Uploaded November 2025 | Updated September 2026, 2 weeks ago
2025 US LLVM Developers' Meeting
llvm.org/devmtg/2025-10
------
Title: Timing-Resistant Coding Support in LLVM
Speaker: Julius Alexandre
------
Slides: llvm.org/devmtg/2025-10/slides/quick_talks/alexandre.pdf
-----
There is a fundamental tension between cryptographic coding and compiler optimizations. When cryptographers write C and C++ code that needs to be constant-time, they tend to follow bitwise arithmetic recipes that unfortunately do not always stand up to the optimization pipeline, or they write raw inline assembly. WYSIWYG compiler-level support for constant-time coding will prevent attackers from learning useful information from timing conditional branches, jumps, and memory accesses, and will make it simpler for cryptographers to build the functionality that we all rely on in TLS libraries, hash functions, and more. This talk will cover the technical challenges of constant-time coding support in Clang and LLVM, and how optimization passes can inadvertently introduce timing vulnerabilities.
-----
Videos Edited by Bash Films: BashFilms.com
2025 US LLVM Developers' Meeting
llvm.org/devmtg/2025-10
------
Title: Timing-Resistant Coding Support in LLVM
Speaker: Julius Alexandre
------
Slides: llvm.org/devmtg/2025-10/slides/quick_talks/alexandre.pdf
-----
There is a fundamental tension between cryptographic coding and compiler optimizations. When cryptographers write C and C++ code that needs to be constant-time, they tend to follow bitwise arithmetic recipes that unfortunately do not always stand up to the optimization pipeline, or they write raw inline assembly. WYSIWYG compiler-level support for constant-time coding will prevent attackers from learning useful information from timing conditional branches, jumps, and memory accesses, and will make it simpler for cryptographers to build the functionality that we all rely on in TLS libraries, hash functions, and more. This talk will cover the technical challenges of constant-time coding support in Clang and LLVM, and how optimization passes can inadvertently introduce timing vulnerabilities.
-----
Videos Edited by Bash Films: BashFilms.com
