Проверка подписи

Результаты серверных запросов (методы getMe, getPhone и getContacts) содержат специальное поле sign.

С помощью этого поля серверная сторона вашего приложения может убедиться, что клиент отправил данные, действительно полученные со стороны Aitu Bridge.

В конце статьи предоставлены референсные имплементации для проверки подписи на некоторых серверных языках, которые можно скопировать и использовать на вашем сервере.

Если у ответа нет поля sign, то возможность проверить подлинность отсутствует. В таком случае относитесь к клиентским данным с опаской.

Подлинность данных гарантируется тем, что API-ключ для подписывания данных хранится только в Aitu и на стороне вашего сервера.

Не передавайте API-ключ третьим лицам!

В случае подозрения на компрометацию API-ключа, следует как можно скорее сформировать новый в личном кабинете. Предыдущий при этом деактивируется.

Алгоритм проверки достоверности данных

Для того, чтобы убедиться в достоверности полученных данных, необходимо следовать следующему алгоритму:

Получить результат ответа API-метода — некий JSON-объект.
Исключить из этого результата поле sign, после чего у него (и у всех вложенных объектов) исключить ключи с false-значениями (0, null , false, пустой строкой ""), пустыми массивами [] или пустыми объектами {}. Затем преобразовать его в строку вида ключ1:значение1ключ2:значение2ключ3:значение3, где все ключи объектов отсортированы по алфавиту.
Используя алгоритм проверки целостности HMAC с хеш-функцией sha256 и API-ключом, получить хеш строки, сформированной на предыдущем шаге.
Полученный хеш закодировать в base64-строку (base64url-вариант, с заменой + и / на - и _ соответственно, с сохранением возможных = в конце).
Сравнить результат предыдущего шага с полем sign пришедшего объекта.

При формировании строки для хеширования следует исключить из нее ключ sign.

Ключи вложенных объектов, а также объектов находящихся в списках, также должны сортироваться в алфавитном порядке и добавляться к строке последовательно согласно порядку сортировки их родительских ключей.

Ключи объектов со значениями 0,null, false или "" (пустая строка), [] (пустой массив), {} (пустой объект) опускаются.

В качестве хеш-функции для HMAC необходимо использовать sha256.

Если значение сформированного хеша в base64url совпадает с полем sign полученного объекта, то данные достоверны.

Пример

Пусть API-ключ имеет значение my_secret_key. Предположим, при вызове метода getContacts был получен следующий JSON-объект (для демонстрации в нем намеренно перемешаны ключи и добавлены ключи с опускаемыми значениями):

{
    "empty_string_key": "",
    "sign": "tdMk-vw3bTMPDMldnx4MgCbdJJNH2B60LizMzHv_De4=",
    "contacts": [
        {
            "last_name": "pupkin",
            "phone": "7991118837",
            "first_name": "vasya",
            "null_key_deep": null
        },
        {
            "first_name": "john",
            "last_name": "doe",
            "phone": "79992222210"
        },
        {
            "first_name": "kavychka",
            "last_name": "\"",
            "phone": "79992222211"
        }
    ],
    "zero_key": 0,
    "null_key": null,
    "false_key": false,
    "empty_array": [],
    "empty_object": {}
}

Строка для хэширования, сформированная по описанному выше алгоритму, должна получиться следующей:

contacts:first_name:vasyalast_name:pupkinphone:7991118837first_name:johnlast_name:doephone:79992222210first_name:kavychkalast_name:"phone:79992222211

Обратите внимание, что между парами нет разделителей.

Результат формирования HMAC-хеша (на базе алгоритма sha256) этой строки с ключом my_secret_key с кодированием в base64url должен получиться следующим:

tdMk-vw3bTMPDMldnx4MgCbdJJNH2B60LizMzHv_De4=

Для тестирования генерации HMAC можно воспользоваться online-сервисами. Например, https://www.devglan.com/online-tools/hmac-sha256-online с выводом результата в base64-формате. Обратите внимание, что полученный в этом сервисе хеш нужно дополнительно привести в base64url-формат, заменив все + на -, а / на _.

Полученный хеш совпадает с полем sign исходного объекта, а значит данные подлинные.

