FTB Cryptography

8/4/2019 FTB Cryptography

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PRESENTED BY ARVIND SINGH Guided By

BRANCH : I.T Dr. Gaurav JainCOLLEGE : R.C.E.R.T


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Introductiony Definitions

yWhy cryptography is important?

y Encryption & Decryption

yAvailable technologies

y Benefits & problems

y Future of cryptography


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Essential Termsy Cryptography

y EncryptionPlain text Cipher text

y DecryptionCipher text Plain text

y Cryptanalysis : is the study ofmethods for obtaining the

meaning of encrypted informationy Cryptology : The practice of

analysing encoded messages, inorder to decode them.


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Encryption & Decryptiony Encryption :Encryption is

the conversion of data intoa form, called a ciphertext, that cannot be easily

understood byunauthorized people.

y Decryption : Decryptionis the process ofconverting encrypted databack into its original form,so it can be understood.


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Information Se

curity use

d fory Defending against external/internal hacker

y Securing E-commerce

y

Securing bank accounts/electronic transfersy Securing data transfer


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Thre

ats

to Information Se

curity

y Online storage of sensitiveinformation

y

Insecure technologies (e.g.wireless)

y Trend towards paperlesssociety

y Weak legal protection of email

privacy


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Types of Secret Writing

Secret writing

Steganography Cryptography

Substitution Transposition

Code

Cipher


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Steganography

y Steganography covered writing

is an art of hidinginformation

y Popularcontemporary

steganographictechnologies hideinformation inimages


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Hiding information in pictures

Image in which to hide

another image

Image to hide within the

other image


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Retrieving information from pictures

Image with other

hidden withinRecreated image


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Public Key Cryptographyy Public-key cryptography: refers to a cryptographic

system requiring two separate keys.

yOne to lock or encrypt the plain text.

y One to unlock or decrypt the cipher text.

y Neither key will do both functions.

y One of these keys is public and the other is kept

private.


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Public Key Cryptographyy Private (symmetric) key the same key

used for encryption/decryption.

y Problem of key distribution arises.

y Public (asymmetric) key cryptography apublic key used for encryption and privatekey for decryption.

y Key distribution problem solved.


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Currently Available Crypto Algorithms(private key)

DES (Data Encryption Standard) andderivatives: double DES and triple DES

IDEA (International Data Encryption Standard)

Blowfish

RC5 (Rivest Cipher #5)

AES (Advance Encryption Standard)


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Currently Available Crypto Algorithms(public key)

RSA (Rivest, Shamir, Adleman)

DH (Diffie-Hellman Key AgreementAlgorithm)

ECDH (Elliptic Curve Diffie-Hellman KeyAgreement Algorithm)

RPK (Raike Public Key)


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Currently Available Technologies

PGP (Pretty Good Privacy) a hybrid

encryption technologyy Message is encrypted using a private key

algorithm (IDEA)

y Key is then encrypted using a public keyalgorithm (RSA)

y For file encryption, only IDEA algorithm is usedy PGP is free for home use


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Authe

ntication and DigitalSignatures

Preventing impostor attacks

Preventing content tampering

Preventing timing modification

Preventing repudiation


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Digital Signatures

y It is made by encrypting a message with

the senders private keyy Receiver decrypts with the senders public

key (roles of private and public keys areflipped)

y

Digital signature does not confirm identity


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J

AVA and XML Cryptography

y java.security package includes classes used

for authentication and digital signaturey javax.crypto package contains JavaCryptography Extension classes

yXMLmakes it possible to encrypt or

digitally sign parts of a message, differentencryption for different recipients, etc.


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Benefits of Cryptographic Technologies

y Data secrecy

y Data integrity

yAuthentication ofmessage originator

y Electronic certificationand digital signature


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Problems with Cryptographic Technologies?

y False sense of security ifbadly implemented

y Government regulation ofcryptographic technologiesrestrictions

y Encryption prohibited in

some countries


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H

ow Se

cure

are

Todays

Te

chnologies?

y Encryption does not guarantee security!

y Many ways to beat a crypto system NOTdependent on cryptanalysis, such as:y Viruses, worms, hackers, etc.

y TEMPEST attacks,

y Unauthorized physical access to secret keys

y

Cryptography is only one element ofcomprehensive computer security


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The Future of Secret Writing

Quantum cryptanalysisy A quantum computer can

perform practically unlimited

number of simultaneouscomputations

y Factoring large integers is anatural application for aquantum computer

y Quantum cryptanalysis wouldrender ALLmoderncryptosystems instantly obsolete


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The Future of Secret Writing (continued)

Quantum encryptiony

No need for a quantum computery A key cannot be intercepted without

altering its content

y It is theoretically unbreakable

y Central problem is transmitting a

quantum message over a significantdistance


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Summaryy Cryptography referred almost exclusively

to encryption, which is the process of

converting plaintext into cipher text.y Decryption is the reverse, in other words,

moving from the cipher text back to plain text.

Acipheris a pair of algorithms that create the

encryption and the reversing decryption. The detailedoperation of a cipher is controlled both by thealgorithm and in each instance by a key.


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