What are CAs?
Briefly, a Certification Authority or CA is an entity that digitally signs other entities’ certificates. (A Certification Authority is also sometimes referred to as a Certificate Authority.) As mentioned previously, a certificate contains an entity’s public key, and is digitally signed using some entity’s private key. A “self-signed” certificate is one in which the private key used to digitally sign the certificate is the private key corresponding to the public key in the certificate itself; in other words, the entity signing the certificate is the same entity whose public key is in the certificate (hence the term “self-signed”). Verifying the digital signature on a self-signed certificate can then be done using the public key in the certificate itself, as described above. If the signature is valid then we can be reasonably sure that the public key in the certificate has not been corrupted in any way, and that any other data found in the certificate is as originally put there by the en
