c839 Q&A
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
WROT E T H I S D OWN WH E N T E ST
ST ART E D
MNE MONI C D E VI CE :
S Y M OKE R F RI E ND CARRI E S 3 B I C 'S
S , NAME D D R . 2 S AC , A KA
A DM
PART I ALLY WRONG, D I F F E RE NT
D E R E K , H E A LWAYS S AI D M R S T I G E R M ANUF
F ACT URE D G RE AT M AC
SI T E S H AD D I F F E RE NT I NF O...
What i s Kerchof f 's pri nci pl e?
-A mi ni mum of 15 rounds i s needed f or a F ei stel ci pher to be secure
-Both al gori thm and key shoul d be kept secret Onl y the key needs to be secret, not the actual al gori thm
-Onl y the key needs to be secret, not the actual al gori thm
-A mi ni mum key si ze of 256 bi ts i s necessary f or securi ty
You are tryi ng to f i nd a modern method f or securi ty web traf f i c f or use i n your
company's ecommerce websi te. Whi ch one of the f ol l owi ng i s used to encrypt web
pages and uses bi l ateral authenti cati on?
- SSL -tl s
-AE S
-3D E S
-tl s
A measure of the uncertai nty associ ated wi th a random vari abl e.
-E ntropy
-Whi teni ng -E ntropy
-D i f f usi on
-Col l i si on
Whi ch of the f ol l owi ng i s a substi tuti on ci pher used by anci ent H ebrew schol ars?
-Vi genere
-Caesar Atbash
-Atbash
-Scytal e
John works as a cryptography consul tant. H e f i nds that peopl e of ten mi sunderstand
the real i ty of breaki nga ci pher. What i s the def i ni ti on of breaki ng a ci pher?
-Renderi ng the cypher no l onger useabl e
-F i ndi ng any method that i s more ef f i ci ent than brute f orce
-Uncoveri ng the al gori thm used
-D ecodi ng the key
-F i ndi ng any method that i s more ef f i ci ent than brute f orce
Whi ch of the f ol l owi ng was a mul ti al phabet ci pher wi del y used f rom the 16th
century to the earl y 20thcentury?
-Caesar
- Vi genere
-Scytal e
- Vi genere
-Atbash
Whi ch of the f ol l owi ng i s a bl ock ci pher?
-RC4
-AE S -AE S
-dh
-RSA
, c839 Q&A
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
Whi ch of the f ol l owi ng al gori thms uses three di f f erent keys to encrypt the pl ai n
text?
-Ski pj ack
-3D E S
-AE S
-Bl owf i sh
-3D E S
A symmetri c Stream Ci pher publ i shed by the German engi neeri ng f i rm Sei mans i n
1993. A sof tware basedstream ci pher that uses a Lagged F i bonacci generator
al ong wi th concepts borrowed f rom shri nki nggenerator ci phers.
-i dea -f i sh
-T wof i sh
-desx
-f i sh
Ori gi nal , unencrypted i nf ormati on i s ref erred to as ______.
-ci phertext
-cl eartext -pl ai ntext
-text
-pl ai ntext
Whi ch of the f ol l owi ng are val i d key si zes f or AE S (choose three)?
- 64
-512 -128
-128 -256
-56 -192
-256
-192
Col l i si on resi stance i s an i mportant property f or any hashi ng al gori thm. Joan wants
to f i nd a cryptographi chash that has strong col l i si on resi stance. Whi ch one of the
f ol l owi ng i s the most col l i si onresi stant?
-MD 4 -SH A2
-SH A2
-PI KE
-MD 5
Whi ch one of the f ol l owi ng are characteri sti cs of a hash f uncti on? (Choose two)
-Symmetri c
-One-way
-One-way
-F i xed l ength output
-Requi res a key
-F i xed l ength output
-F ast
What i s the f ormul a mAe %n rel ated to?
-E ncrypti ng wi th E C
-D ecrypti ng wi th RSA -E ncrypti ng wi th RSA
-Generati ng Mersenne pri mes
-E ncrypti ng wi th RSA
A di gi tal document that contai ns a publ i c key and some i nf ormati on to al l ow your
system to veri f y wherethat key came f rom. Used f or web servers, Ci sco Secure
phones, E -Commerce.
-Payl oad -D i gi tal Certi f i cate
-Regi strati on Authori ty
-OCSP
-D i gi tal Certi f i cate
, c839 Q&A
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
A ci pher i s def i ned as what
-T he al gori thm(s) needed to encrypt and decrypt a message
-Any al gori thm used i n cryptography -T he al gori thm(s) needed to encrypt and decrypt a message
-E ncrypted text
-T he key used to encrypt a message
A______i s a f uncti on that takes a vari abl e-si ze i nput m and returns a f i xed-si ze
stri ng.
