ryan torok

Hacker, Computer Enthusiast, Cellist,

Music Composer, and All-Around Nerd!

About Me

Industry Work

Academic Work




Hi! My name is Ryan Torok, and I am a software systems engineer at zeroRISC, a startup company in Boston developing a cloud security service for the OpenTitan silicon root-of-trust project. Over my long-term career, I am interested in how to design and implement secure and usable computer systems in both the commercial and government sectors, leading to a future technology leadership role where I can specialize in making the web a safe place for everyone. I also offer Computer Science tutoring at several universities in the Boston area.

My previous affiliations include the SNS group at Princeton University, where I was advised by Amit Levy and earned my Master's degree in 2023, the ISS and Starliner software teams at Boeing Space, and the Turing Scholars program at the University of Texas, where I was advised by Calvin Lin and Akanksha Jain.

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Industry Work

2023 - Present
Software Engineer — zeroRISC

Winter - Summer 2021
Software Engineer — Boeing CCTS Starliner Program (via Barrios Technology, Ltd) [more]

Summer 2020
Software Engineer Intern — Boeing CCTS Starliner Program

Summer 2019, Spring 2020
Software Engineer Intern — Boeing ISS Program [more]

After finishing my undergraduate degree in December 2020, I returned to Boeing for another six-month stint, this time working on a few years' worth of backlogged updates to the framework responsible for running the Starliner's software qualification tests, whose results are formally documented and sent to NASA. The updates significantly reduced the amount of human inputs necessary to start the tests, eliminating the chance for human error, and reduced the amount of waiting time in between them.

Eight months after departing Boeing to start my Master's degree at Princeton, I was thrilled to watch the Starliner complete its second Orbital Flight Test in May 2022, which saw it successfully dock with the International Space Station for the first time. I am even more looking forward to seeing the spacecraft finally ferry crew to the station after over a decade of development and testing, when it will carry veteran astronauts Sunita Williams and Barry Wilmore on the Crewed Flight Test in spring 2024. [back]

I worked two internships with Boeing's software team in summer 2019 and spring-summer 2020. I worked in the testing groups for the software that runs on the International Space Station as well as Boeing's new Commercial Crew spacecraft, the Starliner. With the critical responsibility to protect the spacecraft and crew, this software has some of the strongest correctness requirements in the world.

During my 2019 internship, I was located on-site at the office just a few miles from NASA's Johnson Space Center, and the company organized several trips to JSC for the roughly 30 interns working for the summer. Pictured is myself in front of the full-scale model of the Boeing Starliner at JSC building five, where we also had the opportunity to see mockups of the ISS and the Space Shuttle flight deck. My group also made trips to see the ISS Software Development Integration Lab (SDIL), housing duplicates of the decades-old Honeywell computers that run the ISS (your phone has more processing power), the Neutral Buoyancy Lab where astronauts train for spacewalks in a 50-foot deep swimming pool, and the ISS Mission Control Center. To round out the experience, everyone remembers the mother duck who built a nest outside the building's entrance, whose eggs hatched into adorable ducklings during the last week of my internship. [back]

Academic Work

Sandcastle: Leveraging Sandboxes for a Minimally Invasive Browser Fingerprinting Defense [PDF][talk][more]
with Amit Levy
In Proceedings of the 44th IEEE Symposium on Security and Privacy

Improving Graph Workload Performance by Rearranging the CSR Memory Layout [PDF][more]
with Calvin Lin and Akanksha Jain
Undergraduate senior thesis, Fall 2020

Sandcastle is a novel browser fingerprinting defense that uses sandboxing techniques to minimize its interference with legitimate applications. Sandcastle works by providing an expressive API that web applications can use to communicate with the browser, which enables the browser to understand to high precision what identifiable information leaked by browser APIs is leaked to the network.

