Es
Electronic Security and Cryptography Quiz
Test your knowledge on electronic security and cryptography with our comprehensive quiz designed for enthusiasts and professionals alike. This quiz covers essential topics such as public key cryptography, digital signatures, and certificate policies.
Key features:
- 44 challenging questions
- Instant feedback on your answers
- Deep dive into cryptographic mechanisms and standards
With regard to the NIST 800-131/2010 document, which are the recommended minimal levels of security for ES?
Until 2010 – DSA : L=1024 bits; N=160 bits; RSA: K=1024 bits; ECDSA: f=160
Until 2030 – DSA : L=4096 bits; N=256 bits; RSA: K=4096 bits; ECDSA: f=256
Until 2010 – DSA : L=2048 bits; N=196 bits; RSA: K=2048 bits; ECDSA: f=196
Until 2030 – DSA : L=2048 bits; N=224 bits; RSA: K=2048 bits; ECDSA: f=224
About public key Cryptographic Systems, we can say that they:
Are symmetric
Use different keys, randomly chosen, for encrypting and decrypting
Use different keys, that are math linked, for encrypting and decrypting
Are based on trap-door, one-way function
The RSA system uses:
Operation on elliptic curves
One public key, one private key
Operations with large integer number
One key, publicly available
The revocation of certificate is done :
When the public key inside the certificate is compromised
When the public key inside the certificate is compromised
When the validity of the certificate has expire
When the private key is compromised
Which is the role of HSM (Hardware Security Mode)?
Keeps the used cryptographic algorithm secret
Assures the protection of the cryptographic keys
Assures the protection of the computer which the CA software is installed
Accelerate the cryptographic operations
The certificate Policy –CP
Represents an operational manual for the CA
Describes the security which governs a CA
Describes in detail the mechanism and procedures of the CA
Describes the registration process of the users
The law regarding the ES adopted by Parliament of Romania, in July 2001, establish :
The conditions for the ES of documents, in electronic communication
The conditions for providing electronic signatures certificate services
The fees for providing CA
The legislative environment to electronic documents
The extended electronic signature represents an electronic signature which complies with the following conditions:
It is uniquely linked to the signer, assuring his identification
It is created with means owned exclusively by signer
It is linked to the electronic document being signed
Is created using specific hardware devices (smart cards or tokens)
RSA is a cryptographic algorithm based on:
Difficulty of computing discrete logarithms in finite field
Difficulty of large integer numbers factorization
Difficulty of computing exponents in finite field
Fermat’s theorem
About time-stamping, we can say that:
The law on time-stamping, adopted in Romania, in 2004, represents its legislative environment
It's generated by the application and counter-signed by a time-stamping service provider
The RFC 3161 – Internet X.509 PKI Time Stamp Protocol (TSP), represents its standard environment
Is accomplished by a certificate service provider
Electronic document is equivalent, in condition of effect, with written documents if:
It has an extended ES associated
The signature is based on a qualified article
The signature is created using a secure mechanism for creating digest signature
The certificate service provider is accredited
The effort for breaking a symmetric system with a 128 bits key, with a specialized system, using brute force attack, is around:
7000 years
18 **18 years
10 **18 years
3.6 hours
DSA is a standard which:
Can be implemented on elliptic curves
Is used only for digital signature
Is used for encrypting data
Was created by Rivest-Shamir and Adleman
Diffie-Hellman key distribution scheme , with 3 users. The common values are the base, a=2 and the modulus , p=7. User A has PubKXA = 3 and computes with Priv KYA . User B has PubKXb =4 and computes with Priv KYb . User C has PubKXc =5 and computes with Priv KYc . The 3 users exchange their Public keys. Compute the secret keys used to encrypt the traffic between users.
KAB=1 , KAC=1 , KBC=4
KAB=1 , KAC=4 , KBC=1
KAB=4 , KAC=1 , KBC=4
KAB=4 , KAC=1 , KBC=1
Which solution(s) was/were proposed for satisfying the WYSIWYG request?
