This project will provide travel support to help U.S.-based researchers (graduate students, postdocs, and tenure-track faculty without NSF support) attend the Seventeenth Algorithmic Number Theory Symposium (https://www.antsxvii.org/), to be held July 6 to 10, 2026 at the Bernoulli Institute in the Netherlands. This award will provide participants with the opportunity to present their work and interact with leading researchers in computational number theory, cryptography, and related fields. Research in these areas is fundamental to our digital security infrastructure, including the security and privacy of electronic communications and financial transactions that take place over the internet. Several major breakthroughs in cryptography and quantum computing were first announced at previous editions of this conference. The Algorithmic Number Theory Symposium (ANTS), held biennially since 1994, is the premier international forum for new research in computational number theory. It covers algorithmic aspects of number theory, including elementary number theory, algebraic number theory, analytic number theory, geometry of numbers, arithmetic algebraic geometry, modular forms, and finite fields, as well as applications of number theory to post-quantum cryptography and quantum information science. As in prior years, the program is expected to consist of 4-5 invited lectures, 20-30 contributed papers, a poster session, a session for shorter contributions, and a business meeting. The program committee will award the Selfridge Prize to the best contributed paper. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.