All Questions
Tagged with file-encryption aes
60 questions
3
votes
1
answer
585
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 ...
- 43
0
votes
1
answer
985
views
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 ...
0
votes
3
answers
3k
views
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 ...
1
vote
0
answers
43
views
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, ...
- 123
2
votes
2
answers
1k
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 ...
- 21
1
vote
1
answer
210
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 ...
- 19
1
vote
3
answers
5k
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 ...
2
votes
2
answers
3k
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 ...
- 553
0
votes
2
answers
159
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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 ...
- 553
2
votes
1
answer
475
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 ...
- 553
2
votes
1
answer
75
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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 ...
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 ...
- 133
1
vote
1
answer
635
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 ...
- 123
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 ...
- 141
1
vote
2
answers
156
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?
Tariq Hasan
1
vote
0
answers
86
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?
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2
votes
2
answers
281
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 ...
4
votes
1
answer
3k
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 ...
-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 ...
3
votes
1
answer
3k
views
In GnuPG, what's the difference between --s2k-cipher-algo and --cipher-algo? [duplicate]
I want to change some encryption options while using GnuPG to encrypt a file symmetrically.
1) However, for choosing the cipher algorithm, GnuPG has two commands and I don't know which one to use.
...
- 45
0
votes
1
answer
391
views
Best practices when encrypting a file with three different ciphers [closed]
I have some files that contain important information, so I want to encrypt them by the most secure encryption method possible.
I've read countless StackExchange answers on similar questions and some ...
- 45
3
votes
2
answers
6k
views
What is a good AES mode to use on file encryption?
I'm new to encryption and cryptography, I was wondering if there is a good or best suited AES mode for file encryption (Planning on zipping a folder and encrypt it as a file). If there is, how complex ...
- 31
1
vote
1
answer
89
views
Which symmetric algorithm should I use for storing files in untrusted servers?
I have gigabites of files, which I have to backup. I have some servers for storing this files. But these servers are untrusted. So I need to encrypt files, then backup files. When my PC breaks down, ...
- 111
2
votes
3
answers
703
views
Do I need to generate unique IV for CBC encryption of a file if I encrypt multiple blocks of data?
The situation is that I download a mp3 file (song) and I encrypt blocks of data (4096 bites for example).
The output of every encryption operation I save it in a new file.
When I play the song (...
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-3
votes
1
answer
3k
views
Best complementary algorithm to AES [closed]
I'm looking to protect sensitive data from deletion by hosting it on Amazon Glacier.
I'd like to secure that data against possible hacks of Amazon by encrypting it, and I'd like for the data to be ...
- 97
1
vote
3
answers
372
views
Can multi-encrypted file be decrypted with one password only?
Let's say I have a single file I want to encrypt with AES and I encrypt it twice (first encrypt the unencrypted file, then encrypt the encrypted file again). The first time I use password 'ABC', the ...
- 113
2
votes
0
answers
260
views
Conforming to best practices in password file (keyring) encryption
In order to implement a plaintext password file safe (keyring), while adhering to best Crypto practices today, I came up with this scheme:
A user's master password is hashed with Argon2 (\$argon2id\$...
- 41
2
votes
0
answers
643
views
AES OCB with Argon2 KDF for keyring file encryption
I've just released a python keyring companion package to encrypt the passwords in a file, available here.
Description
The project is mainly targeted to provide a sufficiently secure storage for ...
- 41
12
votes
1
answer
10k
views
What is a safe maximum message size limit when encrypting files to disk with AES-GCM before the need to re-generate the key or NONCE
The general limits from the NIST recommendation are as follows:
Maximum Encrypted Plaintext Size ≤ 239 - 256 bits;
Maximum Processed Additional Authenticated Data ≤ 264 - 1 bits;
This stack ...
- 390
9
votes
3
answers
36k
views
Best way to generate a IV for AES-CBC when encrypting files?
The situation is that I want to use symmetric encryption to store some info in files. I'm going to use AES-CBC algorithm. The user is going to remember the password (meaning it will not be stored ...
- 193
2
votes
1
answer
256
views
Is this cascading encryption, and is my security weakened as a result?
I'm trying to understand what is, and what is not, considered cascading encryption. All of the posts and conversations I've read over the past few days discourage the practice, including this article. ...
- 21
0
votes
2
answers
1k
views
Password in first line of file for AES-256 encryption
I'm using openssl with aes-256-cbc encryption to encrypt a file. The password is on the first line of the file and the ...
- 13
2
votes
1
answer
2k
views
Best practises to generate IV for AES-CTR in this scenario
I'm building a cloud storage application that will store files on my servers.
