E and F
Cryptographic services include functions for authenticity, confidentiality, integrity, and nonrepudiation.
A and F
Because of its speed, symmetric encryption is a good choice for real-time encryption of bulk data. This speed is achieved because the encryption key is the same as the decryption key.
D and F
Asymmetric encryption is very powerful because it provides a public key (capable of handling encryption and decryption of data) and a private key (also capable of handling encryption and decryption of data). Asymmetric encryption is often used to create signatures and for key exchange only because of the high overhead associated with the algorithm.
B and F
If a hacker obtains a hash of some data, the only method they can use to reverse engineer the data is to use a brute force attack, which is computationally difficult. Hash does work well for ensuring data does not change accidentally; however, it does not protect against man-in-the-middle attacks. Because of this, hashing is often combined with an encryption algorithm, such as AES. AES can use MD5 or SHA-1 for hashing data.
Only F does not apply to digital signatures. Digital signatures are created by encrypting the result of a hashing process using a private key.
SHA-1 is the modern standard for creating a 160-bit hash. MD5 is no longer recommended because it can run into problems with duplicate hashes on large amounts of data.
Nonrepudiation methods prove to others that a certain source sent some data. This is very similar to authentication; however, authentication can only prove to YOU that a certain device sent the data rather than proving to OTHERS that a certain device sent the data.
Rivest, Shamir, and Adleman (RSA) is the only asymmetric algorithm in this list.
Asymmetric algorithms use two keys: one public and one private. The public key can be used for encryption and decryption of data and is sent to any requesting host. The private key can be used for encryption and decryption of data and is kept strictly for the sending host.
With current mathematical algorithms, it is feasibly impossible to generate a private key from a public key.
Part I: Cisco CallManager Fundamentals
Introduction to Cisco Unified Communications and Cisco Unified CallManager
Cisco Unified CallManager Clustering and Deployment Options
Cisco Unified CallManager Installation and Upgrades
Part II: IPT Devices and Users
Cisco IP Phones and Other User Devices
Configuring Cisco Unified CallManager to Support IP Phones
Cisco IP Telephony Users
Cisco Bulk Administration Tool
Part III: IPT Network Integration and Route Plan
Cisco Catalyst Switches
Configuring Cisco Gateways and Trunks
Cisco Unified CallManager Route Plan Basics
Cisco Unified CallManager Advanced Route Plans
Configuring Hunt Groups and Call Coverage
Implementing Telephony Call Restrictions and Control
Implementing Multiple-Site Deployments
Part IV: VoIP Features
Configuring User Features, Part 1
Configuring User Features, Part 2
Configuring Cisco Unified CallManager Attendant Console
Configuring Cisco IP Manager Assistant
Part V: IPT Security
Securing the Windows Operating System
Securing Cisco Unified CallManager Administration
Preventing Toll Fraud
Hardening the IP Phone
Understanding Cryptographic Fundamentals
Understanding the Public Key Infrastructure
Understanding Cisco IP Telephony Authentication and Encryption Fundamentals
Configuring Cisco IP Telephony Authentication and Encryption
Part VI: IP Video
Introducing IP Video Telephony
Configuring Cisco VT Advantage
Part VII: IPT Management
Introducing Database Tools and Cisco Unified CallManager Serviceability
Configuring Alarms and Traces
Using Additional Management and Monitoring Tools
Part VIII: Appendix
Appendix A. Answers to Review Questions