An Example Of Alice And Bob - 942 Words

In Public Key Cryptosystem there are two keys used i.e. a public key and a private key. Consider an example of Alice and Bob. I Bob wants to send a message to Alice, Bob uses Alice’s public key to encrypt the message and then send that encrypted message to Alice. Alice uses her private key to decrypt the message. Here how does Bob know the Public Key of Alice? Alice might have distributed its Public key through a secure communication channel. This method is applicable only if there is trust/familiarity between both Bob and Alice. If Bob and Alice does not know each other this whole method fails.[28] This drawback is removed by using a trusted third party (TTP) to uniquely bind public keys to users or another entity such as an organization. This is the place we require a PKI (Public Key Infrastructure). A PKI has one more trusted elements called Certification Authorities (CAs). For instance, Erin is a CA. CA issues Alice a certificate (which contains the public key of Alice) signed by the CA s public key after checking Alice s credentials. Bob can now recover Alice s certificate and confirm it is authentic by checking the signature on it. Certificates may should be revoked later because of different reasons. For instance, if Alice s private key is stolen, she will need to request that the CA deny its certificate. How does Bob know whether a certificate is revoked? The CA keeps up a revocation list which permits Bob to confirm if a given certificate is revoked or not. TheShow MoreRelatedThe Price Of Two Churro Stands At The Mount1717 Words   |  7 PagesAbove is a matrix that sh ows the prices of two churro stands at The Mount. Alice needs to decide whether she should charge $4 or $4.50, and Bob is deciding whether he should pay one of those two amounts for a churro. 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For Example, 15 mod 4 = 3 mod 4 = 3.† [3] Jacobi symbol: â€Å"The Jacobi symbol, written (n/m) is defined for positive odd m as (n/m)=(n/p_1 )^((a_1 ) ) (n/p_2 )^(a_2 )...(n/p_k )^(a_k ) Where m=p_1^a1 p2^a2...p_k^(a_k ) â€Å" [4] Functionality: The system hasRead MoreElliptic Curve Cryptology Used to Make Keys1066 Words   |  5 Pages where Alice and Bob have agreed in advance to convert it to an integer from some method i.e the image of its x -coordinate under some agreed upon simple map from Fq to the natural numbers. Now that E is an elliptic curve over Fq , and Q is an known decided point on the curve. Alice secretly takes a random integer kA and finds the point kA Q, which will be sent to Bob. Similarly, Bob secretly chooses a random kB computes kB Q, and sends it to Alice. The common key is P = kA kB Q. Alice computesRead MoreRacism : A Form Of Systemic Racism1566 Words   |  7 Pagesfear is at the root of all discrimination and especially racism. 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In this way the communication will be carried in between Bob and Alice