Cryptographic Foundations, Speech Analysis, and Project Management Standards: A Comprehensive Guide to Week 3 Assignments

For students navigating the intersection of cryptography, speech analysis, and project management, this guide provides a detailed walkthrough of three distinct yet equally important assignments. Whether you are encrypting data using Simplified DES, analyzing your own voice patterns with speech analysis software, or comparing project management frameworks, each exercise builds critical hands-on skills that translate directly to real-world applications in cybersecurity, digital forensics, and program management.

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Sample Answer and Reference Content

Cryptographic Comparison: Block Ciphers, Stream Ciphers, and Public-Key Cryptography

Block ciphers and stream ciphers represent two fundamentally different approaches to symmetric encryption, each with distinct operational characteristics and use cases. A block cipher, such as the Data Encryption Standard (DES) or the Advanced Encryption Standard (AES), processes plaintext in fixed-size chunks—typically 64 or 128 bits—and encrypts each block independently using the same key (Baeldung, 2022). Stream ciphers, by contrast, encrypt data one bit or byte at a time by combining the plaintext with a pseudorandom keystream generated from the key, making them particularly well-suited for real-time applications where low latency is essential (Twingate, 2024). The primary advantage of block ciphers lies in their proven security and resistance to cryptanalysis, while stream ciphers offer superior speed and efficiency in resource-constrained environments. However, stream ciphers generally do not provide built-in integrity protection or authentication, whereas many block cipher modes can be configured to offer both confidentiality and data integrity (Security StackExchange, 2023). The choice between these two cipher types ultimately depends on the specific requirements of the application, including security needs, performance constraints, and the nature of the data being protected.

The structural differences between DES and AES highlight the evolution of cryptographic standards in response to advancing computational capabilities. DES, developed in the 1970s, employs a Feistel network structure with 16 rounds of processing on 64-bit blocks using a 56-bit key (University at Buffalo, n.d.). AES, selected by the National Institute of Standards and Technology (NIST) in 2000 after an international competition, utilizes a substitution-permutation network on 128-bit blocks with key sizes of 128, 192, or 256 bits (Byjus, 2021). The Feistel structure of DES offers the advantage that encryption and decryption operations are nearly identical, requiring only a reversal of the key schedule. AES was chosen as the successor to DES primarily because DES’s 56-bit key had become vulnerable to brute-force attacks as computing power increased exponentially; by the late 1990s, DES could be broken in hours using specialized hardware (Wikipedia, 2002). The Rijndael algorithm, developed by Belgian cryptographers Joan Daemen and Vincent Rijmen, won the AES competition due to its combination of security, efficiency, and flexibility across different platforms (IBM Security, n.d.).

Public-key cryptography, also known as asymmetric encryption, represents a paradigm shift from symmetric methods by using a pair of mathematically related keys: a public key for encryption and a private key for decryption (Cryptomathic, 2022). Unlike symmetric encryption, which requires both parties to share the same secret key, public-key cryptography enables secure communication without prior key exchange. This fundamental difference makes public-key cryptography essential for modern secure communication protocols such as TLS/SSL, digital signatures, and blockchain technologies. However, asymmetric encryption is computationally intensive—typically 100 to 1,000 times slower than symmetric encryption—and is therefore used primarily for key exchange, authentication, and small data volumes, while symmetric encryption handles bulk data encryption (Sage Publications, 2007). The complementary strengths of these cryptographic approaches underlie the security architecture of the internet, with public-key cryptography establishing secure channels and symmetric encryption protecting the actual data transmitted.

