Certificate authorities

An organization that guarantees the authenticity of an SSL certificate (a public encryption key issued to a client). The reputation of CAs is generally considered to be beyond doubt, and data verified by them is taken as genuine.

CAs came to prominence following the widespread introduction of the secure HTTPS data transfer protocol. However, the mushrooming of CAs has caused concern about a decline in standards. Therefore, some browser and other software developers may not recognize certificates issued by CAs that they consider to be untrustworthy.