Key pair usage

A key pair is bound to a usage profile by its public key certificate.

• Public keys are seldom multi-purpose.

Typical usages.

• Authentication / key distribution.

  • Digital signature, Key encipherment, Data encipherment, Key agreement.

• Document signing.

  • Digital signature, Non-repudiation.

• Certificate issuing.

  • Certificate signing, CRL signing.

Public key certificates have an extension for this.

• Key usage (critical).