kathrinrin

1) extract key
https://github.com/AbinashBishoyi/WhatsApp-Key-DB-Extractor-UnOfficial

2) run a few commands 
hexdump -e '2/1 "%02x"' whatsapp.key | cut -b 253-316 > aes.txt
hexdump -n 67 -e '2/1 "%02x"' msgstore.db.crypt8 | cut -b 103-134 > iv.txt
dd if=msgstore.db.crypt8 of=msgstore.db.crypt8.nohdr ibs=67 skip=1
openssl enc -aes-256-cbc -d -nosalt -nopad -bufsize 16384 -in msgstore.db.crypt8.nohdr -K $(cat aes.txt) -iv $(cat iv.txt) > msgstore.gz
gzip -cdq msgstore.gz > msgstore.db