Референсные имплементации

function isValidSign(fullBridgeResponse, secretKey) {
    if (
        typeof fullBridgeResponse !== 'string' && typeof fullBridgeResponse !== 'object'
        || typeof secretKey !== 'string'
    ) {
        throw new Error('Can accept string or object as first argument and string as second argument only');
    }

    const { sign: inputSign, ...bridgeResponse } = typeof fullBridgeResponse === 'object'
        ? fullBridgeResponse
        : JSON.parse(fullBridgeResponse);

    const hmac = require('crypto').createHmac('sha256', secretKey);
    const base64URLUnsafeHash = hmac.update(makeStringToHash(bridgeResponse)).digest('base64');
    const calculatedSign = base64URLUnsafeHash.replace(/\+/g, '-').replace(/\//g, '_');

    return inputSign === calculatedSign;

    function makeStringToHash(input) {
        if (Array.isArray(input)) {
            return input.map(makeStringToHash).join('');
        } else if (typeof input === 'object') {
            return Object.keys(input)
                .filter((key) => input[key] && (!Array.isArray(input[key]) || input[key].length > 0) && (typeof input[key] !== 'object' || Object.keys(input[key]).length > 0))
                .sort()
                .map((key) => `${key}:${makeStringToHash(input[key])}`)
                .join('');
        } else {
            return String(input);
        }
    }
}

const bridgeResponseJSONExample = '{"empty_string_key":"","sign":"tdMk-vw3bTMPDMldnx4MgCbdJJNH2B60LizMzHv_De4=","contacts":[{"last_name":"pupkin","phone":"7991118837","first_name":"vasya","null_key_deep":null},{"first_name":"john","last_name":"doe","phone":"79992222210"},{"first_name":"kavychka","last_name":"\\"","phone":"79992222211"}],"zero_key":0,"null_key":null}';
const secretKeyExample = 'my_secret_key';
console.log(isValidSign(bridgeResponseJSONExample, secretKeyExample)); // Should be true

function isValidSign(fullBridgeResponse: Record<string, unknown> | string, secretKey: string) {
    const { sign: inputSign, ...bridgeResponse } = typeof fullBridgeResponse === 'object'
      ? fullBridgeResponse
      : JSON.parse(fullBridgeResponse);

    const hmac = require('crypto').createHmac('sha256', secretKey);
    const base64URLUnsafeHash: string = hmac.update(makeStringToHash(bridgeResponse)).digest('base64');
    const calculatedSign = base64URLUnsafeHash.replace(/\+/g, '-').replace(/\//g, '_');

    return inputSign === calculatedSign;

    function makeStringToHash(input): string {
        if (Array.isArray(input)) {
            return input.map(makeStringToHash).join('');
        } else if (typeof input === 'object') {
            return Object.keys(input)
                .filter((key) => input[key] && (!Array.isArray(input[key]) || input[key].length > 0) && (typeof input[key] !== 'object' || Object.keys(input[key]).length > 0))
                .sort()
                .map((key) => `${key}:${makeStringToHash(input[key])}`)
                .join('');
        } else {
            return String(input);
        }
    }
}

const bridgeResponseJSONExample = '{"empty_string_key":"","sign":"tdMk-vw3bTMPDMldnx4MgCbdJJNH2B60LizMzHv_De4=","contacts":[{"last_name":"pupkin","phone":"7991118837","first_name":"vasya","null_key_deep":null},{"first_name":"john","last_name":"doe","phone":"79992222210"},{"first_name":"kavychka","last_name":"\\"","phone":"79992222211"}],"zero_key":0,"null_key":null}';
const secretKeyExample = 'my_secret_key';
console.log(isValidSign(bridgeResponseJSONExample, secretKeyExample)); // Should be true

require 'JSON'
require 'OpenSSL'
require 'base64'
 
def check_sign(data, secret_key)
  sign = data.delete('sign')
 
  string = build_string(data)
  mac = OpenSSL::HMAC.digest('SHA256', secret_key, string)
  base64_url = Base64.urlsafe_encode64 mac
 
  sign == base64_url
end
 
def build_string(obj)
  if obj.is_a? Hash
    return obj.reject { |_k, v| v == 0 || v.nil? || v == '' || v == false || (v.is_a? Hash && v.empty?) || (v.is_a? Array && v.empty?) }.sort.to_h.map do |k, v|
      k.to_s + ':' + build_string(v)
    end.join
  end
 
  if obj.is_a? Array
    return obj.map { |el| build_string(el) }.join
  end
 
  obj.to_s
end
 
json = <<JSON
{
    "empty_string_key": "",
    "sign": "tdMk-vw3bTMPDMldnx4MgCbdJJNH2B60LizMzHv_De4=",
    "contacts": [
        {
            "last_name": "pupkin",
            "phone": "7991118837",
            "first_name": "vasya",
            "null_key_deep": null
        },
        {
            "first_name": "john",
            "last_name": "doe",
            "phone": "79992222210"
        },
        {
            "first_name": "kavychka",
            "last_name": "\\\"",
            "phone": "79992222211"
        }
    ],
    "zero_key": 0,
    "null_key": null
}
JSON
data = JSON.parse(json)
p check_sign(data, 'my_secret_key')

import base64
import hashlib
import hmac


def get_sign_data_from_dict(obj: dict) -> str:
    result = ''
    keys = sorted(obj.keys())
    for key in keys:
        val = obj[key]

