Lecture 11
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The document discusses the basics of cryptography including its components, categories, and types of cryptographic algorithms. It covers symmetric-key cryptography which uses the same key for encryption and decryption. It also discusses traditional ciphers like substitution and transposition ciphers as well as modern ciphers. Asymmetric-key cryptography which uses public and private key pairs is also summarized. The document concludes with an overview of network security goals like confidentiality, integrity, authentication, and non-repudiation.
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A digital signature is an electronic signature that can authenticate the identity of the sender of a message and ensure that the message has not been altered. Digital signatures are easily transportable, cannot be imitated, and are automatically time-stamped. A digital signature can be used with any message, whether encrypted or not, to verify the sender's identity and that the message was not changed. Digital certificates contain the digital signature of the certificate authority to verify that the certificate is authentic.
Cryptography
Network security relies heavily on cryptography, which transforms messages to make them secure. There are two main categories of cryptography: symmetric-key cryptography where the same key is used to encrypt and decrypt, and asymmetric-key cryptography where different keys are used for encryption and decryption. Traditional symmetric-key ciphers include substitution ciphers that replace symbols and transposition ciphers that rearrange symbols. Modern symmetric-key ciphers operate on bits and are more complex.
Symmetric and asymmetric key cryptography
The document discusses symmetric and asymmetric key cryptography. It begins with an introduction to cryptography and its objectives of confidentiality, integrity, authentication and non-repudiation. It then explains the differences between symmetric and asymmetric cryptosystems. Symmetric cryptosystems involve a shared key between sender and receiver, while asymmetric cryptosystems use public and private key pairs. Examples of traditional symmetric ciphers like simple substitution and transposition ciphers are provided. The document also outlines the RSA algorithm as an example of asymmetric cryptography and discusses some limitations of both symmetric and asymmetric approaches.
Cyptography ece 702
This document provides an overview of cryptography presented by Mr. Anupam Kumar. It begins with an introduction to cryptography, including the components involved such as plaintext, ciphertext, ciphers, keys, and common roles like Alice, Bob and Eve. It then describes the two main categories of cryptography - symmetric-key and asymmetric-key cryptography. Symmetric-key uses a shared secret key for encryption and decryption, while asymmetric-key uses separate public and private keys. The document provides examples of traditional ciphers like substitution, shift and transposition ciphers, as well as modern ciphers like the XOR cipher.
Cyptography ece 702
This document provides an overview of cryptography concepts. It begins with definitions of cryptography, plaintext, ciphertext, ciphers, keys, and common roles (Alice, Bob, Eve). It then describes the two main categories of cryptography: symmetric-key using a shared secret key, and asymmetric-key using public/private key pairs. The document goes on to provide examples of traditional ciphers like the Caesar cipher and modern ciphers like DES. It also describes components of ciphers like substitution boxes and permutation boxes.
Computer Network Unit-5 (Part-1).pdf
This document discusses different techniques used in cryptography. It describes symmetric and asymmetric key cryptography. Symmetric cryptography uses a single secret key for encryption and decryption, while asymmetric cryptography uses public and private key pairs. The document also explains the Caesar cipher, Playfair cipher, polyalphabetic cipher, and transposition ciphers like the rail fence technique. It provides examples to illustrate how each technique works and encrypts messages.
Introduction to Cryptography Week4 Part1-ISrevisionSu.docx
Introduction to Cryptography
Week4 Part1-ISrevisionSu2013
Introduction to Cryptography
If you are implementing a secure environment and you do not implement encryption you
will not have a secure environment. You can implement routers, firewalls, intrusion
detection, virus protection, policies and procedures, but if there is no encryption you will
not have a secure environment.
Encryption is fundamental to a secure information environment. Passing data around a
system and over the network in a clear text form is very insecure. Systems and
communication lines can be monitored by unscrupulous individuals who make valuable
information vulnerable to viewing or modification. Encryption in a secure information
infrastructure is implemented at various levels in the architecture and in various
components. This is consistent with the idea of security in depth. Encryption technologies
are included as part of many products; applications, operating systems, network devices.
How (and if) the encryption technology is used is dependent on the organization and its
users.
Cryptography is the science of disguising messages. Disguising a readable message is
called encryption. Translating the disguised message back to a readable form is called
decryption.
Encryption has been used for centuries to disguise messages from adversaries. The
Romans used encryption in their military operations to protect sensitive messages. The
Germans during World War 2 used the enigma machine to encrypt messages about
military secrets so the allies would not be aware of strategy and tactics.
Nowadays in addition to protecting government secrets there are many uses for
encryption technology in commercial applications. The need to protect medical, financial
records or company trade secrets are a few of the areas that encryption is used.
Terminology
Cryptography is a field loaded with terminology, acronyms and concepts. Many of the
concepts are rooted in mathematics and computer science. Following are some common
terms you should become familiar with for understanding encryption.
Cryptosystem – A cryptosystem encrypts and decrypts messages allowing only
people (or processes) that possess the correct keys to read the messages.
Cryptography – The science of designing, developing and using cryptosystems.
Cryptanalysis – The science of breaking a cryptosystem, so that the content of
messages is no longer hidden.
Cryptology – The study of cryptography and cryptanalysis.
Cipher – another term used to describe an encryption or decryption algorithm.