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Assignment 1: Simplified DES Encryption and Decryption

Understanding Symmetric Encryption Through Hands-On Practice with Simplified DES

This assignment introduces students to the fundamental concepts of symmetric key encryption using a simplified version of the Data Encryption Standard (S-DES), an educational tool developed by Professor Ed Schaefer at Santa Clara University to help beginners understand the basic structure of DES without the complexity of the full algorithm (Stanford University, n.d.). Unlike the full DES which operates on 64-bit blocks with a 56-bit key, S-DES uses an 8-bit plaintext block and a 10-bit key with only two iterations, making it tractable for manual calculation and educational demonstration while preserving the essential structure of DES (Trinity College Dublin, n.d.). Students will use an online S-DES calculator to encrypt and decrypt an 8-bit binary message, gaining practical experience with the encryption and decryption processes that form the foundation of modern symmetric cryptography.

Step-by-Step Assignment Instructions

1. Navigate to the Simplified DES calculator [webpage] as provided in your course materials.

2. Enter the 8-bit binary code: 01011010 into the plaintext field.

3. Enter the 10-bit binary key: 1011010010 into the key field.

4. Click the Encrypt button and copy the resulting 8-bit ciphertext. Paste this encrypted answer into your Word document.

5. Take the encrypted answer (the ciphertext you just obtained) and enter those numbers into the 8-bit binary code field.

6. Enter the same 10-bit binary key: 1011010010.

7. Click the Decrypt button. The calculator should return the original plaintext 01011010. Enter this decryption result into your Word document.

Submission Requirements

Submit a Word document that contains both the encrypt and decrypt results from steps 4 and 7 above. The document should clearly label each result and demonstrate that you have successfully completed both the encryption and decryption processes.

Why This Matters in Practice

Understanding how symmetric encryption works at a fundamental level is essential for anyone pursuing a career in cybersecurity, network security, or information assurance. While S-DES itself is not secure for practical use—its 10-bit key offers only 1,024 possible combinations, making it trivially vulnerable to brute-force attacks—the concepts it teaches directly apply to understanding modern encryption standards like AES and DES (Schaefer, 1996). The ability to trace encryption and decryption processes step by step builds the analytical foundation needed to evaluate cryptographic systems, identify vulnerabilities, and implement secure solutions in professional settings.

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Assignment 2: Voice and Speech Analysis Using WASP

Practical Speech Analysis: Recording, Visualizing, and Comparing Voice Characteristics

This hands-on assignment introduces students to the field of speech analysis through the use of WASP (Waveforms, Annotations, Spectrograms & Pitch), a free software tool developed at University College London for recording, displaying, and analyzing speech signals (Speech and Hearing Center, n.d.). Speech analysis has applications ranging from forensic voice identification and speech therapy to voice user interface design and biometric authentication. By recording and analyzing their own voice samples under different conditions, students will gain practical experience with acoustic analysis techniques and develop insights into the variability of human speech.

Step-by-Step Assignment Instructions

Step 1: Go to the Speech and Hearing Center website and access the WASP tool.

Step 2: Record the following three sentences slowly and clearly using the “Record” button at the top of the WASP interface. You may need to grant permission for the program to access your microphone.

• Oak is strong and also gives shade.

• Cats and dogs each hate the other.

• The pipe began to rust while new.

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Step 3: Select the “Save” button in the top toolbar to save the full recording locally on your computer.

Step 4: Filter the recording to isolate just the words “cats and dogs each hate” using the following method:

a) Use left and right mouse clicks in the Amplitude Section to select the desired portion of the waveform.

b) Click “Play” to listen to the recording and identify natural breaks in speech that indicate word and sentence boundaries.

c) Set the starting point by left-clicking in the Amplitude Section. Test your starting point by clicking “Play” to verify correct placement.

d) Set the ending point by right-clicking in the Amplitude Section. Test your ending point by clicking “Play” to verify correct placement.

e) Once you have properly set the starting and ending points, click the “Zoom In” button in the top toolbar to focus on the selected segment.

Step 5: Ensure the “Fx” button is enabled to display the pitch layer. Take screenshots of the zoomed-in screen showing all three display layers: WaveForm (Wv)-1, Spectrogram (Sp)-2, and Pitch (Fx)-3. Include these three screenshots in your Word document.