Meanwhile, information that is not leaked through the API's dedicated leakage channel, nicknamed the cashier, remains confined inside a carefully designed sandbox that prevents the data leaking through other covert channels, including the execution time or the document state. This allows the browser to avoid applying other, destructive fingerprinting mitigation strategies to API calls within the sandbox, like randomizing return values or limiting the number of calls using an entropy budget, enabling the browser to robustly defend against fingerprinting attacks without harming legitimate applications. [back]

In my final two semesters as an undergraduate, I concluded my Turing Scholars honors Computer Science degree with a research project in Computer Architecture. The project began at the end of Dr. Calvin Lin's graduate research course focusing on hardware prefetching and caching. My final project for the course was an entirely new prefetcher which utilized register data to improve the accuracy of address-correlating prefetchers. The technique showed promise for traditional server workloads, but when I transitioned to focus on memory latency in graph workloads, I discovered the register-based techniques were not producing timely prefetches because of graphs' heavy pointer-chasing behavior. Then, I shifted my focus to different strategies, and ended up discovering two worthwhile techniques, a prefetcher which could extrapolate the neighbor indices in the CSR graph memory layout, and an alternate CSR-like layout which allows the graph to achieve better spatial locality and suffer fewer cache misses. These two topics became the subject of my senior honors thesis in December 2020. [back]


Princeton University
Spring 2023
Teaching Assistant — COS 461, Computer Networks

Fall 2022
Teaching Assistant — COS 316, Principles of Computer System Design

Spring 2022
Teaching Assistant — COS 226, Data Structures and Algorithms

Fall 2021
Teaching Assistant — COS 318, Operating Systems

University of Texas
Fall 2019
Teaching Assistant — CS 314H, Honors Data Structures [more]

Though I have served as a TA a total of five times across two universities, my first TA role at UT Austin is still the most special to me. The cohort of 26 students I taught represented the inaugural class of UT's new joint Honors Computer Science and Business program, and I was granted a chance to interact very closely with my students as they braved a difficult course I remembered struggling with as a freshman.

My students frequently complimented my skill at clearly explaining complicated topics, and I created a few special activities such as a logo contest for the course's final project to make the class fun. It was particularly rewarding for me to see my former students succeed in their future coursework, and I remain friends with several of them even after graduating. Thank you for being some of the best people I have ever worked with. [back]


When I'm not hacking on OpenTitan or research, you might find me playing the cello outside, especially during the holiday season. I also love writing my own music, and I am particularly proud of my 2018 full orchestra composition, Christmas in Boston.

I also love finding new outdoor spaces to explore. During my time at Princeton, I enjoyed running around campus or on the Delaware and Raritan Canal Towpath, and hiking at places like the Delaware Water Gap and Mercer Park.

I have played the cello since age 10, and served as the vice president of my high school orchestra. We regularly placed in the top 15 schools in the state of Texas, also performed at prestigious national competitions, including the Midwest Clinic in Chicago, the ASTA National Orchestra Festival in Pittsburgh, and the National Orchestra Cup in New York City's Lincoln Center (unfortunately I was first chair for this one and my bridge broke on stage during the performance — everyone was absolutely mortified). I also earned the right to perform in the 2015-16 and 2016-17 Region 9 Symphony Orchestra, which accepts the top ten cellists across the North Houston area.

My high school orchestra also had its fair share of fun traditions, such as the annual Cello Ensemble performance of ThePianoGuys' arrangement of Nearer My God to Thee. My most memorable orchestra memory has to be when I soloed Silent Night with the choir at our combined holiday concert. I continued to perform casually throughout college. I love sharing my music outside in campus courtyards, especially during the holidays. My favorite piece to perform is Luigi Boccherini's Cello Concerto in B♭ major, a beautiful piece that takes advantage of the instrument's versatility and range. Advanced players can learn left hand techniques which allow them to play music in higher octaves more commonly played by the violin and viola, giving the cello the largest range of any string instrument outside the piano. [back]

Since my time as a music student in high school, I have dedicated significant time to composing my own orchestra music. I find writing music to be quite theraputic, because while it is primarily a creative activity, it also relies on detailed reasoning about factors such as chord design, instrument ranges, balance across sections, and the timbre of different instruments to discover the best way to translate a desired sound in my head into a real score, and it is this process that involves the same type of logic I use to solve problems in the Computer Science realm. This combination of creative and logical thinking makes the writing process the perfect intersection of art and science that keeps me entertained for hours.

