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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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Which algorithm is safest if we exclude AES, Twofish, Serpent and Whirpool? [closed]

TLDR: Which algorithm is safest if we exclude AES, Twofish, Serpent and Whirpool? Full version: Hello, my threat model is archiving and backing up important and private files. Files will be stored ...
2
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1answer
78 views

How to encrypt sensitive files in a business application? Is it needed? [closed]

I'm currently working on a business Java application, and we store sensitive files related to our users. What is the appropriate approach to store them securely? Is it viable to encrypt/decrypt all ...
2
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1answer
66 views

Authenticated encryption and file data integrity

I've got a task to provide the integrity and an authenticated encryption for files in our application. I need an assurance if my way of thinking is correct. I can't use AES GCM, I have to stay with ...
3
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4answers
718 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 ...
2
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2answers
211 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 ...
0
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0answers
47 views

Verifying valid public key and finding private key? [duplicate]

A naive user of RSA has announced the public key $n = 2903239, e = 5$. Eve has worked out that $n = 1237×2347$. Verify that the public key is valid and explain why the private key is $d = 2319725$. [...
46
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2answers
97k views

What is safer: ZipCrypto or AES-256?

Like in title: which one of these encryption methods (ZipCrypto, AES-256) is more secure and why? I am asking about it because I'd like to know which should be preferred when compressing files with ...
1
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2answers
113 views

How secure is a system that retrieves encrypted private keys from a public database?

The system in question is one with multiple users. Each user has a password associated with their account, and each user owns several public-private keypairs. A user's private keys are encrypted using ...
0
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1answer
56 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, ...
4
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3answers
516 views

Reusing IV in AES for encrypting file

Everyone says that you shouldn't use the same IV and Key. Is it safe to use the same IV and Key on only one file. EDIT: I will be using CBC or CFB encryption modes so the IV will be updated based on ...
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2answers
380 views

Rsa encryption security

What tool is used to measure the security of rsa encryption? If no, is there any tool to measure rsa encryption in terms of security. Or any idea how to measure security of rsa encryption?
1
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1answer
80 views

Robust cryptosystem for files/chunks protection?

I'm not a cryptographic expert by far but I do understand that when it comes to cryptography it's best to stick with established standards. I have to ensure confidentiality and integrity of a bunch ...
1
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1answer
315 views

Why does Apple use One-Pass Diffie-Hellman for file encryption?

I was reading the iOS Security Guide (snapshot) and stumbled upon the following file protection class on page 15: (NSFileProtectionCompleteUnlessOpen): Some files may need to be written while the ...
14
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2answers
47k 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 ...
9
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5answers
5k views

Tamper-proofing log files

Problem Overview I want to securely store log files so the contents are secret, and they can't be modified without detection. The files will be encrypted using authenticated encryption (AES in GCM ...
0
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1answer
57 views

A file chunk in a group/field

I am reading a paper by Shacham and Waters on Compact Proofs of Retrievability. In this paper on page number 3 under section 1.1 in the very first line the author states that an encoded file is broken ...
3
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3answers
451 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 (...
1
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2answers
200 views

Can a hash of the original plain text file be used to brute force an encrypted copy?

I have encrypted files stored on a public cloud, in the same directory on the cloud I have the sha256 hash of the files before they were encrypted in a text file. The keys used to encrypt the files ...
3
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2answers
397 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 ...
1
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1answer
528 views

Simple secret key encryption with PyNaCl [closed]

I am playing around with PyNaCl to get a bit into cryptography atm. Now I wrote two scripts to encrypt a file with a secret key and then decrypt it again using that key. The encryption part works ...
6
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3answers
2k views

Can elliptic curve (25519) be used to encrypt file?

This is probably a simple question, but I haven't been able to see it stated anywhere. Is it possible to directly encrypt a file (of any length) with some form of EC using the 25519 curve. I know it'...
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1answer
641 views

Best complementary algorithm to AES

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 ...
0
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3answers
2k views

how much is secure to encrypt a password using itself (as encryption key) for storing it on an insecure media?

