(Public Key Cryptography Standard #10) A standard that is one of many standards produced and distributed by RSA Data Security, Inc. This standard defines a syntax for a certificate signing request (CSR).

A CSR consists of a distinguished name, a public key, and an optional set of attributes. The CSR is signed by the entity requesting certification. The CSR is sent to a certificate authority (CA) who transfers the request into an X.509 public key certificate.