$ETH About "Do smart contracts have backdoors?"

In short: In theory, they are completely transparent with no backdoors, but developers may intentionally or accidentally leave vulnerabilities that function like backdoors.

The simplest analogy:

A smart contract is like a transparent vending machine:

1. Code is fully public: Everyone can see exactly how every gear (line of code) operates inside.
2. Rules cannot be tampered with: Once launched, no one (including the developer) can change the rules mid-way.

But “backdoors” can still exist if:

· Deliberately left during design: For example, the developer secretly embeds a switch in the code that lets only themselves take all the money.
· Bugs that act as backdoors: If there’s a flaw in the code and a hacker finds and exploits it, the effect is similar to a backdoor.
· Excessive privileges: The contract allows a certain address (such as the developer) to have too much control.

Key points:

· Blockchain transparency makes it difficult to hide malicious code.
· The main risks come from: not thoroughly reviewing the code, or trusting developer privileges too much.
· Before using, choose contracts that have undergone professional audits.

Summary: Blockchain technology itself eliminates hidden backdoors, but “human” factors (malicious design, negligence, centralized control) can introduce risks similar to backdoors.

——Source: “In-depth Exploration”