this presentation is on block cipher modes which are used for encryption and decryption to any message.That are Defined by the National Institute of Standards and Technology . Block cipher modes of operation are part of symmetric key encryption algorithm.
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In cryptography, a block cipher is a deterministic algorithm operating on ... Systems as a means to effectively improve security by combining simple operations such as .... Finally, the cipher should be easily cryptanalyzable, such that it can be ...
In cryptography, a block cipher is a deterministic algorithm operating on ... Systems as a means to effectively improve security by combining simple operations such as .... Finally, the cipher should be easily cryptanalyzable, such that it can be ...
Modern Block Cipher- Modern Symmetric-Key CipherMahbubur Rahman
Introduction to Modern Symmetric-Key Ciphers- This lecture will cover only "Modern Block Cipher".
Slide Credit: Maleka Khatun & Mahbubur Rahman
Dept. of CSE, JnU, BD.
Introduction to Public key Cryptosystems with block diagrams
Reference : Cryptography and Network Security Principles and Practice , Sixth Edition , William Stalling
Information and network security 13 playfair cipherVaibhav Khanna
The Playfair cipher was the first practical digraph substitution cipher. The scheme was invented in 1854 by Charles Wheatstone but was named after Lord Playfair who promoted the use of the cipher. In playfair cipher unlike traditional cipher we encrypt a pair of alphabets(digraphs) instead of a single alphabet
Modern Block Cipher- Modern Symmetric-Key CipherMahbubur Rahman
Introduction to Modern Symmetric-Key Ciphers- This lecture will cover only "Modern Block Cipher".
Slide Credit: Maleka Khatun & Mahbubur Rahman
Dept. of CSE, JnU, BD.
Introduction to Public key Cryptosystems with block diagrams
Reference : Cryptography and Network Security Principles and Practice , Sixth Edition , William Stalling
Information and network security 13 playfair cipherVaibhav Khanna
The Playfair cipher was the first practical digraph substitution cipher. The scheme was invented in 1854 by Charles Wheatstone but was named after Lord Playfair who promoted the use of the cipher. In playfair cipher unlike traditional cipher we encrypt a pair of alphabets(digraphs) instead of a single alphabet
THE UNIFIED OPERATION STRUCTURE FOR SYMMETRIC-KEY ALGORITHMcscpconf
In Cloud Computing, information exchange frequently via the Internet and on-demand. Modern
Internet protocols support several modes of operation to keep up with varied environments and
provide the variant choice, such as SSL and IPSec support multi-mode. The different mode has
the different characters. For example: CFB/OFB can be design operating without padding with
bit size keystream output, CBC/CFB can self synchronize to avoid channel noise, and CFB/OFB
needs encryption module only. The main emphasis is placed on the problem of case by case
operation mode usage. We describe a structure for the analysis of the block operation mode
combination. This unified operation structure, called UOS, combines existing in common and
popular block modes of operation. UOS does multi-mode of operation with most existing
popular symmetric block ciphers and do not only consist of encryption mode such as ECB, CBC,
CFB and OFB, that provides confidentiality but also message authentication mode such as
CBC-MAC in cryptography. It provides low-resource hardware implementation, which is
proper to ubiquitous computing devices such as a sensor mote or an RFID tag. Our contribution
provides a common solution for multi-mode and this is very suitable for ubiquitous computing with several resources and environments. The study indicates a better well-organized structure for symmetric block ciphers so as to improve their application scenarios.
A Novel Structure with Dynamic Operation Mode for Symmetric-Key Block CiphersIJNSA Journal
Modern Internet protocols support several modes of operation in encryption tasks for data confidentiality
to keep up with varied environments and provide the various choices, such as multi-mode IPSec support.
To begin with we will provide a brief background on the modes of operation for symmetric-key block
ciphers. Different block cipher modes of operation have distinct characteristics. For example, the cipher
block chaining (CBC) mode is suitable for operating environments that require self-synchronizing
capabilities, and the output feedback (OFB) mode requires encryption modules only. When using
symmetric-key block cipher algorithms such as the Advanced Encryption Standard (AES), users
performing information encryption often encounter difficulties selecting a suitable mode of operation.
