Securely deleting temporary decrypted files and/or keys from hard drive

When Keybase decrypts files pulled from the Keybase file server, is there any mechanism in place to ensure that the decrypted temporary files are securely deleted from the local hard drive once the user is done working with them? Simply deleting a file from the hard drive is not sufficient, as deleted files can be recovered through a variety of techniques.

Secure delete software can utilize a number of different algorithms to make it very difficult to recover deleted files, but they all work on the basic principle of overwriting the hard disk sector(s) which contained the deleted file with random and/or patterned data several times to reduce the residual magnetic signature of the deleted file. Does Keybase use any such technique to securely delete temporary decrypted files?

In addition to addressing the secure deletion of temporary decrypted files, there is also the issue of decrypted private keys being written to the hard disk. Even if Keybase itself never directly writes decrypted private keys to the hard disk and only handles them "in-memory", the operating system may still write those "in-memory" decrypted private keys to the hard disk temporarily if the kernal swaps the memory addresses containing those decrypted keys out to the paging file while another processes temporarily needs to use that space in RAM. Does Keybase have a way to either prevent the parts of active memory containing decrypted private keys from ever being swapped out to the paging file, or to securely delete them from the paging file if the keys do get swapped out?

Also, does Keybase have a way to address secure deletion of decrypted files in active memory if they get temporarily written to the paging file as well?

@malgorithms

The issue identifies no files, tests, or entry points. Begin by mapping Keybase's handling of temporary decrypted files, private keys, memory, and paging, then define the supported secure-deletion behavior and how it would be verified across affected systems.

Written by the indexing model from the issue text.