crytography
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TRANSCRIPT
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PRESENTED BY:
JATIN KAKKAR - 26 JESO P . JAMES - 28
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• INTODUCTION• HISTORY• OBEJECTIVE & OVERVIEW• APPLICATIONS• CRYPTOGRAPHY COMPONENTS• TERMINOLOGY• ASPECTS• TYPES OF CRYPTOGRAPHY• ADVANTAGES• CONCLUSION• REFERENCES
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• Cryptography is the science of information security.
• The word is derived from the Greek kryptos, meaning hidden.
• Cryptography includes techniques such as microdots, merging words with images, and other ways to hide information in storage or transit.
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• Confidentiality:- the information cannot be understood by anyone for whom it was unintended.
• Integrity :-the information cannot be altered in storage or transit between sender and intended receiver without the alteration being detected.
• Authentication :-the sender and receiver can confirm each others identity and the origin/destination of the information.
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Overview of Cryptography & Its Applications
• People wants and needs privacy and security while communicating.
• In the past, cryptography is heavily used for militaryapplications to keep sensitive information secret from enemies (adversaries).
• Nowadays, with the technologic progress as our dependency on electronic systems has increased we needmore sophisticated techniques.
• Cryptography provides most of the methods and techniquesfor a secure communication
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Cryptography components
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• Encryption – It is a process of changing or converting normal text or data information into gibberish text.
• Decryption – It is a process of changing or converting gibberish text back to correct message or data by using encryption method.
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Cryptology : All-inclusive term used for the study of securecommunication over non-secure channels.
Cryptography : The process of designing systems to realizesecure communications over non-secure channels.
Cryptoanalysis : The discipline of breaking the cryptographicsystems.
Coding Theory : Deals with representing the informationusing codes. It covers compression, secrecy, anderror correction.
Terminology
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The Aspects of Cryptography
• Modern cryptography heavily depends on mathematics and the usage of digital systems.
• It is a inter-disciplinary study of basically three fields:MathematicsComputer ScienceElectrical Engineering
• Without having a complete understanding of crypto analysis(or cryptoanalytic techniques) it is impossible to design good (secure, unbreakable) cryptographic systems.
• It makes use of other disciplines such as error-correcting codescompression.
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Categories of cryptography
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• A single common encryption key is used to encode and decode messages.
• Both sender and receiver must know the common key.
• The common key need to be exchanged before hand by some other secure method.
• Symmetric encryption is simple and fast.• But - key management is impractical with
large number of senders and receivers.
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Symmetric-key cryptography
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• Asymmetric system under, which two different keys are used to encrypt and decrypt the message or received data packet.
• On public key is used to encrypt the data or message and the private key on receiving end is used to decrypt the message or data packet.
• Each user has a Public key and a corresponding Private (secret) key
Asymmetric-key cryptography
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Asymmetric-key cryptography
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Keys used in cryptography
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• Sender”sign” messages by means of his private secret key.
• Recipient verify the senders signature by means of the senders public key.
• The senders identity is certified by means of a”Certificate” which is digitally signed by a trusted third party.
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• public-key cryptography Increased security and convenience.
• public-key cryptography is best suited for an open multi-user environment.
• Symmetric encryption is simple and fast.
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• cryptography = physics + Information theory
• Information is physical.
• Information gain implies disturbances.
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