You can listen to a few of my favorite compositions here:
Christmas in Boston (2018)1, 2 [score][more]
121 Thursdays (2016)3
Spirit of Adventure (2015)4


Christmas in Boston is a holiday-themed full-orchestra piece named not after the city as a whole, but after a small store in Faniuel Hall marketplace, which is open all 12 months of the year and provides an excellent antidote to the summer heat if you visit in July. As my first dive in to full orchestra composition, I felt the piece struck the perfect balance between original melodies and familiar classics to go down as a memorable holiday score. The piece is organized into nine sections, which you can learn about by clicking below.

[0:00]  A Chillier Kind of Season
[1:37]  A Bustling Scene
[3:25]  A Peaceful Night
[5:15]  Snow on the Rooftops
[7:05]  From the Highest Peak
[9:53]  Avalanche
[12:05] Northern Lights, a Winter Ambience
[14:04] The Light Reappears
[16:16] Holiday Spirit in the Air

A Chillier Kind of Season
You may be surprised to learn that I did not notice how much this section's opening line resembles the tenor line from Pachelbel's Canon until multiple years after the piece was completed. Early in writing, I had planned for Christmas in Boston to take on a very different structure, with a few longer movements and a small refrain of this section's main melody in between each, making it similar in structure to Mussorgsky's Pictures at an Exhibition. Though I eventually abandoned this structure in favor of several short sections, both this section's melody and the piece's title are leftovers from that original premise. In fact, the opening line was originally intended to resemble walking down a city street, probably in the heat of the summer, followed by the entry of the main violin melody representing the rapid change from summer to winter one experiences by passing through the doors of the piece's eponymous holiday store. [back]

A Bustling Scene
If I had to choose one, this remains my favorite section. The uplifting melody at the opening is downright addictive, and one I still catch myself humming at any time of the year. The cross-section callbacks with the trombones in the opening melody and the low strings in the middle help the tune capture the same lighthearted bounce as Leroy Anderson's classic Sleigh Ride. Adding more sound from the back of the orchestra on top of the tune interspersed with "The Most Wonderful Time of the Year" in the final stretch of this section transforms the lighthearted melody into an epic voice that is not heard again until the second half of the piece. [back]

A Peaceful Night
When I was growing up, my parents had a set of electronic bells they would hang in our living room each December, and O Come All Ye Faithful was the first song it was programmed to play when it was powered on. Ever since, it has remained one of my favorite Christmas songs, and it was the first holiday tune I learned to play on my cello as far back as fifth grade. In writing this section, I wanted to give the solo violin a lot of freedom without leaving them to play completely on their own. I ended up looking at a guitar arrangement of O Come to help guide what chord progression I chose for the harp and upper winds in the background. I also like how the march feel added by the percussion near the end of the section sound unexpected but not out of place. If I have one regret about this section, it is that I could have put more effort into the intervals between the two violin sections in the final stretch. [back]

Snow on the Rooftops
Fueled by its mysterious arpeggios, this section is very much a fusion of John Williams' Hedwig's Theme from the Harry Potter film series and Stephen Flaherty's Once Upon a December from the 1997 classic Anastasia. Between slowly adding a new instrument to the mix every time the phrase repeats to the introduction of the chromatic note sequences that feature prominently in the James Bond franchise, this section perfectly captures the level of wonder and anticipation I imagine a young child would feel looking out their bedroom window on Christmas Eve, seeing a blanket of snow on the neighboring houses, wondering when a particular red-suited man was going to land on their roof. Oh, and the bassoon melody at the end is pretty awesome, too. [back]

