user13192: This was something that popped into my mind while I was thinking about CPU Only Alt-coins.
Would it be possible to have an ARM-based coin? That is, a coin that could only be mined on ARM devices (iPhone, Android device, etc. )? 

user12835: You just need to find a hashing algorithm which is more cost efficient on an ARM CPU, I found this answer to a similar question which should point you in the right direction :) https://security.stackexchange.com/questions/29941/how-does-processor-architecture-affect-password-hashing-speed

user13751: You can pick a proof-of-work function that runs more efficiently on ARM architecture but you can't define something that's ARM-only. The same function can always be ported to run on Intel CPU or even MIPS.

13192: <p>This was something that popped into my mind while I was thinking about CPU Only Alt-coins.
Would it be possible to have an ARM-based coin? That is, a coin that could only be mined on ARM devices (iPhone, Android device, etc. )? </p>
 12835: <p>You just need to find a hashing algorithm which is more cost efficient on an ARM CPU, I found this answer to a similar question which should point you in the right direction :) <a href="https://security.stackexchange.com/questions/29941/how-does-processor-architecture-affect-password-hashing-speed">https://security.stackexchange.com/questions/29941/how-does-processor-architecture-affect-password-hashing-speed</a></p>
 13751: <p>You can pick a proof-of-work function that runs more efficiently on ARM architecture but you can't define something that's ARM-only. The same function can always be ported to run on Intel CPU or even MIPS.</p>
