5.6. Tokens for Storing Certificate System Subsystem Keys and Certificates

A token is a hardware or software device that performs cryptographic functions and stores public-key certificates, cryptographic keys, and other data. The Certificate System defines two types of tokens, internal and external, for storing key pairs and certificates that belong to the Certificate System subsystems.
An internal (software) token is a pair of files, usually called the certificate database (cert8.db) and key database (key3.db), that the Certificate System uses to generate and store its key pairs and certificates. The Certificate System automatically generates these files in the filesystem of its host machine when first using the internal token. These files are created during the Certificate System subsystem configuration if the internal token was selected for key-pair generation.
These security databases are located in the /var/lib/pki/instance_name/alias directory.
An external token refers to an external hardware device, such as a smart card or hardware security module (HSM), that the Certificate System uses to generate and store its key pairs and certificates. The Certificate System supports any hardware tokens that are compliant with PKCS #11.
PKCS #11 is a standard set of APIs and shared libraries which isolate an application from the details of the cryptographic device. This enables the application to provide a unified interface for PKCS #11-compliant cryptographic devices.
The PKCS #11 module implemented in the Certificate System supports cryptographic devices supplied by many different manufacturers. This module allows the Certificate System to plug in shared libraries supplied by manufacturers of external encryption devices and use them for generating and storing keys and certificates for the Certificate System managers.
Consider using external tokens for generating and storing the key pairs and certificates used by Certificate System. These devices are another security measure to safeguard private keys because hardware tokens are sometimes considered more secure than software tokens.
Before using external tokens, plan how the external token is going to be used with the subsystem:
  • All system keys for a subsystem must be generated on the same token.
  • The subsystem must be installed in an empty HSM slot. If the HSM slot has previously been used to store other keys, then use the HSM vendor's utilities to delete the contents of the slot. The Certificate System has to be able to create certificates and keys on the slot with default nicknames. If not properly cleaned up, the names of these objects may collide with previous instances.
The Certificate System can also use hardware cryptographic accelerators with external tokens. Many of the accelerators provide the following security features:
  • Fast SSL/TLS connections. Speed is important to accommodate a high number of simultaneous enrollment or service requests.
  • Hardware protection of private keys. These devices behave like smart cards by not allowing private keys to be copied or removed from the hardware token. This is important as a precaution against key theft from an active attack of an online Certificate Manager.
The Certificate System supports the nCipher nShield hardware security module (HSM), by default. Certificate System-supported HSMs are automatically added to the secmod.db database with modutil during the pre-configuration stage of the installation, if the PKCS #11 library modules are in the default installation paths.
During configuration, the Security Modules panel displays the supported modules, along with the NSS internal software PKCS #11 module. All supported modules that are detected show a status of Found and is individually marked as either Logged in or Not logged in. If a token is found but not logged in, it is possible to log in using the Login under Operations. If the administrator can log into a token successfully, the password is stored in a configuration file. At the next start or restart of the Certificate System instance, the passwords in the password store are used to attempt a login for each corresponding token.
Administrators are allowed to select any of the tokens that are logged in as the default token, which is used to generate system keys.