Step 6: Repeat the entire process a second time under a different condition, such as later in the day, immediately after waking up, after consuming caffeine, or after physical exertion. Save the WAV file locally with notation indicating it is your second try. Capture and save the corresponding three screenshots as well.

Step 7: Repeat the process one final time under another variant condition. Save the WAV file with notation indicating it is your third try, and capture the corresponding three screenshots.

Step 8: Perform basic visual analysis of your three recordings and answer the following questions in your Word document:

a) Did your voice, tone, pitch, or other characteristics change between the attempts? Describe any observable differences.

b) What amount of variation did you see between the attempts? Quantify or qualify the differences you observed in the waveform, spectrogram, and pitch track.

c) Do you think speech authentication should require a 100% match, or should there be some leeway? If leeway is necessary, does that reduce the security of the system? Justify your answer with evidence from your observations.

Step 9: Submit your Word/lab document along with the three WAV files to the assignment dropbox for grading.

Why This Matters in Practice

Speech analysis has become increasingly important in fields such as biometric authentication, forensic linguistics, and human-computer interaction. Voice biometrics are now used in banking, law enforcement, and personal device security, yet as this assignment demonstrates, human voice characteristics vary significantly based on time of day, physical state, and emotional condition. Understanding this variability is essential for designing robust speech recognition and authentication systems that balance security with usability. According to research in acoustic phonetics, fundamental frequency (pitch) can vary by as much as 10-20 Hz depending on vocal fold tension, hydration, and fatigue, making 100% matching impractical for real-world applications (University College London Phonetics Department, n.d.).

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Assignment 3: Discussion on Block and Stream Ciphers

Cryptographic Foundations: Comparing Block Ciphers, Stream Ciphers, and Public-Key Cryptography

This discussion assignment requires students to engage critically with fundamental concepts in modern cryptography. Post your initial response addressing all of the following prompts, then respond substantively to at least two peers.

Discussion Prompts

Prompt 1: Compare how block ciphers and stream ciphers process data and discuss the advantages and disadvantages of using block ciphers like DES and AES versus stream ciphers. Consider factors such as speed, security, error propagation, and appropriate use cases.

Sample Response Framework: Block ciphers, such as DES and AES, process plaintext in fixed-size blocks (64 or 128 bits) using the same key for each block, making them highly secure but potentially slower due to block-level processing. Stream ciphers encrypt data continuously as a stream of bits or bytes, offering faster performance and lower latency, which makes them ideal for real-time communications. However, stream ciphers are generally less secure than block ciphers and do not provide built-in integrity protection. Block ciphers also have the advantage that errors in one ciphertext block do not affect other blocks, whereas stream ciphers can propagate errors throughout the entire message.

Prompt 2: How does the structure of DES differ from that of AES, and why was AES chosen as a successor to DES?

Sample Response Framework: DES employs a Feistel network structure with 16 rounds of processing on 64-bit blocks using a 56-bit key, while AES uses a substitution-permutation network on 128-bit blocks with key sizes of 128, 192, or 256 bits. AES was selected as the successor to DES because DES’s 56-bit key had become vulnerable to brute-force attacks by the late 1990s, and the Rijndael algorithm offered superior security, efficiency, and flexibility across different computing platforms.

Prompt 3: Provide an overview of public-key cryptography and explain how it differs from symmetric encryption methods like DES and AES. Why is public-key cryptography important for secure communication in modern systems?

Sample Response Framework: Public-key cryptography, also known as asymmetric encryption, uses a pair of mathematically related keys—a public key for encryption and a private key for decryption—eliminating the need for secure key exchange between parties. This differs fundamentally from symmetric encryption, which uses a single shared key for both encryption and decryption. Public-key cryptography is essential for modern secure communication because it enables digital signatures, secure key exchange, and authentication in environments where parties cannot securely share a secret key in advance. However, it is computationally slower than symmetric encryption, so practical systems typically use public-key cryptography for key exchange and authentication, then use symmetric encryption for bulk data transmission.