-Asymmetri c ci pher
-H ash
-H ash
-Symmetri c ci pher
-F ei stel
Whi ch of the f ol l owi ng i s an asymmetri c ci pher?
-AE S
-RSA -RSA
-des
-RC4
Jane i s l ooki ng f or an al gori thm to ensure message i ntegri ty. Whi ch of f ol l owi ng
woul d be an acceptabl echoi ce?
-AE S
-SH A-1
-RSA
-SH A-1
-RC4
When l earni ng al gori thms, such as RSA, i t i s i mportant to understand the
mathemati cs bei ng used. I n RSA,the number of posi ti ve i ntegers l ess than or equal
to some number i s cri ti cal i n key generati on. T he numberof posi ti ve i ntegers l ess
than or equal to n that are copri me to n i s cal l ed_______. -E ul er's toti ent
-F ermat's pri me
-E ul er's toti ent
-F ermat's number
-Mersenne's number
Message hi dden i n unrel ated text. Sender and recei ver have pre-arranged to use a
pattern to remove certai nl etters f rom the message whi ch l eaves onl y the true
message behi nd.
-Caesar Ci pher -Nul l Ci phers
-Nul l Ci phers
-Vi genere Ci pher
-Pl ayf ai r Ci pher
T he Cl i pper chi p i s notabl e i n the hi story of cryptography f or many reasons. F i rst,
i t was desi gned f orci vi l i an used secure phones. Secondl y, i t was desi gned to use
a very speci f i c symmetri c ci pher. Whi ch one of the f ol l owi ng was ori gi nal l y
desi gned to provi de bui l t-i n cryptography f or the Cl i pper chi p? -Ski pj ack
-Ski pj ack
-Bl owf i sh
-T wof i sh
-Serpent
What i s a sal t?
-Key rotati on
-Key whi teni ng -Random bi ts i ntermi xed wi th a hash to i ncrease randomness and reduce col l i si ons
-Random bi ts i ntermi xed wi th a symmetri c ci pher to i ncrease randomness and make hi stori cal l y used to protect at rest passwords
i t more secure
-Random bi ts i ntermi xed wi th a hash to i ncrease randomness and reduce col l i si ons
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
WROT E T H I S D OWN WH E N T E ST
ST ART E D
MNE MONI C D E VI CE :
S Y M OKE R F RI E ND CARRI E S 3 B I C 'S
S , NAME D D R . 2 S AC , A KA
A DM
PART I ALLY WRONG, D I F F E RE NT
D E R E K , H E A LWAYS S AI D M R S T I G E R M ANUF
F ACT URE D G RE AT M AC
SI T E S H AD D I F F E RE NT I NF O...
What i s Kerchof f 's pri nci pl e?
-A mi ni mum of 15 rounds i s needed f or a F ei stel ci pher to be secure
-Both al gori thm and key shoul d be kept secret Onl y the key needs to be secret, not the actual al gori thm
-Onl y the key needs to be secret, not the actual al gori thm
-A mi ni mum key si ze of 256 bi ts i s necessary f or securi ty
You are tryi ng to f i nd a modern method f or securi ty web traf f i c f or use i n your
company's ecommerce websi te. Whi ch one of the f ol l owi ng i s used to encrypt web
pages and uses bi l ateral authenti cati on?
- SSL -tl s
-AE S
-3D E S
-tl s
A measure of the uncertai nty associ ated wi th a random vari abl e.
-E ntropy
-Whi teni ng -E ntropy
-D i f f usi on
-Col l i si on
Whi ch of the f ol l owi ng i s a substi tuti on ci pher used by anci ent H ebrew schol ars?
-Vi genere
-Caesar Atbash
-Atbash
-Scytal e
John works as a cryptography consul tant. H e f i nds that peopl e of ten mi sunderstand
the real i ty of breaki nga ci pher. What i s the def i ni ti on of breaki ng a ci pher?
-Renderi ng the cypher no l onger useabl e
-F i ndi ng any method that i s more ef f i ci ent than brute f orce
-Uncoveri ng the al gori thm used
-D ecodi ng the key
-F i ndi ng any method that i s more ef f i ci ent than brute f orce
Whi ch of the f ol l owi ng was a mul ti al phabet ci pher wi del y used f rom the 16th
century to the earl y 20thcentury?
-Caesar
- Vi genere
-Scytal e
- Vi genere
-Atbash
Whi ch of the f ol l owi ng i s a bl ock ci pher?
-RC4
-AE S -AE S
-dh
-RSA
, c839 Q&A
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
Whi ch of the f ol l owi ng al gori thms uses three di f f erent keys to encrypt the pl ai n
text?
