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Overview of cryptography
This document provides an overview of cryptography. It discusses that cryptography is the practice of secure communication in the presence of others. The purpose of cryptography is to defend against hackers and industrial espionage while securing e-commerce, bank accounts, intellectual property, and avoiding liability. Cryptography provides authentication, privacy, integrity, and non-repudiation. Encryption converts plain text to cipher text using a key while decryption converts cipher text to plain text. Common cryptographic algorithms are secret key cryptography, public key cryptography, and hash functions. Secret key cryptography uses a private key for encryption while public key cryptography uses a public key exchanged over an insecure channel. Hash functions produce a checksum of data. AES encryption is now commonly used and
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Overview of cryptography
- 1. Overview of Cryptography by Roshan Chaudhary 13ITU031
- 2. Introduction Cryptography isthe practice and study of techniques for secure communication in the presence of third parties. Encrypted messages can sometimes be broken by cryptanalysis, also called codebreaking.
- 3. THE PURPOSE OFCRYPTOGRAPHY Defending against external/internal hackers Defending against industrial espionage Securing E-commerce Securing bank accounts/electronic transfers Securing intellectual property Avoiding liability
- 4. Some specific securityrequirements Authentication Privacy 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.
- 5. What is Encryption/ Decryption Encryption – The process of converting plain text into an unintelligible format (cipher text) is called Encryption. Decryption – The process of converting cipher text into a plain text is called Decryption.
- 6. What isa Key In cryptography, a key is a variable value that is applied using an algorithm to a string or block of unencrypted text to produce encrypted text, or to decrypt encrypted text What is a Block Cipher? A method of encrypting / decrypting data Key is used for encryption / decryption. What is Initialization Vector? An initialization vector (IV) is an arbitrary number that can be used along with a secret key for data encryption.
- 7. TYPES OF CRYPTOGRAPHIC ALGORITHMS Secret Key Cryptography (SKC) Public Key Cryptography (PKC) Hash Functions
- 8. Secret Key Cryptography Encryption involves applying an operation (an algorithm) to the data to be encrypted using the private key to make them unintelligible. The slightest algorithm can make the system nearly tamper proof.
- 9. Public Key Cryptography In a public-key encryption system, users choose a random key that only they know. From this key, they each automatically deduce an algorithm. Users exchange this public key over an insecure channel.
- 10. HASH FUNCTIONS A cryptographic hash function is a kind of algorithm that can be run on a piece of data, often an individual file, producing a value called a checksum. Some commonly used cryptographic hash functions include MD5 and SHA-1, though many others also exist.
- 12. DES Encryption AESEncryption DES uses only 56 bits key which provides a combination of 2^56 combinations for encryption. AES can use 128, 192, 256 bits keys which provides 2^128, 2^192, 2^256 combinations for encryption. DES is restricted to use a Block Size of only 64 bits AES is restricted to use a Block Size of 128 bits (double of what is used in DES) With 64 bits block size, the amount of data that can be transferred with a single encryption key is just 32GB. With AES, it is possible to transfer around 256 billion GB of data. DES encryption is breakable through Brute Force attack. AES encryption on the other hand is still not breakable, though there are some theoretical discussions about breaking the AES. DES is an old technique used for encryption/decryption AES is relatively new.
- 13. Where to usecryptography ? Anywhere you want to have something remain secret SSL, TLS, IPv6, SSH, IPSec all keep information secure in transit Any Symmetric Algorithm can keep your files safe in storage You can add encryption at the application level, or at the server level for storing database information securely
- 14. Advantages Ithides the message and your privacy is safe. No one would be able to know what it says unless there's a key to the code. You can write what ever you want and how ever you want (any theme any symbol for the code) to keep your code a secret. You are able to use cryptography during lessons without the teacher knowing.
- 15. Disadvantages Takesa long time to figure out the code. It takes long to create the code. If you were to send a code to another person in the past, it will take long to get to that person. Overall it’s a long process.
- 16. Steganography Theart and science of hiding information by embedding messages within other, seemingly harmless messages. Steganography works by replacing bits of useless or unused datain regular computer files (such as graphics, sound, text, HTML, or even floppy disks ) with bits of different, invisible information
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