Cscu module 04 data encryption

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

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

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 Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

CommonTerminologies
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
5
Copyright © by EC-Council

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
Encrypted DATA is
received by Alice
Alice receives the
plain data after
What Is Encryption?
Plain text
Bob (‘Morpheus’) Alice
decryption
Encrypted DATA
(‘3*.,~’@!w9”)

Objectives of Encryption
Data Integrity
Authentication
Non‐repudiation
The receiver of a message can check whether the message
was modified during transmission, either accidentally or
deliberately
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)
The sender of a message cannot deny that he/she has sent
the message

Usage of Encryption
It helps to safely store
sensitive information on a
computer or external storage
media
Encryption is used to protect
user credentials such as user
name and passwords
Encryption provides
assurance of a sender’s
identity
Encryption provides a secure
medium for users to connect
to their friends’ or employees’
network from outside of the
home or office
It is also used as a resource
for web‐based information
exchange to protect
important information such
as credit card numbers
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

Module Flow
Encryption Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

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

Symmetric vs. Asymmetric Encryption
Symmetric Encryption Asymmetric Encryption
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 Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

Encryption Standards
Data Encryption
Standard (DES)
Advanced Encryption
Standard (AES)
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) 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
Encryption Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

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:
Digital Certificates
Details of owner’s public key
Digital signature of the
CA (issuer)
Serial number of digital
signature
Owner’s name
Expiration date of
public key
Name of the Certificate
Authority (CA) who issued the
digital certificate

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

Module Flow
Encryption Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

Digital Signature
Digital signature implements asymmetric cryptography to 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
SIGN
SEAL
DELIVER
ACCEPT
OPEN
VERIFY
Encrypt message using
one‐time symmetric key
Encrypt the symmetric key
using recipient’s PUBLIC key
Mail electronic envelopes
to the recipient
Confidential
Information
Rehash the
message and
compare it
with the hash
value attached
with the mail
Recipient decrypt one‐time symmetric
key using his PRIVATE key
Decrypt message using
one‐time symmetric key
Hash value Sender signs hash code using
his PRIVATE key
Append the signed
hash code to message
Unlock the hash value using
sender’s PUBLIC key

Module Flow
Encryption Types of
Encryption
Encryption
Standards
Digital
Certificates
Digital
Signature
Cryptography
Tools

Cryptography Tool: TrueCrypt
http://www.truecrypt.org
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

PixelCryptor
http://www.codegazer.com
Folder Lock
http://www.newsoftwares.net
EncryptOnClick
http://www.2brightsparks.com
AxCrypt
http://www.axantum.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
Cryptography Tools

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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