The signing of a graphic representation of the document
The use of logos for certifying the authenticity of the document
The use of a secure display program, for viewing the documents
The use of a document format, which has an unique graphic representation
If, at the moment of validating a signature, the signing certificate is revoked, the signature may be declared valid only if:
The signed document was time-stamped after being stamped and before the revocation of the certificate
The certificate of the signer hasn't expired at the moment of validation
The signature will be declared invalid anyway, because the certificate is revoked when the validations is done
The signed document was time-stamped before being signed
The secured mechanism for creating electronic signatures must satisfy the following conditions:
The signature creation data must be protected effectively by the signer against their use by unauthorized persons
It must not modify the electronic document which will be signed and not prevent its view by the signer, before finishing the signing process
The signature creation data must not be deduced and the signature must be protected against forgery
The signature creation data must appear only once and its confidentiality must be assured
Which of the following devices are specific for Secure Signature Creation Devices (SSCD)?
Biometric readers
USB tokens
PCMCIA
Smart cards
The electronic signature assures:
The authentication of the signed message (its integrity verification)
The authentication of the data link between sender and receiver
The authentication of the receiver of the signed message
The authentication of the sender of the signed message
The OCSP server, in order to obtain revocation information, may:
Process CRLs, issued by the Certification Authority
Use SSL protocol
Use LDAP v2 protocol
Call the services of another OCSP server, authoritative for the PKI domain in which the certificate was issued
The law no. 589/2004, regarding the legislative environment for the electronic notary activity states that:
The electronic notary closure contains as signatures: the extended electronic signature of the parties, the extended electronic signature of the public notary, the extended electronic signature of the notary bureau
The electronic notary closure contains as signatures: the extended electronic signature of the parties, the extended electronic signature of the notary bureau
The requests for an electronic notary document shall be handed to the public notary in electronic form, signed with the extended electronic signature of the requester
The public notary is obliged to keep the electronic archive of electronic notary documents for 20 years
Let there be a RSA protocol for transporting the key, with 2 users. User A publishes his public key [eA =3, nA =55] and computes his private key [dA =27, nA =55]. Let us suppose that user B wants to issue an encrypted message towards user A. User B envelopes the session key (KAB=7), using the public key of user A: K’ = (KAB )eA mod nA = 73 mod 55 = 13. Please show the way in which user A determines the session key (KAB =7), using his private key and the received enveloped key (K’=13).
KAB = (K’ )nA mod dA = (13)55 mod 27
KAB = (K’ )nA mod eA = (13)55 mod 3
KAB = (K’ )dA mod nA = (13)27 mod 55
KAB = (K’ )eA mod nA = (13)3 mod 55
The Windows operating system, in order to build the certificate chain, it automatically discovers the necessary certificates in the following certificate stores:
Intermediate Certification Authorities“
Trusted Root Certification Authorities”
Enterprise Trust”
Personal”
According to the time stamping law, the time stamp information contains, among other data:
The extended electronic signature of the time-stamping issuing authority
The electronic data or a hash function of it
The extended electronic signature of the author of the electronic data
Date and time
A variation of the Diffie Hellman scheme, for signature is: The public elements: q (prime number), a<q (prime root of q-1) Private key: X, X<q Public key: Y=a^X mod q The message to be signed M and its hash h(M) The signature: a^Z, where Z satisfies the equation Z * h = X (mod q-1) Show the way in which the verification of the signature is done:
Y = (a^Z)^M = a^X mod q
Y = (a^M)^h = a^X mod q
Y = (a^Z)^h = a^X mod q
Y = (a^Y)^h = a^X mod q
In Chaum blind signature scheme, for (blinding) A computers: m*=mkemod n.indicate the signing and un-blinding mechanism:
(un-blinding) A computes: s*=(m*)^d mod n
(signing) B computes: s=K^-1s* mod n
