Hello,
I am using VeraCrypt system-encryption.
My system has only one HDD and only one partition on it (= system partition), if that matters.
In order to reinstall Windows 10, I decrypted the VC volume permanently, formated my HDD (overwritten a couple of times), installed Windows 10, installed VC and encrypted my HDD with the same type of encryption as before (system encryption). I also used the same password as before.
1. Question: Is it safe to use the same password as before?
I am aware that the master key has changed (which is not the case, when you just change the password), but AFAIK there are certain techniques...
...to to recover the overwritten header, such as magnetic force microscopy or magnetic force scanning tunneling microscopy.
Would it be safer to chose another password, in case the old header hasn't been overwritten (several times)? An old header would give you the salt for example, with which the old password has been encrypted with.
Bruteforcing would be quicker I guess, since there are two headers to compute the passwords for and not only one (I have 0 experience in this topic, so this is just a very wild guess.).
**2. Question (small one): **
On the webiste, there is this line:
Where exactly is that free space? Where the encrypted data will be saved? Where the header will be placed?
It doesn't get quite clear from the context (for me at least)
Last edit: tesa235 2020-05-12
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Like you, I have zero experience with the minutia of encryption, but unless there are issues beyond what you've described as to why you did what you did, it seems like you expended significant unnecessary time and effort, not to mention inflicting additional stress on your hard drive. You seem to have wanted to do nothing more than install a fresh copy of Windows 10 on an encrypted drive that already had Windows installed. Am I understanding that correctly? Decrypting that drive first was not only unnecessary, but actually put your privacy at risk for a limited time. Before you decrypted it, that data was ONLY accessible to you, using your password/PIM. The safer, quicker method of installing fresh Windows on an encrypted drive is to simply delete any existing partitions from within the Windows setup program itself, and once the drive has nothing but free space, Windows setup continues. It takes only a couple of seconds.
The reason I'm inferring that you were installing fresh Windows is because you formatted and overwrote the system partition multiple times after decryption. All that was completely unnecessary. The only reasons I can think of to permanently decrypt a system partition is 1) perform an in-place Windows upgrade, or 2) shrink or move a partition. Personally, I've never decrypted a partition but I've heard it can take quite awhile. I always install fresh Windows and resize my partitions before encrypting.
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Yes, I understand your reasoning. I was asking myself that question on wether I should decrypt first or not. Then I stumbled upon this in the VeraCrypt FAQs:
If the system partition/drive is encrypted and you want to reinstall or upgrade Windows, you need to decrypt it first (select System > Permanently Decrypt System Partition/Drive).
This is why I did the steps mentioned above. Still doesn't answer my original question though, but thank you for your input, anyways. :)
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello,
I am using VeraCrypt system-encryption.
My system has only one HDD and only one partition on it (= system partition), if that matters.
In order to reinstall Windows 10, I decrypted the VC volume permanently, formated my HDD (overwritten a couple of times), installed Windows 10, installed VC and encrypted my HDD with the same type of encryption as before (system encryption). I also used the same password as before.
1. Question: Is it safe to use the same password as before?
I am aware that the master key has changed (which is not the case, when you just change the password), but AFAIK there are certain techniques...
Source: (https://www.veracrypt.fr/en/Program%20Menu.html)
Would it be safer to chose another password, in case the old header hasn't been overwritten (several times)? An old header would give you the salt for example, with which the old password has been encrypted with.
Bruteforcing would be quicker I guess, since there are two headers to compute the passwords for and not only one (I have 0 experience in this topic, so this is just a very wild guess.).
**2. Question (small one): **
On the webiste, there is this line:
Where exactly is that free space? Where the encrypted data will be saved? Where the header will be placed?
It doesn't get quite clear from the context (for me at least)
Last edit: tesa235 2020-05-12
Like you, I have zero experience with the minutia of encryption, but unless there are issues beyond what you've described as to why you did what you did, it seems like you expended significant unnecessary time and effort, not to mention inflicting additional stress on your hard drive. You seem to have wanted to do nothing more than install a fresh copy of Windows 10 on an encrypted drive that already had Windows installed. Am I understanding that correctly? Decrypting that drive first was not only unnecessary, but actually put your privacy at risk for a limited time. Before you decrypted it, that data was ONLY accessible to you, using your password/PIM. The safer, quicker method of installing fresh Windows on an encrypted drive is to simply delete any existing partitions from within the Windows setup program itself, and once the drive has nothing but free space, Windows setup continues. It takes only a couple of seconds.
The reason I'm inferring that you were installing fresh Windows is because you formatted and overwrote the system partition multiple times after decryption. All that was completely unnecessary. The only reasons I can think of to permanently decrypt a system partition is 1) perform an in-place Windows upgrade, or 2) shrink or move a partition. Personally, I've never decrypted a partition but I've heard it can take quite awhile. I always install fresh Windows and resize my partitions before encrypting.
Yes, I understand your reasoning. I was asking myself that question on wether I should decrypt first or not. Then I stumbled upon this in the VeraCrypt FAQs:
This is why I did the steps mentioned above. Still doesn't answer my original question though, but thank you for your input, anyways. :)