---
id: 1316
title: "Introducing constant-time support for LLVM to protect cryptographic code"
source_domain: blog.trailofbits.com
source_url: "https://blog.trailofbits.com/2025/12/02/introducing-constant-time-support-for-llvm-to-protect-cryptographic-code/"
published_at: "2025-12-02 12:00"
tags: ["developer-security", "cryptography", "llvm", "trail-of-bits", "compilers", "constant-time", "timing-attack"]
phying_url: "https://phying.com/item/1316"
lang: en
---

# Introducing constant-time support for LLVM to protect cryptographic code

## Summary

Trail of Bits added constant-time support to LLVM, introducing the __builtin_ct_select intrinsics that stop compilers from optimizing cryptographic code into timing-attack-vulnerable branching.

## Intelligence Metadata

- **Sources:** blog.trailofbits.com
- **Published:** 2025-12-02 12:00
- **Original:** https://blog.trailofbits.com/2025/12/02/introducing-constant-time-support-for-llvm-to-protect-cryptographic-code/
- **Phying News:** https://phying.com/item/1316