Explanation/Reference:
Explanation:
A vulnerability is defined as "the absence or weakness of a safeguard that could be exploited".
A vulnerability is a lack of a countermeasure or a weakness in a countermeasure that is in place. It can be a software, hardware, procedural, or human weakness that can be exploited. A vulnerability may be a service running on a server, unpatched applications or operating systems, an unrestricted wireless access point, an open port on a firewall, lax physical security that allows anyone to enter a server room, or unenforced password management on servers and workstations.
Incorrect Answers:
A: A threat is any potential danger that is associated with the exploitation of a vulnerability.
C: A risk is the likelihood of a threat agent exploiting a vulnerability and the corresponding business impact.
D: An exposure is an instance of being exposed to losses. A vulnerability exposes an organization to possible damages.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 26

Triple DES encrypts a message three times. This encryption can be accomplished in several ways. The most secure form of triple DES is when the three encryptions are performed with three different keys. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 152).

The public key would be found. The public key is used to validate the Digital Signature contained within the Digital Certificate. As you well know the private key would never be distributed and only the owner of the certificate would have a copy of the private key.
In cryptography and computer security, a root certificate is either an unsigned public key certificate or a self-signed certificate that identifies the Root Certificate Authority (CA). A root certificate is part of a public key infrastructure scheme. The most common commercial variety is based on the ITU-T X.509 standard, which normally includes a digital signature from a certificate authority (CA).
Digital certificates are verified using a chain of trust. The trust anchor for the digital certificate is the Root Certificate Authority (CA).
A certificate authority can issue multiple certificates in the form of a tree structure. A root certificate is the top-most certificate of the tree, the private key of which is used to "sign" other certificates. All certificates immediately below the root certificate inherit the trustworthiness of the root certificate a signature by a root certificate is somewhat analogous to "notarizing" an identity in the physical world. Certificates further down the tree also depend on the trustworthiness of the intermediates (often known as "subordinate certification authorities").
Many software applications assume these root certificates are trustworthy on the user's behalf. For example, a web browser uses them to verify identities within SSL/TLS secure connections. However, this implies that the user trusts their browser's publisher, the certificate authorities it trusts, and any intermediates the certificate authority may have issued a certificate-issuingcertificate, to faithfully verify the identity and intentions of all parties that own the certificates. This (transitive) trust in a root certificate is the usual case and is integral to the X.509 certificate chain model. The root certificate is usually made trustworthy by some mechanism other than a certificate, such as by secure physical distribution. For example, some of the most well-known root certificates are distributed in the Internet browsers by their manufacturers
The following answers are incorrect:
The Private Key is never distributed, only the owner would have a copy of the private key.
Symmetric keys have no direct relation to Public Key cryptosystems.
A recovery key is usually used with full drive encryption tool when a user has lost or damage his
key.
The following reference(s) were/was used to create this question:
http://en.wikipedia.org/wiki/Root_certificate
and
Getting a root CA accepted within browsers

Section: Security Architecture and Engineering