From the Highest Peak
Though I had a rough idea about what I wanted to do with this section for a long time, it was challenging to come up with a unique-sounding melody that well-captured the thrill of skiing or snowboarding down a mountain at impressive speed (I've never done either, by the way). I ended up making heavy use of the upper strings playing a 2-againt-3 rhythm to make the melody sound fun, leaving the low strings to keep the mood of epic excitement. Meanwhile, the middle stretch just begs the audience to take a break from the intensity and grab a cup of coffee and watch the little kids on the bunny slope. If you'd like an excuse to read the score, you can look for the harp roll leading into the repeated 6/4 measure that completely fails to show up in the recording. [back]

This section got a lot of attention from me, and there are so many fun stories I could tell here, like the note in the French Horn section near the end that started out as a typo. This section had much more of a story in my head during writing than most of the others, with the desceptive cadence that ends the previous section representing the collective gasp of the skiers noticing they are on the verge of an avalanche, that is eventually set off by a bird (represented by the piccolo) landing on a tree and causing enough vibration to push the mountain over the edge. Following the blare of the avalanche warning horn, the section proceeds with a frantic escape down the mountain, highlighted by a slew of augmented chords and inconsistent odd phrase lengths. The unique chord progression in the final buildup evokes a sense of last-ditch confidence before the outcome is left uncertain up until the final downbeat. [back]

Northern Lights: A Winter Ambience
This section was heavily inspired by David Wise's Aquatic Ambience from the first entry in the Donkey Kong Country game series. In hindsight, I think Northern Lights resembles Aquatic Ambience a bit too much, since the heavy use of strings for the ambient chord progression makes this section sound more like water than snow. The main idea I intended for the start of this section, which isn't caputred well by the recording, is that the final downbeat of the previous section should reverberate in the hall long enough for the upper strings to begin this section without its start being heard by the audience. Admittedly, I didn't have many ideas for building on top of the peaceful, yet melancholy melody provided by the harp and vibraphone. I ended up introducing a rhythmic variation of Blue Christmas, followed by a brass doubling of the strings' ambient progression to provide a strong "lonely holiday" vibe, meant to contrast heavily with the final two sections. [back]

The Light Reappears
This section got the least amount of attention from me. I did achieve my major goal of including a movement that keeps the peace of the previous section but abandons the melancholy feel in favor of a more optimistic, reflective one. However, I definitely think I could have developed the Greensleeves motif much more than I did. Though it was definitely meant to be more minimalistic and reflective, being the last chance for the audience to catch their breath before the fast-paced final section, I still feel like the middle of this section lacks the amount of forward motion I was going for. [back]

Holiday Spirit in the Air
There's a lot to love here, and a lot I could talk about. Beginning with the classic "clock tower bell" note pattern, my goal was to capture the same epic feel of Spirit of the Season from the classic children's holiday film The Polar Express. Meanwhile, the bass line in the low strings was loosely based on that of the theme The Reaper's Line of Sight from the game Kid Icarus: Uprising. Following the fun rhythmless variant of Deck the Halls, we move into a thick, sensitive arrangement of Silent Night, which is a subtle nod to my favorite memory from my high school orchestra days: when I played Silent Night along with the choir at our combined holiday concert. From there until the end of the piece, the goal was simply to stack as many classic holiday melodies in between the angelic violin runs until every major section of the orchestra was playing a different line. Though this section was written in only a few days, it definitely provides the illustrious, cheerful ending this piece deserved. [back]

I decided I had to include this picture I took in August 2022 from the peak of Mount Tammany at the Delaware Water Gap. In the lower-right corner, you can see the Delaware River carving through the Kittatinny Mountains, paralleled on its right by Interstate 80, whose vehicles look like tiny matchbox cars from this 1500-foot vantage point.

Hiking up the mountain is an intense climb, with steep inclines and a rocky trail where flat places to plant your feet are few and far between. After encountering a pair of waterfalls near the mountain's base, you find yourself surrounded by trees, giving no indication of your elevation for the entire ascent, until it opens up beautifully at the peak to the view you see here, making the trek up the mountain more than worth it. Though it was a fairly hazy day, you can make out the peaks of mountains across the river on the Pennsylvania side that are several miles downrange. With the upper-level winds in your face and the sheer vastness of the space you can see, the pictures absolutely do not do the experience justice. [back]