104201-DIGITALENVELOP

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Digital Envelope

Presented by :

Afjal Das P (104201)

Advanced Communication

Systems

M. Tech, 3rd Semester


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Contents

Introduction Why Digital Envelop

Formation of Digital Envelop

Reading Digital Envelop Common Algorithms used

Advantages

Applications Conclusion

Refernces


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Symmetric Key Cryptography

Helloeveryone

Dhfksadfhgein

Helloeveryone

Encryption Decryption

Key#1

Key#1

Plain Text Plain TextCipher Text


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Public Key Cryptography

Knowledge of the encryptionkey doesnt giveyou knowledge of the decryptionkey

Receiver of information generates a pair ofkeys

Publish the public key in a directory

Then anyone can send him messages thatonly he can read

Strength :

High Security

Need not pass key for decryption

Weakness

Very slow process


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Public Key Cryptography

Helloeveryone

Dhfksadfhgein

Helloeveryone

Encryption Decryption

Key#1

Key#2

Plain Text Plain TextCipher Text


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Digital Envelop

Two layers of encryption to protect amessage Message encoded using symmetric key

key to decode the message is encryptedusing public- key encryption

Overcomes the problem of public keyencryption

Only the key is protected with public keyencryption

Little overhead


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Plain Text

message

Receivers

Public key

Hash FunctionSymmetric

Key

Encryption

Symmetric

Key

Asymmetric

Key

Encryption

Message

Digest Encrypted

Text

Encrypted

Symmetric

Key

Digital Envelope

Asymmetric Key

EncryptionEncrypted

Message Digest

Encrypted

Hash ValueCipher Text

Encrypted Symmetric

Key

Digital Envelope


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Receivers

Private key

Encrypted

Hash ValueCipher Text

Encrypted Symmetric

Key

Secure Data

SymmetricKey

Message

Digest Plain Text

Hash

FunctionCompar

e

DiscardYes

No

Decryption

Asymmetric Key

Decryption

Asymmetric Key

Decryption

Hash

Value

Reading Digital Envelope


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Common Algorithms used

Hash algorithms MD5

SHA with at least 128 bits,256 bits better

Symmetric key cryptography

AES

min. 128 bits for RC-2 & RC-5,

3DES

CAST-128

Modified RC-4

Asymmetric key cryptography

RSA


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Advantages

Increased performance withoutsacrificing security

Multi addressed communications

email Single copy of encrypted message

Different public keys for each user

Switch secret keys as frequently aspossible


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Applications

Key exchange protocols

PGP open source for email security

Oracle S-MIME (Multipurpose Internet

Mail Extension)

SSL (Secure Socket Layer)


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Conclusion

Using Digital envelop we can achieve High security

High performance

Little overhead


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References

Ramachandran Ganesan1, Mohan Gobi1andKanniappan Vivekanandan Novel Digital EnvelopeApproach for A Secure E-Commerce ChannelInternational Journal of Network Security, Vol.11, No.3,PP.121{127, Nov. 2010

Wenping Guo, Ying Chen, and Xiaoming Zhao A Studyon High-Strength Communication Scheme Based onSigned Digital Envelope Proceedings of the SecondInternational Symposium on Networking and NetworkSecurity (ISNNS 10) Jinggangshan, P. R. China, 2-4,

April. 2010, pp. 190-192 Jinggangshan, P. R. China, 2-4, April. 2010, pp. 190-

192

W. Stallings, Cryptography and Network Security:Principles and Practice, 2nd Edition, Pearson

Education, 2002.
http://www.rsa.com/rsalabs/node.asp?id=2184


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104201-DIGITALENVELOP

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