I want these files to be encrypted with AES in CTR mode and the key will be always the same.
I'm wondering what would be ...
- 23
2
votes
1
answer
2k
views
Can a file encrypted with one tool be decrypted with different tool? [closed]
I'm new to cryptography and I'm trying implement a file encryption feature into a Python program but I'm running into a big issue...what is needed for someone else to decrypt the file?! Obviously, I ...
- 41
2
votes
1
answer
2k
views
What is required to decrypt an encrypted file?
At the risk of sounding stupid and being laughed at...I must ask this question. What is required to decrypt an encrypted file? Obviously you need the appropriate key to decrypt, but is any other ...
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8
votes
4
answers
2k
views
Switching between AES and a highly performant algorithm
I want to de/encrypt several binary files rather frequently on a normally battery-powered device. My goal is to use AES-256 when the device is AC-powered and a highly performant algorithm when it's ...
- 473
3
votes
1
answer
1k
views
File encryption with AES CTR mode
I understand that encrypting files in CTR mode is not perfectly safe, because it potentially leaves the files open for cryptanalysis, if the attacker has access to previous versions of the same files. ...
- 31
1
vote
1
answer
3k
views
What do I use as the encryption key and initialization vector in AES cfb128
I'm writing a program that can encrypt a file using AES cfb128 (using Openssl and C++).
The scenario of the program is this:
Person A visits computer, encrypts a file they make, takes away a key (on ...
- 255
1
vote
0
answers
784
views
FileVault AES-XTS decryption with cipher text that's missing a part
My mac was recently upgraded to OS X Yosemite and FileVault2 full disk encryption was turned on. Encryption finished, but things went horribly wrong and key parts of the disk are filled with all 0s (...
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17
votes
2
answers
71k
views
Twofish vs. Serpent vs. AES (or a combo)
I've seen some posts and info online, but they are from 2009, 2010, 2011 or 2012, which is 3-6 years ago, which is a very long time. So I'm looking for an up-to-date answer about which of these is the ...
- 273
-1
votes
4
answers
5k
views
Secure way to encrypt and decrypt a folder on Mac or Linux? [closed]
I am looking for a way to securely encrypt files on Mac and Debian. OpenSSL comes pre-installed on Mac OSX and Debian/Ubuntu. Therefore, is this a safe/recommended way of encrypting individual files? (...
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2
votes
1
answer
2k
views
How secure is file header encryption for large files?
I'm having trouble location information about whether or not encrypting a file's header is good enough. The files in question are media files that range in size from 500mb to 4GB.
If I had no ...
- 121
1
vote
2
answers
3k
views
How to handle authenticated encryption for big files?
First I need to mention that I can't use BouncyCastle to implement this solution.
I have to encrypt files into the file system. Those files are not going to be tranfered over the wire to any other ...
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10
votes
3
answers
16k
views
Encryption of big files in Java with AES/GCM
I have to encrypt big files. Say their size ranges from 500mb to several of gigabytes.
I would like to use AES/GCM/NoPadding as provided by Java 1.8 since that gives me automatic authentication and ...
- 127
4
votes
2
answers
5k
views
How to encrypt a file for random access
I am a programmer familiar with C/C++ and Python. Lately, we got an assignment from a team asking us to work on one of their projects: we need to make a small program to encrypt a large file using ...
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6
votes
0
answers
585
views
File Encryption (EFS method)
I'm implementing (for learning purposes) a file encryptor, which uses the following method (from http://en.wikipedia.org/wiki/Encrypting_File_System). I have 3 kinds of keys: RSA public/private, AES, ...
- 203
2
votes
1
answer
2k
views
AES mode for file encryption
I'm working on software that should eventually result in a crypto file system similar to encfs. So far, i have a user password that goes through PBKDF2 using
...
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3
votes
2
answers
580
views
How to design a cryptographically secure file hosting service
How would one go about designing something like Google Drive/Dropbox providing the following features:
files are encrypted and decrypted on the client
files can be synced between devices
the service ...
- 237
6
votes
1
answer
2k
views
AES file encryption with PBKDF2. Safe parameters?
I'm developing an application that will use public key authentication to contact some webservice. So the user has his keypair on his computer, and I want that file to be encrypted using AES with a key ...
3
votes
4
answers
2k
views
Non-malleable file encryption using AES XTS 256?
I'm looking to do file encryption of a bunch of individual files, some small, some quite large. The files will be write-once/read-many, so I could use CBC, however, since the read-access needs to ...
- 139