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Questions tagged [file-encryption]

The process of encrypting individual files on a storage medium and permitting access to the encrypted data only after proper authentication is provided.

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ChaCha20 1Gb encryption speed question

I wrote a simple implementation of ChaCha20 encryptor for files in C using MbedTLS implementation. The process of encryption is standard - I set key, then for each block of fixed size I generate new ...
Enty AV's user avatar
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Why does symmetric encryption not provide authentication and integrity? Is it only this type of encryption or cryptology in general have this issue?

Studying for Cryptology and came across a presentation regarding on "Integrity vs Authenticity" where the discussion briefly mentions how Encryption "does not provide integrity or ...
omar7439's user avatar
3 votes
1 answer
416 views

Is there any way to measure entropy of encryption algorithms in python?

I am new to cryptography and I am trying to find a way to measure ciphertext entropy of encryption algorithms such as AES, Chacha20, etc for a school project. Is there any way to do it on Python? I ...
Jake's user avatar
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2 votes
1 answer
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Would encrypting several layers of a filesystem be a waste?

I've been thinking about ways to improve the security of my data stored and backed up using the "3-2-1" method. Moreover by using several layers of encryption to encrypt and decrypt a ...
Xcrowzz's user avatar
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-1 votes
1 answer
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What's the best encryption algorithm for storing files on a server?

I'm making a cloud-based service. So, basically, my users will be able to upload files (any type of files) and they will be uploaded to a server. I am aware that I have two options: Upload the files ...
Gaurav Mall's user avatar
2 votes
3 answers
177 views

Long Random Key and XOR - How Secure?

I have an application that encrypts files in the following manner (I think I can hear sighs already but bear with me): Start with two byte arrays generated from random strings of lengths l1 and l2 (...
mrrrk's user avatar
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1 answer
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Deterministic salt for KDF

What would be recommended way to make deterministic password based file encryption? I can use SIV mode, but KDF (like Argon) takes salt for which I could use SIV tag, but I cannot make it because I ...
LightBit's user avatar
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File Size Shrinks After Encryption

I am a Bitcoin enthusiast, but I have never been formally trained in the study of computer science and cryptography. Recently, I tried a new way to encrypt my private key: I wrote it down on a paper, ...
Valac's user avatar
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1 answer
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Encrypt multiple chunks of data with an AEAD

Assuming that I want to encrypt a 1 GB file with e.g. AES in GCM mode or ChaCha20Poly1305. [I'm specifically referring to the cryptography module for Python: https://cryptography.io/en/latest/hazmat/...
Missionar's user avatar
-1 votes
2 answers
1k views

Can I 100% trust the PBKDF2(HMAC-SHA256) AES-256 CBC encryption algorithm for file encryption purposes or not, and why? (Winrar) [closed]

I am not an expert in cryptography and therefore I would like to address this problem to people who have been working on this topic for a long time and thus verify the facts from several sources. I ...
Hasbo's user avatar
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1 answer
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GnuPG - provide encryption key for AES rather than deriving it from passphrase

I'd like to encrypt a file with AES256 and provide my own 32-bytes for the encryption, rather than having GPG derive it from the passphrase. I could not find such option, but I'm thinking about a ...
Slimevine's user avatar
1 vote
1 answer
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multi-user deterministic symmetric encryption

I was wondering whether there exists a symmetric encryption scheme such that there is 1 sender and n receivers. Each receiver has 1 random and independent symmetric key. The sender knows the ...
M.Z.'s user avatar
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2 votes
1 answer
109 views

Get Pixel Data from JPG/JPEG but still bring the integrity? [closed]

As far as I know, JPG is a lossy image compression format Meanwhile, BMP is a generally uncompressed image format, whose file structure consists of bitmapFileHeader (14 bytes) and bitmapInfoHeader (40 ...
akez's user avatar
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2 answers
737 views

Hash Comparison to Detect Ransomware File Encryption

As detailed in a separate question, I thought I had a way to detect the type of ransomware that encrypts files silently, and then decrypts them on the fly, so as to prevent the user from realizing ...
Ray Woodcock's user avatar
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Is CBC mode of encryption still safe as long as it's not use to send messages over a network?

I'm still reading about the Padding Oracle attack and Side Channel attack that can be performed to decrypt cipher text encrypted with CBC though it's still not clear to me. But base on my little ...
0xdeadbeef's user avatar
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Does using ECB mode of Vigenère cipher on files (no plain text) with a key of 10,000 byte(char) is secure in today's standard?

