Page 1 of 52
WGU D830 OA - INTRODUCTION TO
CRYPTOGRAPHY | {LATEST 2026/ 2027 UPDATE}
COMPLETE ACTUAL AND AUTHENTIC EXAM |
BRAND NEW!
Avalanche effect - ✔✔✔ Correct Answer > changing a few bits in the
plaintext (resp. in ciphertext) results in a lot of changes in the
ciphertext (resp. in plaintext), which is known as avalanche effect; i.e.
a small change in either the key or the plaintext should cause a drastic
change in the ciphertext.
Substitution Boxes - ✔✔✔ Correct Answer > An S-Box is an array of rows by
columns. It contains elements of a specific length; for example, TDEA
S-Boxes are of a length of four bits, while those of AES are of a length
of eight bits. In general, the number of rows or columns is at most 16.
Stream cipher - ✔✔✔ Correct Answer > An algorithm that takes one
character and replaces it with one character.
keystream generator - ✔✔✔ Correct Answer > is an algorithm that creates
a keystream. A data sender and receiver use the same key and
keystream generator to encrypt or decrypt data.
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A5/1 - ✔✔✔ Correct Answer > The first stream cipher that we'll examine is
A5/1, which is used for confidentiality in GSM cell phones (GSM is
discussed in the chapter titled "Real-World Security Protocols).
RC4 - ✔✔✔ Correct Answer > An RC stream cipher that will accept keys up
to 128 bits in length.
Ephemeral Key - ✔✔✔ Correct Answer > An ephemeral key is a key
generated for each execution of a key-establishment process.
Static Key - ✔✔✔ Correct Answer > A static key is a long-term key intended
to be used over an extended period of time.
Session key - ✔✔✔ Correct Answer > A session key is a symmetric key that
is only used for the duration of a single communication session.
Public Key Infrastructure (PKI) - ✔✔✔ Correct Answer > the system for
issuing pairs of public and private keys and corresponding digital
certificates
Certificate Authority (CA) - ✔✔✔ Correct Answer > issues, renews, revokes,
and distributes digital certificates. A CA is a third-party trusted by both
the certificate's owner, the subject, and the certificate user, the relying
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party. The relying party relies upon the accuracy of the binding
between the certificate's public key and the certificate owner's
identity.
Registration Authority (RA) - ✔✔✔ Correct Answer > verifies the identity of
a digital certificate applicant. A certificate applicant sends a Certificate
Signing Request (CSR) to an RA.
CSR (Certificate Signing Request) - ✔✔✔ Correct Answer > A CSR contains
the applicant's public key and includes the applicant's name,
organization, department, physical and email addresses. An RA
validates the applicant's identity and approves or rejects the
applicant's CSR. If the RA approves the CSR, the RA forwards the CSR
to the CA for the issuing of the applicant's digital certificate.
Certificate Repository (CR) or central directory - ✔✔✔ Correct Answer >
tores the digital certificates issued by a CA. A CR also contains the
Certificate Revocation List (CRL). A CRL is a list of certificates a CA has
revoked prior to the expiration of certificates' validity periods.
Certificate Revocation List (CRL) - ✔✔✔ Correct Answer > A CRL is a list of
certificates a CA has revoked prior to the expiration of certificates'
validity periods.
, Page 4 of 52
Certificate Policy (CP) - ✔✔✔ Correct Answer > defines the structure of a
PKI, describes a PKI's entities and roles, and specifies a PKI's
procedures and operational requirements.
Certificate Practice Statement (CPS) - ✔✔✔ Correct Answer > describes
how a CA issues, renews, revokes, and distributes certificates. A CPS
helps a certificate user to decide whether or not to trust a PKI's
certificates.
Issuance - ✔✔✔ Correct Answer > A certificate is issued by a CA after a
certificate applicant's identity is validated by an RA. An issued
certificate is stored in a CR.
Revocation - ✔✔✔ Correct Answer > A certificate is revoked by a CA before
the end of the certificate's validity period. A revoked certificate is
added to the CRL.
Suspension - ✔✔✔ Correct Answer > A certificate's validity is temporarily
suspended by a CA. The validity of a suspended certificate may be re-
established, or a suspended certificate may be revoked.
Expiration - ✔✔✔ Correct Answer > A certificate is expired when the end
of the certificate's validity period is reached. A PKI's CP defines the
process of applying for a new certificate after a certificate has expired.
