Page 82 - DCAP306_DCAP511_E-COMMERCE_AND_E-BUSINESS

Unit 6: Security Framework

To overcome information processing overhead, hash functions are used. Hash functions have the
capability to handle information of any size. They break down the information into fixed size bits that
are of small size. The generated information bits are then encrypted with the private key to create the
sender’s digital signature. At the receiving end, the encrypted information is decrypted using the
sender’s public key and the information bits are recomputed and verified with the original information
bits. If the match is found, then the receiver is assured of the sender’s authentication and integrity of the
information.

A useful advantage of using hash functions is that, any modification made to the original information
will alter the information size and thus, result in an entirely different information bits.

Did you know? The hash functions used for implementing digital signatures include algorithms such
as Secure Hash Algorithm (SHA) combined with Digital Signature Algorithm (DSA),
Message Digest Algorithms 4 (MD4), and Message Digest Algorithms 5 (MD5) from
RSA Data Security Inc.
6.2.4 Public Key Cryptography Standards
Public Key Cryptography Standards (PKCS) designed a standard format to transmit data over the
network using public key cryptography technique. PKCS is compatible with the Open System
Interconnection (OSI) Model standards and includes various aspects like RSA encryption, Diffie-
Hellman key exchange agreement, private key information syntax, and so on.

PKCS consists of various components designated as PKCS #1, PKCS #2, PKCS #3, PKCS
#4,……………… PKCS #10.
1. PKCS #1: Defines a standard for RSA Cryptography Specifications.
2. PKCS #2: It is incorporated into PKCS#1.
3. PKCS #3: Defines Diffie-Hellman key agreement standard.

4. PKCS #4: It is incorporated into PKCS#1.
5. PKCS #5: Defines a standard for Password-Based Cryptography Specifications.
6. PKCS #6: Defines extended-certificate syntax standard.
7. PKCS #7: Defines a Cryptographic Message Syntax for information that has cryptography applied
to it such as, digital signatures and digital envelopes.

8. PKCS #8: Defines private-key information syntax standard.
9. PKCS #9: Defines selected object classes and attribute types.
10. PKCS #10: Defines Certification Request Syntax for public-key certificates. The certification
request consists of a Distinguished Name (DN), public key, and other attributes signed by the
entity making the request. The request is sent to a Certification Authority (CA), who in turn
converts the request to an X.509 public-key certificate and returns it in PKCS #7 format.
6.2.5 Protocols for Secure Messaging

Security protocols form an important basis for sending information over communication networks.
They provide security for the transmitted information and assure secured communication without any
addition or deletion.

The various messaging protocols used for establishing a secured communication are:
1. Privacy Enhanced Mail (PEM): It is an Internet standard established to provide secure transfer of
electronic mail. PEM uses various cryptographic techniques to ensure confidentiality and integrity
of information. The integrity feature ensures a user that the transmitted information is not
modified. The authentication feature verifies that the PEM information received by the user is sent
by the original sender and not from any other source that claims to be the sender. The
confidentiality feature ensures that the transmitted information is not made available for

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