Use CryptUnprotectData() to decrypt DPAPI encrypted data on Windows using your current user context. Might be handy if you don't have the domain backup key or the user's password.
Pass in b64 encoded + DPAPI encrypted blob, decrypt, get b64 encoded + decrypted blob, profit.
Can write output to a file if you've converted this to shellcode using something like Donut and are executing it that way.