This paper describes a structure for analyzing the block operation mode combination. This unified
operation structure (UOS) combines existing common and popular block modes of operation. UOS does
multi-mode of operation with most existing popular symmetric-key block ciphers and do not only consist
of encryption mode such as electronic codebook (ECB) mode, cipher block chaining (CBC) mode, cipher
feedback (CFB) mode and output feedback (OFB) mode, that provides confidentiality but also message
authentication mode such as the cipher block chaining message authentication code (CBC-MAC) in
cryptography. In Cloud Computing, information exchange frequently via the Internet and on-demand.
This research provides an overview and information useful for approaching low-resource hardware
implementation, which is proper to ubiquitous computing devices such as a sensor mote or an RFID tag.
The use of the method is discussed and an example is given. This provides a common solution for multimode and this is very suitable for ubiquitous computing with several resources and environments. This
study indicates a more effectively organized structure for symmetric-key block ciphers to improve their
application scenarios. We can get that it is flexible in modern communication applications.
Advanced Encryption Standard, Multiple Encryption and Triple DES, Block Cipher Modes of
operation, Stream Ciphers and RC4, Confidentiality using Symmetric Encryption, Introduction
to Number Theory: Prime Numbers, Fermat’s and Euler’s Theorems, Testing for Primality, The
Chinese Remainder Theorem, Discrete Logarithms, Public-Key Cryptography and RSA
Unit 1
Information System Security
(According RTU Syllabus)
1-Introduction to security attacks Services and mechanism
2-Classical encryption techniques
3-Cryptanalysis, stream and block ciphers
4- Modern Block Ciphers: Block ciphers principals
5- Shannon’s theory of confusion and diffusion
6- Fiestal structure
7- Data encryption standard(DES)
8- Differential and linear cryptanalysis of DES
9- Block cipher modes of operations.
10- Triple Data Encryption Standard (Triple-DES)
Training and Tips that are very helpful to gain knowledge in the field of information Security and passing your CISSP Certification Exam.
To be CISSP Certified Please Check out the link below:
http://asmed.com/cissp-isc2/
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http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Split Bills in the Odoo 17 POS ModuleCeline George
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It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
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Model Attribute Check Company Auto PropertyCeline George
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The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Sectors of the Indian Economy - Class 10 Study Notes pdf
Block cipher modes of operation
1.
2. In cryptography, a block cipher is a deterministic algorithm
operating on fixed-length groups of bits, called blocks, with an
unvarying transformation that is specified by a symmetric key.
A block cipher algorithm is a basic building block for
providing data security.
To apply a block cipher in a variety of applications, five
“modes of operations” are defined by NIST.
What is block cipher?
3. NIST : National Institute of Standards and Technology
That five modes of operations are :
1. Electronic code book
2. Cipher chaining block
3. Cipher feedback mode
4. Output feedback mode
5. Counter mode
Introduction to block cipher modes of
operation
4. Block cipher only allow to encrypt entire blocks.
What if our message is longer/shorter than the block size?
When message is longer/shorter than the block size , we use
modes of operations.
Algorithms that exploit a block cipher to provide a service
(e.g. confidentiality ).
When we use block cipher modes of
operation?
5. Electronic codebook
ECB is the simplest mode of operation.
The plain text is divided into N blocks.
The block size is n bits.
If the plaintext size is not multiple of the block size , the
text is padded to make the last block the same size other
blocks.
Same key is used to encrypt and decrypt each block.
10. Electronic codebook
encryption/decryption Security issues
Patterns at the block level are preserved.
For example equal blocks in the plain text become equal
block in the cipher text.
If any person finds out the cipher text block 1,5 and 10 are
the same ,that person knows that plaintext blocks 1, 5 and
10 are the same.
This is a leak in security.
11. What is initialization vector?
An initialization vector (IV) or starting variable is a
block of bits that is used by several modes to randomize
the encryption and hence to produce distinct cipher texts
even if the same plain text is encrypted multiple times,
without the need for a slower re-keying process.
