Protection against untrusted certificates

Your personal data and payment information should be protected when you send them to a website. Websites use the HTTPS protocol for secure connection. The protocol activates an asymmetric encryption algorithm, where data is encrypted with a public key and decrypted with a private key. For each session, the browser regenerates the private key and transmits it to the website in addition to taking precautionary measures to prevent theft.

However, if you end up on a phishing website, it might get the private key and then decrypt your data. To protect against phishing, websites use digital certificates issued by special certification authorities. The certificate guarantees that the encryption keys actually belong to the website owner.

You may end up on a phishing website, or your data will not get the necessary protection on the original website (for example, if the website's certificate has expired). As a result, hackers can:

• Intercept or replace your personal data and read your correspondence.
• Get your payment data (card number, holder's name, expiry date and CVV2) and use it to steal money from your account.

Yandex Browser blocks websites that have the following certificate problems:

The certificate authority is unknown

The certificate might have been installed by a hacker or special software. Ad blockers and similar applications may replace website certificates with their own certificates. If the certificate was installed by an application, you need to find it and disable checking HTTPS in it.

You can also decide to trust your data to such a certificate, but be aware of two potential dangers:

• Your data may become available to unknown application developers.
• The certificate may be installed by malware pretending to be the application. Modern browsers do not know how to verify the authenticity of certificates installed by special applications.

Incorrect site address

The website's security certificate refers to another website. The server may be just incorrectly configured, but it's possible that you have ended up on a phishing website. If this is the case, hackers can intercept your data.

Self-signed certificate

The site certificate is issued by the site itself, rather than by a certification authority. To find out more, see Self-signed certificate. Malware or hackers can intercept your data.

Untrusted root certificate

The authority that signed the certificate is not trusted. Malware or hackers can intercept your data. For more on root certificates, see the article Root Certificate.

The certificate has expired

The data that is sent will not be encrypted, which means that hackers can intercept it.

Certificate has been revoked

The site's certificate was compromised and revoked. The data that is sent will not be encrypted, which means that hackers can intercept it.

Outdated encryption

The server uses an outdated, untrustworthy encryption algorithm. Hackers can intercept your data.

Ciphers are not supported

An HTTPS connection cannot be established, because the website uses ciphers not supported by the browser. The data that is sent will not be encrypted, which means that hackers can intercept it.

The certificate key does not match the pinned key

The certificate key does not match the pinned website key. Hackers may try to replace the root certificate. Then they can intercept your data. To find out more about pinning (linking) a key, see HTTP Public Key Pinning.

Data can not be encrypted over HSTS

The browser could not enable encryption and broke the connection. The server where the website is located normally uses encryption, since the HSTS protocol is enabled on it. Lack of encryption may be a sign of a hacker attack. In this case, hackers or malware can intercept your data.