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
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.
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
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.
Information and data security block cipher and the data encryption standard (...Mazin Alwaaly
Information And Data Security Block Cipher and the data encryption standard (DES) seminar
Mustansiriya University
Department of Education
Computer Science
OFB 는 CFB 모드와 비슷하다
암호의 출력 기능은 피드백되어 다음 ofb 에 입력된다.
CFB에서 출력 XOR 단위는 다음 블록을 암호화하기위한 입력이되도록 피드백됩니다.
다른 차이점은 OFB 모드가 S 비트 서브 세트가 아닌 일반 텍스트 및 암호 텍스트의 전체 블록에서 작동한다는 것입니다.
CBC 및 CFB의 경우 OFB 모드에는 초기화 벡터 (IV)가 필요합니다.
OFB에서 IV는 nonce 여야합니다.
암호화 출력 블록 Oi의 시퀀스는 키와 IV에만 의존하며 일반 텍스트에 의존하지 않습니다.
주어진 키와 IV, 평문 비트 스트림과 XOR하는 데 사용되는 출력 비트 스트림이 고정됩니다.
OFB 방법의 장점은 전송의 비트 오류가 전파되지 않는다는 것입니다.
OFB의 단점은 CFB보다 메시지 스트림 수정 공격에 더 취약하다는 것입니다.
단일 블록에서의 작동
(1) j 데이터 단위 내의 128 비트 블록의 순차 번호.
(2) i 128 비트 비틀기의 가치. 각 데이터 단위 (섹터)가 할당됩니다.
j 함수는 동일한 평문 블록이 데이터 유닛 내의 서로 다른 두 위치에 나타나면 두 개의 서로 다른 암호문 블록으로 암호화 함을 보장합니다.
i 함수는 동일한 평문 블록이 두 개의 다른 데이터 단위에서 같은 위치에 나타나는 경우 두 개의 다른 암호문 블록으로 암호화 함을 보장합니다.
Reference
William Stallings/“Cryptography and Network Security(Sixth Edition)”/PEARSON/2014
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.
i hope you may like this.
Information and data security block cipher and the data encryption standard (...Mazin Alwaaly
Information And Data Security Block Cipher and the data encryption standard (DES) seminar
Mustansiriya University
Department of Education
Computer Science
OFB 는 CFB 모드와 비슷하다
암호의 출력 기능은 피드백되어 다음 ofb 에 입력된다.
CFB에서 출력 XOR 단위는 다음 블록을 암호화하기위한 입력이되도록 피드백됩니다.
다른 차이점은 OFB 모드가 S 비트 서브 세트가 아닌 일반 텍스트 및 암호 텍스트의 전체 블록에서 작동한다는 것입니다.
CBC 및 CFB의 경우 OFB 모드에는 초기화 벡터 (IV)가 필요합니다.
OFB에서 IV는 nonce 여야합니다.
암호화 출력 블록 Oi의 시퀀스는 키와 IV에만 의존하며 일반 텍스트에 의존하지 않습니다.
주어진 키와 IV, 평문 비트 스트림과 XOR하는 데 사용되는 출력 비트 스트림이 고정됩니다.
OFB 방법의 장점은 전송의 비트 오류가 전파되지 않는다는 것입니다.
OFB의 단점은 CFB보다 메시지 스트림 수정 공격에 더 취약하다는 것입니다.
단일 블록에서의 작동
(1) j 데이터 단위 내의 128 비트 블록의 순차 번호.
(2) i 128 비트 비틀기의 가치. 각 데이터 단위 (섹터)가 할당됩니다.
j 함수는 동일한 평문 블록이 데이터 유닛 내의 서로 다른 두 위치에 나타나면 두 개의 서로 다른 암호문 블록으로 암호화 함을 보장합니다.
i 함수는 동일한 평문 블록이 두 개의 다른 데이터 단위에서 같은 위치에 나타나는 경우 두 개의 다른 암호문 블록으로 암호화 함을 보장합니다.
