AWS 忘记密码：无法验证 iOS 客户端的秘密哈希

Question

iOS 解决方案

向 aws cognito 身份池提交忘记密码请求时，该请求必须使用客户端密码以及忘记密码请求中提交的用户名进行签名。

我们如何在 swift 中以 aws 要求的格式从客户端密码和用户名创建“secretHash”？

Answer 1

此功能未记录在案，仅在某些 AWS 库的测试中发现。此代码用作提交忘记密码请求的示例，直到该功能在 AWSCongitoIdentityUserPool 库中得到更好的支持。

Swift 3.2

func forgotPassword(username: String) {
   let pool = AWSCognitoIdentityUserPool.default()

   let request = AWSCognitoIdentityProviderForgotPasswordRequest()
   request?.username = username
   request?.clientId = pool.userPoolConfiguration.clientId
   request?.secretHash = pool.calculateSecretHash(username: username)

   AWSCognitoIdentityProvider.default().forgotPassword(request!) { (response, error) in
       if let error = error {
           print(error)
       }
       else {
           print("success")
       }
    }
}

使用来自用户池的客户端密码对用户名进行签名。

extension AWSCognitoIdentityUserPool {
    func calculateSecretHash(username: String) -> String? {
        guard let clientSecret = userPoolConfiguration.clientSecret else {
            return nil
        }
        guard let key = clientSecret.data(using: String.Encoding.ascii) else {
            return nil
        }
        guard let data = (username + userPoolConfiguration.clientId).data(using: String.Encoding.utf8) else {
            return nil
        }

        let hmac = sign256(data: data, key: key)
        return hmac.base64EncodedString()
    }

    fileprivate func sign256(data: Data, key: Data) -> Data {
        let algorithm: CCHmacAlgorithm = CCHmacAlgorithm(kCCHmacAlgSHA256)
        let digestLength =  Int(CC_SHA256_DIGEST_LENGTH)
        let signature = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: digestLength)
        defer { signature.deallocate(capacity: digestLength) }

        data.withUnsafeBytes { dataBytes in
            key.withUnsafeBytes { keyBytes in
                CCHmac(algorithm, keyBytes, key.count, dataBytes, data.count, signature)
            }
        }

        return Data(bytes: signature, count: digestLength)
    }

}