Flashcards
Lecture 3,4,6
Cards in this deck (21)
- 1What is a digital signature?Provides evidence of the person/identity or origin of an electronic document, transaction or message.
- 2What is a digital certificate?A file or an electronic document that contains data fields.
- 3What are the steps to create a digital signature? & How to verify it?1. Generate message,
Calculate the hash of the message,
You encrypt the hash with the private key.
2. Calculate the hash of message
Use public key of sender to verify signature. - 4One time Signature?Is when the user needs a new public key for every message sent.
- 5Properties of digital signature?-Depends on the message sent.
-Must use information unique to the sender.
-Easy to produce, recognize and verify. - 6Undeniable signatureSignature verification requires corporation of signer.
- 7What do digital signatures achieve?Message authentication, but not trust.
Provides guarantee of authorship, integrity and non-repudiation. = when you can't say you've sent a message you did send. - 8What is asymmetric encryption?-Public key & Private key.
- 9What are the 4 authentication steps? Why is periodic re-authentication done?1. Initial negotiation. / Security Parameter.
2. Mutual authentication.
3. Key exchange / Key agreement.
4. Ongoing communication
To ensure hackers haven't hijacked the connection. - 10What does the simple authentication dialog know about users?Authentication server knows passwords of all users and shares an unique secret key which each server.
- 11Match each layer with the ITS system? A , T, I, DLApplication = Kerberos
Transport = SSL / SLT
Internet = ISPEC
Data Link = PPTP / L2TP - 12What is symmetric encryption?Encryption and decryption using the same key. The key represents the ongoing communication.
- 13What are Kerberos requirements?1. Secure: To avoid impersonation of user.
2. Reliable: Lack of availability = lack of control.
3. Transparent: User should not know authentication is taking place, beyond the password. - 14What is group signature?Unforgeable: Only members of group can create valid group signatures.
Anonymity: Individual signer cannot determine without the group manager's secret key.
Tractability: Group managers should be able to trace which user issued a signature. - 15What can Eve not do?-Guess a random number.
-She cannot link a private key with a public key.
-Without the correct key, Eve cannot retrieve plain-text from a given cipher-text.
-Create valid cipher-text without the encryption key. - 16The notion of authentication can be broken down into three categories.Data origin authentication: Identifying the source of a message and establishes freshness.
Entity authentication: What someone knows.
Authentication key establishment: Two parties that agreed on a secret key for communication. - 17What is a certification authority?A trusted server used to perform key management of Public key.
Special and well-known principle.
Every public key certificate the CA issues, it certifies the users key material. - 18What is included in both physical and digital certificate.-Who it is issued to.
-The expiry date.
-The signature.
-Who issued the certificate. - 19What security service does certification authority provide?Message authentication without the need of handling any secret.
- 20Why do certificates use the trust model?To enable users to know where the certificate has come from and whether it is genuine or not.
- 21What is blind signature?When customer A does not want Bob (Bank) to be capable to associate with the M (Money) with the spender or service purchased.
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- Flashcards on Lecture 3,4,6, created by xManisha12 . on 06/01/2017.
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- xManisha12 . · Jan 2017
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- Jan 10, 2017
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