Introduction-to-Cryptography Exam Dumps - WGU Introduction to Cryptography HNO1

AES (Advanced Encryption Standard) is a symmetric block cipher standardized to operate on a fixed 128-bit block size and supports key sizes of 128, 192, and 256 bits. When the key size is 256 bits, the cipher is commonly referred to as AES-256, but the block size remains 128 bits regardless of key length. This combination (256-bit key, 128-bit block) matches the question precisely. By comparison, DES uses a 64-bit block size with a 56-bit effective key. 3DES also uses a 64-bit block size and effectively applies DES three times, yielding an effective key length typically cited as 112 bits (two-key 3DES) or 168 bits (three-key 3DES), depending on how keys are configured. IDEA uses a 64-bit block size with a 128-bit key. Therefore, the only listed algorithm that supports a 256-bit key while maintaining a 128-bit block size is AES. This is one reason AES is widely adopted for modern symmetric encryption: strong key sizes with efficient implementation and broad standardization.

NIST’s lightweight cryptography effort targets environments like IoT and embedded systems where CPU, memory, energy, and bandwidth are constrained, yet strong security is still required. Ascon is an authenticated encryption with associated data (AEAD) family designed to be efficient in both hardware and software with small footprint, making it well-suited for constrained devices. NIST selected Ascon because it offers a strong security design with good performance and implementability under tight resource budgets, while providing modern protections (confidentiality + integrity) through AEAD. That aligns with option C: secure and efficient encryption for resource-constrained devices. The selection was not primarily about authenticating users (that is typically handled by protocols and identity systems, not an AEAD primitive). It was also not mainly about legacy compatibility; lightweight cryptography aims at new and constrained deployments rather than preserving outdated stacks. And while Ascon can certainly be used to protect data at rest, that is only one application; the core reason for the choice is its suitability for constrained environments and robust, efficient authenticated encryption.

SHA-1 (Secure Hash Algorithm 1) produces a fixed-size output of 160 bits (20 bytes). Hash output size matters in cryptography because it influences collision resistance and the effort required for various attacks. For an ideal n-bit hash, finding a collision by generic means is expected around 2^(n/2) operations (birthday bound). With SHA-1’s 160-bit output, that generic bound would be about 2^80, which was once considered strong; however, SHA-1 has been broken in practice with significantly less work due to cryptanalytic advances, and it is now deprecated for most security uses. Still, the question is strictly about output length, not current suitability. The other options do not match SHA-1: 40 bits would be far too small for a modern hash, 80 bits is not SHA-1’s output, and 320 bits would imply a much larger digest (closer to SHA-256’s 256 bits or SHA-384’s 384 bits). Therefore, the correct SHA-1 output length is 160 bits.

802.1X is a port-based network access control framework that enables centralized authentication using an authentication server (commonly RADIUS). EAP (Extensible Authentication Protocol) runs within 802.1X to support many credential types (password-based methods like PEAP, certificate-based methods like EAP-TLS, and others). WPA-Enterprise is the wireless security mode that explicitly uses 802.1X + EAP with an authentication server to perform per-user/per-device authentication and to derive dynamic session keys. By contrast, WPA-PSK uses a pre-shared key without an external authentication server; all users share the same PSK, which is weaker for enterprise identity management. WEP is an older mechanism using static keys and does not provide modern 802.1X/EAP enterprise authentication in the WPA-Enterprise sense. TKIP is an encryption/integrity protocol used under WPA, not the full authentication “standard” involving an authentication server. Therefore, the correct choice is WPA-Enterprise.

HMAC (Hash-based Message Authentication Code) is a standard mechanism used to verify both integrity and authenticity of a message when two parties share a secret key. It combines a cryptographic hash function (such as SHA-256) with a secret key in a structured way that resists common attacks on naïve keyed-hash constructions. The sender computes an HMAC tag over the message and transmits the message plus tag. The receiver recomputes the HMAC using the same shared secret key and compares the result; if the tag matches, the receiver can be confident the message was not modified in transit and that it came from someone who knows the shared key. AES is an encryption algorithm primarily providing confidentiality; it can provide integrity only when used in authenticated modes (e.g., GCM) but “AES” alone is not the integrity component. An IV helps randomize encryption but does not validate integrity. TKIP is a legacy WLAN protocol component, not the general integrity verifier. Therefore, the correct component for verifying message integrity among the options is HMAC.