Technical Fundamentals & Core Skills Topics
Core technical concepts including algorithms, data structures, statistics, cryptography, and hardware-software integration. Covers foundational knowledge required for technical roles and advanced technical depth.
Operating System Fundamentals
Comprehensive knowledge of operating system concepts and practical administration across Linux, Unix, and Windows platforms. Core theoretical topics include processes and threads, process creation and termination, scheduling and context switching, synchronization and deadlock conditions, system calls, kernel versus user space, interrupt handling, memory management including virtual memory, paging and swapping, and input and output semantics including file descriptors. Practical administration and tooling expectations include file systems and permission models, user and group account management, common system utilities and commands such as grep, find, ps, and top, package management, service and process management, startup and boot processes, environment variables, shell and scripting basics, system monitoring, and performance tuning. Platform specific knowledge should cover Unix and Linux topics such as signals and signal handling, kernel modules, initialization and service management systems, and command line administration, as well as Windows topics such as the registry, service management, event logs, user account control, and graphical and command line administration tools. Security and infrastructure topics include basic system hardening, common misconfigurations, and an understanding of containerization and virtualization at the operating system level. Interview questions may probe conceptual explanations, platform comparisons, troubleshooting scenarios, or hands on problem solving.
Technical Problem Solving and Learning Agility
Evaluates a candidates ability to diagnose and resolve technical challenges while rapidly learning new technologies and concepts. Topics include systematic troubleshooting approaches, root cause analysis, debugging strategies, how the candidate breaks down ambiguous problems, and examples of self directed learning such as studying new frameworks, libraries, or application programming interfaces through documentation, courses, blogs, or side projects. Also covers intellectual curiosity, baseline technical comfort, the ability to learn from peers and feedback, and collaborating with engineers to understand architectures and tradeoffs. Interviewers may probe how the candidate acquires new skills under time pressure, transfers knowledge across domains, and applies new tools to deliver outcomes.
OSI Model and TCP IP Stack
Comprehensive knowledge of the seven layer Open Systems Interconnection model, including Layer One Physical, Layer Two Data Link, Layer Three Network, Layer Four Transport, Layer Five Session, Layer Six Presentation, and Layer Seven Application. Understand the primary responsibilities and services at each layer, how data is packaged and transformed as it moves down and up the stack through encapsulation and decapsulation, and the unit of data at each stage such as bits at the physical layer, frames at the data link layer, packets at the network layer, and segments at the transport layer. Be able to identify common protocols and services that operate at each layer, for example Ethernet and link layer protocols at the data link layer, Internet Protocol at the network layer, Transmission Control Protocol and User Datagram Protocol at the transport layer, and application layer protocols such as Hypertext Transfer Protocol and Domain Name System at the application layer. Understand which hardware devices operate at which layers, such as cabling and transceivers at the physical layer, switches and bridges at the data link layer, and routers at the network layer, and how these devices affect forwarding and inspection. Know how the Open Systems Interconnection model maps to and differs from the four layer Transmission Control Protocol and Internet Protocol stack, including which functions are combined or abstracted differently, and how layering choices affect security placement, encryption strategy, performance, and troubleshooting. Be able to apply this knowledge to diagnose faults by mapping symptoms to layer specific causes and to reason about header fields, addressing and port schemes, segmentation and retransmission behavior, and cross layer interactions.
Cryptography and Encryption Fundamentals
Comprehensive understanding of modern cryptography and encryption principles used to build secure systems. Candidates should be able to explain the differences between symmetric and asymmetric encryption, appropriate use cases for each, and common algorithms by full name such as Advanced Encryption Standard and Data Encryption Standard for symmetric ciphers and Rivest Shamir Adleman and elliptic curve based algorithms such as Elliptic Curve Digital Signature Algorithm and Elliptic Curve Diffie Hellman for public key operations. Describe hybrid encryption patterns in which asymmetric cryptography is used to protect a symmetric session key, and discuss block cipher modes of operation including cipher block chaining and authenticated encryption modes such as Galois Counter Mode, as well as the role of initialization vectors and nonces. Cover hash functions and integrity checks with properties such as collision resistance and preimage resistance, message authentication codes, authenticated encryption, and digital signatures for authentication and nonrepudiation. Include high level Public Key Infrastructure concepts including certificates and certificate authorities and how certificates are used to establish trust, together with foundational Transport Layer Security and Secure Sockets Layer principles without requiring deep certificate lifecycle management knowledge. Emphasize key management and operational concerns including secure key generation, secure storage, rotation and compromise handling, randomness and entropy sources, recommended key lengths and algorithm lifecycle considerations, and performance and scalability trade offs. Be prepared to discuss common implementation pitfalls and failures such as weak key sizes, poor random number generation, improper key reuse, and lack of authenticated encryption, plus threat models and practical applications including encrypting data at rest and in transit, secure channels, and signing and verification. Avoid deep mathematical proofs unless specifically requested, but be ready to reason about practical trade offs, algorithm selection, and secure implementation patterns.