I need to do something like this in my system:
Backend Server had a password "12345678"
hashed it to other string like "5f4dcc3b5aa265d61d8327aeb882cf39"
Frontend Server generated and use this hashed string to encrypte a pdf file
User download this pdf file and use password "12345678" to open it!
Is this possible and how to do it?
Hashing's irrelevant here. Backend needs plaintext password. PDF uses KDF, not hashes for encryption. Use pikepdf
or similar, AES-256. Frontend? HTTPS for password transit. User types original password to open. Clear now?