The implications of the government’s demands are chilling. If the government can use the All Writs Act to make it easier to unlock your iPhone, it would have the power to reach into anyone’s device to capture their data. The government could extend this breach of privacy and demand that Apple build surveillance software to intercept your messages, access your health records or financial data, track your location, or even access your phone’s microphone or camera without your knowledge.
— Tim Cook’s letter to Apple Customers
Read this. If you value you freedom, your security, and your privacy, read this.
A backdoor for the government can be used by malicious actors, both within the government and without. It can be used to spy on anyone, whether they are a suspect in a crime, a political agitator who has done nothing against the law, or even an ordinary, law-abiding citizen. A backdoor can be used to spy on ex-lovers or new flames, and existing ones already are.
That is the crux of the issue. There is no way to ensure that a backdoor will only be used by the “good guys.” It is impossible to do so. The only way to avoid this is not to have a backdoor in the first place—for anyone.