Open-source software makes its source code publicly available for inspection. In security, this transparency is cited as a major advantage: anyone can find vulnerabilities and no one can hide backdoors. The principle suggests that given enough eyeballs, all bugs are shallow. But the reality is more nuanced.
The Reality of Code Review
Simply being open-source does not guarantee competent review. The Heartbleed vulnerability in OpenSSL went undetected for over two years despite the code being publicly available. This demonstrated that visibility alone is insufficient — active, funded, expert review is what actually finds vulnerabilities.
What Makes Open Source Trustworthy
Look for projects with professional security audits by independent firms, active development communities, responsive handling of security reports, and transparent patch histories. A project maintained by a single developer with infrequent updates may be open-source in name but lacks the community review that provides real security benefits.
The Build Verification Problem
Even if source code is perfect, how do you know the binary you downloaded was built from that exact code? Reproducible builds address this, but few mobile apps have achieved them. This trust gap between source code and installed application remains partially unresolved.
Independent Audits
Professional security audits are the strongest signal of trustworthiness for any security app. An audit by a reputable firm involves experienced researchers actively trying to break the software. The most trustworthy projects conduct regular audits and publish results transparently.
Beyond the Binary
The question is not simply "open source or not?" but whether the security claims are verifiable. Clear documentation of encryption methods, data handling practices, and threat models — subjected to independent verification — builds trust regardless of source code availability.
Making Informed Decisions
LockWhisper prioritizes transparency about its security architecture, using well-established standards like AES-256 and PGP. By combining proven algorithms with local-only data storage, it provides a trustworthy security solution where the implementation matches the claims.