Recovering Encrypted Data
A Public Key Infrastructure (PKI) is a group of technologies used to request, create, manage, store, distribute, and revoke digital certificates. A PKI allows two entities to privately share symmetric keys without any prior communication. If you’re planning to take the Security+ exam, you should have a basic understanding of cryptographic keys that establish secure access to data.
For example, can you answer this question?
Q. A user’s laptop developed a problem and can no longer boot. Help desk personnel tried to recover the data on the disk, but the disk is encrypted. Which of the following can be used to retrieve data from the hard drive?
A. A trust relationship
B. Public key
C. Recovery agent
D. CRL
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.
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Online access includes all of the content from the
CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide
- Introduction
- About the exam (including types of questions and strategies for performance-based questions)
- 100 question pre-assessment exam
- Mastering Security Basics (full content from Chapter 1 of the study guide including the exam topic review and 20 practice test questions)
- Exploring Control Types and Methods (full content from Chapter 2 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Basic Network Security (full content from Chapter 3 of the study guide including the exam topic review and 20 practice test questions)
- Securing Your Network (full content from Chapter 4 of the study guide including the exam topic review and 20 practice test questions)
- Securing Hosts and Data (full content from Chapter 5 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Malware and Social Engineering (full content from Chapter 6 of the study guide including the exam topic review and 20 practice test questions)
- Identifying Advanced Attacks (full content from Chapter 7 of the study guide including the exam topic review and 20 practice test questions)
- Managing Risk (full content from Chapter 8 of the study guide including the exam topic review and 20 practice test questions)
- Preparing for Business Continuity (full content from Chapter 9 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Cryptography (full content from Chapter 10 of the study guide including the exam topic review and 20 practice test questions)
- Exploring Operational Security (full content from Chapter 11 of the study guide including the exam topic review and 20 practice test questions)
- 100 question post-assessment exam
- Security+ Acronyms
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Random 100-question tests
Random practice tests from the all of the practice test questions in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide. All questions include explanations so you'll know why the correct answers are correct, and why the incorrect answers are incorrect.34 Simulated Performance-based Questions
Eight sets of performance-based questions with multiple questions in each set. These questions help you understand and prepare for performance based questions.22 Realistic Performance-based Questions
Two new sets of performance-based questions with a total of 22 questions. These new questions use a new testing engine that includes realistic drag and drop, matching, sorting, and fill in the blank questions.
Flashcard Set
- 273 Security+ Flashcards to reinforce key testable concepts
- 280 Security+ acronyms flashcards to help you master the required acronyms
- 204 Security+ Remember This slides
Audio - SY0-401 Security+ Remember This Audio Files
Learn by Listening. Over one hour and 15 minutes of audio (MP3 downloads.)Audio - SY0-401 Security+ Question and Answer Audio Files
Learn by Listening. Over three hours hour and 15 minutes of audio (MP3 downloads.)Bonus #1
Audio from the end of chapter reviews from each of the chapters in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide
. Over one hour and 15 minutes of additional audio.Bonus #2
Subnetting mini-tutorial that will help you answer two key question types:- Identify how many hosts a subnet supports
- Identify valid IP addresses within a subnet
Bonus #3
Access the study materials for a total of 60 days because sometimes life happens.Wildcard Certificates
In some situations, organizations choose to use wildcard certificates to reduce the management burden associated with certificates. As an example, imagine a web site with the domain name of GetCertifiedGetAhead.com. If a typical certificate is associated with this web site, it will only be valid for web pages in that domain. However, an organization can get a wildcard certificate for *. GetCertifiedGetAhead.com. This wildcard certificate is valid for the following domain names, too:
- train.GetCertifiedGetAhead.com
- blogs.GetCertifiedGetAhead.com
The * in the wildcard certificate will work for any single name added onto the domain name. In other words, administrators only need to purchase and install a single certificate for all three domain names. However, it only works for one level of domain names. It wouldn’t be valid for something like this: north.train.GetCertifiedGetAhead.com.
Remember this
A PKI requires a trust model between CAs. Most trust models are hierarchical and centralized with a central root CA. Wildcard certificates reduce the management burden associated with certificates.
Outdated Certificates
In some situations, users can find that they can no longer access data because they don’t have access to a previously used certificate. The classic example occurs when users are issued new smart cards. As an example, many contractors have contracts of a specific length, such as one year. When the year expires, the contract is typically renewed, but they need to get a new smart card. They’ll have problems digitally signing email and opening encrypted email.
The problem is that their previous certificate is published in the organization, typically in a global address list accessible to everyone else in the organization. What these users need to do is publish the new certificate embedded in their new smart card and this will resolve the problem.
Remember this
When an organization issues a user a new certificate, such as with a new smart card, the user needs to publish it within the organization, such as via a global address list. Otherwise, other people in the organization use the original certificate.