I want to store a password securely on a storage (suppose in a usual unencrypted file). I use this password as AES key to encrypt itself (using AES-ECB) & then store it on the media (the password ...
0
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1answer
111 views

What is the fuss about 'dot blockchain' and music metadata? [closed]

and how does it work? http://wmot.org/post/music-money-and-metadata-promise-blockchain#stream/0 claims that this is an answer to the metadata woes of the music/recorded media industry. I don't see ...
1
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3answers
107 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 ...
2
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0answers
177 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\$...
2
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0answers
359 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 ...
2
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1answer
489 views

Can I use a deterministic NONCE for AES-GCM file encryption if I generate “fresh” keys for each encrypted file

The NIST specification states that the deterministic NONCE(IV) should be 96 bits. It should consist of two fields: fixed field of 32 bits and a 64 bit counter. The use of a random 96 bit NONCE is ...
8
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1answer
3k 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 ...
6
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1answer
464 views

Derivation of many (Key, IV) pairs from random 128 nonces and one secret 512 master key

The ext4 encryption system encrypt files with aes-256-xts. Each file uses two unique keys which are derived from a 512 bit master key and a per-file 128 bit nonce randomly generated when the file is ...
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1answer
72 views

Warding an ECIES setup against MitM: ECDSA?

Is it necessary/appropriate to digitally sign an ETM file in an ECIES context? The encryption mode is CTR(using Inferno). The current output is: [shared public key] [ciphertext] [MAC]. The encrypted ...
0
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1answer
207 views

Implementing Inferno's ECIES: Creating a symmetric key from sender's public key [closed]

I'm coding(in C#) an offline(no network or server), hybrid file encryption app, implementing Inferno's ECIES. The user's private key is to be stored either on the pc drive or on a usb key, after ...
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2answers
2k 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 ...
0
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1answer
185 views

How to effectively apply combination of Block and Stream Cipher?

I have used TrueCrypt but it uses a cascaded encryption. I want to know about encrypting a file using two ciphers with each cipher having different key. Cipher A (Block Cipher) - with Key KA Cipher ...
8
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4answers
1k views

Does exposing algorithm, key size and IV weaken the security?

I am using an encryption program to encrypt my documents. Previously I have used PGP and AxCrypt, so I just wanted to see how this new tool encrypts the file. This tool is keeping parameters like ...
5
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3answers
10k 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 ...
5
votes
4answers
1k views

Alternative to NSA encryption algorithm

I am looking for a strong alternative to elliptic curve cryptography. It should be something that could face quantum computing attacks, but nothing created by the NSA. I heard about isogeny key ...
5
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2answers
2k views

Would it be better to split a file and then encrypt, or vice versa?

Assuming that you are paranoid before storing your file (distributed across a shared location), which will be the best case scenario: splitting the file first and then encrypting or encrypting first ...
1
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1answer
55 views

Crypto lib that use files instead of passphrase [closed]

I would like to program an application to allow people to encrypt files without using a password or pass-phrase but an arbitrary long file. I'm searching for a library that allows me to safely create ...
2
votes
1answer
163 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. ...
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1answer
253 views

I homebrewed an algorithm. Is it secure?

This is a bit of a cross-posted question which I first asked at StackOverflow, however I was not satisfied with stackoverflow, so I came here for an in depth answer. I, as they say, "rolled my own ...
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2answers
104 views

Using what we already know about the data to decrypt it?

Are there any methods or tools out there that let us use what we know about the data in order to crack the encryption? For example let's say I get access to an encrypted database file but I know ...
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1answer
794 views

can pdfcrack software crack a 128 bit encrypted pdf file

One day ago,i downloaded a pdf that requires password then i search a software to decrypt the password that's s/w called pdfcrack Then i install pdfcrack and run a cmd in terminal pdfcrack -f ...
4
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1answer
222 views

(How) Can we use HOTP for file encryption?

I recently went through the list of available KeePass plug-ins and noticed one that advertises support for HOTP as a means to derive the database key. Now I trust the developer of this plug-in who is ...
2
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1answer
2k views

Encryting data with password for local storage using libsodium

I want to encrypt data that is stored on the hard disk using a user-entered password. For this I look into the sodium docs and all I can find for symmetric encryption is authenticated encryption. ...
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1answer
504 views

Dangers of using CTR mode for encryption

I know that it is never suggested to use the same key or key/IV pair twice for a stream cipher or for a block cipher operating in CTR mode. Filesystem-level encryption reuses the same key for a file ...
0
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1answer
90 views

Considerations on using a single long-term key for file encryption

I'm thinking about designing my own container file format that allows me to store a file in it along with, say, a thumbnail or other metadata. Some of these files are confidential and therefore must ...
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0answers
1k views

Using RSA key pair for file encryption [closed]

I'm looking for a way to perform encrypted nightly backups of a server I administer, without storing the decryption key on the server. A form of PK encryption seems ideal for this, as I can store the ...
0
votes
2answers
432 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 ...
2
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1answer
929 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 ...