Security Hash Algorithm (SHA) was developed in 1993 by the National Institute of Standards and Technology (NIST) and National Security Agency (NSA).
It was designed as the algorithm to be used for secure hashing in the US Digital Signature Standard.
• Hashing function is one of the most commonly used encryption methods. A hash is a special mathematical function that performs one-way encryption.
• SHA-l is a revised version of SHA designed by NIST and was published as a Federal Information Processing Standard (FIPS).
• Like MD5, SHA-l processes input data in 512-bit blocks.
• SHA-l generates a 160-bit message digest. Whereas MD5 generated message digest of 128 bits.
• The procedure is used to send a non secret but signed message from sender to receiver. In such a case following steps are followed:
1. Sender feeds a plaintext message into SHA-l algorithm and obtains a 160-bit SHA-l hash.
2. Sender then signs the hash with his RSA private key and sends both the plaintext message and the signed hash to the receiver.
3. After receiving the message, the receiver computes the SHA-l hash himself and also applies the sender's public key to the signed hash to obtain the original hash H.
Pgp-Pretty Good Privacy is the open source freely available tool to encrypt your emails then you can very securely send mails to others over internet without fear of eavesdropping by cryptanalyst.
Security Hash Algorithm (SHA) was developed in 1993 by the National Institute of Standards and Technology (NIST) and National Security Agency (NSA).
It was designed as the algorithm to be used for secure hashing in the US Digital Signature Standard.
• Hashing function is one of the most commonly used encryption methods. A hash is a special mathematical function that performs one-way encryption.
• SHA-l is a revised version of SHA designed by NIST and was published as a Federal Information Processing Standard (FIPS).
• Like MD5, SHA-l processes input data in 512-bit blocks.
• SHA-l generates a 160-bit message digest. Whereas MD5 generated message digest of 128 bits.
• The procedure is used to send a non secret but signed message from sender to receiver. In such a case following steps are followed:
1. Sender feeds a plaintext message into SHA-l algorithm and obtains a 160-bit SHA-l hash.
2. Sender then signs the hash with his RSA private key and sends both the plaintext message and the signed hash to the receiver.
3. After receiving the message, the receiver computes the SHA-l hash himself and also applies the sender's public key to the signed hash to obtain the original hash H.
Pgp-Pretty Good Privacy is the open source freely available tool to encrypt your emails then you can very securely send mails to others over internet without fear of eavesdropping by cryptanalyst.
CMACs and MACS based on block ciphers, Digital signatureAdarsh Patel
cmcs
MACs based on Block Ciphers
Digital Signature
Properties , Requirements and Security of Digital Signature
Various digital signature schemes ( Elgamal and Schnorr )
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 ...
The Diffie-Hellman algorithm was developed by Whitfield Diffie and Martin Hellman in 1976.
This algorithm was devices not to encrypt the data but to generate same private cryptographic key at both ends so that there is no need to transfer this key from one communication end to another.
Diffie – Hellman algorithm is an algorithm that allows two parties to get the shared secret key using the communication channel, which is not protected from the interception but is protected from modification.
A single pass assembler scans the program only once and creates the equivalent binary program. The assembler substitute all of the symbolic instruction with machine code in one pass.
Introduction to Public key Cryptosystems with block diagrams
Reference : Cryptography and Network Security Principles and Practice , Sixth Edition , William Stalling
CMACs and MACS based on block ciphers, Digital signatureAdarsh Patel
cmcs
MACs based on Block Ciphers
Digital Signature
Properties , Requirements and Security of Digital Signature
Various digital signature schemes ( Elgamal and Schnorr )
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 ...
The Diffie-Hellman algorithm was developed by Whitfield Diffie and Martin Hellman in 1976.
This algorithm was devices not to encrypt the data but to generate same private cryptographic key at both ends so that there is no need to transfer this key from one communication end to another.
Diffie – Hellman algorithm is an algorithm that allows two parties to get the shared secret key using the communication channel, which is not protected from the interception but is protected from modification.
A single pass assembler scans the program only once and creates the equivalent binary program. The assembler substitute all of the symbolic instruction with machine code in one pass.
Introduction to Public key Cryptosystems with block diagrams
Reference : Cryptography and Network Security Principles and Practice , Sixth Edition , William Stalling
Modes of Operation and its applications
Multiple Encryption and Meet-in-the Middle Attack
SHA-1 and SHA-3
HMAC and CBC-MAC and its Security
CBC-MAC implementation
Applications of IoTs in Home,City,HealthRajapriya82
This Video describes the various applications of IoT in various domains such as Home Automation, Cities, Agriculture, Health & Fitness, Environment, Logistics, Industry, Energy and Retail.
