DST will make your certificate available on the World Wide Web to enable others to find it. Because your certificate contains your identity information and the associated public key, it does not need to be kept private. Your private key is separate from your certificate. It is not displayed in your certificate and cannot be determined from the information displayed in your certificate. You must protect your private key and keep it a secret.
Most people store their private keys using the password protection of their Web browser.
Your private encryption key is literally the key that opens up your digital certificate. The private key is used to digitally sign documents which others can verify using your public key that is part of your certificate. Your private key is also used to decrypt private information so that only you may read it. If someone else obtained your private key, that person could masquerade as you, digitally sign as you, and read your encrypted information.