https://peterlyons.com/problog/2017/12/openssh-ed25519-private-key-file-format/
https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key
	canonical: https://cvsweb.openbsd.org/src/usr.bin/ssh/PROTOCOL.key?annotate=HEAD
https://stackoverflow.com/a/56300901/733214
https://stackoverflow.com/a/59283692/733214
https://coolaj86.com/articles/the-openssh-private-key-format/
https://coolaj86.com/articles/the-ssh-public-key-format/
https://crypto.stackexchange.com/a/40910
https://flak.tedunangst.com/post/new-openssh-key-format-and-bcrypt-pbkdf
("(Technical note: PBKDF2, aka PKCS #5, supports pluggable hash functions, though in practice everybody uses HMAC-SHA1. The bcrypt pbkdf essentially is PBKDF2, but with bcrypt plugged into it instead.)"
http://www.tedunangst.com/flak/post/bcrypt-pbkdf

## UPSTREAM
https://github.com/openssh/openssh-portable/blob/master/sshkey.c
	funcs:
	sshkey_generate (~L1714)
	sshkey_private_to_blob2 (~L3833)
	sshkey_private_to_fileblob (~L4413)
https://github.com/openssh/openssh-portable/blob/master/cipher.c
	funcs:
	cipher_ivlen	
https://github.com/openssh/openssh-portable/blob/master/ed25519.c
	funcs:
	crypto_sign_ed25519_keypair (~L26)
https://github.com/openssh/openssh-portable/blob/master/authfile.c
	funcs:
	sshkey_save_private (~L68)
	sshkey_save_private_blob (~L56)
https://github.com/openssh/openssh-portable/blob/master/ssh-keygen.c
	funcs:
	main (~L3145; ~L3673 onwards for key generation)