Reference
William Stallings/“Cryptography and Network Security(Sixth Edition)”/PEARSON/2014
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.
i hope you may like this.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
2. Chapter 6 – Block Cipher
Operation
Many savages at the present day regard
their names as vital parts of themselves,
and therefore take great pains to conceal
their real names, lest these should give to
evil-disposed persons a handle by which
to injure their owners.
— The Golden Bough, Sir James George
Frazer
3. Multiple Encryption & DES
clear a replacement for DES was needed
theoretical attacks that can break it
demonstrated exhaustive key search attacks
AES is a new cipher alternative
prior to this alternative was to use multiple
encryption with DES implementations
Triple-DES is the chosen form
4. Why not Double-DES?
could use 2 DES encrypts on each block
C = EK2(EK1(P))
concern at time of reduction to single stage
“meet-in-the-middle” attack
works whenever use a cipher twice
since X = EK1(P) = DK2(C)
attack by encrypting P with all keys and store
then decrypt C with keys and match X value
can show takes O(256) steps
Requires… known plaintext
5. Triple-DES with Two-Keys
hence must use 3 encryptions
would seem to need 3 distinct keys
but can use 2 keys with E-D-E sequence
C = EK1(DK2(EK1(P)))
n.b. encrypt & decrypt equivalent in security
if K1=K2 then can work with single DES
standardized in ANSI X9.17 & ISO8732
no current known practical attacks
several proposed impractical attacks might
become basis of future attacks
6. Triple-DES with Three-Keys
although are no practical attacks on two-
key Triple-DES have some indications
can use Triple-DES with Three-Keys to
avoid even these
C = EK3(DK2(EK1(P)))
has been adopted by some Internet
applications, e.g., PGP, S/MIME
7. Modes of Operation
block ciphers encrypt fixed size blocks
e.g., DES encrypts 64-bit blocks
need some way to en/decrypt arbitrary
amounts of data in practice
NIST SP 800-38A defines 5 modes
have block and stream modes
to cover a wide variety of applications
can be used with any block cipher
8. Electronic Codebook Book (ECB)
message is broken into independent
blocks that are encrypted
each block is a value which is substituted,
like a codebook, hence name
each block is encoded independently of
the other blocks
Ci = EK(Pi)
uses: secure transmission of single
values
10. Advantages and Limitations of
ECB
message repetitions may show in ciphertext
if aligned with message block
particularly with data such graphics
or with messages that change very little, which
become a code-book analysis problem
weakness is due to the encrypted message
blocks being independent
vulnerable to cut-and-paste attacks
main use is sending a few blocks of data
11. Cipher Block Chaining (CBC)
message is broken into blocks
linked together in encryption operation
each previous cipher block is chained with
current plaintext block, hence name
use Initial Vector (IV) to start process
Ci = EK(Pi XOR Ci-1)
C-1 = IV
IV prevents same P from making same C
uses: bulk data encryption, authentication
13. Message Padding
at end of message must handle a possible
last short block
which is not as large as blocksize of cipher
pad either with known non-data value
• e.g., nulls
or pad last block along with count of pad size
• e.g., [ b1 b2 b3 0 0 0 0 5]
• means have 3 data bytes, then 5 bytes pad+count
this may require an extra entire block over
those in message
there are other, more esoteric modes, which
avoid the need for an extra block
14. Ciphertext Stealing
Use to make ciphertext length same as
plaintext length
Requires more than one block of ptxt
Pn-1
En-1
Pn
En-1
Pn
Head n
T
T
Head n
Pn-1
En-1
Pn
En-1
Pn
Head n
T
T
Head n
15. Advantages and Limitations of
CBC
a ciphertext block depends on all blocks
before it
any change to a block affects all following
ciphertext blocks...
