Public Key in NS2 (Cryptography)

Public Key in Ns2

HI everybody here like to brief or just info about the Public Key infrastructure (Pki). Public Key is one of the method for cryptography using digital certificates used to transfer the data safe and securely. Explains how is done in Ns2.General explanation follows

Public-key cryptography requires that entities that want to communicate in a secure manner, possess certain security credentials. This collection of security credentials is stored in a wallet. Security credentials consist of a public/private key pair, a "user" certificate, a certificate chain, and "trusted" certificates.
The secrecy of encrypted data generally depends on the existence of a secret key shared between the communicating parties. Providing and distributing such secret keys is one aspect of key management. In a multiuser environment, secure key distribution may be difficult; public key cryptography was invented to solve this problem.

Public key cryptography is based on a secure secret key pair. Each key (one half of the pair) can only decrypt information encrypted by its corresponding key (the other half of the pair). A key pair includes:
• The private key, known only to its owner
• The public key, distributed widely, but still associated with its owner
Use of the cryptographic key pair to set up a secure, encrypted channel ensures the privacy of a message and validates the authenticity of the sender of the message. It also provides an important benefit: the ability to widely distribute the public key on a server, or in a central directory, without jeopardizing the integrity of the private key component of the key pair. This eliminates the need to transmit the public key to every correspondent in the system.
Each entity that participates in a public key system must have a public/private key pair. The public key for an entity is published by a certificate authority (CA) in a user certificate. Then, other entities that want to send it secure information can encrypt the information with the recipient entity's public key. Another use for a public key is for an entity that receives a communication to validate the sender's organizational affiliation.

Main Useful of Public Key

The PKI approach to security does not take the place of all other security technologies; rather, it is an alternative means of achieving security. The following advantages of PKI have led to its emergence as an industry standard for securing Internet and e-commerce applications.

• PKI is a standards-based technology.

• It allows the choice of trust provider.

• It is highly scalable. Users maintain their own certificates, and certificate authentication involves exchange of data between client and server only. This means that no third party authentication server needs to be online. There is thus no limit to the number of users who can be supported using PKI.

• PKI allows delegated trust. That is, a user who has obtained a certificate from a recognized and trusted certificate authority can authenticate himself to a server the very first time he connects to that server, without having previously been registered with the system.

• Although PKI is not notably a single sign-on service, it can be implemented in such a way as to enable single sign-on.
A certificate authority (CA) is a trusted third party that certifies that other entities--users, databases, administrators, clients, servers--are who they say they are. When it certifies a user, the certificate authority verifies the user's identity and grants a certificate, signing it with the certificate authority's private key. The certificate authority has its own certificate and public key, which it publishes, as well as a private key, which is securely maintained. Servers and clients use the CA's root certificate to verify signatures that the certificate authority has made. A certificate authority might be an external company that offers certificate services, or an internal organization such as a corporate MIS department
Public certificates

A certificate is like an electronic passport that proves the identity of a user or device that seeks to access the network. The certificate ensures that the entity's information is correct and that the public key actually belongs to that entity. A certificate is created when an entity's public key is signed by a trusted identity (a certificate authority). It contains information such as the following:
• the certificate user's name
• an expiration date
• a unique serial number assigned to the certificate by the CA
• the user's public key
• information about the rights and uses associated with the certificate
• the name of the certificate authority that issued the certificate
• the CA's signature
• an algorithm identifier that identifies which algorithm was used to sign the certificate

A trusted certificate, sometimes known as a root key certificate, typically belongs to a third party entity that is trusted to issue certificates. It is obtained in a secure manner and, operationally, does not need to be validated for its authenticity each time it is accessed because it is self-signed. A client or a server can validate that an entity is who it claims to be by verifying that the entity's certificate was issued by a known and trusted certificate authority.
Typically, certificate authorities whom you trust issue the user certificates. Oracle provides several default trusted certificates, so users do not have to install their own. These trusted certificates also enable servers to perform SSL authentication to clients who have wallets containing only trusted certificates.

