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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72 views

Securing a file from getting stolen in an Android application?

I have a secret file which I cannot encrypt (because I am using it in a third party library) in an Android app which I want to protect from reverse engineering. The app will go public on Google Play ...
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226 views

What are `dd` input blocks? [closed]

I'm looking for a semi-technical explanation of "input blocks". When creating encrypted containers we use dd with "count=n", but I'm not sure of the difference between "count=0" and "count=1". The dd ...
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Win10: Access other logged on users' memory

How easily can admin users access the data of other users' running processes on Windows 10? Especially webpages loaded by Chrome. Example Context Bob and Alice share a single Windows 10 ...
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607 views

Should a password based AES CBC encrypted string have extra security?

For a Java application that I wrote, I take a password provided by a user and generate a 128-bit AES key from it using 100,000 iterations of PBKDF2-HMAC-SHA512 with a randomly generated 512-bit salt. ...
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1answer
1k views

Outsmart Google Drive censorship with 7zip encryption

I use sometimes Google Drive for sharing large files. Google Drive is fast and user friendly. I don't wish that Google sees the content of my files and try to encrypt the filename and content. My ...
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2answers
262 views

Encryption before backing up to the Cloud

I have collected a lot of data (approx 3TB) in photos and videos over the years, I've been upgrading to newer and bigger hard disks and luckily they've not failed on me. I've realized that my access ...
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134 views

lost key-files for encrypted files [closed]

I had encrypted a file on my computer but the computer got infected by a virus, so I reinstalled Windows on my computer. All my key-files have gone. Is there a way to recreate the lost key-files, as ...
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1answer
238 views

Is an HMAC hash of plaintext data secure enough to use as a lookup index for encrypted data

I'm working on an app that will download files from external servers over https and store them on disk in a relatively secure way. Specifically, using a cryptographically unique IV, an AES256 cipher ...
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179 views

What client side encryption algorithm/libraries should I use to make syncing easier?

I want to build a webapp and a sister mobile app (using react native) that uses client side encryption. The encryption would be for text entries written on a daily basis that the user could create and ...
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Decrypt to memory for editing

I am looking for a secure way to edit sensitive text data, using Git and Vim in the process. An ideal solution would be: clone the encrypted git repository into memory; decrypt into memory; do the ...
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2answers
656 views

Encryption - how to secure files - decrypting exposes them on SSD

Let's say I have an encrypted file. Now I decrypt it but since my computer only has SSD, i decrypt it on the SSD drive. Say, I make changes or I finish using the decrypted file so I encrypt it again. ...
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Why would I ever use AES-256-CBC if AES-256-GCM is more secure?

I guess the gist of my question is: Are there cases in which CBC is better than GCM? The reason I'm asking is that from reading this post by Matthew Green, and this question on cryptography stack ...
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267 views

Should I store my encrypted password's salt and initialization vector as clear text?

I'm encrypting some file with AES-256-CBC, and I'm planning to store the cipher text in a json file, with something like: { "data": "0123456789ABCDEF...", "salt": "00123ABCAABBCCDD...", "...
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143 views

What kind of encryption is this file using? It used to be plain text

I was collecting data and building a database from a mobile game on Android. Here's an after/before image. If I do CTRL + A and copy paste on the left side, all information gets copied to clipboard ...
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138 views

The data(username,passwords) stored in app bundle is safe in a jailbroken ios device

I was testing an iphone application in a jail broken device. I happend to see an intresting thing that the username and passwords are stored in a plist file and Cache.db file in preferences directory ...
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930 views

Encrypt entire CSV file, but decrypt only specific fields?

I have some data in CSV file, say data.csv with columns age, sex, country and status. Is it possible I could encrypt the entire CSV file some way which allows me to fetch only selected columns, say ...
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144 views

Program or method to create an encrypted bulk file container [closed]

I have several hundred gigs of data that I store on a NAS for my own usage. The NAS storage solution manages local encryption, however I am looking into cloud backup solutions for disaster recovery. ...
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3answers
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Susceptibility of 7z encrypted archive files to man in the middle attacks

Given: A file (assume 1 GB in size) is encrypted along with filenames using 7zip into a 7z archive using AES-256 The file is uploaded to a cloud storage service such as those offered by Google, ...
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372 views

What is the best practice for encrypting and storing temp data on client?