Hi I'm fairly new to studying cryptography and I'm just curious about the security of Vigenère cipher. Given today's powerful super computers, how secure/unsecure does Vigenère cipher can get? let us ...
0xdeadbeef's user avatar
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3 answers
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Encryption using ASCII instead of bits and bytes (clarification in the body)

I am new to cryptography and I am trying to understand something. I searched it on the internet, though the question is probably a simple one, couldn't find an answer. So, please don't judge me by ...
Electricity's user avatar
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How does encryption systems encrypt strings? (More clarification in the explanation) [duplicate]

I am new to cryptography and I am trying to understand something. I searched it on the internet, though the question is a simple one, couldn't find an answer. So, please don't judge me by that. Here ...
Electricity's user avatar
2 votes
1 answer
3k views

Why use ASCII armor for file encryption?

GPG and age both offer a --armor option but what is the use case when it comes to file encryption? Surely most channels allow for transmitting binary data nowadays? ...
guest's user avatar
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1 vote
0 answers
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Does my asymmetric/symmetric mixed file encryption pseudo code pass sanity check?

I realize this depends on my implementation and the implementation of the libraries I use. I am asking about my process assuming that the encryption libraries and my code are not flawed/compromised, ...
Stoopkid's user avatar
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1 answer
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Faster alternatives to RSA trapdoor permutation

We're working on web3.0 decentralized internet, a big part of which is a decentralized file storage system where clients upload files to storage providers and pay them for the services. Storage ...
Serge Uvarov's user avatar
1 vote
1 answer
249 views

How to hide multiple types of information in the same file?

I have a vague memory of watching a video of a guy "unraveling the secret story / lore" from the game Doki Doki Literature Club. And I remember that he took a file, converted it to .txt and ...
MessiasOF's user avatar
2 votes
2 answers
768 views

How much data can we encrypt using AES 256 before changing the key?

Although this question has been answered in this link (After How Much Data Encryption (AES-256) we should change key?), I am not satisfied with the answers because the Recommendation for Block Cipher ...
user48217's user avatar
1 vote
1 answer
197 views

Low Encrypted Entropy on PDF File

Thank you for the answers, I have edited my questions. It is a known fact that encrypting the files increases the file entropy. You can see the average entropy values of encrypted and non-encrypted ...
kkk001's user avatar
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3 votes
2 answers
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What are best practices for long term storage (~20 years) of encrypted / sensitive files?

I have some very sensitive family files that I want to store in the cloud on multiple providers for maximal reliability and redundancy. It's essentially a large archive of all our family photos, ...
Evan Su's user avatar
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1 answer
283 views

Making a secure file sharing scheme usable

I am trying to realize a secure file sharing scheme based on asymmetric crypto. Users will access this via browser. In short, it works like this: Users register and set their username and password. ...
Theodor Straube's user avatar
1 vote
3 answers
3k views

What's the preferable encryption for large data and files in terms of speed and security other than AES?

First of all, I'm relatively new to encryption so please bear with me. I'm looking for a way to encrypt large amounts of data only on my device, no need to transfer my encrypted files/data (10-20GB or ...
Ilkay Solotov's user avatar
2 votes
2 answers
2k views

Encrypt a big file in blocks with AES-GCM: how many nonce do we need?

I need to encrypt big files using AES-GCM, potentially 10 GB or more. For memory (RAM) reasons, I need to processs them by blocks (let's say 16 MB), rather than doing ...
Basj's user avatar
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0 votes
2 answers
146 views

How to be able to change the password to access data encrypted with AES-GCM, without reencrypting?

Let's say you need to encrypt plaintext which is 1 TB big. You have a password pwd. This very classical AES-GCM process is ...
Basj's user avatar
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2 votes
1 answer
453 views

How to encrypt many files with AES-GCM, without running the key derivation function each time?

Linked question: AES encrypting multiple files With a password, I have 100k files to encrypt. (Maybe 100k files today; or maybe 50k today, 10k tomorrow, and 40k ...
Basj's user avatar
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0 answers
109 views

How secure is the encryption with OTP and an OneRNG?

I bought an HWRND last week. What do you think, how secure is the encryption with that and the OTP? See the OneRNG theory of operation here.
TheDummy's user avatar
2 votes
1 answer
72 views

End-to-end photo storage

I've been tasked with developing an app that will need to store photos a user takes securely, and I've been struggling to think up a method to do this. What I was thinking so far is as follows: When ...
George Herbert's user avatar
3 votes
1 answer
1k views

Is it dangerous to encrypt lots of small files with the same key?

I want to encrypt 1000s of old files on old hard drives before uploading them to the cloud. I'm planning to use AES-GCM with only one or a few keys. (I'm using Apple's CryptoKit library which provides ...
Rob N's user avatar
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3 votes
1 answer
523 views

AES-CTR security if S-boxes substituion is omitted?