Synopsis of NS2

Hi Students

Here like to discuss few points in NS2

1) Ns2 is the nice tool using for research and study purpose.
2) Mostly Ns2 is made up of C++
3) Even other language like Java, Dot net can also use only with separate patches
4) Flexible language but difficult to get materials and datas
5) Excellent tool for network engineers research people


Enjoy learning NS2

Sample Coding in Wireless

Here Guys this is an sample tcl coding


# Define options
set val(chan) Channel/WirelessChannel ;# channel type
set val(prop) Propagation/TwoRayGround ;# radio-propagation model
set val(netif) Phy/WirelessPhy ;# network interface type
set val(mac) Mac/802_11 ;# MAC type
set val(ifq) Queue/DropTail/PriQueue ;# interface queue type
set val(ll) LL ;# link layer type
set val(ant) Antenna/OmniAntenna ;# antenna model
set val(ifqlen) 50 ;# max packet in ifq
set val(nn) 50 ;# number of mobilenodes
set val(rp) DSDV ;# routing protocol
set val(x) 1000 ;# X dimension of topography
set val(y) 1000 ;# Y dimension of topography
set val(stop) 150 ;# time of simulation end

set ns [new Simulator]
set tracefd [open simple.tr w]
set namtrace [open simwrls.nam w]

$ns trace-all $tracefd
$ns namtrace-all-wireless $namtrace $val(x) $val(y)

# set up topography object
set topo [new Topography]

$topo load_flatgrid $val(x) $val(y)

create-god $val(nn)



# configure the nodes
$ns node-config -adhocRouting $val(rp) \
-llType $val(ll) \
-macType $val(mac) \
-ifqType $val(ifq) \
-ifqLen $val(ifqlen) \
-antType $val(ant) \
-propType $val(prop) \
-phyType $val(netif) \
-channelType $val(chan) \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace OFF \
-movementTrace ON

for {set i 0} {$i < $val(nn) } { incr i } {
set n($i) [$ns node]
}

# Provide initial location of mobilenodes
$n(0) set X_ 347.0
$n(0) set Y_ 3.0
$n(0) set Z_ 0.0

$n(1) set X_ 345.0
$n(1) set Y_ 36.0
$n(1) set Z_ 0.0

$n(2) set X_ 330.0
$n(2) set Y_ 121.0
$n(2) set Z_ 0.0

$n(3) set X_ 316.0
$n(3) set Y_ 152.0
$n(3) set Z_ 0.0

$n(4) set X_ 246.0
$n(4) set Y_ 90.0
$n(4) set Z_ 0.0

$n(5) set X_ 379.0
$n(5) set Y_ 6.0
$n(5) set Z_ 0.0



# Set a TCP connection between n(1) and n(31)
set tcp [new Agent/TCP/Newreno]
$tcp set class_ 2
set sink [new Agent/TCPSink]
$ns attach-agent $n(1) $tcp
$ns attach-agent $n(31) $sink
$ns connect $tcp $sink
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ns at 10.0 "$ftp start"

# Set a TCP connection between n(31) and n(43)
set tcp [new Agent/TCP/Newreno]
$tcp set class_ 2
set sink [new Agent/TCPSink]
$ns attach-agent $n(31) $tcp
$ns attach-agent $n(43) $sink
$ns connect $tcp $sink

#defining heads
$ns at 0.0 "$n(0) label CH"
$ns at 0.0 "$n(1) label Source"
#$ns at 0.0 "$n(2) label N2"



$ns at 10.0 "$n(5) setdest 785.0 228.0 5.0"
$ns at 13.0 "$n(26) setdest 700.0 20.0 5.0"
$ns at 15.0 "$n(14) setdest 115.0 85.0 5.0"

