>The Fifth Amendment, like the others, generally applies to not just citizens, but legal residents and others who are on U.S. soil.
This true only once you are on the soil, not at the entry points. If you are not a US citizen, or at least granted some form of acknowledgement by the government i.e. a visa, the protections of the Constitution and the Bill of Rights do not apply to you. Again, this is true at the entry point to the US[1].
So to come back to the original example: if I enter the US as a non-citizen, can TSA or border security force me to decrypt my hard drive? The answer, with no doubt, is 'absolutely, yes they can'. In the eyes of Homeland security, if you are not a US citizen, you have no rights at the border and they will not hesitate to detain you or send you right back if you are uncooperative.
This true only once you are on the soil, not at the entry points. If you are not a US citizen, or at least granted some form of acknowledgement by the government i.e. a visa, the protections of the Constitution and the Bill of Rights do not apply to you. Again, this is true at the entry point to the US[1].
So to come back to the original example: if I enter the US as a non-citizen, can TSA or border security force me to decrypt my hard drive? The answer, with no doubt, is 'absolutely, yes they can'. In the eyes of Homeland security, if you are not a US citizen, you have no rights at the border and they will not hesitate to detain you or send you right back if you are uncooperative.
[1]https://www.aclu.org/files/kyr/kyr_english_5.pdf