I understand why s-boxes are needed in general especially when ECB mode is used(because of using the same key for encryption of other blocks)but I wonder if it's ...
KMG's user avatar
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1 vote
1 answer
559 views

How do I safely encrypt a file for transport and storage?

So I need to encrypt a file server-side for transport from server to client and storage on client-side. I'm quite confused as to what I have to watch out for, as it seems like it's insanely easy to ...
thebear8's user avatar
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0 votes
0 answers
40 views

How Should Form Input be Encrypted for sending to a Server?

I apologise if this question is a duplicate. I couldn't find any similar questions. I am writing a web app that consists of a series of drop-down style question menus. These generate more drop-downs ...
Huw Evans's user avatar
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2 votes
1 answer
107 views

Can I use my own implementation of a widely used, supposedly secure cryptographic algorithm for securing data at rest?

I know you shouldn't roll your own crypto and generally its not a good idea to implement (and then deploy) any extensively tested and recommended algorithms by yourself either. I have already seen ...
nobody's user avatar
  • 133
4 votes
1 answer
4k views

Proper way of encrypting large files with AES-256-GCM

I would like to encrypt and decrypt files with AES-256-GCM. I need a solution that works with Java, PHP and JavaScript. In practice, users can upload, download files via web browser and/or desktop app ...
Vmxes's user avatar
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0 votes
1 answer
294 views

Reducing a 64 digit integer to 10 digit

Situation:- I am using Python. I am using RSA and I am using two 64 bit keys. I am not an cryptographer . I can provide you the RSA code if needed but i am not posting it as it doesn't have to do ...
Ritvik's user avatar
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1 vote
2 answers
148 views

Does encrypting different versions of the same file or folder with the same key make it easier for hackers to attempt the decoding?

Assuming the hacker has access to the ciphers of each of the versions, will it help him/her to decipher the original file(s) by doing some sort of comparison of the ciphers?
user avatar
2 votes
1 answer
356 views

Does Encryption add difficulties to File Recovery?

Seems Yes. People always tell us, it is very hard (or almost impossible) to recover an encrypted hard disk. But after a second thought. I think this is not true. Given that we know the KEY, and the ...
midnite's user avatar
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1 vote
0 answers
68 views

How to crack rar file with protected pass with only the AES-256 key [closed]

I have rar with protected pass.But I have the AES-256 key can I crack it and if I can. how?
עידן כהן's user avatar
2 votes
2 answers
276 views

Is this correct/incorrect password for file encryption scheme secure?

I'm writing an AES file encryption program, and I'd like to put in a way to tell whether or not the user has entered the correct password without decrypting the entire file and GCM telling me the tag ...
LittleBlueDragon's user avatar
0 votes
0 answers
69 views

How to recover deleted-recovered windows efs-encrypted files?

I'd some EFS-encrypted files on a HDD which were deleted unintentionally. I used a data recovery software to restore them, but afterward, windows does not recognize those recovered files as encrypted ...
Ehsan Khodarahmi's user avatar
-1 votes
1 answer
58 views

What are the general rules to follow if I want to design a block cipher suitable for file encryption? [duplicate]

Can you please tell me what should be the quality of an encryption function using a key size of 256 bits... I realized from my previous question that a simple XOR of plaintext (256 bits) with a ...
Aravind A's user avatar
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3 votes
1 answer
77 views

Isn't the use of public key encryption a redundant step in Encrypting File System, which doesn't improve the security of the File Encryption Key?

With EFS, we know that a symmetric key, File Encryption Key (FEK), is used for encrypting files. The FEK is then protected by encrypting it with the public key of the user that can be recovered by ...
Newbie's user avatar
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1 vote
0 answers
112 views

Safest method for encrypting a file on a local machine

I am looking for a safe method to encrypt a local file on my machine. Let's say I have a file containing my logins and passwords -- how can I make sure that the encryption is reasonably sufficient in ...
Proto Ukr's user avatar
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4 votes
1 answer
2k views

How does gpg know what cipher algorithm is needed for decryption?

I am using gpg to make encrypt a tar.gz. My first try uses --verbose --symmetric and then the decryption is done with ...
Trevor Boyd Smith's user avatar
-2 votes
1 answer
2k views

AES encryption with 2048-bit RSA key

I have the following draft to keep my data secure in transit. Generate 2048 bit RSA key sha256sum that private key and use that sum as aad, key and iv parameters in the following aes encryption ...
kurt hectic's user avatar
18 votes
7 answers
20k views

How to check a file was encrypted (really & correctly)

I would like to audit how an implementation of an encryption algorithm is really performed with the following given data of the problem: the encryption mechanism is reversible (this isn’t a signature)...
dan's user avatar
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