Cscu module 04 data encryption

1Copyright © by EC-Council
All Rights Reserved. Reproduction is Strictly Prohibited.
Data Encryption
Module 4
Simplifying Security.

May 23, 2011
40 Percent of IT Workers Could Hold Employer Networks Hostage, Survey Finds
Roughly 40 percent of IT workers believe they could hold an employer’s network hostage — even after
leaving the company — by withholding or hiding encryption keys, according to a recent survey of 500
IT security specialists.
The study, released Monday, May 23, also revealed that a third of survey respondents were confident
that their knowledge and access to encryption keys and certificates could bring a company to a halt
with little effort. Conducted in April 2011, the survey was sanctioned by Venafi, a network key and
encryption provider.
“It’s a shame that so many people have been sold
encryption but not the means or knowledge to
manage it,” said Jeff Hudson, CEO of Venafi, in a
statement. “IT departments must track where the
keys are and monitor and manage who has access to them. ... It’s no longer rocket science. Yet recent,
costly breaches at Sony, Epsilon and elsewhere reinforce the need for both more encryption and
effective management.”
http://www.govtech.com
2 Copyright © by EC-Council

Module Objectives
Common Terminologies
What Is Encryption?
Objectives of Encryption
Types of Encryption
Encryption Standards
Symmetric vs. Asymmetric
Encryption
Usage of Encryption
Digital Certificates
Working of Digital Certificates
Digital Signature
How Digital Signature Works?
Cryptography Tools

Module Flow
Encryption
Cryptography
Tools

5
Common Terminologies
Plaintext
Plaintext or cleartext is unencrypted readable text
Cipher Text
Cipher text is encrypted and unreadable until it is decrypted to
plaintext with a key
Encryption Key
An encryption key is a piece of information that is used to
encrypt and decrypt data

What Is Encryption?
Encryption is the process of converting data into a cipher text that cannot be
understood by the unauthorized people
To read an encrypted file, you must have access to a secret key or password that
enables you to decrypt it
Encryption is used to protect sensitive information during transmission and storage
Plain text
(‘ Morpheus ’)
Encrypted DATA
!@’~,.*3‘(w)”9
Alice receives the
plain data after
decryption
Encrypted DATA is
received by AliceBob Alice

7
Objectives of Encryption
Data Integrity The receiver of a message can check whether the message
was modified during transmission, either accidentally or
deliberately
Authentication The receiver of a message can verify the origin of the message
No other user should be able to send a message to the
recipient as the original sender (data origin authentication)
Non‐repudiation
The sender of a message cannot deny that he/she has sent
the message

Copyright © by EC-Council
served. Reproduction is Strictly Prohibited.
8
All Rights
Usage of Encryption
It helps to safely store
Encryption is used to protect
user credentials such as user
name and passwords
sensitive information on a
computer or external storage
media
Encryption provides a secure
medium for users to connect
to their friends’ or employees’
network from outside of the
home or office
It provides a higher level of
trust when receiving files from
other users by ensuring that the
source and contents of the
message are trusted
It is also used as a resource
for web‐based information
exchange to protect
important information such
as credit card numbers
Encryption provides
assurance of a sender’s
identity
Re

Module Flow
Types of
Encryption
Cryptography
Tools

Types of Encryption
Symmetric Encryption
Encryption Decryption
Dear John,
This is my
A/C number
7974392830
Symmetric encryption (secret‐key, shared‐key,
and private‐key) uses the same key for
encryption and decryption
Guuihifhofn
kbifkfnnfk
Nklclmlm
#^*&(*)_(_
Dear John,
This is my
A/C number
7974392830
Plain text Cipher text Plain text
Asymmetric Encryption
Asymmetric encryption (public key) uses
different encryption keys for encryption and
decryption. These keys are known as public
and private keys
DecryptionEncryption
Dear John,
This is my
A/C number
7974392830
Guuihifhofn
kbifkfnnfk
Nklclmlm
^#*&)*(_(_
Dear John,
This is my
A/C number
7974392830
Plain text Cipher text Plain text
Hash function
Hash Function
Hash function (message digests or one‐way
encryption) uses no key for encryption and
decryption
Hash function
Plain text Cipher text