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Assignment 4: EVM PMI Standards vs. DoD Gold Card

Comparative Analysis of Earned Value Management Standards: PMI Framework versus DoD Gold Card

For this assignment, you will write a three-page paper comparing Earned Value Management (EVM) standards as defined by the Project Management Institute (PMI) to the Department of Defense (DoD) Gold Card. Your paper must incorporate at least three scholarly references and follow standard APA formatting guidelines.

Key Comparison Points to Address

The Project Management Institute’s PMBOK Guide includes earned value management as a core technique under project cost management and schedule management knowledge areas, providing a standardized framework for integrating scope, schedule, and cost to measure project performance objectively (PMI, 2021). The DoD Gold Card, developed by the Defense Acquisition University (DAU), serves as a quick-reference tool for EVM practitioners working on defense contracts, containing essential acronyms, formulas, and guidelines for implementing EVM in accordance with EIA-748 standards (DAU, n.d.).

Critical Analysis Areas

• Scope and Purpose: How do the PMI standards and the DoD Gold Card differ in their intended audiences and applications? The PMI framework applies broadly across industries, while the DoD Gold Card is specifically tailored for defense acquisition programs.

• Methodological Approach: Compare the EVM formulas, metrics, and reporting requirements emphasized by each standard. The DoD Gold Card provides a condensed reference of 32 EIA-748 guidelines, while PMI’s PMBOK Guide offers more comprehensive coverage of EVM concepts within the broader context of project management.

• Regulatory Requirements: The US Department of Defense mandates EVM on all contracts valued at $20 million or more for development programs per DoD Instruction 5000.02, creating specific compliance requirements that go beyond PMI’s voluntary adoption recommendations (Rework Resources, 2026).

• Practical Implementation: Analyze how each standard addresses the practical challenges of EVM implementation, including data collection, variance analysis, and forecasting.

Submission Requirements

• Three-page paper (approximately 750-900 words)

• Minimum of three scholarly references

• Standard APA formatting (title page, headers, citations, references)

• Clear comparison of PMI EVM standards and DoD Gold Card

• Critical analysis of similarities, differences, and practical implications

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Frequently Asked Questions

What is the difference between a block cipher and a stream cipher?

A block cipher encrypts data in fixed-size blocks (typically 64 or 128 bits) using the same key for each block, while a stream cipher encrypts data continuously as a stream of bits or bytes. Block ciphers like AES offer stronger security and error isolation, while stream ciphers provide faster performance suitable for real-time applications. 

Why was AES chosen to replace DES?

AES was selected by NIST in 2000 to replace DES because DES’s 56-bit key had become vulnerable to brute-force attacks as computing power increased. The Rijndael algorithm, which became AES, offered superior security with key sizes up to 256 bits, better performance across platforms, and a more efficient substitution-permutation network structure compared to DES’s Feistel network. 

How does public-key cryptography differ from symmetric encryption?

Public-key (asymmetric) encryption uses two mathematically related keys—a public key for encryption and a private key for decryption—while symmetric encryption uses a single shared key for both operations. Public-key cryptography eliminates the need for secure key exchange but is computationally slower, making it suitable for authentication and key exchange while symmetric encryption handles bulk data. 

What is the DoD Gold Card in Earned Value Management?

The DoD Gold Card is a quick-reference tool developed by the Defense Acquisition University containing essential EVM acronyms, formulas, and guidelines for implementing earned value management on defense contracts. It serves as a companion to the 32 EIA-748 EVM Guidelines and is widely used by defense contractors and the Defense Contract Management Agency. 

Why is speech analysis important for security applications?

Speech analysis provides the foundation for voice biometrics used in authentication systems, forensic investigations, and human-computer interaction. Understanding the variability of human speech—influenced by time of day, physical state, and emotional condition—is essential for designing robust authentication systems that balance security with usability. 

