It is essential that your blog is encrypted with trusted CA SSL Certificate instead of self –signed certificates.
SSL provides data integrity, authenticity and security for your blog and helps to protect the site from man-in-the-middle and eavesdropping attacks, so hackers cannot modify the content. CA signed certificates offers industry standard 2048-bit encryption key length and validates your control over the domain to prove website trustworthiness.
For these reasons, over the past few months we’ve been running tests taking into account whether sites use secure, encrypted connections as a signal in our search ranking algorithms. We’ve seen positive results, so we’re starting to use HTTPS as a ranking signal. For now, it's only a very lightweight signal—affecting fewer than 1% of global queries, and carrying less weight than other signals such as high-quality content—while we give webmasters time to switch to HTTPS. But over time, we may decide to strengthen it, because we’d like to encourage all website owners to switch from HTTP to HTTPS to keep everyone safe on the web.
Self-signed vs CA signed SSL certificates
When we talk about security-wise, both certificates provide the same protection and encryption for your website and your shared information will be safe and secure on the Internet. The difference between both certificates is customers’ trust.
CA is an entity who verifies the website and/or business ownership before issuing a digital certificate for your website. It means authentication process handling by third-party as well CA singled certificates are recognized by all browsers and discover secure signs – green padlock and HTTPS:// as well, therefore, your web users can easily notice that website is safe and reliable.
A self-signed certificate is self-generated where verification process missing, it means there is the big question for website honesty. Browsers don’t support self-signed certificates and encounter your web pages with a warning message.
Read more risk involved in self-signed certificate: https://www.ssl2buy.com/wiki/self-signed-certificate-vs-trusted-ca-signed-certificate/