In cryptography, PKCS stands for “Public Key Cryptography Standards”. These are a group of public-key cryptography standards devised and published by RSA Security LLC, starting in the early 1990s.
The company published the standards to promote the use of the cryptography techniques to which they had patents, such as the RSA algorithm, the Schnorr signature algorithm and several others. Though not industry standards (because the company retained control over them), some of the standards in recent years have begun to move into the “standards-track” processes of relevant standards organizations such as the IETF and the PKIX working-group.
Personal Information Exchange Syntax Standard
See RFC 7292. Defines a file format commonly used to store private keys with accompanying public key certificates, protected with a password-based symmetric key. PFX is a predecessor to PKCS #12.
This container format can contain multiple embedded objects, such as multiple certificates. Usually protected/encrypted with a password. Usable as a format for the Java key store and to establish client authentication certificates in Mozilla Firefox. Usable by Apache Tomcat.