RSA Algorithm

RSA Algorithm (Rivest, Shamir, Adelson) helps to effective and efficient encryption and decryption of data and information in a network communication.

Summary

RSA Algorithm (Rivest, Shamir, Adelson) helps to effective and efficient encryption and decryption of data and information in a network communication.

Things to Remember

Encryption: Ciphertext (C)=p^e mod (n)
Decryption: p=C^d mod (n)
K^-_B (K⁺_B(m))=m= K⁺_B(K^-_B(m)) i.e. we can use public key first, followed by private key or we can use private key first, followed by the public key.

MCQs

No MCQs found.

Subjective Questions

Q1:

Define Connective Tissue and state its Types.

Type: Long Difficulty: Easy

Show/Hide Answer

Answer: <h3>2. Connective Tissue</h3>
<p><br />Connective tissue is composed of different types of cells (fibroblasts,plasma cells, fast and mast cells)combined with large amounts of intracellular matter(collagenous,elastic and fiber).It provides support and structure and also provides integrity to the organs, protect the body and acts as the storehouse of mineral and fats.Connective tissue<br />.Connective tissues are fibrous tissues which are made up of many types of specialized cells.Connective tissue is the most abundant and widely distributed tissue type found in the human body. The role of connective tissue is to protect, support, and bind together parts of the body. While other functions are attributed to connective tissues.</p>
<h4>Functions</h4>
<p><br />1. Provides support for organs.<br />2. Stores nutrient and storage of lipids, water, electrolyte, and plasma protein.<br />3. Helps in the regeneration of the specialized tissue.<br />4. Connects and bind cells and organs to support the body.<br />5. Helps in the transport of nutrients from blood.</p>
<h3>Types of Connective Tissue</h3>
<h4><br />1) Proper Connective tissue</h4>
<p><br /><strong>(a) Areolar tissue</strong>-It is almost found in all parts of the body connecting and supporting other tissues and provides blood supply to epithelial tissues.It can be found in<br />• the lining of blood vessels and nerves, between muscles and tendons<br />• and provides blood supply to an epithelial tissue<br />• Under the skin and in the alimentary canal etc.</p>
<p><strong>(b) Adipose tissue</strong>- It consists of a collection of fats cells containing fat globules and also known as fat tissue.It is typically found in close proximity to the loose connective tissue.It is the storehouse for nutrients and stores fats that can be used as energy for the body.</p>
<p>There are 2 types of adipose tissue</p>
<ul>
<li><br />White tissue</li>
</ul>
<p>-It is found in the supporting kidneys, eyes, under the skin and acts as a thermal insulator.</p>
<ul>
<li><br />Brown adipose tissue</li>
</ul>
<p>-It is present in small quantities mainly lies in between scapula , in the nape of the neck and in the walls of the large blood vessels. It helps to maintain and regulate body temperature and prevent obesity.</p>
<p> </p>
<p><strong>(c) Fibrous tissue</strong>-It is a dense and strong connective tissue made up of closely packed bundles of collagen fibers with a very little matrix. It is found in:<br />Ligaments, which bind bone togetherPeriosteum; outer protective covering of bone</p>
<ul>
<li>Periosteum; outer protective covering of bone</li>
<li>An outer covering of kidney, lymph nodes and brain.</li>
</ul>
<p><strong>(d) Elastic tissue</strong>- A type of connective tissue consisting mainly of elastic fibers and found in the walls of arteries, dermis of the skin,and certain ligaments and tendon,made up of yellow elastic fibers, frequently massed into sheets. It has a capability of stretching and recoiled. It is found in the organs where alteration of shape is required such as large blood vessels, epiglottis, trachea and external ears.</p>
<p><strong>(e) The lymphoid tissue</strong>-Lymphoid tissue has a semi-solid matrix with fine branching reticulum fibers. Lymphoid tissue is present throughout the body lymph nodes, spleen, tonsils, adenoids, blood and other structures (small intestine,walls of the large intestine).</p>
<h4><br />2) Skeletal Tissue</h4>
<p><br /><strong>a) Bone</strong></p>
<p><br /><strong>b) Cartilage</strong></p>
<p>- Cartilage is a flexible connective tissue, including the joints between bones, the rib cage, the ear, the nose, the bronchial tubes and the intervertebral disk,firm, rubbery tissue that cushions bones at joints.Cartilage is much firmer tissue than other types of connective tissue. The cells are in less number.<br />There are three types of cartilage and they are:</p>
<ul>
<li>Hyaline cartilage=Appear as a smooth bluish white tissue which is found in the surface parts of the bone which forms joints and forming other parts of the larynx, trachea, and bronchi.</li>
<li>White fibrous cartilage=White fibrous tissue is a connective tissue in which there is a great portion of white inelastic fibers than elastic fibers. It is tough, slightly flexible tissue found in an intervertebral disc, semilunar cartilage and hip and shoulder joints.</li>
<li>Yellow elastic cartilage=It consists of yellow elastic fiber running through a solid matrix. The cell is lies between the matrix and found in the pinna of the ear, epiglottis, and laryngeal cartilages.</li>
</ul>
<h4>3) Fluid tissue</h4>
<h4> </h4>
<div class="f kv _SWb"> </div>

