1. Authentication: HTTPS certificates ensure that users communicate with legal and trusted entities by verifying the identity of websites or applications. Certification center (CA) will carry out strict authentication and verification process for the identity of the website or application to ensure its legitimacy and credibility.

2. Data encryption: HTTPS certificate uses encryption algorithm to encrypt the transmitted data to ensure the security of sensitive information during transmission. Only by mastering the correct private key can the encrypted data be decrypted and read, which improves the confidentiality of the data.

3. Integrity protection: HTTPS certificates use digital signatures to protect data to prevent data from being tampered with or manipulated during transmission. The receiver can use the public key in the certificate to verify the digital signature and ensure the integrity and credibility of the data.

4. User trust establishment: HTTPS certificates can be verified and identified by the root certificate authority built into the browser or operating system, and trust indications of websites or applications can be displayed to users, such as green HTTPS lock icons or green address bars of names. This helps users build trust in websites or applications.