Week 2 - #2 - IT Security - Defense Against Digital Arts Questions and Answers Rated A+

Week 2 - #2 - IT Security - Defense Against Digital Arts Questions and Answers Rated A+ ____________ is a type of cryptography based on algorithms that require two keys -- one of which is secret (or private) and one of which is public (freely known to others). Also known as public key ciphers. asymmetric encryption Person A and Person B need to communicate securely: 1. Each generates a private key 2. A public key for each person is derived using their private keys. 3. Person A and Person B exchange public keys. 4. When Person A wants to send Person B an encrypted message, she uses Person B's public key to encrypt the message and then send the ciphertext. 5. Person B uses his private key to decrypt the message and read it. 6. When Person B replies to Person A's message, he will use her public key to encode his message and she will use her private key to decrypt the message. How does asymmetric encryption work? 1) Person A composes her confidential message and combines it with her private key to generate a digital signature. 2) She sends the message along with the associated digital signature to Person B. 3) Assuming that Person A and Person B have already exchanged public keys, Person B can verify the message's origin and authenticity by combining the message, the digital signature, and Person A's public key. 4) If the message was actually signed using Person A's private key and not someone else's and the message wasn't modified at all, then the digital signature should validate.5) If the message was modified, even by one whitespace character, the validation will fail and Person B shouldn't trust the message. How can Person A make sure that a message sent to Person B arrives without being tampered with and let Person B know that it was really sent by her? The three concepts that an asymmetric cryptosystem grants us are: 1) ________________, 2) ___________________ and 3) ______________________. confidentiality, authenticity, nonrepudiation. _____________________ is granted through the encryption-decryption mechanism if encrypted data is kept confidential and secret from unauthorized third parties. Confidentiality __________________ is granted by the digital signature mechanism, as long as the message can be authenticated or verified that it wasn't tampered with. Authenticity ___________________ means that the author of the message isn't able to dispute the origin of the message. In other words, this allows us to ensure that the message came from the person claiming to be the author. Non-repudiation Pros: