M. Tech Thesis AN EFFICIENT ALGORITHM USED FOR RESOURCE RESERVATION FOR REAL TIME TRAFFIC IN PACKET SERVICE NETWORK WITH MOBILE HOSTS This work describes an efficient algorithm for resource reservation to provide services to mobile hosts. Mobility of hosts has an important impact over the quality of services provided to a real time applications. The hosts freqquently change their positions among several subnets. So it is required to make advance resource reservations in the possible subnets the hosts may visit to reduce the impact of mobility. B.E. Project SECURITY OF EMAIL USING CRYPTOGRAPHIC TECHNIQUES
INTRODUCTION
The present world is the world of communication. Every where and in all the fields we can see the effects of fast communication. One of the fastest and the most widely used means of communication is e-mail, which is sent between two (or more) people through the Internet. There are various mailing softwares available for sending and receiving emails on the Internet, and most of them are free. Therefore an unexpectedly large population of people (among the Internet user) enjoy using these softwares for free mailing. But the basic problem with these packages is that they are not secure. During these passage from a number of computers on the Internet, these emails can be hacked by the hackers that is they can be read, manipulated and then rewritten and then sent to the persons or can be sent to unauthorised persons, and thus the needy people can suffer from great losses. So in my project entitled " Development Of An E-mail Security System", I am trying to develop a package for securing these e_mails and dealing with the aforesaid problems.
PUBLIC KEY CRYPTOGRAPHY
Historically the key distribution has been a weak link in most techniques. The key has to be delivered to the receiver by physical means. This approach is very short-sighted, because the key has to be protected from the theft, but it has to be distributed also. Thus the concept of PUBLIC KEY CRYPTOGRAPHY system arises. This system was proposed by Diffie and Hallman in their revolutionary paper " NEW DIRECTION ON CRYPROGRAPHY" published in year 1976. They proposed a system in which the encryption and decryption keys were different and decryption key could not be devised from the encryption key. In their proposal encryption key (Ek) algorithm and decryption key (Dk) algorithm must follow three requirements:- (i) Dk(Ek(P))=P, (P=plaintext) (ii) It is exceedingly difficult to deduce Dk from Ek. (iii) Ek cannot be broken by chosen plaintext. The method works as follows:- Any organization or person who wants to receive secret message devices algorithms to produce Ek and Dk, meeting the above requirements. The encryption key Ek is made public, hence the name public key cryptography. Thus the problem of establishing a secure channel between two parties, let Debopam and Nitin, who never had previous contact, is solved. Both Nitin's encryption key En and Debopam's encryption key Ed are assumed to be made public. Also their decryption keys Dn and Dd respectively are private. Now Nitin takes his message P, computes Ed(P) and thus gets the ciphertext. This is then transmitted to Debopam. Debopam then decrypts it by applying Dd(P) to produce the plaintext P. No one else can read the encrypted message Ed(P). Thus Debopam and Nitin can communicate securely.
EXAMPLE:
SAMPLE EMAIL :
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hi,
This is the text file which i am going to encrypt by the Cryptomaster. The Cryptomaster is based on public key cryptography and uses
the RSA algorithm. My present algorithm can handle upto staggering 10(exp(500)) multiplications. This is developed in Turbo C++ version 3.
bye debopam
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
ENCRYPTED EMAIL:
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
150$157$153$31$31$159$147$157$70$178$157$70$178$36$147$198$178$36$198$95$36$178$122$157$250$198$178$63
$147$157$104$147$178$157$178$118$29$178$39$21$157$38$39$178$36$21$178$198$38$104$138$5$33$36$178$51$5$
178$36$147$198$178$48$138$5$33$36$21$29$118$70$36$198$138$44$178$159$147$198$178$48$138$5$33$36$21$29$
118$70$36$198$138$178$157$70$178$51$118$70$198$142$178$21$38$178$33$163$51$250$157$104$178$156$198$5$
178$104$138$5$33$36$21$39$138$118$33$147$5$178$118$38$142$178$163$70$198$70$178$36$147$198$178$52$84$1$
178$118$250$39$21$138$157$36$147$29$44$178$193$5$178$33$138$198$70$198$38$36$178$118$250$39$21$138$157
$36$147$29$178$104$118$38$178$147$118$38$142$250$198$178$163$33$36$21$178$70$36$118$39$39$198$138$157$
38$39$178$221$165$2$198$95$33$2$42$165$165$8$8$178$29$163$250$36$157$33$250$157$104$118$36$157$21$38$70
$44$178$159$147$157$70$178$157$70$178$142$198$123$198$250$21$33$198$142$178$157$38$178$159$163$138$51$21
$178$48$56$56$178$123$198$138$70$157$21$38$178$246$44$31$31$51$5$198$31$142$198$51$21$33$118$29$178$
---------------------------------------------------------------------------------------------------------------------------------------------------------------------