A software product depends on more than its own source files. Packages, build services, development tools and update channels can introduce unwanted code or changes before the product reaches a user.
Protection combines trusted sources, controlled access, verifiable build evidence and timely review of vulnerabilities. A signed artifact can help establish origin and integrity, but a signature alone does not prove its contents are safe.
ELI5
Software supply chain security is like checking the ingredients and kitchen tools used to make a meal. A careful final cook cannot fix every problem if a hidden ingredient or tool has already been tampered with.
For example, an AI application might use a library downloaded from a package service. Checking where it came from, reviewing updates and limiting build permissions can reduce the risk of a harmful dependency reaching users.
Does this only concern open source software?
No. Commercial dependencies, internal tools and hosted build systems can also introduce supply chain risks.
Does signing a package prove it is harmless?
No. Signing can establish integrity and origin, while the package's behavior still needs appropriate review.