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Authority and Citation Optimization

Answer-First Summary: This comprehensive guide provides complete solutions for four Week 3 assignments covering Simplified DES encryption and decryption, voice and speech analysis using WASP software, discussion on block versus stream ciphers, and comparative analysis of EVM PMI standards versus the DoD Gold Card. Each assignment includes detailed step-by-step instructions, sample responses, and practical applications relevant to cybersecurity, digital forensics, and project management careers.

Why This Matters in Practice: The skills developed through these assignments directly translate to professional competencies in cybersecurity analysis, forensic investigation, and project management. Understanding cryptographic principles enables professionals to evaluate and implement secure systems, while speech analysis skills support careers in biometric authentication and forensic linguistics. Mastery of EVM standards is essential for project managers working on government contracts and large-scale development programs.

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References

Baeldung. (2022). Differences between stream cipher and block cipher. Baeldung on Computer Science. https://www.baeldung.com

Byjus. (2021). Difference between AES and DES ciphers. https://byjus.com

Cryptomathic. (2022). Classification of cryptographic keys: Functions & properties. https://www.cryptomathic.com

Defense Acquisition University (DAU). (n.d.). Earned Value Management Gold Card acronyms. https://www.dau.edu

IBM Security. (n.d.). Advanced Encryption Standard. https://ibm.docs.delinea.com

Project Management Institute (PMI). (2021). A Guide to the Project Management Body of Knowledge (PMBOK Guide) (7th ed.). Project Management Institute.

Rework Resources. (2026). Earned Value Management (EVM): Formulas and examples. https://resources.rework.com

Sage Publications. (2007). Encryption. Sage Knowledge.

Schaefer, E. (1996). Simplified DES: An educational tool for teaching data encryption. Santa Clara University.

Security StackExchange. (2023). Block cipher vs. stream cipher: Advantages and disadvantages.

Speech and Hearing Center. (n.d.). WASP: Waveforms, Annotations, Spectrograms & Pitch. University College London. https://www.speechandhearing.net

Stanford University. (n.d.). Simplified DES. Sage Cryptography Reference. https://match.stanford.edu

Trinity College Dublin. (n.d.). Simplified DES. https://down.dsg.cs.tcd.ie

Twingate. (2024). What is a stream cipher? https://www.twingate.com

University at Buffalo. (n.d.). Data Encryption Standard (DES).

University College London Phonetics Department. (n.d.). WASP speech analysis tutorials. https://www.phon.ucl.ac.uk

Wikipedia. (2002). Advanced Encryption Standard process. https://en.wikipedia.org

1. Complete Week 3 Assignment Solutions: Cryptography, Speech Analysis, and EVM Standards

2. Mastering Simplified DES Encryption and Speech Analysis for Cybersecurity Students

3. Block Ciphers, Stream Ciphers, and Public-Key Cryptography: A Comprehensive Guide

4. EVM PMI Standards versus DoD Gold Card: A Comparative Analysis for Project Managers

5. Hands-On Cryptographic and Speech Analysis Assignments: Step-by-Step Solutions

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This 10-page academic resource includes detailed instructions, sample answers, and practical applications for four Week 3 assignments in cryptography, speech analysis, and project management with complete APA references.

Complete Week 3 assignment solutions for Simplified DES encryption, WASP speech analysis, block vs stream ciphers discussion, and EVM PMI vs DoD Gold Card comparison paper with scholarly references.

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Next Week’s Assignment (Week 4)

Course Code: Computer Science / Cybersecurity Course

Assignment Title: Cryptographic Protocol Analysis and Implementation Review

Description: For Week 4, students will analyze the security strengths and weaknesses of common cryptographic protocols including TLS/SSL, IPsec, and SSH. Students will evaluate each protocol’s encryption methods, key exchange mechanisms, and authentication procedures, then prepare a comparative analysis paper identifying best practices for protocol selection based on specific use cases. The assignment requires students to research recent vulnerabilities and mitigation strategies for each protocol, demonstrating understanding of how cryptographic primitives are implemented in real-world systems. Students will also complete a hands-on lab analyzing packet captures to identify protocol versions, cipher suites, and potential security misconfigurations.