Security Issue: Archive Encryption is not safe?

Hi Max.

Even if someone finds the hash, he/she won't be able to recover the password, because hashing is a one-way mathematical operation nearly impossible (at this time) to revert.

Greetings

Are you kidding me?
I quoted text above, have you seen it?
========The encryption key is then encrypted with AES-256 using a SHA-256 hash of the password as a key.==========
That means, if you have hash, you can decrypt encryption key and eventially decrypt entire archive!

Hello Max,

Thank you very much for opening this thread.

Hyphen Italia is correct in his statements, but I will try to explain it better.

Acronis uses AES-256, which is a government grade encryption algorithm. This algorithm is symmetric, which means that the same key is used to encrypt and decrypt the data.

So, imagine that you want to create an encrypted archive with Acronis. The program will generate a random encryption key (let's call it "key A"). This is the one that will be used to encrypt and decrypt the data from the archive.

"Key A" is, again, encrypted using AES-256 algorithm. In this case, the key to encrypt "key A" is calculated from what you enter in the "password" field. We create a hash value of that password, which will create a "key B".

"Key B" is used to encrypt "Key A", and the resulting "encrypted Key A" is stored in the archive.

Should you know "encrypted key A", you will not be able to decrypt the entire archive. You will need to first decrypt "key A". The information needed to decrypt "key A" is not stored anywhere in the archive, and it is only calculated from the password that you enter.

Please, if you have any other question or concern, do not hesitate in letting us know. We will be glad to assist you further.

We are looking forward to hearing from you.

Thanks,
Asier

=== The information needed to decrypt "key A" is not stored anywhere in the archive, and it is only calculated from the password that you enter.===

Yes, it's 'SHA-256 hash of the password', right? And, as far as I understood, it's stored somewhere in AB&R10 settings, right? This allow AB&R10 request password only once, and then encrypt archive as many times as needed. And "If malefactor will have access to your computer with AB&R10, he will be able to recover password hash and with it decrypt secret backup archive", because he will get 'SHA-256 hash of the password' stored in AB&R10 settings, right? Because, if AB&R10 do not store 'SHA-256 hash of the password' in its settings, it must re-request password every time it encrypt a volume, right?

Hello Max,

What you mentioned is what I called "key B". This key is not stored anywhere, neither in the archive, nor anywhere else.

The "key B" is calculated on the fly from the password that you enter.

Let me know if you have any other question. I will be glad to assist you further.

Thank,
Asier

If the key hash not stored anywhere, AB&R have to ask for password every time it encrypt archive, right?

Hello, Acronis guys! Answer a few question please:

1) If password or password hash (key B) is not stored anywhere on the disk, you have to ask password every time task is started? Otherwise you cannot encrypt key A, and then encrypt archive?

2) If password or password hash (key B) is stored in AB&R settings, it's possible, if malefactor has access to you computer, for him to decrypt key A and eventually decrypt entire archive?

Hello Max,

I am sorry for the delayed answer.

Let me clarify all your questions and concerns.

What is more important is to secure then content of the backup archive.

So, regarding your questions:

1. We store the hashed password (key B) with the backup plan. The reason is that if you schedule an encrypted backup at 1am every day, you do not want to connect to the server at 1am in order to enter the password.

2. This question is related to your first question. In order to find out key B, you should be able to have the same access privileges as the user that created the backup plan. In other words, if you schedule a backup, to be able to find out key B, you need to have the same access credentials, which means that you already have access to all the data that was backed up.

In any case, even if somebody was able to find key B, this would not allow him to decrypt the archive.

The Acronis backup archive is a complex structure that contains not only the data, but a lot of metadata that is used to open the archive. The only way to open the archive is to use the Acronis low level mount driver, which is capable of reading the metadata.

When you try to open an encrypted backup archive, our low level driver detects it, and it asks for the original password, not key B. This means that if you supply, at this stage, key B, you will not be able to decrypt the archive.

Max, feel free to ask any other question regarding this topic.

Thanks,
Asier

Thanks for the answers!

Q: In what file exactly backup plan is stored?