As the most open communication tool on the Internet, email is used very frequently in everyone's work and life. Especially in the field of business office, email communication will involve a lot of commercial secrets and transaction procedures. Because of this, e-mails are often subject to *** or criminal ***.
So how can we ensure that the mail is safe and reliable?
We can solve this problem through the S/MIME protocol. The S/MIME protocol supports mail authentication, integrity protection, authentication, and data confidentiality, etc., which is what you often hear about using mail security certificates (S/MIME) to achieve mail Encryption and digital signature (the role of encryption is to encrypt the content of the email, and the role of digital signature is to ensure that the content of the email has not been tampered with and to ensure the integrity of the email content).
Currently, there are only MeSince mail clients in China that support the S/MIME protocol, and Outlook, Thunderbird, Imail, etc. abroad.
Email security certificates, like SSL certificates, are divided into two types: trusted and untrusted. The status displayed in the trusted mail certificate outlook are as follows:
Trusted email security certificates are all paid. At present, there are many domestic manufacturers that can apply for trusted email security certificates, but from the perspective of price and application convenience, the trusted email security certificates currently provided by MeSince are cost-effective The highest price is 98 yuan/year, and the average day is only 0.26 yuan.
Today I will teach you how to apply for a global trust mail security certificate in MeSince, I hope it can help you.
(1) Open Mesign's official website (www.mesign.com) and click on the global trusted mail certificate purchase link under the "Take a glance" column; 
(2) Fill in the email information, select the purchase quantity and age;
(3) Complete the payment; 
(4) After the payment is completed, you will receive two emails in your mailbox, which are the verification code to download the email certificate and the link to download the certificate;
(5) Set the certificate protection password and download the certificate;
At this step, you will have a globally trusted mail certificate, which can be configured to a mail client that supports the S/MIME protocol to open a more secure way of mail communication.
As for how to configure the email security certificate to the email client, you can refer to this article, here is a more detailed email certificate configuration guide.
The article link is: https://www.mesign.com/zh-cn/e-mail/Vp_email_certificate_export_import_guide.html .