fiotestnet",
      "namehash": "0xeb0816aeb936141ebec9a4a76c64df58",
      "domain": "fiotestnet",
      "domainhash": "0x010fc709075388aae56c74a0dfaea9e5",
      "expiration": 1615398509,
      "owner_account": "ykspncqykk2w",
      "addresses": [
          "token_code": "FIO",
          "chain_code": "FIO",
          "public_address": "FIO584WnfHaMNjvQ1UnqtNokx7S8zT4Pr4XgejF3yKcYpWfXcEHKa"
      "bundleeligiblecountdown": 100
  "more": false


The domain table is almost the same, but the domain hash is in index 4.

curl -s -d '{
  "code": "fio.address",
  "scope": "fio.address",
  "table": "domains",
  "lower_bound": "0x010fc709075388aae56c74a0dfaea9e5",
  "upper_bound": "0x010fc709075388aae56c74a0dfaea9e5",
  "key_type": "i128",
  "index_position": "4",
  "json": true
}' | jq .


  "rows": [
      "id": 8651,
      "name": "fiotestnet",
      "domainhash": "0x010fc709075388aae56c74a0dfaea9e5",
      "account": "tw4tjkmo4eyd",
      "is_public": 1,
      "expiration": 1646934285
  "more": false
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