WGU C839 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+||BRAND NEW
________ is an alternative to PKI (Public Key Infrastructure), and
involves generating the encryption key from a piece of the identity of the
recipient. Ans✓✓✓ Identity-based Encryption (IBE) is an alternative to
PKI (Public Key Infrastructure), and involves generating the encryption
key from a piece of the identity of the recipient such an email address or
similar
____ calculations can be used to justify that RSA works correctly and
accurately, i.e. prove that the decrypted message is indeed the original
message from the sender. Ans✓✓✓ Fermat's little theorem is used to
justify RSA. We use the Fermat's Little Theorem to prove that RSA
works correctly and accurately. In other words, the decrypted message is
indeed the original message from the sender.
Steve is looking for a mechanism to use to for generating RSA private
keys and does not have budget to leverage any pricey solution. What
would you recommend Steve look into as a potential solution? Ans✓✓✓
OpenSSL is an open-source command line tool that is commonly used to
generate private keys, create CSRs, install your SSL/TLS certificate, and
identify certificate information
With Bitcoins, the _____ key defines our identity and we use it to sign
for transactions, and prove our identity to others with the ______ key
when making use of ECC. Ans✓✓✓ With Bitcoins, the private key
defines our identity and we use it to sign for transactions, and prove our
identity to others with the public key.
,Select the options from the list below that support some form of
homomorphic encryption. Select all that apply. Ans✓✓✓ With
homomorphic encryption, we can perform mathematical operations with
ciphered values. For RSA, we have a partially homomorphic
cryptosystem, where we can take two values and the cipher them. Next
we multiply the results together, and the deciphered result will be the
multiplication of the two values. RSA is a partially homomorphic crypto
system.
The Paillier cryptosystem supports homomorphic encryption, where two
encrypted values can be added together, and the decryption of the result
gives the addition
What methods can be use to overcome the weakness in Diffie Hellman
involving the ease at which values of Diffie Hellman parameters that use
the DHE_EXPORT cipher set are precomputed? Select all that apply.
Ans✓✓✓ The ways to overcome the problems are to:
• Disable Export Cipher Suites. With this we disable any negotiation of
the key using export grade ciphers. This will have no effect on
connections, as no existing version of Web browsers actually depend on
export level ciphers.
• Use (Ephemeral) Elliptic-Curve Diffie-Hellman (ECDHE). This
method uses a key exchange method based on an Elliptic-Curve
DiffieHellman (ECDH) key exchange.
• Uses a strong group. With this we make sure that we are using the
strong generation of a prime number which cannot be precomputing.
Currently 2,048-bit prime numbers are recommended. A strong prime
number is generated with "openssl dhparam -out dhparams.pem 2048".
, Normally this will take a few minutes to compute, as it involves a
random process, so can only be used to statically assign the parameters.
Diffie Hellman group 1 uses a _____-bit prime number. Ans✓✓✓ The
strength of the Diffie-Hellman method normally relates to the size of the
prime number bases which are used in the key exchange, where Group 5
uses a 1,536-bit prime number, Group 2 uses a 1,024-bit prime, and
Group 1 uses a 768-bit prime number.
With key exchange we typically have a time-out for the key to be used.
At the end of this period what happens to the key? Ans✓✓✓ With key
exchange we typically have a time-out for the key to be used, after
which time the key is renegotiated.
_____-bit prime numbers is the minimum recommended for use with
Diffie Hellman to counter attacks involving key precomputation.
Ans✓✓✓ Uses a strong group. With this we make sure that we are using
the strong generation of a prime number which cannot be precomputing.
Currently 2,048-bit prime numbers are recommended. A strong prime
number is generated with "openssl dhparam -out dhparams.pem 2048".
Normally this will take a few minutes to compute, as it involves a
random process, so can only be used to statically assign the parameters.
Regarding keys generated for Diffie Hellman operations, what is the
difference between a static key and a ephemeral key? Ans✓✓✓ The
keys can either come from a digital certificate (which uses static keys) or
can be ephemeral, and where the public and private keys are generated
for each connection.