        if not val:
            continue

        if isinstance(val, dict):
            result += key + ':' + get_sign_data_from_dict(val)
            continue

        if isinstance(val, list):
            result += key + ':' + get_sign_data_from_list(val)
            continue

        result += key + ':' + str(val)

    return result


def get_sign_data_from_list(data: list) -> str:
    result = ''
    for d in data:
        result += get_sign_data_from_dict(d)
    return result


data = {
    "contacts": [
        {"first_name": "FirstName", "last_name": "LastName", "phone": "PhoneNumber"},
        {"first_name": "OnlyFirstName", "last_name": "", "phone": ""},
        {"first_name": "", "last_name": "OnlyLastName", "phone": ""},
        {"first_name": "", "last_name": "", "phone": "OnlyPhoneNumber"}
    ]
}

message = get_sign_data_from_dict(data)
assert message == 'contacts:first_name:FirstNamelast_name:LastNamephone:PhoneNumberfirst_name:OnlyFirstNamelast_name:OnlyLastNamephone:OnlyPhoneNumber'

message = bytes(message, 'utf-8')
secret = bytes('secret', 'utf-8')
signature = base64.urlsafe_b64encode(hmac.new(secret, message, digestmod=hashlib.sha256).digest())
assert signature.decode('utf8') == 'LNfD638IVfC5x-XVhKXWFE7ztRRATDbLgqNgiOvefuo='

data = {"contacts": []}

message = get_sign_data_from_dict(data)
assert message == ''

message = bytes(message, 'utf-8')
secret = bytes('secret', 'utf-8')
signature = base64.urlsafe_b64encode(hmac.new(secret, message, digestmod=hashlib.sha256).digest())
assert signature.decode('utf8') == '-eZuF5tnR65UEI-C-K3os8Jddv0wr95sOVgixTAZYWk='


import com.fasterxml.jackson.databind.ObjectMapper;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class SignValidator {
    private final StringBuilder result = new StringBuilder();
    private String calculatedSign;
    private String sign;

    public SignValidator(Object object, String secret) {
        try {
            ObjectMapper om = new ObjectMapper();
            String jsonString = om.writeValueAsString(object);
            Map<String, Object> map = om.readValue(jsonString, Map.class);
            calcSign(map, secret);
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

    public SignValidator(Map<String, Object> jsonMap, String secret) {
        calcSign(jsonMap, secret);
    }

    private void calcSign(Map<String, Object> jsonMap, String secret) {
        fillSignStringForMap(jsonMap);

        byte[] signature = calcHmacSha256(secret.getBytes(StandardCharsets.UTF_8),
                result.toString().getBytes(StandardCharsets.UTF_8));

        calculatedSign = Base64.getUrlEncoder().encodeToString(signature);
        sign = getExpectedSign(jsonMap);
    }

    byte[] calcHmacSha256(byte[] secret, byte[] data) {
        try {
            Mac mac = Mac.getInstance("HmacSHA256");
            SecretKeySpec secretKeySpec = new SecretKeySpec(secret, "HmacSHA256");
            mac.init(secretKeySpec);
            return mac.doFinal(data);
        } catch (Exception e) {
            throw new RuntimeException("Failed to calculate hmac-sha256", e);
        }
    }

    public String getCalculatedSign() {
        return calculatedSign;
    }

    public String getSign() {
        return sign;
    }

    public boolean isValid() {
        if (sign == null)
            return false;
        return sign.equals(calculatedSign);
    }

    public String getSignString() {
        return result.toString();
    }

    private String getExpectedSign(Map<String, Object> map) {
        Object elem = map.get("sign");
        if (elem != null) {
            return elem.toString();
        } else {
            return null;
        }
    }

    private void fillSignStringForMap(Map<String, Object> map) {

        List<String> sortedKeys = map.keySet().stream()
                .filter(key -> !key.equalsIgnoreCase("sign"))
                .sorted(String::compareToIgnoreCase)
                .collect(Collectors.toList());

        for (String key : sortedKeys) {
            Object value = map.get(key);

            if (isEmptyValue(value)) {
                continue;
            }

            result.append(key.toLowerCase())
                    .append(":");

            if (value instanceof Map) {
                fillSignStringForMap((Map) value);
            } else if (value instanceof Collection) {
                fillSignStringForCollection((Collection) value);
            } else if (value instanceof Array) {
                fillSignStringForArray((Array) value);
            } else {
                result.append(value);
            }
        }
    }

    private void fillSignStringForCollection(Collection collection) {
        for (Object elem : collection) {
            if (!(elem instanceof Map)) {
                throw new IllegalArgumentException("Collection must contain only objects.");
            }
            fillSignStringForMap((Map) elem);
        }
    }