Symmetricvs. AsymmetricEncryption
Symmetric encryption uses only one key
for both encryption and decryption
The key cannot be shared freely
Symmetric encryption requires that both
the sender and the receiver know the
secret key
Using symmetric encryption, data can
be encrypted faster
This algorithm is less complex and faster
Symmetric encryption ensures
confidentiality and integrity
Asymmetric Encryption uses a public key
for encryption and a private key for
decryption
In asymmetric encryption, the public key
can be freely shared, which eliminates the
risk of compromising the secret key
The encryption process using Asymmetric
Encryption is slower and more complex
Asymmetric encryption ensures
confidentiality, integrity, authentication,
and non‐repudiation

Module Flow
Encryption
Standards
Cryptography
Tools

13
Encryption Standards
Data Encryption
Standard (DES)
Data Encryption Standard (DES) is the name
of the Federal information Processing
Standard (FIPS) 46‐3, which describes the
data encryption algorithm (DEA)
The DEA is a symmetric cryptosystem
originally designed for implementation in
hardware
DEA is also used for single‐user encryption,
such as to store files on a hard disk in
encrypted form
Advanced Encryption
Standard (AES)
Advanced Encryption Standard (AES) is
a symmetric‐key encryption standard
adopted by the U.S. government
It has a 128‐bit block size, with key
sizes of 128, 192 and 256 bits,
respectively, for AES‐128, AES‐192 and
AES‐256

Module Flow
Digital
Certificates
Cryptography
Tools

Digital Certificates
A digital certificate is an electronic card that provides credential information while
performing online transactions
It acts as an electronic counterpart to a drivers license, passport, or membership
card and verifies the identity of all users involved in online transactions
A digital certificate generally contains:
Details of owner’s public key Owner’s name
Digital signature of the
CA (issuer)
Expiration date of
public key
Name of the Certificate
Authority (CA) who issued the
digital certificate
Serial number of digital
signature

AAuthority (CA)
Request for Issuin
Certificate
Registration
Authority (RA)
How Digital
Certification
CertificatesWork
Validation
uthority (VA)Updates Information
g
Public Key
Certificate
Determined
Result
Public Key
Certificate
User Applies for
Certificate
User Message in public key certificate
signed with digital signature


Validation of electronic signature
Inquires about public key certificate
validity to validation authority
Public Key
Private Key

Module Flow
Digital
Signature
Cryptography
Tools

Digital Signature
Digital signature implements asymmetric cryptographyto simulate the security
properties of a signature in digital, rather than written form
Digital signature schemes involve two encryption keys: a private key for signing the
message and a public key for verifying signatures
Digital standards follow the open standards as they are not tied to an individual or
manufacturer
It is often used to implement electronic signatures and can be used by any type of
message
It is independent of the signature verification between the sender and the receiver

How Digital Signature Works
hash code to message
one‐time symmetric key
to the recipient sender’s PUBLIC key
SIGN Appendthe signed ACCEPT
Confidential Hash value Sendersigns hash code using
Information his PRIVATE key
SEAL OPEN Decryptmessage using
Encryptmessage using Encryptthe symmetric key Recipient decryptone‐time symmetric
one‐timesymmetric key using recipient’s PUBLIC key key using his PRIVATE key
DELIVER VERIFY
Rehash the
message and
compare it
with the hash
value attached
Mail electronic envelopes Unlock the hash value using with the mail

Module Flow
Cryptography
Tools

Cryptography Tool: TrueCrypt
TrueCrypt creates a virtual encrypted disk within a
file and mounts it as a real disk
Encrypts an entire partition or storage device such
as USB flash drive or hard drive
Encrypts a partition or drive where Windows is
installed (pre‐boot authentication)
Encryption is automatic, real‐time (on‐the‐fly), and
transparent
http://www.truecrypt.org

Cryptography Tools
Folder Lock
http://www.newsoftwares.net
PixelCryptor
http://www.codegazer.com
AxCrypt
http://www.axantum.com
EncryptOnClick
http://www.2brightsparks.com
Cryptainer LE
http://www.cypherix.co.uk
SafeHouse Explorer
http://www.safehousesoftware.com
Advanced Encryption Package
http://www.intercrypto.com
Kruptos 2 Professional
http://www.kruptos2.co.uk

Module Summary
 Encryption is the process of converting data into a cipher text that cannot be understood
by the unauthorized people
Symmetric encryption uses only one key for both encryption and decryption, whereas
asymmetric encryption uses a public key for encryption and a private key for decryption
Encryption provides a higher level of trust when receiving files from other users by
ensuring that the source and contents of the message are trusted
A digital certificate is an electronic card that provides credential information when
performing online transactions
A digital signature implements asymmetric cryptography to simulate the security
properties of a signature in digital, rather than written form





Cscu module 04 data encryption

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Cscu module 04 data encryption