An initialization vector has different security
requirements than a key, so the IV usually does not need
to be secret
However, in most cases, it is important that an
initialization vector is never reused under the same key.
12. What is initialization vector?
(continue…)
For CBC and CFB, reusing an IV leaks some information
about the first block of plaintext, and about any common prefix
shared by the two messages.
For OFB and CTR, reusing an IV completely destroys security.
This can be seen because both modes effectively create a bit
stream that is XORed with the plaintext, and this bit stream is
dependent on the password and IV only. Reusing a bit stream
destroys security.
In CBC mode, the IV must, in addition, be unpredictable at
encryption time; in particular, the (previously) common practice
of re-using the last cipher text block of a message as the IV for
the next message is insecure.
13. Cipher block chaining mode
IBM invented the Cipher Block Chaining (CBC)
mode of operation in 1976.
In CBC mode, each block of plaintext is XORed
with the previous cipher text block before being
encrypted.
This way, each cipher text block depends on all
plaintext blocks processed up to that point. To make
each message unique, an initialization vector must
be used in the first block.
14. Cipher block chaining mode
encryption
IV = initialization vector
Cipher texti = encryption with key (plain text XOR cipher text i-
1)
15. Cipher block chaining mode
Decryption
IV = initialization vector
plain texti = Decryption with key (cipher text XOR cipher text i-1)
16. The patterns at the block level are not preserved.
In CBC mode, equal plain text block belonging to the same
message are enciphered into different cipher text block.
However ,if two message are equal ,their encipherment is
the same if they use the same IV.
As a matter of fact ,if the first M blocks in two different
message are equal , they are enciphered into equal blocks
unless different IVs are used.
For this reason , some people recommended the use of time-
stamp as an IV.
Any person can add some cipher text blocks to the end of
the cipher text stream.
Cipher block chaining mode
Security issues
17. Cipher feedback mode
ECB and CBC modes encrypt and decrypt blocks of the
message.
Block size n is predetermine by the underlying cipher ; for
example , for DES n = 64
for AES n =128
In some situations, we need use DES or AES as secure
cipher , but the plain text or cipher text block size are to be
smaller.
For example , to encrypt and decrypt 8-bit characters , you
would not want to use one of the traditional cipher like
Caesar cipher.
The solution is to use DES or AES in cipher feedback mode
20. Cipher feedback mode
Security issues
Just like CBC , patterns at the block level are not preserved.
More than one message can be encrypted with the same key ,
but the value of the IV should be changed for each message.
This means that sender needs to use a different IV each time
sender sends a message.
Attacker can add some cipher text block to the end of the
cipher text stream.
21. Cipher output feedback mode
Output feedback mode is very similar to CFB mode , with
one difference: each bit in the cipher text is independent of
the previous bit or bits.
This avoids error propagation.
If an error occur in transmission , it does not affect the bits
that follow.
Note that , like cipher feedback mode , both the sender and
the receiver use the encryption algorithm.
22. Cipher output feedback mode
encryption
IV = initialization vector
cipher texti =
plain texti XOR Encryption
(k , [cipher text i-1 XOR plain text i-1] )
23. Cipher output feedback mode
Decryption
IV = initialization vector
Plain texti =
cipher texti XOR Encryption
(k , [cipher text i-1 XOR plain text i-1] )
24. Cipher output feedback mode
Security issues
Just like CBC , patterns at the block level are not preserved.
Any change in the cipher text affects the plain text encrypted
at the receiver side.
25. Counter
In the counter mode , there is no feedback.
The pseudo randomness in the key streams achieved using a
counter.
An n bit counter is initialized to a predetermined value(IV)
and incremented based on a predefined rule(mod 2n)
To provide a better randomness , the increment value can
depend on the block numbers to be incremented.
The plain text and cipher block text block have same block
size as the underlying cipher.
Both encryption and decryption can be performed fully in
parallel on multiple blocks .
Provides true random access to cipher text blocks