    private void fillSignStringForArray(Array array) {
        int length = Array.getLength(array);

        for (int i = 0; i <= length - 1; i++) {
            Object elem = Array.get(array, i);
            if (!(elem instanceof Map)) {
                throw new IllegalArgumentException("Collection must contain only objects.");
            }
            fillSignStringForMap((Map) elem);
        }
    }

    private boolean isEmptyValue(Object value) {
        if (value == null) {
            return true;
        }

        if (value instanceof Collection) {
            return ((Collection) value).isEmpty();
        } else if (value instanceof Map) {
            return ((Map) value).isEmpty();
        } else if (value instanceof Array) {
            return Array.getLength(value) == 0;
        } else if (value instanceof String) {
            return ((String) value).isEmpty();
        } else if (value instanceof Boolean) {
            return !(Boolean) value;
        } else if (value instanceof Number) {
            return isZero((Number) value);
        } else {
            throw new IllegalArgumentException("Unsupported value type");
        }
    }

    private boolean isZero(Number number) {
        if (number instanceof Byte) {
            return number.byteValue() == 0;
        } else if (number instanceof Short) {
            return number.shortValue() == 0;
        } else if (number instanceof Integer) {
            return number.intValue() == 0;
        } else if (number instanceof Long) {
            return number.longValue() == 0;
        } else if (number instanceof Float) {
            return number.floatValue() == 0;
        } else if (number instanceof Double) {
            return number.doubleValue() == 0;
        } else if (number instanceof BigInteger) {
            return number.equals(BigInteger.ZERO);
        } else if (number instanceof BigDecimal) {
            return number.equals(BigDecimal.ZERO);
        } else {
            throw new IllegalArgumentException("Unsupported number type");
        }
    }

    // Должны быть включены ассерты java -ea SignChecker
    public static void main(String[] args) throws IOException {
        ObjectMapper om = new ObjectMapper();

        String[] inputs = new String[]{
                "{\n" +
                        "    \"empty_string_key\": \"\",\n" +
                        "    \"sign\": \"NAZEing3oTCZX8UFFjy_noJAWKUSpv2SYxPYjdGsp50=\",\n" +
                        "    \"contacts\": [\n" +
                        "        {\n" +
                        "            \"last_name\": \"pupkin\",\n" +
                        "            \"phone\": \"7991118837\",\n" +
                        "            \"first_name\": \"vasya\",\n" +
                        "            \"null_key_deep\": null\n" +
                        "        },\n" +
                        "        {\n" +
                        "            \"first_name\": \"john\",\n" +
                        "            \"last_name\": \"doe\",\n" +
                        "            \"phone\": \"79992222210\"\n" +
                        "        },\n" +
                        "        {\n" +
                        "            \"first_name\": \"kavychka\",\n" +
                        "            \"last_name\": \"\\\"\",\n" +
                        "            \"phone\": \"79992222211\"\n" +
                        "        }\n" +
                        "    ],\n" +
                        "    \"zero_key\": 0,\n" +
                        "    \"null_key\": null\n" +
                        "}",

                "{\n" +
                        "    \"sign\": \"LNfD638IVfC5x-XVhKXWFE7ztRRATDbLgqNgiOvefuo=\",\n" +
                        "    \"contacts\": [\n" +
                        "        {\"first_name\": \"FirstName\", \"last_name\": \"LastName\", \"phone\": \"PhoneNumber\"},\n" +
                        "        {\"first_name\": \"OnlyFirstName\", \"last_name\": \"\", \"phone\": \"\"},\n" +
                        "        {\"first_name\": \"\", \"last_name\": \"OnlyLastName\", \"phone\": \"\"},\n" +
                        "        {\"first_name\": \"\", \"last_name\": \"\", \"phone\": \"OnlyPhoneNumber\"}\n" +
                        "    ]\n" +
                        "}",
                "{" +
                        "    \"sign\": \"-eZuF5tnR65UEI-C-K3os8Jddv0wr95sOVgixTAZYWk=\",\n" +
                        "    \"contacts\": []" +
                        "}"};

        String[] resultString = new String[]{"contacts:first_name:vasyalast_name:pupkinphone:7991118837first_name:johnlast_name:doephone:79992222210first_name:kavychkalast_name:\"phone:79992222211",
                "contacts:first_name:FirstNamelast_name:LastNamephone:PhoneNumberfirst_name:OnlyFirstNamelast_name:OnlyLastNamephone:OnlyPhoneNumber",
                ""};

        for (int i = 0; i < 3; i++) {
            Map<String, Object> map = om.readValue(inputs[i], Map.class);
            SignValidator validator = new SignValidator(map, "secret");
            assert validator.getSignString().equals(resultString[i]);

