Johan Yim - Software Developer

• johanyim.com
• johanjyyim@gmail.com
• +44 7510787854
• linkedin.com/in/johanjyyim
• github.com/johanyim

Experience

Software Engineer - BG Automotive

2024-05 - Present

• Implemented stateless, secure authentication using JWTs stored in HTTP-only cookies, with access and refresh token rotation for session management.
• Implemented HTTP middleware in Rust using Redis as an intermediary cache layer, Server-Sent Events, and frontend Virtualization/Windowing to handle payloads 600 times larger.
• Developed a silent background process that monitors key presses and recognizes barcode syntax, triggering image capture from the warehouse CCTV system.
• Applied systems programming concepts, including mutex-based synchronization, to prevent race conditions and manage concurrent write operations.
• Used cron, the GNU coreutils, and git to create an automated deployment pipeline for various automated services.
• Deployed 10 containerized cloud applications optimized for resource efficiency, achieving reliable operation on a single low-tier cloud instance.
• Interfaced with the xlsxwriter C library to programmatically generate non-trivial excel spreadsheets, such as spawning charts and extracting/including VBA macros at compile time.

Volunteer Data Assistant - Bath Royal Literary and Scientific Institution

2024-03 - 2024-05

• Used text-manipulation tools from the GNU coreutils such as awk and sed to process and clean existing tabular data.

Projects

Structure-Preserving Encryption and Decryption - https://github.com/johanyim/spead

• Implemented key derivation with Argon2 algorithm to derive cryptographically strong keys to mitigate brute-force and GPU-based attacks.
• Applied Format-Preserving Encryption (FPE) to encrypt and decrypt structured data without altering data formats or types, reducing the effect of encryption on data type validation.
• Combined concepts from JSON traversal/pointers (RFC 6901) with nonce selection to produce deterministic encryption, while resisting ciphertext-equality attacks.

Education

Computer Science MComp (Hons) - University of Bath

2019-09 - 2023-05

• Functional Programming (82%)
• Machine Learning (77%)
• Statistics for Data Science (73%)
• Cryptography (78%)
• Data Structures and Algorithms (82%)
• Computer Systems Architecture (82%)

International Baccalaureate (iB) - King George V School

2017-09 - 2019-05

• HL Maths (7)
• HL Physics (7)
• HL Computing (5)