#Color change while moving from one group to another
$ns at 73.0 "$n(2) delete-mark N2"
$ns at 73.0 "$n(2) add-mark N2 pink circle"
$ns at 124.0 "$n(11) delete-mark N11"
$ns at 124.0 "$n(11) add-mark N11 purple circle"
$ns at 103.0 "$n(5) delete-mark N5"
$ns at 103.0 "$n(5) add-mark N5 white circle"
$ns at 87.0 "$n(26) delete-mark N26"
$ns at 87.0 "$n(26) add-mark N26 yellow circle"
$ns at 92.0 "$n(14) delete-mark N14"
$ns at 92.0 "$n(14) add-mark N14 green circle"

# Define node initial position in nam
for {set i 0} {$i < $val(nn)} { incr i } {
# 20 defines the node size for nam
$ns initial_node_pos $n($i) 20
}

# Telling nodes when the simulation ends
for {set i 0} {$i < $val(nn) } { incr i } {
$ns at $val(stop) "$n($i) reset";
}

# ending nam and the simulation
$ns at $val(stop) "$ns nam-end-wireless $val(stop)"
$ns at $val(stop) "stop"
$ns at 150.01 "puts \"end simulation\" ; $ns halt"
proc stop {} {
global ns tracefd namtrace
$ns flush-trace
close $tracefd
close $namtrace
exec nam simwrls.nam &
}

$ns run

Reduction of Rekeyying process to overcome Security

Hello Peoples

Here This topic is to discuss the overhead problem while continuous rekeying, The experts can suggest idea are the students can discuss about that , actually using the Tree structure other than that new ideas needed . share with us

Installation of Wimax in NS2.31

Hello Guys

First of all i like to apologies for delay posting in Ns2 , because busy with my Research area. Now i like to share some thoughts in Wimax 3G, here iam going to give the installation of Wimax in ns 2.31

1) at present the UMTS and the Wimax 3G research going on the Area6 but now iam posting for startup people to implement the wimax

2) download ns-allinone-2.31



#########################


wimax implementation ....

The patch file is only provided for ns-2.31.

a- Using the ns-allinone installation
step1: install the patch by running "patch -p0 step2: re-run "./configure ; make clean ; make" in the ns-2.31 directory.

b- From the ns-2.31 directory
step1: install the patch by running "patch -p1 step2: re-run "./configure ; make clean ; make" in the ns-2.31 directory.

download file from here
http://www.mediafire.com/file/apk8x0dvkj6hl5x/wimaximp.rar

RSA algorithm in Ns2

RSA This algorithm is used in cryptography Technique in that RSA is added along with it. These are procedures followed



Key generation

RSA involves a public key and a private key. The public key can be known to everyone and is used for encrypting messages. Messages encrypted with the public key can only be decrypted using the private key. The keys for the RSA algorithm are generated the following way:

1. Choose two distinct prime numbers p and q.
* For security purposes, the integers p and q should be chosen uniformly at random and should be of similar bit-length. Prime integers can be efficiently found using a primality test.
2. Compute n = pq.
* n is used as the modulus for both the public and private keys
3. Compute φ(pq) = (p − 1)(q − 1). (φ is Euler's totient function).
4. Choose an integer e such that 1 < e < φ(pq), and e and φ(pq) share no divisors other than 1 (i.e., e and φ(pq) are coprime).
* e is released as the public key exponent.
* e having a short bit-length and small Hamming weight results in more efficient encryption. However, small values of e (such as e = 3) have been shown to be less secure in some settings.[4]
5. Determine d (using modular arithmetic) which satisfies the congruence relation d e \equiv 1\pmod{\varphi(pq)}.
* Stated differently, ed − 1 can be evenly divided by the totient (p − 1)(q − 1).
* This is often computed using the extended Euclidean algorithm.
* d is kept as the private key exponent.

The public key consists of the modulus n and the public (or encryption) exponent e. The private key consists of the private (or decryption) exponent d which must be kept secret.

