8. Cryptography: digital signatures and PKI Flashcards
1
Q
What does a public key certificate consist of?
A
- Public key - Subject (identity of owner) - Signature binding subject and key by a certificate authority
2
Q
What is the chain of trust?
A
Root CA’s sign certificates for level 1 CA’s, level 1 CA’s sign certificates for level 2 CA’s, etc
3
Q
Whats the definition of existential unforgability?
A
4
Q
Whats the advantages of digitial signatures over message authentication codes? (2)
A
- Digital signitures are publically verifiable
- Non-repudiation (whoever signed it can’t say they didn’t)
5
Q
Whats the basic idea for using RSA as a digital signiture?
A
Encrypt (sign) using a secret key, decrypt (verify) using the public key
6
Q
Whats the key generation function for RSA signitures?
A
7
Q
Whats the signing function for RSA signitures?
A
8
Q
Whats the verification function for RSA signitures?
A
9
Q
What is the problem with RSA signitures?
A
Does not provide existential unforgeability
10
Q
How can we add existential unforgeability?
A