Videos

Connective Tissue: The Basics

RSA Algorithm

RSA Algorithm (Rivest, Shamir, Adelson)

RSA algorithm is the most common public key encryption algorithm used in Network Security. It uses two numbers ‘e’ and’ as public and private which have a special relationship to each other. These two key helps to encrypt and decrypt the information.

Selecting keys:

Choose two large prime numbers: p and q such that p is not equal to q.
Compute n=pq, z=(p-1) (q-1).
Choose e (with e<n) that has no common factors with z (e and z are relatively prime).
Choose d such that ed-1 is exactly divisible by z (i.e. ed mod z=1).
A public key is (n,e) and a Private key is (n,d).

Encryption: Cipher text (C)=p^e mod (n)
Decryption: p=C^d mod (n)

Question-1:

1)Encrypt SUZANNE using RSA algorithm.

Let,

p=3 and q=11 are the two prime numbers.

Thus, n=p*q=33 and z=(3-1)(11-1)=20.

Let, e=3 such that e and z are relatively prime.

Thus, d=7.

Letters	P	P^e	C=p^e mod(n)	C^d	p=C^d mod(n)
S	19	6859	28	28⁷	19
U	21	9261	21	21⁷	21
Z	26	17576	20	20⁷	26
A	1	1	1	1⁷	1
N	14	2744	5	5⁷	14
N	14	2744	5	5⁷	14
E	5	125	26	26⁷	5

K^-_B (K⁺_B(m))=m= K⁺_B(K^-_B(m)) i.e. we can use public key first, followed by private key or we can use private key first, followed by the public key.

Question-2:

Encrypt Message “LOVE” using RSA Algorithm

Let p=5, q=7 (Smaller numbers are selected for simplicity)

Then n = pq = 5*7 = 35 â–« And z = (p-1) (q-1) = 4*6 = 24

Selecting e = 5 (e < n and no common factor with z) and d = 29 (such that: ed mod z = 1)

=> Public Key (n, e) = (35, 5)

=> Private Key (n, d) = (35, 29)

Letters	P	P^e	C=p^e mod(n)	C^d	p=C^d mod(n)
L	12	248832	17(Q)	17²⁹	12(L)
O	15	759375	15(O)	15²⁹	15(O)
V	22	5153632	22(V)	22²⁹	22(V)
E	5	3125	10(J)	10²⁹	5(E)

Encryption (LOVE => QOVJ)

Decryption (QOVJ => LOVE)

References:

A.S. Tanenbaum, “Computer Networks”, 3rd Edition, Prentice Hall India, 1997.
W. Stallings, “Data and Computer Communication”, Macmillan Press, 1989.
Kurose Ross, “Computer Networking: A top-down approach”, 2nd Edition, Pearson Education
Larry L. Peterson, Bruce S. Davie, “Computer Networks: A Systems Approach”, 3rd Edition, Morgan Kaufmann Publishers

Lesson

Network Security

Subject

Computer Engineering

Grade

Engineering

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