# Secureboot guide for linux:
# Im using void but this should work on most distros. You will just have to replace stuff like xbps-install with apt for example.
0.1. Enter Root
sudo su
1. Install efitools sbsigntool
sudo xbps-install efitools efitools-efi
2.Create a GUID for owner identification
uuidgen --random > GUID.txt
3. Platform key
openssl req -newkey rsa:4096 -nodes -keyout PK.key -new -x509 -sha256 -days 3650 -subj "/CN=my Platform Key/" -out PK.crt
openssl x509 -outform DER -in PK.crt -out PK.cer
cert-to-efi-sig-list -g "$(< GUID.txt)" PK.crt PK.esl
sign-efi-sig-list -g "$(< GUID.txt)" -k PK.key -c PK.crt PK PK.esl PK.auth
3.1 Sign an empty file to allow removing Platform Key when in "User Mode"
sign-efi-sig-list -g "$(< GUID.txt)" -c PK.crt -k PK.key PK /dev/null rm_PK.auth
4. Key Exchange Key
openssl req -newkey rsa:4096 -nodes -keyout KEK.key -new -x509 -sha256 -days 3650 -subj "/CN=my Key Exchange Key/" -out KEK.crt
openssl x509 -outform DER -in KEK.crt -out KEK.cer
cert-to-efi-sig-list -g "$(< GUID.txt)" KEK.crt KEK.esl
sign-efi-sig-list -g "$(< GUID.txt)" -k PK.key -c PK.crt KEK KEK.esl KEK.auth
5. Signature Database key
openssl req -newkey rsa:4096 -nodes -keyout db.key -new -x509 -sha256 -days 3650 -subj "/CN=my Signature Database key/" -out db.crt
openssl x509 -outform DER -in db.crt -out db.cer
cert-to-efi-sig-list -g "$(< GUID.txt)" db.crt db.esl
sign-efi-sig-list -g "$(< GUID.txt)" -k KEK.key -c KEK.crt db db.esl db.auth
6. Signing Bootloader and Kernel. (I use grub)
sbsign --key db.key --cert db.crt --output /boot/vmlinuz(enter version here) /boot/vmlinuz(enter version here)
sbsign --key db.key --cert db.crt --output /boot/efi/EFI/BOOT/BOOTX64.EFI /boot/efi/EFI/BOOT/BOOTX64.EFI
7. Enroll your keys
cp /root/*.cer /root/*.esl /root/*.auth /boot/efi/

Follow this guide: https://wiki.gentoo.org/wiki/User:Sakaki/Sakaki%27s_EFI_Install_Guide/Configuring_Secure_Boot#Method_3:_Inserting_Keys_via_Keytool

Keys should be added in this order: db => KEK => PK

8. Enable SecureBoot and Enjoy!