This presentation describes about the various memory allocation methods like first fit, best fit and worst fit in memory management and also about fragmentation problem and solution for the problem.
The Presentation describes about the Transmission media and in detail about coaxial cable,Twisted pair, Fiber optics, Power lines and their comparisons
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
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.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
2. SHA 1 ALGORITHM
SHA-1 or Secure Hash Algorithm 1 is a cryptographic hash function which
takes an input and produces a 160-bit (20-byte) hash value.
This hash value is known as a message digest.
This message digest is usually then rendered as a hexadecimal number
which is 40 digits long.
It is a U.S. Federal Information Processing Standard and was designed by
the United States National Security Agency.
6. SHA1 ALGORITHM DESCRIPTION
It is a 6-step process of padding of '1000...',
appending message length,
preparing 80 process functions,
preparing 80 constants,
preparing 5 word buffers,
processing input in 512 blocks.
7. SHA1 ALGORITHM CONSISTS OF 6 TASKS:
Task 1.Appending Padding Bits.
The original message is "padded" (extended) so that its length (in bits) is
congruent to 448, modulo 512.
The padding rules are:
The original message is always padded with one bit "1" first.
Then padded with as many 0’s as necessary to bring the message length
to 64 bits fewer than a multiple of 512.
8.
9. CONT...
Task 2.Appending Length.
64 bits are appended to the end of the padded message to indicate the length
of the original message.
The rules of appending length are:
The length of the original message in bytes is converted to its binary
format of 64 bits.
If overflow happens, only the low-order 64 bits are used.
Break the 64-bit length into 2 words (32 bits each).
The low-order word is appended first and followed by the high-order
word.
10.
11. CONT…
Task 3.Preparing Processing Functions.
SHA1 requires 80 processing functions defined as:
f(t;B,C,D) = (B AND C) OR ((NOT B) AND D) ( 0 <= t <= 19)
f(t;B,C,D) = B XOR C XOR D (20 <= t <= 39)
f(t;B,C,D) = (B AND C) OR (B AND D) OR (C AND D) (40 <= t <= 59)
f(t;B,C,D) = B XOR C XOR D (60 <= t <= 79)
12. CONT…
Task 4.Preparing Processing Constants.
SHA1 requires 80 processing constant words defined as:
K(t) = 5A827999 ( 0 <= t <= 19)
K(t) = 6ED9EBA1 (20 <= t <= 39)
K(t) = 8F1BBCDC (40 <= t <= 59)
K(t) = CA62C1D6 (60 <= t <= 79)
13. CONT…
Task 5.Initializing Buffers.
SHA1 algorithm requires 5 word buffers with the following initial values:
H0 = 67452301
H1 = EFCDAB89
H2 = 98BADCFE
H3 = 10325476
H4 = C3D2E1F0
14. CONT…
Task 6.Processing Message in 512-bit Blocks.
This is the main task of SHA1 algorithm, which loops through the padded and
appended message in blocks of 512 bits each.
For each input block, a number of operations are performed
15. COMPUTING THE MESSAGE DIGEST
The message digest is computed using the final padded message.
The computation uses two buffers:
each consisting of five 32-bit words
a sequence of eighty 32-bit words.
The words of the first 5-word buffer are labeled A,B,C,D,E.
The words of the second 5-word buffer are labeled H0, H1, H2, H3, H4.
The words of the 80-word sequence are labeled W0, W1,..., W79.
A single word buffer TEMP is also employed.
To generate the message digest, the 16-word blocks M1, M2,..., Mn .
The processing of each Mi involves 80 steps.
16. SHA-1 FRAMEWORK FINAL STEP
Input and predefined functions:
M[1, 2, ..., L]: Blocks of the padded and appended message
f(0;B,C,D), f(1,B,C,D), ..., f(79,B,C,D): 80 Processing Functions
K(0), K(1), ..., K(79): 80 Processing Constant Words
H0, H1, H2, H3, H4, H5: 5 Word buffers with initial values
17. SHA-1 FRAMEWORK CONTINUED
Pseudo Code….
For loop on k = 1 to L
(W(0),W(1),...,W(15)) = M[k] /* Divide M[k] into 16 words */
For t = 16 to 79 do:
W(t) = (W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16)) <<< 1
A = H0, B = H1, C = H2, D = H3, E = H4
For t = 0 to 79 do:
TEMP = A<<<5 + f(t;B,C,D) + E + W(t) + K(t) E = D, D = C,
C = B<<<30, B = A, A = TEMP
End of for loop
H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E
End of for loop
Output:
H0, H1, H2, H3, H4, H5: Word buffers with final message digest
