Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

2005 - 200912020 - 20221

Settings

Subject: search.filters.subject.amplification

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Automating the Discovery of Censorship Evasion Strategies
    (2022) Bock, Kevin; Levin, Dave; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Censoring nation-states deploy complex network infrastructure to regulate what content citizens can access, and such restrictions to open sharing of information threaten the freedoms of billions of users worldwide, especially marginalized groups. Researchers and censoring regimes have long engaged in a cat-and-mouse game, leading to increasingly sophisticated Internet-scale censorship techniques and methods to evade them. In this dissertation, I study the technology that underpins this Internet censorship: middleboxes (e.g. firewalls). I argue the following thesis: It is possible to automatically discover packet sequence modifications that render deployed censorship middleboxes ineffective across multiple application-layer protocols. To evaluate this thesis, I develop Geneva, a novel genetic algorithm that discovers packet-manipulation-based censorship evasion strategies automatically against nation-state level censors. Training directly against a live adversary, Geneva com- poses, mutates, and evolves sophisticated strategies out of four basic packet manipulation primitives (drop, tamper, duplicate, and fragment). I show that Geneva can be effective across different application layer protocols (HTTP, HTTPS+SNI, HTTPS+ESNI, DNS, SMTP, FTP), censoring regimes (China, Iran, India, and Kazakhstan), and deployment contexts (client-side, server- side), even in cases where multiple middleboxes work in parallel to perform censorship. In total, I present 112 client-side strategies (85 of which work by modifying application layer data), and the first ever server-side strategies (11 in total). Finally, I use Geneva to discover two novel attacks that show censoring middleboxes can be weaponized to launch attacks against innocent hosts anywhere on the Internet. Collectively, my work shows that censorship evasion can be automated and that censorship infrastructures pose a greater threat to Internet availability than previously understood.
  • Thumbnail Image
    Item
    How Incarceration Affects Juveniles: A Focus on the Changes in Frequency and Prevalence of Criminal Activity
    (2005-05-27) Giguere, Rachelle Marie; Bushway, Shawn D; Criminology and Criminal Justice; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    There has been a longstanding debate over the effectiveness of correctional institutions. Some argue that incarceration deters offenders while others argue that the experience of being incarcerated causes individuals to continue in their life of crime. Resolving this debate is of particular importance for young individuals when there is a national push for the increased treatment of youth as adults. Using NLSY panel data, this study focuses on how the criminal offending of a sample of incarcerated youth changes over time in relation to incarceration while including a control group of youth who are not incarcerated but are similar in demographics. Close attention is paid to overcome past problems with validity. The findings suggest that incarceration does little to stop criminal paths or future contacts with the criminal justice system, but perhaps may even have harmful effects on youth, particularly drug sellers, over the short term.