Both certificates work in the same way. They enable you to create sites that are inaccessible to third parties. Data transferred through an SSL or HTTPS connection is encrypted to provide a high level of security.

A certificate from a CA implies that your website is secure, because it is certified by a trusted source. CA's like Verisign verify the ownership of the domain and check the trustworthiness of the business before issuing an SSL security certificate.

A self-signed certificate can be useful in testing environments or when the transmitted data is not particularly sensitive.