            assert validator.isValid();
        }
    }

}

import com.fasterxml.jackson.databind.ObjectMapper
import java.lang.reflect.Array
import java.math.BigDecimal
import java.math.BigInteger
import java.nio.charset.StandardCharsets
import java.util.Base64
import javax.crypto.Mac
import javax.crypto.spec.SecretKeySpec

class SignValidator {
    val result = StringBuilder()
    private var calculatedSign: String? = null
    private var sign: String? = null

    constructor(obj: Any, secret: String) {
        val om = ObjectMapper()
        val jsonString = om.writeValueAsString(obj)
        val map = om.readValue(jsonString, Map::class.java)
        calcSign(map as Map<String, Any?>, secret)
    }

    constructor(jsonMap: Map<String, Any?>, secret: String) {
        calcSign(jsonMap, secret)
    }

    private fun calcSign(jsonMap: Map<String, Any?>, secret: String) {
        fillSignStringForMap(jsonMap)

        val signature = calcHmacSha256(
            secret.toByteArray(StandardCharsets.UTF_8),
            result.toString().toByteArray(StandardCharsets.UTF_8)
        )

        calculatedSign = Base64.getUrlEncoder().encodeToString(signature)
        sign = getExpectedSign(jsonMap)
    }

    fun calcHmacSha256(secret: ByteArray, data: ByteArray): ByteArray {
        val mac = Mac.getInstance("HmacSHA256")
        val secretKeySpec = SecretKeySpec(secret, "HmacSHA256")
        mac.init(secretKeySpec)
        return mac.doFinal(data)
    }

    fun isValid(): Boolean {
        if (sign == "") {
            return false
        }
        return sign == calculatedSign
    }

    fun getSignString() = result.toString()

    private fun getExpectedSign(map: Map<String, Any?>): String? {
        val elem = map.get("sign")
        if (elem != null) {
            return elem.toString()
        } else {
            return null
        }
    }

    private fun fillSignStringForMap(map: Map<String, Any?>) {

        val sortedKeys = map.keys
            .filter { key -> !key.equals("sign", ignoreCase = true) }
            .sortedBy { it.lowercase() }

        for (key in sortedKeys) {
            val value = map[key]

            if (isEmptyValue(value)) {
                continue
            }

            result.append(key.lowercase())
                .append(":")

            if (value is Map<*, *>) {
                fillSignStringForMap(value as Map<String, Any?>)
            } else if (value is Collection<*>) {
                fillSignStringForCollection(value)
            } else if (value is Array) {
                fillSignStringForArray(value)
            } else {
                result.append(value)
            }
        }
    }

    private fun fillSignStringForCollection(collection: Collection<*>) {
        for (elem in collection) {
            if (elem !is Map<*, *>) {
                throw IllegalArgumentException("Collection must contain only objects.")
            }
            fillSignStringForMap(elem as Map<String, Any?>)
        }
    }

    private fun fillSignStringForArray(array: Array) {
        val length = Array.getLength(array)

        for (i in 0..length - 1) {
            val elem = Array.get(array, i)
            if (elem !is Map<*, *>) {
                throw IllegalArgumentException("Collection must contain only objects.")
            }
            fillSignStringForMap(elem as Map<String, Any?>)
        }
    }

    private fun isEmptyValue(value: Any?): Boolean {
        if (value == null) {
            return true
        }

        return if (value is Collection<*>) {
            value.isEmpty()
        } else if (value is Map<*, *>) {
            value.isEmpty()
        } else if (value is Array) {
            Array.getLength(value) == 0
        } else if (value is String) {
            value.isEmpty()
        } else if (value is Boolean) {
            !value
        } else if (value is Number) {
            isZero(value)
        } else {
            throw IllegalArgumentException("Unsupported value type")
        }
    }

    private fun isZero(number: Number): Boolean {
        if (number is Byte) {
            return number.toByte().toInt() == 0
        } else if (number is Short) {
            return number.toShort().toInt() == 0
        } else if (number is Int) {
            return number == 0
        } else if (number is Long) {
            return number == 0L
        } else if (number is Float) {
            return number == 0.0f
        } else if (number is Double) {
            return number == 0.0
        } else if (number is BigInteger) {
            return number == BigInteger.ZERO
        } else if (number is BigDecimal) {
            return number == BigDecimal.ZERO
        } else {
            throw IllegalArgumentException("Unsupported number type")
        }
    }
}

fun main(args: kotlin.Array<String>) {
    val om = ObjectMapper()

    val inputs = arrayOf(
        """
         {
                "empty_string_key": "",
                "sign": "NAZEing3oTCZX8UFFjy_noJAWKUSpv2SYxPYjdGsp50=",
                "contacts": [
                    {
                        "last_name": "pupkin",
                        "phone": "7991118837",
                        "first_name": "vasya",
                        "null_key_deep": null
                    },
                    {
                        "first_name": "john",
                        "last_name": "doe",
                        "phone": "79992222210"
                    },
                    {
                        "first_name": "kavychka",
                        "last_name": "\"",
                        "phone": "79992222211"
                    }
                ],
                "zero_key": 0,
                "null_key": null
            }
            """,