(un-blinding) A computes: s=k^-1s* mod n
(signing) B computes: s*=(m*)^d mod n
The correct equation, which has to be verified for validating the signature, is: In Shamir's identity based signature scheme, in which (e,d) are the RSA master keys, the signing (s,t) has the following steps: it randomly chooses r -> it computes t=r^e mod n -> it computes f = H(t, m) -> it computes sid = ID^d mod n -> it computes s=sidr^f mod n
S^E=?=IDt^H(t,m) mod n
S^E=?=H(t,m) t^ID mod n
S^E=?=H(m) t^ID mod n
S^E=?=t^H(t,m) mod n
About blind signatures, we can say that:
They were theoretically developed bu Chaum
They were initially designed as a protoclo for securing Web applications
They are used in the field of electronic cash
They were theoretically developed by Chaum-van Antwerpen
MQV (Menezes -Qu-Vanstone) is:
An authentication protocol based on Diffie-Hellman
Based on a pair of keys: a static one and an ephemeral one
An authenticated protocol for establishing a key, based on Deffie-Hellman
A distribution key protocol. Based on Defiie-Hellman
DSA is a crytographic algorithm based on:
The difficulty of multiplying large prime numbers
The difficulty of large integer numbers factorization
The difficulty of computing discrete logarithms in finite field
The difficulty of computing exponents in finite field
Electronic signatures are based on:
Cryptographic systems with secret keys and hash functions
Cryptographic systems with public keys and hash functions
Scanned handwritten signatures
Biometric data (finger print, iris, etc.)
Signing a document is done using:
The private key of the message recipient
The sender's public key message
The private key of the private message sender
The public key of the recipient
Signature Verification of n document is done using:
The private key of the message recipient
The public key of the sender
The public key of the recipient
The private key of message sender
For electronic signature can be used the next cryptographic algorithms:
SHA-1
AES over elliptic curve
RSA, DSA, DSA over elliptic curves
DES
XML signatures are:
Data structures containing the signature value and the necessary data for the verification process
At the envaloped XML signatures, the signed object encapsulates signature
At the enveloped XML signatures, the signed object encapsulates signature
Data structures containing the signature value and signature algorithms used
Time stamping
It is legal regulated by RFC-3161 Internet X.509 PKI Time Stamp Protocol (TSP);
Is performed by a certification service provider
It is realized by the the application and countersigned by a time stamping service provider
It is legal regulated by time stamping law enacted in Romania in 2004
RFC 2587 (Internet X.509 PKI Operational Protocols - LDAPv2):
Defines the method of online checking certificates
Defines the attributes and object classes supported by the LDAP server
Defines the access method to the certificates repository
Is a PKCS standard developed by RSA Data Security for access to storage repository
Among static biometric methods are:
Voice recognition
Identification of the retina
Hand geometry
Fingerprint
For an RSA cryptographic system with public key (e = 5, n = 21), the pair private key (d, n) of this key is:
R: d=___5__ , n=___21__
Main current issues concerning the use of biometric signature methods are:
Lack of smartcards with biometric sensors
The impossibility of memorizing biometric characteristics due to lack of space on card
The reliability of biometric identification methods
Lack of appropriate standard
The electronic signatures Directive issued by the Commission of the European Communities the subject of debate and adoption in the Parliament and the Europe Council in 1999 refers to:
The requirements for certification service providers and how their certification and authorization
International aspects of using electronic signatures
The legal effects of electronic signatures
The definition of terminology used in electronic signature
A secure mechanism to create electronic signature must meet the following conditions:
Not to change the content of the document that must be electronically signed and shall not prevent it to be presented to signer prior to the completion of signature
Signature creation dates can not occur only once and their confidentiality to be assured
Signature creation dates to be effectively protected by the signatory against their use by unauthorized persons
Signature creation dates can not be deducted and the signature to be protected against forgery
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