CompTIA Security+ Study Guide (SY0-401)
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Over 400 realistic practice test questions with in-depth explanations will help you test your comprehension and readiness for the exam. The book includes:
- A 100 question pre-test
- A 100 question post-test
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Key Escrow
Key escrow is the process of placing a copy of a private key in a safe environment. This is useful for recovery. If the original is lost, the organization retrieves the copy of the key to access the data. Key escrow isn’t required, but if an organization determines that data loss is unacceptable, it will implement a key escrow process.
In some cases, an organization provides a copy of the key to a third party. Another method is to designate employees within the organization who will be responsible for key escrow. These employees maintain and protect copies of the key, and if the original key is lost, they check out a copy of the key to an administrator or user.
Recovery Agent
A key recovery agent is a designated individual who can recover or restore cryptographic keys. In the context of a PKI, a recovery agent can recover private keys to access encrypted data. The recovery agent may be a security professional, administrator, or anyone designated by the company.
In some cases, the recovery agent can recover encrypted data using a different key. For example, Microsoft’s BitLocker supports encryption of entire drives. It’s possible to add a data recovery agent field when creating a BitLocker encrypted drive. In this case, BitLocker uses two keys. The user has one key and uses it to unlock the drive during day-to-day use. The second key is only accessible by the recovery agent and used for recovery purposes if the original key is lost or becomes inaccessible.
Remember this
Recovery agents can recover user messages and data when users lose access to their private keys. In some cases, recovery agents can recover the private key from a key escrow.
Full Security+ Course
Full Security+ Course Now Available
Helping you Pass the First Time
Online access includes all of the content from the
CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide
- Introduction
- About the exam (including types of questions and strategies for performance-based questions)
- 100 question pre-assessment exam
- Mastering Security Basics (full content from Chapter 1 of the study guide including the exam topic review and 20 practice test questions)
- Exploring Control Types and Methods (full content from Chapter 2 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Basic Network Security (full content from Chapter 3 of the study guide including the exam topic review and 20 practice test questions)
- Securing Your Network (full content from Chapter 4 of the study guide including the exam topic review and 20 practice test questions)
- Securing Hosts and Data (full content from Chapter 5 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Malware and Social Engineering (full content from Chapter 6 of the study guide including the exam topic review and 20 practice test questions)
- Identifying Advanced Attacks (full content from Chapter 7 of the study guide including the exam topic review and 20 practice test questions)
- Managing Risk (full content from Chapter 8 of the study guide including the exam topic review and 20 practice test questions)
- Preparing for Business Continuity (full content from Chapter 9 of the study guide including the exam topic review and 20 practice test questions)
- Understanding Cryptography (full content from Chapter 10 of the study guide including the exam topic review and 20 practice test questions)
- Exploring Operational Security (full content from Chapter 11 of the study guide including the exam topic review and 20 practice test questions)
- 100 question post-assessment exam
- Security+ Acronyms
Get the Full Security+ Course Here
Full Security+ Course Now Available
Test your readiness with these quality materials
Random 100-question tests
Random practice tests from the all of the practice test questions in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide. All questions include explanations so you'll know why the correct answers are correct, and why the incorrect answers are incorrect.34 Simulated Performance-based Questions
Eight sets of performance-based questions with multiple questions in each set. These questions help you understand and prepare for performance based questions.22 Realistic Performance-based Questions
Two new sets of performance-based questions with a total of 22 questions. These new questions use a new testing engine that includes realistic drag and drop, matching, sorting, and fill in the blank questions.
Flashcard Set
- 273 Security+ Flashcards to reinforce key testable concepts
- 280 Security+ acronyms flashcards to help you master the required acronyms
- 204 Security+ Remember This slides
Audio - SY0-401 Security+ Remember This Audio Files
Learn by Listening. Over one hour and 15 minutes of audio (MP3 downloads.)Audio - SY0-401 Security+ Question and Answer Audio Files
Learn by Listening. Over three hours hour and 15 minutes of audio (MP3 downloads.)Bonus #1
Audio from the end of chapter reviews from each of the chapters in the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide. Over one hour and 15 minutes of additional audio.Bonus #2
Subnetting mini-tutorial that will help you answer two key question types:- Identify how many hosts a subnet supports
- Identify valid IP addresses within a subnet
Bonus #3
Access the study materials for a total of 60 days because sometimes life happens.
Q. A user’s laptop developed a problem and can no longer boot. Help desk personnel tried to recover the data on the disk, but the disk is encrypted. Which of the following can be used to retrieve data from the hard drive?
A. A trust relationship
B. Public key
C. Recovery agent
D. CRL
Answer is C. Recovery agents can decrypt data and messages if the user’s private key is no longer available.
Although certificate authorities use trust models, a trust relationship doesn’t directly apply here.
A user’s public key is already publicly available, so it isn’t useful here.
A certificate revocation list (CRL) is a list of revoked certificates and doesn’t apply in this scenario.
