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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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A specific way for deniable encryption

I read the summary of deniable encryption on wikipedia: https://en.wikipedia.org/wiki/Deniable_encryption Then I read a question, by doom123 on security.SE: https:/...
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1answer
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Learning to encrypt/encryption algorithms [closed]

I am a beginning programmer interested in coding an application of my own to encrypt sensitive files of mine. For example: lists of passwords, bank accounts, Credit Card numbers etc. I was wondering ...
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Is the decompression of compressed and encrypted data without decryption also theoretically impossible?

We have two communication points in an information system, call them A(lice) and B(ackup). B has to store encrypted data received from A. The storage of B is encrypted, but not compressed1. B should ...
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Is EFS vulnerable to chosen plaintext attack?

I have some backup files encrypted with EFS, but I lost the EFS certificate--thus I am unable to decrypt the files. I understand that EFS uses the user certificate public key to encrypt the symmetric ...
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1answer
76 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 ...
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1answer
343 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. ...
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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 ...
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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)...
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Encrypting (CBC) identical files with same key and different IV, is it less secure?

I would like to learn more about cryptography. Let's say you encrypt multiple files with CBC encryption using the same key, but each file has a unique (and pseudorandom) IV. Does this weaken the ...
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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 ...
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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 ...
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1answer
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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 ...
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1answer
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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 ...
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4answers
857 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 ...
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2answers
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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 ...
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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 $d = 2319725$. [...
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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 ...
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1answer
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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, ...
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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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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?
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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 ...
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1answer
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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 ...
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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 ...
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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 ...
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1answer
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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 ...
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3answers
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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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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 ...
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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 ...
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1answer
794 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 ...
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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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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 ...
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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 ...
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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 ...
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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 ...
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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\$...
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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 ...
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1answer
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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 ...
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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 ...
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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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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 ...
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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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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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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 ...
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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 ...
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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 ...