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Last Updated: Jul 25, 2022

  1. Are transactions stored in real time?

    A: Unlike traditional transactional databases, transactions are asynchronous in blockchains. Up to 25,000 notary transactions can be made every second.

  2. Is it synchronous with relational databases?

    A: It subscribes to block notifications and pulls notifications on demand from the blockchain. Or it uses the business view system.

  3. Are public and private keys legally recognized?

    A: The certificate is a legally-recognized certificate that Alipay uses to access a third party.

  4. What method is used to protect data privacy?

    A: To protect notary data privacy, data is encrypted and only authorized users can decrypt data.

  5. The client has been initialized successfully but can not comminicate with the blockchain, I also found the error log below, may I ask why is this happening?

    connect to /123.12.XX.XX:8080 success!
    old is not null, async resend subscribe events

    A: Usually this happens because of mistakes in the client configurations, please make sure you use the right private key file, password and certificate file.

  6. What can I do if TimeoutException is reported after the client is initialized?


    A: Obtain information about the blockchain node from the configuration file and run the telnet command to check whether the client properly communicates with the node. Then check whether directories in are correct for the private key, certificate, and trust.keystore files.

  7. How can I create private keys and certificate requests in Windows?

    A: In Windows, use the OpenSSL tool to create private keys and certificate requests.

    We recommend that you go to and download OpenSSL ver1.0.2o instead of OpenSSL ver1.1.0, which has a known bug when extracting private keys.

    The following are two backup links:

    1) OpenSSL (32-bit):

    2) OpenSSL (64-bit):

    Use OpenSSL to create private keys and certificate requests by:In cmd, go to the path of Openssl.exe:cd Openssl_path

    Configure the OpenSSL configuration file under the current path.set OPENSSL_CONF=openssl.cfg

    Generate private keys and corresponding certificate requests under the current pathopenssl req -newkey rsa:2048 -keyout key_pkcs10.pem -out csr.pem

    When running this command, you will be prompted to enter the following information:

    Country name (2-letter code): Enter a two-letter ISO country code. For China, enter CN.
    State or province name (full name): Enter a province, for example, Shanghai.
    Locality name (for example, city): Enter a city, for example, Shanghai.
    Organization name (for example, company): Enter an organization, for example, Pinyin of a company name.
    Organizational unit name (for example, section): For example, IT Dept.
    Common name (for example, your website domain name): Enter an identity used for SSL encryption.
    Email address: email address (optional)
    Challenge password: (optional)
    Optional company name: (optional)

    Convert private keys from pkcs10 to pkcs8

    openssl pkcs8 -in key_pkcs10.pem -inform PEM -out pkcs8.pem -outform PEM -topk8

  8. What can I do if contracts fail to be deployed on the Cloud IDE?

    A: The name of a contract must be unique on a blockchain. Since there may be a large amount of users using the test blockchain, if your contract deployment fails, try to change the contract name.