In the US, insults are not something for which you can be prosecuted. Calling someone a son of a bitch is not defamatory. No one believes you are really the child of a dog. So that is an opinion. Defamation requires a false factual statement. Truth is a complete defense.
What is Public Key Infrastructure (PKI)? Public Key Infrastructure (PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a certificate authority (CA). Wikipedia.org
A data summary of the information (called a message digest) is created through the use of a hash function (called the Secure Hash Standard, or SHS, and specified in FIPS 180). The data summary is used in conjunction with the DSA algorithm to create the digital signature that is sent with the message. digital signature (not to be confused with a digital certificate) is a mathematical technique used to validate the authenticity... See complete definition. PKI (public key infrastructure). A public key infrastructure (PKI) supports the distribution and identification of public encryption keys, enabling users and ...