        """
            {
                "sign": "LNfD638IVfC5x-XVhKXWFE7ztRRATDbLgqNgiOvefuo=",
                "contacts": [
                    {"first_name": "FirstName", "last_name": "LastName", "phone": "PhoneNumber"},
                    {"first_name": "OnlyFirstName", "last_name": "", "phone": ""},
                    {"first_name": "", "last_name": "OnlyLastName", "phone": ""},
                    {"first_name": "", "last_name": "", "phone": "OnlyPhoneNumber"}
                ]
            }
            """,
        """
            { 
                "sign": "-eZuF5tnR65UEI-C-K3os8Jddv0wr95sOVgixTAZYWk=",
                "contacts": []
            }
            """
    )

    val resultString = arrayOf(
        """contacts:first_name:vasyalast_name:pupkinphone:7991118837first_name:johnlast_name:doephone:79992222210first_name:kavychkalast_name:"phone:79992222211""",
        "contacts:first_name:FirstNamelast_name:LastNamephone:PhoneNumberfirst_name:OnlyFirstNamelast_name:OnlyLastNamephone:OnlyPhoneNumber",
        ""
    )

    for (i in 0..2) {
        val map = om.readValue(inputs[i], Map::class.java)
        val validator = SignValidator(map, "secret")
        assert(validator.getSignString() == resultString[i])
        assert(validator.isValid())
    }
}

Для упрощения тестирования вашей собственной реализации подписи мы подготовили интерактивную форму на codepen.io