Types of Encryption Technology
There are several technologies, tools and techniques we will be discussing that fall under
the category of encryption.
Encryption algorithms fall into two broad categories; symmetric and asymmetric
encryption. Let’s first look at the components that make up a symmetric encryption
system or symmetric crypt.
Introduction to Cryptography and the Public Key Infrastructure
A white paper introducing the basics of cryptography and the Public Key Infrastructure (PKI). Those just getting into the arena of cybersecurity or those just simply curious about the topic will likely learn something new.
Cryptography by manisha jha
This document provides an overview of cryptography. It defines cryptography as the practice of securing communications through codes and algorithms. The document then discusses features of cryptography like confidentiality and integrity. It provides an example of a basic cryptography technique using a letter substitution cipher. Additionally, it outlines different types of ciphers and cryptography techniques, including symmetric key cryptography, hash functions, and asymmetric key cryptography. The document aims to introduce fundamental concepts in the field of cryptography.
Crypt
The document discusses cryptography and the RSA encryption algorithm. It begins with an introduction to cryptography and its uses. It then covers the history of cryptography, common security issues, and different cryptographic techniques like symmetric and asymmetric encryption. The document focuses on explaining the RSA algorithm, how it works using public and private keys, and why factoring large numbers makes RSA secure. It provides an overview of the key aspects of cryptography and the RSA algorithm.
Crypto
• What is cryptography?
• Why it’s helpful in a network and how hackers broke security?
• Different methods of encryption and decryption?
Enhancing security of caesar cipher using different
Abstract Cryptography is an art and science of converting original message into non readable form. There are two techniques for converting data into no readable form:1)Transposition technique 2)Substitution technique. Caesar cipher is an example of substitution method. As Caesar cipher has various limitations so this talk will present a perspective on combination of techniques substitution and transposition. In this paper I have focused on the well known classical techniques the aim was to induce some strength to these classical encryption for that purpose I blended classical encryption with the some more techniques. my proposed method showed that it is better in terms of providing more security to any given text message. In our experiments I took Caesaer Ciphers as representatives of Classical Techniques. To make it more secure I have used some techniques like I have used multiple level Row Transposition Ciphers, encryption with same key at each level and encryption with different key at each level. Keywords— substitution, transposition, cryptography, Caesar cipher
Cryptography
Cryptography is used to secure data by encrypting it so that only authorized users can access it. It provides confidentiality, integrity, and authentication. There are different types of encryption algorithms like symmetric key cryptography where one key is used to encrypt and decrypt, and asymmetric key cryptography where public and private keys are used. The goals of cryptography are to ensure confidentiality so unauthorized users cannot understand encrypted data, authenticate users, maintain data integrity so it is not altered without detection, and provide non-repudiation and access control.
Cryptography 387 © David Lippman Creative Commons BY-.docx
This document discusses cryptography techniques including substitution ciphers, transposition ciphers, and advanced symmetric key methods. It provides examples of encrypting and decrypting messages using a Caesar cipher with shifting substitutions, a transposition cipher that writes messages in rows and reads them out in columns according to a keyword, and a simplified polyalphabetic cipher that shifts the substitution after each character. Frequency analysis and brute force attacks are also discussed as techniques for breaking simple ciphers.
Enhancing security of caesar cipher using different
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Is case study
Cryptography is the science of keeping communications secure through various encryption techniques. There are two main types: symmetric encryption which uses a shared secret key for encryption and decryption, and asymmetric encryption which uses a public/private key pair. Symmetric encryption is faster but more difficult to implement for multiple parties, while asymmetric encryption using algorithms like RSA enables easy key distribution and digital signatures.
Cryptography and E-Commerce
The document discusses the history and concepts of cryptography, especially in the context of e-commerce. It explains how cryptography evolved from ancient times to modern applications. Symmetric and asymmetric encryption methods are described, including how public/private key pairs work. Digital signatures are introduced as a way to provide authentication, integrity, and non-repudiation for electronic transactions.
Cryptography
This document provides an overview of cryptography concepts including:
- Cryptography transforms intelligible messages into unintelligible messages and vice versa. Plaintext is the original message and ciphertext is the encrypted message.
- Traditional ciphers include substitution ciphers that replace characters and transposition ciphers that change character positions. Simple shift and transcomposition ciphers are examples.
- Modern ciphers like the XOR cipher encrypt bits by combining the plaintext and key with XOR. The rotation cipher rotates bits left or right based on a key.
- Symmetric ciphers use the same key for encryption and decryption while asymmetric ciphers use public and private key pairs.
Similar to Lecture 11 (20)
Introduction to Cryptography Week4 Part1-ISrevisionSu.docx
Introduction to Cryptography Week4 Part1-ISrevisionSu.docx
Introduction to Cryptography and the Public Key Infrastructure
Introduction to Cryptography and the Public Key Infrastructure
Enhancing security of caesar cipher using different
Enhancing security of caesar cipher using different
Cryptography 387 © David Lippman Creative Commons BY-.docx
Cryptography 387 © David Lippman Creative Commons BY-.docx
Enhancing security of caesar cipher using different
Enhancing security of caesar cipher using different
Lecture 11
- 1. CRYPTOGRAPHY & NETWORK SECURITY
- 15. COMPARISON BETWEEN TWO CATEGORIES OF CRYPTOGRAPHY
- 16. NETWORK SECURITY