Peter Todd invented stealth addresses.
I wouldn't say I "invented" stealth addresses; I'd say I
designed stealth addresses. The part that you could call an "invention" was created by ByteCoin (the bitcointalk user) years ago - what I did was take that math and figured out a good way to use it given real world constraints. (some of them 100% political!)
To be perfectly honest, I
don't really understand the math behind ECC signatures, and hence stealth addresses. My original stealth addresses writeup actually got some of the details there wrong, basically because I was copying-and-pasting from the BIP32 writeup. But IMO that's actually a nice example of how you can treat the math as a "black-box" with known properties and do your innovation elsewhere - no different than how most of you probably don't know much about how compilers work under the hood, yet successfully use them every day to make software.