PreviousПроверка поддержки метода NextgetMe

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import com.fasterxml.jackson.databind.ObjectMapper; import javax.crypto.Mac; import javax.crypto.spec.SecretKeySpec; import java.io.IOException; import java.lang.reflect.Array; import java.math.BigDecimal; import java.math.BigInteger; import java.nio.charset.StandardCharsets; import java.util.Base64; import java.util.Collection; import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class SignValidator { private final StringBuilder result = new StringBuilder(); private String calculatedSign; private String sign; public SignValidator(Object object, String secret) { try { ObjectMapper om = new ObjectMapper(); String jsonString = om.writeValueAsString(object); Map<String, Object> map = om.readValue(jsonString, Map.class); calcSign(map, secret); } catch (Exception ex) { throw new RuntimeException(ex); } } public SignValidator(Map<String, Object> jsonMap, String secret) { calcSign(jsonMap, secret); } private void calcSign(Map<String, Object> jsonMap, String secret) { fillSignStringForMap(jsonMap); byte[] signature = calcHmacSha256(secret.getBytes(StandardCharsets.UTF_8), result.toString().getBytes(StandardCharsets.UTF_8)); calculatedSign = Base64.getUrlEncoder().encodeToString(signature); sign = getExpectedSign(jsonMap); } byte[] calcHmacSha256(byte[] secret, byte[] data) { try { Mac mac = Mac.getInstance("HmacSHA256"); SecretKeySpec secretKeySpec = new SecretKeySpec(secret, "HmacSHA256"); mac.init(secretKeySpec); return mac.doFinal(data); } catch (Exception e) { throw new RuntimeException("Failed to calculate hmac-sha256", e); } } public String getCalculatedSign() { return calculatedSign; } public String getSign() { return sign; } public boolean isValid() { if (sign == null) return false; return sign.equals(calculatedSign); } public String getSignString() { return result.toString(); } private String getExpectedSign(Map<String, Object> map) { Object elem = map.get("sign"); if (elem != null) { return elem.toString(); } else { return null; } } private void fillSignStringForMap(Map<String, Object> map) { List<String> sortedKeys = map.keySet().stream() .filter(key -> !key.equalsIgnoreCase("sign")) .sorted(String::compareToIgnoreCase) .collect(Collectors.toList()); for (String key : sortedKeys) { Object value = map.get(key); if (isEmptyValue(value)) { continue; } result.append(key.toLowerCase()) .append(":"); if (value instanceof Map) { fillSignStringForMap((Map) value); } else if (value instanceof Collection) { fillSignStringForCollection((Collection) value); } else if (value instanceof Array) { fillSignStringForArray((Array) value); } else { result.append(value); } } } private void fillSignStringForCollection(Collection collection) { for (Object elem : collection) { if (!(elem instanceof Map)) { throw new IllegalArgumentException("Collection must contain only objects."); } fillSignStringForMap((Map) elem); } } private void fillSignStringForArray(Array array) { int length = Array.getLength(array); for (int i = 0; i <= length - 1; i++) { Object elem = Array.get(array, i); if (!(elem instanceof Map)) { throw new IllegalArgumentException("Collection must contain only objects."); } fillSignStringForMap((Map) elem); } } private boolean isEmptyValue(Object value) { if (value == null) { return true; } if (value instanceof Collection) { return ((Collection) value).isEmpty(); } else if (value instanceof Map) { return ((Map) value).isEmpty(); } else if (value instanceof Array) { return Array.getLength(value) == 0; } else if (value instanceof String) { return ((String) value).isEmpty(); } else if (value instanceof Boolean) { return !(Boolean) value; } else if (value instanceof Number) { return isZero((Number) value); } else { throw new IllegalArgumentException("Unsupported value type"); } } private boolean isZero(Number number) { if (number instanceof Byte) { return number.byteValue() == 0; } else if (number instanceof Short) { return number.shortValue() == 0; } else if (number instanceof Integer) { return number.intValue() == 0; } else if (number instanceof Long) { return number.longValue() == 0; } else if (number instanceof Float) { return number.floatValue() == 0; } else if (number instanceof Double) { return number.doubleValue() == 0; } else if (number instanceof BigInteger) { return number.equals(BigInteger.ZERO); } else if (number instanceof BigDecimal) { return number.equals(BigDecimal.ZERO); } else { throw new IllegalArgumentException("Unsupported number type"); } } // Должны быть включены ассерты java -ea SignChecker public static void main(String[] args) throws IOException { ObjectMapper om = new ObjectMapper(); String[] inputs = new String[]{ "{\n" + " \"empty_string_key\": \"\",\n" + " \"sign\": \"NAZEing3oTCZX8UFFjy_noJAWKUSpv2SYxPYjdGsp50=\",\n" + " \"contacts\": [\n" + " {\n" + " \"last_name\": \"pupkin\",\n" + " \"phone\": \"7991118837\",\n" + " \"first_name\": \"vasya\",\n" + " \"null_key_deep\": null\n" + " },\n" + " {\n" + " \"first_name\": \"john\",\n" + " \"last_name\": \"doe\",\n" + " \"phone\": \"79992222210\"\n" + " },\n" + " {\n" + " \"first_name\": \"kavychka\",\n" + " \"last_name\": \"\\\"\",\n" + " \"phone\": \"79992222211\"\n" + " }\n" + " ],\n" + " \"zero_key\": 0,\n" + " \"null_key\": null\n" + "}", "{\n" + " \"sign\": \"LNfD638IVfC5x-XVhKXWFE7ztRRATDbLgqNgiOvefuo=\",\n" + " \"contacts\": [\n" + " {\"first_name\": \"FirstName\", \"last_name\": \"LastName\", \"phone\": \"PhoneNumber\"},\n" + " {\"first_name\": \"OnlyFirstName\", \"last_name\": \"\", \"phone\": \"\"},\n" + " {\"first_name\": \"\", \"last_name\": \"OnlyLastName\", \"phone\": \"\"},\n" + " {\"first_name\": \"\", \"last_name\": \"\", \"phone\": \"OnlyPhoneNumber\"}\n" + " ]\n" + "}", "{" + " \"sign\": \"-eZuF5tnR65UEI-C-K3os8Jddv0wr95sOVgixTAZYWk=\",\n" + " \"contacts\": []" + "}"}; String[] resultString = new String[]{"contacts:first_name:vasyalast_name:pupkinphone:7991118837first_name:johnlast_name:doephone:79992222210first_name:kavychkalast_name:\"phone:79992222211", "contacts:first_name:FirstNamelast_name:LastNamephone:PhoneNumberfirst_name:OnlyFirstNamelast_name:OnlyLastNamephone:OnlyPhoneNumber", ""}; for (int i = 0; i < 3; i++) { Map<String, Object> map = om.readValue(inputs[i], Map.class); SignValidator validator = new SignValidator(map, "secret"); assert validator.getSignString().equals(resultString[i]); assert validator.isValid(); } } }

