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Presentation on Cryptography
- 1. INTRODUCTION TO CRYPTOGRAPHY Name: KaranJaiswal Dept.: B.C.A(H), 6th Semester College: Siliguri Institute of Technology
- 2. CONTENTS • Security • SecurityThreats • Security Goals • Cryptography • Types of Cryptography • Symmetric Key Cryptography • Asymmetric Key Cryptography • Basic Terms • Cipher • Types of Cipher • Substitution Cipher • Transposition Cipher • Ciphertext • Encryption & Decryption • Types of Keys • Symmetric Vs Asymmetric • Applications of Cryptography • Conclusion
- 3. ARE WE SECURETODAY? Security?
- 4. SECURITY THREATS Passive ThreatsActive Threats Release of Message Contents Traffic Analysis Masquerade Replay Modification of Message Contents Denial of Service Passive & Active Security Threats
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- 6. CRYPTOGRAPHY Cryptography is the scienceand art of transforming messages to make them secure and immune to attack. Hi Hi x0Ak3 o$2Rj x0Ak3 o$2Rj
- 7. TYPES OF CRYPTOGRAPHY CRYPTOGRAPHY SYMMETRICKEY CRYPTOGRAPHY ASYMMETRIC KEY CRYPTOGRAPHY
- 8. SYMMETRIC KEY CRYPTOGRAPHY EncryptionDecryption Cipher Text Sender Receiver Secret Key * Sender & receiver uses same key & an encryption/decryption algorithm to encrypt/decrypt data. i.e. the key is shared.
- 9. ASYMMETRIC KEY CRYPTOGRAPHY EncryptionDecryption Cipher Text Sender Receiver Public Key * Sender & receiver uses different keys for encryption & decryption namely Public & Private respectively. Private Key
- 10. BASIC TERMS • CIPHER •CIPHERTEXT • ENCRYPTION & DECRYPTION • KEYS
- 11. CIPHER In cryptography, acipher (or cypher) is an algorithm for performing encryption or decryption - a series of well- defined steps that can be followed as a procedure.
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- 13. SUBSTITUTION CIPHER A substitutiontechnique is one in which the letters / number / symbols of plaintext are replaced by other letters/numbers/symbols. Ex.: A→D, T→Z, 2→5, 3→6
- 14. TRANSPOSITION CIPHER In thetransposition technique the positions of letters / numbers / symbols in plaintext is changed with one another. Ex.: 1 2 3 4 5 6 M E E T M E A F T E R P A R T Y 4 2 1 6 3 5 T E M E E M E F A P T R Y R A T Plain text: MEET ME AFTER PARTY Cipher text: TEMEEMEFAPTRYRAT KEY USED: 421635
- 15. CIPHERTEXT In cryptography, ciphertextor cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher to decrypt it.
- 16. ENCRYPTION & DECRYPTION CONFIDENTIAL DOCUMENT ABCD qANQr1DBw1il U+DBlzrGY ZyXw CONFIDENTIAL DOCUMENT ABCD PlainText Plain TextCipher TextEncryption Decryption
- 17. TYPES OF KEYS PublicKey Private KeySecret Key SYMMETRIC KEY CRYPTOGRAPHY ASYMMETRIC KEY CRYPTOGRAPHY
- 18. SYMMETRIC VS ASYMMETRIC SYMMETRICKEY CRYPTOGRAPHY ASYMMETRIC KEY CRYPTOGRAPHY 1) The same algorithm with the same key is used for encryption and decryption. 1) One algorithm is used for encryption and decryption with a pair of keys, one for encryption and one for decryption. 2) The key must be kept secret. 2) One of the two keys must be kept secret. 3) Symmetric encryption takes relatively less time than the asymmetric encryption. 3) Asymmetric encryption takes relatively more time than the symmetric encryption.
- 19. APPLICATIONS OF CRYPTOGRAPHY •Defence services • Secure data manipulation • E – commerce • Business transactions • Internet payment systems • User identification systems • Access control • Data security
- 20. CONCLUSION By the useof cryptography a fair unit of confidentiality, authentication, integrity, access control and availability of data is maintained.
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