-Ski pj ack
-3D E S
-AE S
-Bl owf i sh
-3D E S
A symmetri c Stream Ci pher publ i shed by the German engi neeri ng f i rm Sei mans i n
1993. A sof tware basedstream ci pher that uses a Lagged F i bonacci generator
al ong wi th concepts borrowed f rom shri nki nggenerator ci phers.
-i dea -f i sh
-T wof i sh
-desx
-f i sh
Ori gi nal , unencrypted i nf ormati on i s ref erred to as ______.
-ci phertext
-cl eartext -pl ai ntext
-text
-pl ai ntext
Whi ch of the f ol l owi ng are val i d key si zes f or AE S (choose three)?
- 64
-512 -128
-128 -256
-56 -192
-256
-192
Col l i si on resi stance i s an i mportant property f or any hashi ng al gori thm. Joan wants
to f i nd a cryptographi chash that has strong col l i si on resi stance. Whi ch one of the
f ol l owi ng i s the most col l i si onresi stant?
-MD 4 -SH A2
-SH A2
-PI KE
-MD 5
Whi ch one of the f ol l owi ng are characteri sti cs of a hash f uncti on? (Choose two)
-Symmetri c
-One-way
-One-way
-F i xed l ength output
-Requi res a key
-F i xed l ength output
-F ast
What i s the f ormul a mAe %n rel ated to?
-E ncrypti ng wi th E C
-D ecrypti ng wi th RSA -E ncrypti ng wi th RSA
-Generati ng Mersenne pri mes
-E ncrypti ng wi th RSA
A di gi tal document that contai ns a publ i c key and some i nf ormati on to al l ow your
system to veri f y wherethat key came f rom. Used f or web servers, Ci sco Secure
phones, E -Commerce.
-Payl oad -D i gi tal Certi f i cate
-Regi strati on Authori ty
-OCSP
-D i gi tal Certi f i cate
, c839 Q&A
WGU C839 Cybersecurity Foundations q&aStudy Guide, Practice Questions & Verified Answers (2026 Updated)
Study this set o nline at: https://www.cram.co m/flashcards/c839-11870529
A ci pher i s def i ned as what
-T he al gori thm(s) needed to encrypt and decrypt a message
-Any al gori thm used i n cryptography -T he al gori thm(s) needed to encrypt and decrypt a message
-E ncrypted text
-T he key used to encrypt a message
A______i s a f uncti on that takes a vari abl e-si ze i nput m and returns a f i xed-si ze
stri ng.
-Asymmetri c ci pher
-H ash
-H ash
-Symmetri c ci pher
-F ei stel
Whi ch of the f ol l owi ng i s an asymmetri c ci pher?
-AE S
-RSA -RSA
-des
-RC4
Jane i s l ooki ng f or an al gori thm to ensure message i ntegri ty. Whi ch of f ol l owi ng
woul d be an acceptabl echoi ce?
-AE S
-SH A-1
-RSA
-SH A-1
-RC4
When l earni ng al gori thms, such as RSA, i t i s i mportant to understand the
mathemati cs bei ng used. I n RSA,the number of posi ti ve i ntegers l ess than or equal
to some number i s cri ti cal i n key generati on. T he numberof posi ti ve i ntegers l ess
than or equal to n that are copri me to n i s cal l ed_______. -E ul er's toti ent
-F ermat's pri me
-E ul er's toti ent
-F ermat's number
-Mersenne's number
Message hi dden i n unrel ated text. Sender and recei ver have pre-arranged to use a
pattern to remove certai nl etters f rom the message whi ch l eaves onl y the true
message behi nd.
-Caesar Ci pher -Nul l Ci phers
-Nul l Ci phers
-Vi genere Ci pher
-Pl ayf ai r Ci pher
T he Cl i pper chi p i s notabl e i n the hi story of cryptography f or many reasons. F i rst,
i t was desi gned f orci vi l i an used secure phones. Secondl y, i t was desi gned to use
a very speci f i c symmetri c ci pher. Whi ch one of the f ol l owi ng was ori gi nal l y
desi gned to provi de bui l t-i n cryptography f or the Cl i pper chi p? -Ski pj ack
-Ski pj ack
-Bl owf i sh
-T wof i sh
-Serpent
What i s a sal t?
-Key rotati on
-Key whi teni ng -Random bi ts i ntermi xed wi th a hash to i ncrease randomness and reduce col l i si ons
-Random bi ts i ntermi xed wi th a symmetri c ci pher to i ncrease randomness and make hi stori cal l y used to protect at rest passwords
i t more secure
-Random bi ts i ntermi xed wi th a hash to i ncrease randomness and reduce col l i si ons