import com.fasterxml.jackson.databind.ObjectMapper import java.lang.reflect.Array import java.math.BigDecimal import java.math.BigInteger import java.nio.charset.StandardCharsets import java.util.Base64 import javax.crypto.Mac import javax.crypto.spec.SecretKeySpec class SignValidator { val result = StringBuilder() private var calculatedSign: String? = null private var sign: String? = null constructor(obj: Any, secret: String) { val om = ObjectMapper() val jsonString = om.writeValueAsString(obj) val map = om.readValue(jsonString, Map::class.java) calcSign(map as Map<String, Any?>, secret) } constructor(jsonMap: Map<String, Any?>, secret: String) { calcSign(jsonMap, secret) } private fun calcSign(jsonMap: Map<String, Any?>, secret: String) { fillSignStringForMap(jsonMap) val signature = calcHmacSha256( secret.toByteArray(StandardCharsets.UTF_8), result.toString().toByteArray(StandardCharsets.UTF_8) ) calculatedSign = Base64.getUrlEncoder().encodeToString(signature) sign = getExpectedSign(jsonMap) } fun calcHmacSha256(secret: ByteArray, data: ByteArray): ByteArray { val mac = Mac.getInstance("HmacSHA256") val secretKeySpec = SecretKeySpec(secret, "HmacSHA256") mac.init(secretKeySpec) return mac.doFinal(data) } fun isValid(): Boolean { if (sign == "") { return false } return sign == calculatedSign } fun getSignString() = result.toString() private fun getExpectedSign(map: Map<String, Any?>): String? { val elem = map.get("sign") if (elem != null) { return elem.toString() } else { return null } } private fun fillSignStringForMap(map: Map<String, Any?>) { val sortedKeys = map.keys .filter { key -> !key.equals("sign", ignoreCase = true) } .sortedBy { it.lowercase() } for (key in sortedKeys) { val value = map[key] if (isEmptyValue(value)) { continue } result.append(key.lowercase()) .append(":") if (value is Map<*, *>) { fillSignStringForMap(value as Map<String, Any?>) } else if (value is Collection<*>) { fillSignStringForCollection(value) } else if (value is Array) { fillSignStringForArray(value) } else { result.append(value) } } } private fun fillSignStringForCollection(collection: Collection<*>) { for (elem in collection) { if (elem !is Map<*, *>) { throw IllegalArgumentException("Collection must contain only objects.") } fillSignStringForMap(elem as Map<String, Any?>) } } private fun fillSignStringForArray(array: Array) { val length = Array.getLength(array) for (i in 0..length - 1) { val elem = Array.get(array, i) if (elem !is Map<*, *>) { throw IllegalArgumentException("Collection must contain only objects.") } fillSignStringForMap(elem as Map<String, Any?>) } } private fun isEmptyValue(value: Any?): Boolean { if (value == null) { return true } return if (value is Collection<*>) { value.isEmpty() } else if (value is Map<*, *>) { value.isEmpty() } else if (value is Array) { Array.getLength(value) == 0 } else if (value is String) { value.isEmpty() } else if (value is Boolean) { !value } else if (value is Number) { isZero(value) } else { throw IllegalArgumentException("Unsupported value type") } } private fun isZero(number: Number): Boolean { if (number is Byte) { return number.toByte().toInt() == 0 } else if (number is Short) { return number.toShort().toInt() == 0 } else if (number is Int) { return number == 0 } else if (number is Long) { return number == 0L } else if (number is Float) { return number == 0.0f } else if (number is Double) { return number == 0.0 } else if (number is BigInteger) { return number == BigInteger.ZERO } else if (number is BigDecimal) { return number == BigDecimal.ZERO } else { throw IllegalArgumentException("Unsupported number type") } } } fun main(args: kotlin.Array<String>) { val om = ObjectMapper() val inputs = arrayOf( """ { "empty_string_key": "", "sign": "NAZEing3oTCZX8UFFjy_noJAWKUSpv2SYxPYjdGsp50=", "contacts": [ { "last_name": "pupkin", "phone": "7991118837", "first_name": "vasya", "null_key_deep": null }, { "first_name": "john", "last_name": "doe", "phone": "79992222210" }, { "first_name": "kavychka", "last_name": "\"", "phone": "79992222211" } ], "zero_key": 0, "null_key": null } """, """ { "sign": "LNfD638IVfC5x-XVhKXWFE7ztRRATDbLgqNgiOvefuo=", "contacts": [ {"first_name": "FirstName", "last_name": "LastName", "phone": "PhoneNumber"}, {"first_name": "OnlyFirstName", "last_name": "", "phone": ""}, {"first_name": "", "last_name": "OnlyLastName", "phone": ""}, {"first_name": "", "last_name": "", "phone": "OnlyPhoneNumber"} ] } """, """ { "sign": "-eZuF5tnR65UEI-C-K3os8Jddv0wr95sOVgixTAZYWk=", "contacts": [] } """ ) val resultString = arrayOf( """contacts:first_name:vasyalast_name:pupkinphone:7991118837first_name:johnlast_name:doephone:79992222210first_name:kavychkalast_name:"phone:79992222211""", "contacts:first_name:FirstNamelast_name:LastNamephone:PhoneNumberfirst_name:OnlyFirstNamelast_name:OnlyLastNamephone:OnlyPhoneNumber", "" ) for (i in 0..2) { val map = om.readValue(inputs[i], Map::class.java) val validator = SignValidator(map, "secret") assert(validator.getSignString() == resultString[i]) assert(validator.isValid()) } }