Questions tagged [xts]
XTS is a block cipher mode of operation, which is most commonly used when random accessible data (like a hard disk or RAM) is to be encoded.
49 questions
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XTS/XEX mode encrypt/decrypt on partial sector
If I understand correctly, XEX/XTS use a second key to create a "tweak" XORed with the plaintext before and after encryption. The tweak input starts with the encrypted sector number, but is ...
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2 votes
1 answer
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Tweakable block cipher & XTS for FDE?
When you have a tweakable block cipher such as Threefish and your objective is full disk encryption: Is XTS mode unnecessary? Do you just use the block-length data address (sector + offset, etc) as ...
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5 votes
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Why was Adiantum chosen over an ARX block cipher in XTS mode?
In Android, Adiantum is an alternative to AES-XTS for devices without AES instructions. I cannot understand the reason for why such a convoluted scheme was chosen. There are 128-bit ARX block ciphers ...
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0 votes
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Is it possible for XTS to use two different key sizes?
As an example could be XTS with a 512-bit key that treats the key as one 128-bit key and one 348-bit key. As to why I'm asking it's because XTS runs on one large key that it treats like two keys. ...
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Required Block Size for XTS Using MSFT CNG
I am struggling with using Microsoft's BCrypt library in AES-XTS mode. I've confirmed that the Cipher Block Size is 16 bytes (by getting the BCRYPT_BLOCK_LENGTH property). I'm setting the Data Unit ...
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Disk encryption and advanced format
As far as I understand, the biggest problem of requesting authentication in disk encryption is that the plaintext and ciphertext are not having the same size -because of tag-. The XTS mode is already ...
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Authenticated Encryption with Length Expansion for Storage Devices
Recently, I've been working on disk encryption. I started with the AES-XTS mode which is the standard for this purpose and tried to understand the concept of disk encryption in general. I know that ...
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2 votes
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Why is using ChaCha20 for disk encryption insecure?
https://en.wikipedia.org/wiki/Disk_encryption_theory Why do we use XTS over CTR for disk encryption? If we used ChaCha20 (without authentication) by simply encrypting each disk sector with the same ...
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1 vote
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Is multiple encryption with XTS mode susceptible to Meet-in-the-middle attacks?
Let's suppose I encrypt something with AES-256 in XTS mode two times (there will be 4 four keys, 2 for each encryption operation), wanting to achive 512-bits of security. Will this scheme be ...
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1 vote
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Is it OK to use a doubled key for XTS-AES?
https://en.wikipedia.org/wiki/Disk_encryption_theory#Xor%E2%80%93encrypt%E2%80%93xor_(XEX) reads: The standard supports using a different key for the IV encryption than for the block encryption; this ...
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1 vote
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Can XEX or XTS modes be used with only one tweak? (part 2)
This question is similar to Can XEX or XTS modes be used with only one tweak? except I am interested to know if one can instead use $X = E_{k}(0) \otimes \alpha^j \\ C = E_{k}(P \oplus X) \oplus X$ in ...
4 votes
1 answer
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Is XTS always better than GCM?
XTS is suitable for disk encryption while GCM doesn't. Both require the same number of block encryption calls. Both are parallel in encryption and decryption. XTS is actually even faster in openssl ...
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Should I be worried about XTS tampering when encrypting backups using VeraCrypt?
From Wikipedia: XTS mode is susceptible to data manipulation and tampering, and applications must employ measures to detect modifications of data if manipulation and tampering is a concern: "......
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1 vote
1 answer
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EAX vs CTR vs XTS + cascade ciphers in disk encryption hell
Often when I stumble across something interesting, I lose myself in the most overkill ways of implementing it. Today it was full disk encryption: I'm about to move to QubesOS, and I want to secure my ...
user80551
0 votes
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Is XEX/XTS good for deterministic file encryption?
My understanding about XEX/XTS mode is limited. But from what I see, it has two good properties: It is length-preserving so that encryption doesn't cost additional space. It is deterministic, which is ...
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