WGU Introduction-to-Cryptography Dumps - Pass WGU Introduction to Cryptography HNO1 Exam in First Attempt 2026

OTP systems (such as HOTP and TOTP) generate a sequence of passwords using a shared secret and a moving factor (counter or time). The critical secret that underpins the ability to compute past or future OTP values is the seed (also called the shared secret key). In HOTP, the seed is used with an HMAC function and an incrementing counter; in TOTP, the seed is used with HMAC and a time-step value. If an attacker obtains the seed and knows the algorithm and moving factor, they can compute future OTPs. The ''function'' and ''encryption algorithm'' are typically standardized and public; security relies on keeping the seed secret. An initialization vector is not a standard OTP component in HOTP/TOTP generation. Therefore, the component needed to predict future OTP values is the seed. Protecting the seed is essential: it should be stored securely (e.g., hardware token secure storage) and transmitted only through controlled provisioning processes. If compromised, OTP becomes predictable and no longer serves as a strong second factor.

Lattice-based cryptography refers to cryptographic constructions whose security is based on the computational hardness of problems on mathematical lattices (regular grids of points in high-dimensional space). Examples of hard lattice problems include the Shortest Vector Problem (SVP) and Closest Vector Problem (CVP), and practical schemes often use related problems like Learning With Errors (LWE) or Ring-LWE. These problems are believed to remain hard even for quantum computers, making lattice-based cryptography a major candidate family for post-quantum cryptography. Lattice schemes can support encryption, digital signatures, and key exchange, often with strong security reductions (worst-case to average-case) and efficient implementations. The word ''lattice'' here is not about simple point encoding; it's about relying on geometric/algebraic structures and noise-based hardness assumptions. It is also unrelated to blockchain ''options.'' While many lattice schemes do involve modular arithmetic internally, what defines the category is the underlying lattice hardness assumptions, not modular arithmetic alone. Therefore, the correct definition is a cryptographic scheme based on geometric lattices.

RC4 is unique among the RC family listed because it is a stream cipher. It generates a pseudorandom keystream and encrypts data by XORing that keystream with plaintext bytes (and decryption is the same XOR operation). This differs from RC5 and RC6, which are block ciphers: they encrypt fixed-size blocks of data through multiple rounds of operations (such as modular addition, XOR, and rotations) using a secret key. The stream-cipher design means RC4 historically fit protocols where data arrives continuously (e.g., early wireless and web encryption) and where simple, fast software implementation was desired. However, stream ciphers demand careful handling of nonces/IVs to avoid keystream reuse; reuse can catastrophically leak plaintext relationships. RC4 also has well-documented statistical biases in its keystream, leading to practical attacks in protocols like WEP and later concerns in TLS, which is why RC4 has been deprecated in modern security standards. Still, from a classification standpoint, ''stream'' is the distinguishing characteristic versus RC5/RC6 being block ciphers.

CBC mode introduces dependency between blocks to prevent the pattern leakage seen in ECB. It starts with a random (or unpredictable) IV for the first block. Before encrypting block 1, CBC XORs plaintext block 1 with the IV, then encrypts the result. For block 2 and onward, CBC XORs each plaintext block with the previous ciphertext block before encryption. This chaining means that changing one plaintext block affects that block's ciphertext and also influences the next block's computation. The IV ensures that encrypting the same message twice under the same key produces different ciphertexts (assuming a fresh IV). Option A (ECB) has no IV or chaining. OFB and CFB are feedback modes that effectively generate a keystream; they do use an IV, but the ''uses the result to encrypt the next block'' wording most directly matches CBC's ciphertext-chaining description in standard teaching. CBC still requires integrity protection (e.g., HMAC or an AEAD mode) because it can be malleable without authentication. Therefore, the correct mode is Cipher Block Chaining (CBC).

Code-signing is used to provide verifiable assurance that software comes from a known publisher and has not been modified since it was signed. In a typical code-signing workflow, the publisher computes a cryptographic hash (digest) of the executable or package and then creates a digital signature over that digest using the publisher's private key. Operating systems, browsers, and application platforms verify the signature using the corresponding public key (usually delivered via a code-signing certificate chained to a trusted root). If verification succeeds, the system can trust that the code's contents match what the publisher signed (integrity) and that the signer identity is authenticated by the certificate chain (authenticity). This helps defend against tampering, malware injection, and supply-chain attacks where attackers alter binaries or updates in transit or at rest. Code-signing does not primarily generate randomness, compress data, or authenticate users; it authenticates the software publisher and validates the software artifact. Modern ecosystems also use timestamping and revocation checking to handle certificate expiration and compromised signing keys, reinforcing trust over time.