When a virtual machine is encrypted, the VMX config file is encrypted, too. Sometimes it's necessary to make a change to the config file by manually editing it, like when you have to add a "cpuid.1.eax = ..." line. This isn't possible with the encrypted file. VMware's official solution is to decrypt the whole virtual machine, make the changes to the then unencrypted VMX file and encrypt the whole machine again. This isn't a smart solution and it takes a lot of time with virtual machines with large virtual disk images. I don't know why there's no way to alter the VMX file of an unlocked halted virtual machine.
So, is there a tool which does nothing more than decrypt/encrypt a VMX file with a given password?
I would write this tool by myself if somebody can explain to me what two parameters of the encrypted VMX file are used for. Right after "vmware:key/list/(pair/(phrase/", there are 8 bytes encoded with base64 (maybe some kind of checksum), and after "HMAC-SHA-1" there are 116 bytes encoded with base64 (no idea what they're used for). I assume the 256 bit AES encryption key for the AES-256 algorithm is the result of the PBKDF2-HMAC-SHA-1 function with the password and 1000 rounds, but I also need to know the IV (initialization vector, 16 bytes) for the AES algorithm.