I had a banking issue this past week. When I telephoned my bank, the automated system asked me to dial several digits of my bank card and the password that allows me to access my online banking system.

It occurred to me while making those calls that telephones are an analog medium that predates information security. I don't know how easy they would be to tap, but is it feasible for a malicious utility worker to "tap into" the line, record the call, and map the key tones to numbers? The automated voice on the other end would have told an attacker that it was banking information for a certain website.

  • there's 2 parts: 1. "tap into": not easy because it's encrypted. 2. map the tones: trivial.
    – dandavis
    Jun 14, 2017 at 16:01

1 Answer 1


There is no technical protection that DTMF tones provide. The sounds are easily decoded using readily available software, or using an online web tool.

However, in the United States, there are strict anti-wiretapping laws that provide severe penalties for anyone caught intercepting a phone call. Anyone working for the phone company would be aware of them.

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