Note:

* An alternative, used by PKCS#1, is to choose d matching e d ≡ 1 (mod λ) with λ = lcm(p-1,q-1), where lcm is the least common multiple. Using λ instead of φ(n) allows more choices for d. λ can also be defined using the Carmichael function λ(n).
* For efficiency the following values may be precomputed and stored as part of the private key:
o p and q: the primes from the key generation,
o d\mod (p - 1) and d\mod(q - 1),
o q^{-1} \mod(p).

[edit] Encryption

Alice transmits her public key (n,e) to Bob and keeps the private key secret. Bob then wishes to send message M to Alice.

He first turns M into an integer 0 < m < n by using an agreed-upon reversible protocol known as a padding scheme. He then computes the ciphertext c corresponding to:

c = m^e\,\bmod\,n

This can be done quickly using the method of exponentiation by squaring. Bob then transmits c to Alice.
[edit] Decryption

Alice can recover m from c by using her private key exponent d by the following computation:

m = c^d\,\bmod{\,n}.

Given m, she can recover the original message M by reversing the padding scheme.

(In practice, there are more efficient methods of calculating cd using the pre computed values above.)
[edit] A worked example

Here is an example of RSA encryption and decryption. The parameters used here are artificially small, but one can also use OpenSSL to generate and examine a real keypair.

1. Choose two prime numbers

p = 61 and q = 53 Make sure that these prime numbers are distinct.

2. Compute n = pq

n=61\cdot53=3233

3. Compute the totients of product. For primes the totient is maximal and equals the prime minus one. Therefore \varphi(pq) = (p-1)(q-1) \,

\varphi(61\cdot53) = (61 - 1)\cdot(53 - 1) = 3120\,

4. Choose any number e > 1 that is coprime to 3120. Choosing a prime number for e leaves you with a single check: that e is not a divisor of 3120.

e = 17

5. Compute d such that d e \equiv 1\pmod{\varphi(pq)}\, e.g., by computing the modular multiplicative inverse of e modulo \varphi(pq)\,:

d = 2753
since 17 · 2753 = 46801 and 46801 mod 3120 = 1, this is the correct answer.
(iterating finds (15 times 3120)+1 divided by 17 is 2753, an integer, whereas other values in place of 15 do not produce an integer. The extended euclidean algorithm finds the solution to Bézout's identity of 3120x2 + 17x-367=1, and -367 mod 3120 is 2753)

The public key is (n = 3233, e = 17). For a padded message m the encryption function is m^{17} \mod {3233} or abstractly:

c = m^e\mod {n}

The private key is (n = 3233, d = 2753). The decryption function is c^{2753} \mod {3233} or in its general form:

m = c^d\mod {n}

For instance, in order to encrypt m = 65, we calculate

c = 2790 = 65^{17}\mod {3233}

To decrypt c = 2790, we tap

m = 65 = 2790^{2753}\mod {3233}.

Both of these calculations can be computed efficiently using the square-and-multiply algorithm for modular exponentiation. In real life situations the primes selected would be much larger; in our example it would be relatively trivial to factor n, 3233, obtained from the freely available public key back to the primes p and q. Given e, also from the public key, we could then compute d and so acquire the private key.

These Procedures implemented in TCL coding to run in NS2 .For codings and queries please send the mail to admin.

NS2 Projects

Hello Everyone
sorry for not posting about NS2 about two months.I know many students facing difficulties in doing Projects in Ns2. Here iam helping out doing Projects in NS2 ,
I can help Masters,PHD students,UG students and also for Researchers.
But for doing the Projects Cost will be added .
The services will be available like Online chatting, Voice Chatting,Even remote connection and i will help you people to know about Ns2. Any networking Projects can be done in NS2.

For this please contact to this mail id : clickprasan@gmail.com

still more post will be added on this blog keep reading, Ns2 Rocks.
still any doubts can ask me are can mail me I will clarify the doubts with my Best.