Recovering Encrypted Data

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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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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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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

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  • 280 Security+ acronyms flashcards to help you master the required acronyms
  • 204 Security+ Remember This slides

Audio - SY0-401 Security+ Remember This Audio Files

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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.

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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.

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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)

The 401 Version of the Study Guide is Now Available

SY0-401 Study GuideThe CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide is an update to the top-selling SY0-201 and SY0-301 study guides, which have helped thousands of readers pass the exam the first time they took it.

CompTIA Authorized Quality Content (CAQC)After a comprehensive review by ProCert Labs, the SY0-401 version has been certified as CompTIA Approved Quality Content (CAQC) and covers every aspect of the SY0-401 exam.

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Each of the eleven chapters presents topics in an easy to understand manner and includes real-world examples of security principles in action.

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If you plan to pursue any of the advanced security certifications, this guide will also help you lay a solid foundation of security knowledge. Learn this material, and you’ll be a step ahead for other exams. This SY0-401 study guide is for any IT or security professional interested in advancing in their field, and a must read for anyone striving to master the basics of IT security.

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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.

Restoring Cryptographic Keys

 

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.

Get the Full Security+ Course Here


 

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.

See Chapter 10 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide for more information on PKI components.

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