CS442 - Chapter 13
________ is when a signature is forged for any available message.
existential forgery
True or False: DSA security does not depend on discrete logs.
false
True or False: Digital signatures do not provide the ability to authenticate message contents.
false
True or False: Direct Digital Signatures do not only involve sender and receiver.
false
True or False: In elliptic curve DSA, users all have different global domain parameters.
false
True or False: The security of Schnorr digital signatures does not depend on discrete logs.
false
True or False: There was proof of RSA security prior to PSS.
false
ElGamal signatures use exponentiation in a _______ field.
galois
The process for MGF is to repeatedly use the hash function until the string length is _________ the mask length.
greater than or equal to
Schnorr minimizes the message dependent computation because the main part can be done in _________.
idle time
A _________ (MGF) is used in RSA PSS.
mask generation function
Which of these is not a type of attack given for digital signatures? > key-only > known-message > generic chosen message > masquerade > directed chosen message > adaptive chosen message
masquerade
The parameters in elliptic curve DSA define the elliptic curve and the ________.
point of origin
The digital signature for a direct digital signature is the message or hash sent with a ________ key.
private
The RSA _________ (PSS) is the most secure of RSA.
probabilistic signature scheme
Why does MAC or cipher not work for a digital signature?
provides authentication but no protection of two parties against each other
DSA keys are generated by the user choosing a _________ private key and computing the public key.
random
_________ is when signatures are forged for a specific message.
selective forgery
The process followed by direct digital signatures is ________.
sign then encrypt
In ElGamal signatures, the private key is for ________ and the public key is for ________.
signing; verification
DSA is _________ and _________ than RSA.
smaller; faster
In Schnorr signatures, p is typically 1024-bits and q is typically _________-bits.
160
Schnorr message dependent computation is the product of a _________-bit integer and a _________-bit integer.
2n; n
The Digital Signature Standard (DSS) uses the __________ hash.
SHA
Direct digital signatures provide _______ and _______,
confidentiality; validity
MGF is usually based on a ________, such as SHA-1.
cryptographic hash
A _________ attack is when a list of messages to be signed is chosen after the recipient knows the key but before signatures are seen.
directed chosen message
A ________ attack is a request for signatures of messages that depend on previously obtained message-signature pairs.
adaptive chosen message
Digital signatures provide the ability to verify the _______, _______, and _________.
author; date; time
Types of forgeries include ________, universal forgery, selective forgery, and existential forgery.
total break
True or False: A signature must be a bit pattern that depends on the message being signed.
true
True or False: DSA is a variant of ElGamal and Schnorr.
true
True or False: DSS is a public key scheme and is digital signature only (unlike RSA).
true
True or False: Digital signatures are required to be easy to produce, recognize, and verify.
true
True or False: Digital signatures do not address issues of lack of trust.
true
True or False: Digital signatures must authenticate message contents at the time of the signature.
true
True or False: Digital signatures must be practical to store and computationally infeasible to forge.
true
True or False: Digital signatures provide the ability to verify by third party to resolve disputes.
true
True or False: ElGamal signatures depend on the difficulty of computing discrete logarithms.
true
True or False: In direct digital signatures, it is assumed that the receiver has the sender's public key.
true
True or False: PSS includes a randomization process.
true
True or False: Schnorr digital signatures use exponentiation in a finite Galois field.
true
True or False: The algorithm used in DSS is DSA.
true
True or False: The signature in elliptic curve DSA is generated with the private key, parameters, and hash value.
true
True or False: The signer generates the public/private key pair.
true
True or False: To deal with threats of lost/stolen/forged signatures, use a digital certificate and certificate authorities.
true
Using the sender's ________ information prevents forgery and denial.
unique
_________ is a signature reconstruction.
universal forgery
