Public key cryptography

What is the diffie- hellman key exchange?

To exchange 2 separate keys securely using compute discrete logarithms. The key exchange algorithm using public and private values

How does the diffie-hellman key exchange work?

Bob and alice agrees on two values, g and n. Then, generates a random number for both of them, x and y. Then, use the formula: Alice = g^x mod n, and Bob = g^y mod n. Then, exchange the values of Alice and Bob with each other. Then use the formula : Key1= Bob^x mod n

What are the principles of public key cryptography?

It uses two keys, public and private. Then, it uses clever number theoritic concepts to function which complements private key crypto instead of replacing it

Why is public-key cryptography used?

To know how to have a secure communication without depending on KDC and to know how to verify message comes intact from the sender Signup and view all the answers

What is the public key?

Known to anybody and can be used to encrypt messages and verify signatures Signup and view all the answers

What is the private key?

Known only to recipient, used to decrypt messages, and sign signatures Signup and view all the answers

What are the six ingredients in the public key cryptography principles scheme?

Plaintext, Encryption Algorithm, Public Key, Private Key, Cipher text, Decryption Algorithm Signup and view all the answers

Difference between authenticating and encrypting using public key cryptography?

For authentication, encryption done using private key. For encryption, encryption done using public key. Signup and view all the answers

What are the applications for public key cryptosystems?

Encryption/decryption, digital signature, key exchange Signup and view all the answers

What are the two cryptographic algorithms?

RSA and Diffie-Hellman Signup and view all the answers

In symmetric vs asymmetric, what is the difference between those two cryptography methods in terms of algorithm and keys?

In symmetric, only one same key and algorithm is used VS in asymmetric, two keys and algorithm is used each for encryption and decryption Signup and view all the answers

In symmetric vs asymmetric, what is the difference between those two cryptography methods in terms of possession of the keys?

In symmetric, both sender and receiver has to have the key and share the same algorithm VS in asymmetric, sender and receiver must each have one of the key pairs which are not the same ones. Signup and view all the answers

In symmetric vs asymmetric, what is the difference between those two cryptography methods in terms of security?

For symmetric, the key must be kept secret VS for asymmetric, one of the keys must be kept secret. Then, it must be impossible to decipher the message without any other information for both methods. Then, knowledge of the algorithm + samples of ciphertext must be insufficient to determine the key Signup and view all the answers

Another cryptographic algorithm is called digital signature standard (DSS). What is that?

It makes use of the SHA-1 and not for encryption or key exchange Signup and view all the answers

Another cryptographic algorithm is called Elliptic-Curve Cryptography. What is that?

It is good for smaller bit size and it is very complex. Less confidence level compared to RSA Signup and view all the answers

What are the steps in public key certificate use?

First there is an unsigned certificate. Then, a hash code of unsigned certificate is generated. Then, the hash code is encrypt with CA’s private key to form signature. Finally the ceritificate is signed Signup and view all the answers

What does message authentication specialise in?

Protect integrity of message, validating identity of the sender, non-repudiation of origin Signup and view all the answers

What are the three alternative functions used in message authentication?

Hash function, message encryption, message authentication code Signup and view all the answers

What are the three approaches to message authentication?

Using conventional encryption, message authentication without message encryption, authentication code Signup and view all the answers

What is one-way hash function?

It is an alternative to MAC. It takes a variable sized message as input and produced a fixed sized message digest as output Signup and view all the answers