Cryptography by Durlab Kumbhakar
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Cryptography is the practice of hiding information to store or communicate it in a secure way. It allows for confidentiality, integrity, and authentication of messages. There are two main types: symmetric key cryptography which uses a single key for encryption and decryption, and asymmetric key cryptography which uses different public and private keys. Popular symmetric algorithms include AES and DES, while RSA is an example of an asymmetric algorithm. The seminar discussed the components, processes, and applications of cryptography as well as examples of algorithms and common attacks.
Cryptography by Durlab Kumbhakar
- 2. What is Cryptography? Cryptography derived its name from the Greek words called “krypto’s” which means “Hidden or Secrets” and “graphein” which means “Writing or Study.” Cryptography is the practice and study of hiding information or secret writing. It is the Art or Science of converting a plain intelligible data into an unintelligible data and again retransforming that message into its original form. It provides Confidentiality, Integrity, and Accuracy.
- 3. Purpose of Cryptography Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver. Integrity: Assuring the receiver that the received message has not been altered in any way from the original. Non-repudiation: A mechanism to prove that the sender really sent this message.
- 4. Component of Cryptosystem • Plaintext • Encryption Algorithm • Ciphertext • Decryption Algorithm • Encryption Key • Decryption Key
- 6. Types of Cryptography Two types of Cryptography is available 1. SYMMETRIC KEY CRYPTOGRAPHY 2. ASYMMETRIC KEY CRYPTOGRAPHY
- 7. • Single key used to encrypt and decrypt. • Key must be known by both parties. • Assuming we live in a hostile environment, it may be hard to share a secret key.. • Examples of popular symmetric algorithms include DES, 3DES, AES, Blowfish, etc. 1. Symmetric Key Cryptography
- 8. Different keys are used to encrypt and decrypt the information. Each entity has 2 keys: Private Key (a secret) Public key (well known); one key is used for encryption, the other can decrypt the ciphertext back to the original plaintext. Examples of popular Asymmetric algorithms include RSA, DSA, etc 2. Asymmetric Key Cryptography
- 9. TYPES OF CRYPTOGRAPHIC ALGORITHMS
- 10. 3DE S • DES (the data encryption standard) is a symmetric block cipher. The algorithm uses a 56-bit key to encipher/decipher a 64-bit block of data. The key is always presented as a 64-bit block, every 8th bit of which is ignored. However, it is usual to set each 8th bit so that each group of 8 bits has an odd number of bits set to 1. Use of multiple length keys leads us to the Triple-DES algorithm, in which DES is applied three times. If we consider a triple length key to consist of three 56-bit keys K1, K2, K3 then encryption and decryption is beside the table: . Encryption Decryption( in reverse of Encryption) • Encrypt with K1 • Decrypt with K2 • Encrypt with K3 • Decrypt with K3 • Encrypt with K2 • Decrypt with K1 DES: DATA ENCRYPTION STANDARD
- 11. fig:- RSA1 RSA is a public key algorithm invented by Rivest, Shamir and Adleman. The key used for encryption is different from (but related to) the key used for decryption. Algorithm is in fig:- RSA1 RS A
- 12. Hash functions Is a type of one-way function this are fundamental for much of cryptography. A one way function - is a function that is easy to calculate but hard to invert. It is difficult to calculate the input to the function given its output. The precise meanings of "easy" and "hard" can be specified mathematically. With rare exceptions, almost the entire field of public key cryptography rests on the existence of one-way functions.
- 13. Applications of Cryptography 1. Defense Services 2. Secure Data Manipulation 3. E-Commerce 4. Business Transactions 5. Internet Payment System 6. Secure Internet Communication 7. Data Security 8. Secure Access to Corresponding data
- 14. Cryptographic Attacks Ciphertext only attack The only data available is a target cipher text Known plaintext attack A target cipher text Pairs of other cipher text and plaintext (say, previously broken or guessing) Chosen plaintext attacks A target cipher text Can feed encryption algorithm with plaintexts and obtain the matching cipher texts and so many attacks available like Dictionary Attack, Timing Attacks etc.
- 15. CONCLUSION We use different types of algorithms to establish security services in different service mechanisms. We use either private key cryptography or public key cryptography according to requirement. If we want to send message quickly we use private key algorithm and if we want to send messages secretly we use public key algorithm.
- 16. References www.google.com en.wikipedia.org www.youtube.com www.tutorialspoint.com
- 17. Thank You