Why were the trust certificates that are “blocked” actually blocked, and what do all the other certificates do?

When a certificate is marked as "blocked" on an iPhone, it means that the device has determined that the certificate is not trustworthy and may pose a security risk. This can happen for a variety of reasons, such as the certificate being expired, revoked, or issued by an untrusted authority.

Certificates on an iPhone are used to verify the identity of websites and other online services, as well as to establish secure connections for data transmission. When you visit a website or use an app that requires a secure connection, your device will check the certificate associated with that connection to ensure that it is valid and trustworthy.

In general, there are several types of certificates that you may encounter on an iPhone:

1. Root certificates: These are trusted certificates that are used to verify the identity of other certificates. They are issued by trusted certificate authorities and are pre-installed on your device.
2. Intermediate certificates: These certificates are used to chain the trust between root certificates and the end-entity certificates that are used to secure websites and other online services.
3. End-entity certificates: These certificates are used to secure websites and other online services, and are issued by trusted certificate authorities.

If a certificate is blocked on your iPhone, it means that your device has determined that the certificate is not trustworthy and may pose a security risk. In general, it is best to avoid websites or services that use blocked certificates, as they may be vulnerable to security threats or other issues. If you encounter a blocked certificate while browsing the web or using an app, it is recommended to close the website or app and contact the website or app's support team for assistance.