Ryan Castellucci
Principal Security Engineer at Amazon
Stony Stratford, England, United Kingdom
Summary
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SeniorRyan Castellucci is a Principal Security Engineer with 15+ years focused on security and two decades of broader IT experience spanning software development, network engineering, and Linux systems administration. He has led security research and engineering at Amazon and HUMAN, and earlier built operational security and Unix infrastructure at Palantir and a regional ISP. His deep competencies include applied cryptography, embedded systems, and low-level tooling—demonstrated by contributions to crypto-focused tools like brainflayer where he optimized bloom-filter based key-cracking workflows. An active community participant, he regularly speaks, competes in Capture the Flag events, and blends hands-on offensive techniques with production-grade defensive engineering. Based in the UK, he pairs rapid learning and pragmatic problem-solving with a taste for technically sophisticated, sometimes irreverent, open-source work.
15 years of coding experience
20 years of employment as a software developer
English
Stackoverflow
1,314reputation
548kreached
9answers
1question
openssl
top-5%
ssh
top-5%
certificate
top-5%
Github Skills (18)
c1110
bloom-filter10
c1710
cryptography10
bitcoins9
bitcoin9
openssl9
certificate9
ssh9
pkcs6
x5096
linear-algebra6
codec6
telecommunication6
python6
Programming languages (18)
Github contributions (5)
ryancdotorg/brainflayer
Jun 2015 - Nov 2020
A proof-of-concept cracker for cryptocurrency brainwallets and other low entropy key algorithms.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:116 commits, 9 PRs, 51 pushes in 5 years 6 months
Contributions summary:Ryan primarily focused on implementing and improving core functions related to cryptocurrency brainwallet cracking. They contributed code for creating and utilizing bloom filters to efficiently filter potential private keys. Furthermore, the user developed and implemented the `hex2blf.c` tool to generate bloom filters from hex-encoded hash values. They also added support for multiple input types and implemented the ability to check against a full address list, indicating a focus on enhancing the tool's functionality and efficiency.
cryptographyentropycrackerethereumbrainwallet
ryancdotorg/rya.nc-theme
Feb 2018 - Aug 2024
Contributions:33 pushes, 3 branches in 6 years 6 months
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