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED
A+||BRAND NEW
________ is an alternative to PKI (Public Key Infrastructure), and
involves generating the encryption key from a piece of the identity of the
recipient. Ans✓✓✓ Identity-based Encryption (IBE) is an alternative to
PKI (Public Key Infrastructure), and involves generating the encryption
key from a piece of the identity of the recipient such an email address or
similar
____ calculations can be used to justify that RSA works correctly and
accurately, i.e. prove that the decrypted message is indeed the original
message from the sender. Ans✓✓✓ Fermat's little theorem is used to
justify RSA. We use the Fermat's Little Theorem to prove that RSA
works correctly and accurately. In other words, the decrypted message is
indeed the original message from the sender.
Steve is looking for a mechanism to use to for generating RSA private
keys and does not have budget to leverage any pricey solution. What
would you recommend Steve look into as a potential solution? Ans✓✓✓
OpenSSL is an open-source command line tool that is commonly used to
generate private keys, create CSRs, install your SSL/TLS certificate, and
identify certificate information
With Bitcoins, the _____ key defines our identity and we use it to sign
for transactions, and prove our identity to others with the ______ key
when making use of ECC. Ans✓✓✓ With Bitcoins, the private key
defines our identity and we use it to sign for transactions, and prove our
identity to others with the public key.
,Select the options from the list below that support some form of
homomorphic encryption. Select all that apply. Ans✓✓✓ With
homomorphic encryption, we can perform mathematical operations with
ciphered values. For RSA, we have a partially homomorphic
cryptosystem, where we can take two values and the cipher them. Next
we multiply the results together, and the deciphered result will be the
multiplication of the two values. RSA is a partially homomorphic crypto
system.
The Paillier cryptosystem supports homomorphic encryption, where two
encrypted values can be added together, and the decryption of the result
gives the addition
What methods can be use to overcome the weakness in Diffie Hellman
involving the ease at which values of Diffie Hellman parameters that use
the DHE_EXPORT cipher set are precomputed? Select all that apply.
Ans✓✓✓ The ways to overcome the problems are to:
• Disable Export Cipher Suites. With this we disable any negotiation of
the key using export grade ciphers. This will have no effect on
connections, as no existing version of Web browsers actually depend on
export level ciphers.
• Use (Ephemeral) Elliptic-Curve Diffie-Hellman (ECDHE). This
method uses a key exchange method based on an Elliptic-Curve
DiffieHellman (ECDH) key exchange.
• Uses a strong group. With this we make sure that we are using the
strong generation of a prime number which cannot be precomputing.
Currently 2,048-bit prime numbers are recommended. A strong prime
number is generated with "openssl dhparam -out dhparams.pem 2048".
, Normally this will take a few minutes to compute, as it involves a
random process, so can only be used to statically assign the parameters.
Diffie Hellman group 1 uses a _____-bit prime number. Ans✓✓✓ The
strength of the Diffie-Hellman method normally relates to the size of the
prime number bases which are used in the key exchange, where Group 5
uses a 1,536-bit prime number, Group 2 uses a 1,024-bit prime, and
Group 1 uses a 768-bit prime number.
With key exchange we typically have a time-out for the key to be used.
At the end of this period what happens to the key? Ans✓✓✓ With key
exchange we typically have a time-out for the key to be used, after
which time the key is renegotiated.
_____-bit prime numbers is the minimum recommended for use with
Diffie Hellman to counter attacks involving key precomputation.
Ans✓✓✓ Uses a strong group. With this we make sure that we are using
the strong generation of a prime number which cannot be precomputing.
Currently 2,048-bit prime numbers are recommended. A strong prime
number is generated with "openssl dhparam -out dhparams.pem 2048".
Normally this will take a few minutes to compute, as it involves a
random process, so can only be used to statically assign the parameters.
Regarding keys generated for Diffie Hellman operations, what is the
difference between a static key and a ephemeral key? Ans✓✓✓ The
keys can either come from a digital certificate (which uses static keys) or
can be ephemeral, and where the public and private keys are generated
for each connection.
