Software Library

A software library is a collection of prewritten, tested code that programmers reuse in their own programs, calling its functions rather than writing the same logic again. Libraries handle common jobs such as reading dates, sending network requests, doing maths or performing cryptography, and are usually published with documentation that explains how to use them. A library differs from a framework mainly in control: the programmer's code calls a library when it needs it, while a framework calls the programmer's code. In crypto, wallets and exchanges rely on libraries for key generation, signing and talking to blockchain nodes, and many are open source. Because one popular library can sit inside thousands of apps, a bug or a malicious update to it can spread widely, which is the risk behind a supply chain attack.