hkp literally stands for HTTP keyserver protocol. Does your corporate proxy really mess up HTTP connections?
Why does it matter how apt-key is implemented? Its purpose is key management, and whether it uses bash for the job or perl or C is completely irrelevant. It's been in use for over a decade. Do you have any reason to suspect deficiencies in it just because it uses shell scripts?
Why does it matter how apt-key is implemented? Its purpose is key management, and whether it uses bash for the job or perl or C is completely irrelevant. It's been in use for over a decade. Do you have any reason to suspect deficiencies in it just because it uses shell scripts?