need Initialization Vector (IV)
which must be known to sender & receiver
if sent in clear, attacker can change bits of first block,
by changing corresponding bits of IV
hence IV must either be a fixed value (as in EFTPOS)
or derived in way hard to manipulate
or sent encrypted in ECB mode before rest of message
or message integrity must be checked otherwise
avalanche effect
16. Stream Modes of Operation
block modes encrypt entire block
may need to operate on smaller units
real time data
convert block cipher into stream cipher
cipher feedback (CFB) mode
output feedback (OFB) mode
counter (CTR) mode
use block cipher as some form of pseudo-
random number generator... Vernam cipher
17. Cipher FeedBack (CFB)
message is treated as a stream of bits
added to the output of the block cipher
result is feed back for next stage (hence name)
standard allows any number of bits (1,8, 64 or
128 etc) to be feed back
denoted CFB-1, CFB-8, CFB-64, CFB-128, etc.
most efficient to use all bits in block (64 or 128)
Ci = Pi XOR EK(Ci-1)
C-1 = IV
uses: stream data encryption, authentication
19. Advantages and Limitations of
CFB
most common stream mode
appropriate when data arrives in bits/bytes
limitation is need to stall while do block
encryption after every s-bits
note that the block cipher is used in
encryption mode at both ends (XOR)
errors propagate for several blocks after
the error ... how many?
20. Output FeedBack (OFB)
message is treated as a stream of bits
output of cipher is added to message
output is then feed back (hence name)
Oi = EK(Oi-1)
Ci = Pi XOR Oi
O-1 = IV
feedback is independent of message
can be computed in advance
uses: stream encryption on noisy channels
Why noisy channels?
22. Advantages and Limitations of
OFB
needs an IV which is unique for each use
if ever reuse attacker can recover outputs...
OTP
can pre-compute
bit errors do not propagate
more vulnerable to message stream modification...
change arbitrary bits by changing ciphertext
sender & receiver must remain in sync
only use with full block feedback
subsequent research has shown that only full block
feedback (ie CFB-64 or CFB-128) should ever be used
23. Counter (CTR)
a “new” mode, though proposed early on
similar to OFB but encrypts counter value
rather than any feedback value
Oi = EK(i)
Ci = Pi XOR Oi
must have a different key & counter value
for every plaintext block (never reused)
again, OTP issue
uses: high-speed network encryptions
25. Advantages and Limitations of
CTR
efficiency
can do parallel encryptions in h/w or s/w
can preprocess in advance of need
good for bursty high speed links
random access to encrypted data blocks
provable security (good as other modes)
never have cycle less than 2b
but must ensure never reuse key/counter
values, otherwise could break (cf OFB)
27. XTS-AES Mode
need mode for block oriented storage
– No extra room in sector – data only
– Disk addressed by sector number
– Encryption can only take key externally
– Encryption can also use sector#, block#
Access to any sector should be
independent of other sectors
Must prevent attack that copies sector to
unused sector, then requests decryption
28. XTS-AES Mode
new mode, for block oriented storage use
in IEEE Std 1619-2007
concept of tweakable block cipher
different requirements to transmitted data
uses AES twice for each block
Tj = EK2(i) XOR αj
Cj = EK1(Pj XOR Tj) XOR Tj
where i is tweak & j is sector no
each sector may have multiple blocks
29. XTS-AES
Mode
per block
Key whitening applied by XOR
With “tweak” that depends on
- sector
- block
- second key
Makes attacks more difficult
Makes operations depend on
data location
31. Advantages and Limitations of
XTS-AES
efficiency
can do parallel encryptions in h/w or s/w
random access to encrypted data blocks
has both nonce & counter
addresses security concerns related to
stored data
32. Summary
Multiple Encryption & Triple-DES
Modes of Operation
ECB, CBC, CFB, OFB, CTR, XTS-AES
Next – Stream ciphers (Ch 7), then hash
functions (Ch 11)