WGU D830 OA - INTRODUCTION TO
CRYPTOGRAPHY | {LATEST 2026/ 2027 UPDATE}
COMPLETE ACTUAL AND AUTHENTIC EXAM |
BRAND NEW!
Avalanche effect - ✔✔✔ Correct Answer > changing a few bits in the
plaintext (resp. in ciphertext) results in a lot of changes in the
ciphertext (resp. in plaintext), which is known as avalanche effect; i.e.
a small change in either the key or the plaintext should cause a drastic
change in the ciphertext.
Substitution Boxes - ✔✔✔ Correct Answer > An S-Box is an array of rows by
columns. It contains elements of a specific length; for example, TDEA
S-Boxes are of a length of four bits, while those of AES are of a length
of eight bits. In general, the number of rows or columns is at most 16.
Stream cipher - ✔✔✔ Correct Answer > An algorithm that takes one
character and replaces it with one character.
keystream generator - ✔✔✔ Correct Answer > is an algorithm that creates
a keystream. A data sender and receiver use the same key and
keystream generator to encrypt or decrypt data.
,Page 2 of 52
A5/1 - ✔✔✔ Correct Answer > The first stream cipher that we'll examine is
A5/1, which is used for confidentiality in GSM cell phones (GSM is
discussed in the chapter titled "Real-World Security Protocols).
RC4 - ✔✔✔ Correct Answer > An RC stream cipher that will accept keys up
to 128 bits in length.
Ephemeral Key - ✔✔✔ Correct Answer > An ephemeral key is a key
generated for each execution of a key-establishment process.
Static Key - ✔✔✔ Correct Answer > A static key is a long-term key intended
to be used over an extended period of time.
Session key - ✔✔✔ Correct Answer > A session key is a symmetric key that
is only used for the duration of a single communication session.
Public Key Infrastructure (PKI) - ✔✔✔ Correct Answer > the system for
issuing pairs of public and private keys and corresponding digital
certificates
Certificate Authority (CA) - ✔✔✔ Correct Answer > issues, renews, revokes,
and distributes digital certificates. A CA is a third-party trusted by both
the certificate's owner, the subject, and the certificate user, the relying
,Page 3 of 52
party. The relying party relies upon the accuracy of the binding
between the certificate's public key and the certificate owner's
identity.
Registration Authority (RA) - ✔✔✔ Correct Answer > verifies the identity of
a digital certificate applicant. A certificate applicant sends a Certificate
Signing Request (CSR) to an RA.
CSR (Certificate Signing Request) - ✔✔✔ Correct Answer > A CSR contains
the applicant's public key and includes the applicant's name,
organization, department, physical and email addresses. An RA
validates the applicant's identity and approves or rejects the
applicant's CSR. If the RA approves the CSR, the RA forwards the CSR
to the CA for the issuing of the applicant's digital certificate.
Certificate Repository (CR) or central directory - ✔✔✔ Correct Answer >
tores the digital certificates issued by a CA. A CR also contains the
Certificate Revocation List (CRL). A CRL is a list of certificates a CA has
revoked prior to the expiration of certificates' validity periods.
Certificate Revocation List (CRL) - ✔✔✔ Correct Answer > A CRL is a list of
certificates a CA has revoked prior to the expiration of certificates'
validity periods.
, Page 4 of 52
Certificate Policy (CP) - ✔✔✔ Correct Answer > defines the structure of a
PKI, describes a PKI's entities and roles, and specifies a PKI's
procedures and operational requirements.
Certificate Practice Statement (CPS) - ✔✔✔ Correct Answer > describes
how a CA issues, renews, revokes, and distributes certificates. A CPS
helps a certificate user to decide whether or not to trust a PKI's
certificates.
Issuance - ✔✔✔ Correct Answer > A certificate is issued by a CA after a
certificate applicant's identity is validated by an RA. An issued
certificate is stored in a CR.
Revocation - ✔✔✔ Correct Answer > A certificate is revoked by a CA before
the end of the certificate's validity period. A revoked certificate is
added to the CRL.
Suspension - ✔✔✔ Correct Answer > A certificate's validity is temporarily
suspended by a CA. The validity of a suspended certificate may be re-
established, or a suspended certificate may be revoked.
Expiration - ✔✔✔ Correct Answer > A certificate is expired when the end
of the certificate's validity period is reached. A PKI's CP defines the
process of applying for a new certificate after a certificate has expired.