I have a client-server system, where the client is an Android app. The client and the server communicate over HTTP. If the server/network is not available, then the client has to store the data ...
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1answer
920 views

What is Cryptographic metadata

I'm learning about how to encrypt a file in a computer system. I'm reading this: https://wiki.archlinux.org/index.php/disk_encryption Here I found an notation: Cryptographic metadata. As I know, ...
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1answer
736 views

eCryptfs: what if I remove ~/.ecryptfs

I'm learning how to use eCryptfs: https://wiki.archlinux.org/index.php/ECryptfs I get things as below from the link: This is used to derive the actual file encryption master key. Thus, you ...
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1answer
4k views

Differences between using an encrypted container and encrypting a partition

I would like to store encrypted backups on an external hard disk and am wondering what the differences are between creating an encrypted (Veracrypt) container and creating an encrypted partition. Are ...
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truecrypt volume - Recover 18char known password with hashcat (characters variations)

I have an old truecrypt file that I'd like to decrypt. I know the 18 characters password I was using at the time, I'm sure of it. However I made a "variation" of it : I mapped some characters to l33t ...
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1answer
948 views

How to encrypt files on my SD card and still be able to access them on my phone seamlessly?

I'm looking for a way to encrypt files on my SD card in a way that I could still access them on my phone without huge delays if the file is big (100mb). Is there such a way to do it? I'm using ...
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1answer
434 views

Are encrypted files safe in Windows 10 when using PINs?

In Secrets and Lies, Bruce Schneier writes: Many keys are generated from passwords or passphrases. A system that accepts 10-character ASCII passwords might require 80 bits to represent, but has ...
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1answer
716 views

Storing encryption keys [closed]

Think of this scenario: you've got an application that manages some files some of these files contain sensitive data that should be encrypted on disk the application is configured to start by itself ...
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Is it possible to read a text file inside a password-protected zip file without the password?

I have a text file (.txt) compressed in ZIP format protected by a password. I think it has only one line of text and I want to see the contents of this file. I tried fcrackzip but I think the ...
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Is this protection for customer data both secure and fast enough?

A small electrical installation company has a big list of customers. The list contains personal information like names, phone numbers, addresses, info (like what product/installation) and some small ...
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1answer
702 views

Why are SSH host keys stored un-encrypted?

Do we have any standard way to encrypt SSH host keys (like /etc/ssh/ssh_host_rsa_key)? If not, why is it stored in plaintext? Isn't it sensitive information?
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Recommended practice for laptop encryption: nested encryption?

Until now I have used a laptop that has a single folder encrypted (using filevault2) containing my passwords and bank stuffs. I am getting a new laptop that encourages full-disk encryption. This ...
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1answer
517 views

Using unencrypted parts of encrypted file to recover password (7zip)

I have forgotten the password for an encrypted 7zip file (the filenames are not hidden), and I have copies of some of the unencrypted files. Is there a way I can use this to find out what the password ...
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Rar password when you have unencrypted and encrypted file

I have two files (file1 and file2) where file1 is encrypted with rar software and file2 is the original plain text. Does anyone know the fastest way to get the password used to rar the file?
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Securing integrity of a large file with cryptography

Let say I have a large file that is of considerable interest to the public and I want to publish it. The plan is to hash it using reliable function and publish its hash on a public blockchain (btc or ...
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1answer
121 views

Best way to reduce encryption of the big files

I want to share a big file(All existing formats) with others. As I'm using Android phones as client/server I want to reduces the CPU overhead and Time it takes to encrypt/decrypt. My idea is to use a ...
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2answers
273 views

How can I select a compression utility that is popular and secure enough

In a previous posting on Which is a safe way to transfer a copy of a sensitive document?, I have received suggestions to compress and encrypt an attachment file using the options of utilities such as ...
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1answer
131 views

Way to secure store personal data

This is not for business or corporations, but for personal situations. I rely on gsuite, google drive, google docs, etc.. not that too much 'heavily', but I use it to send most of my business emails, ...
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980 views

Securely storing AES key with public key cryptography

Security newbie here I have a bash script that recursively enumerates all files and directories from a given path (say /home/user) and encrypts individual files and stores them into another directory ...
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Is volume level encryption enough to satisfy compliance requirements?

We are implement a cloud application and using nosql technology. We know there are quite a few compliance requirements out there require doing data encryption at rest. However, we would like to know ...
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Data encryption risk with bad sectors?

A few decades ago, I've known hard disks and floppy disks which developed bad sectors or crashed. So now when I want to use an external hard disk for backups for a startup company, the first thing ...
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1answer
377 views

(Why) does an encrypted MS Office 2010 Spreadsheet (need to) have the password hash “written down”?

To my naive mind, it seems like the encryption of a document with AES should go like this: HumanPassword ---|hash|--> key ---|AES|--> Ciphertext plaintext|--^ And the ...
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126 views

Encrypted file system in a hosted linux system

I'm considering to use an encrypted file system (dm-crypt or gocryptfs) in a linux system hosted by Linode. Can the administrators of Linode access the mounted (i.e., decrypted) contents? I'm not sure ...
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Is it possible to recreate a file using only its hash [duplicate]

To my knowledge, a file can have only one hash and a hash corresponds to only that file(keeping aside the 2 file one hash bug). Using that knowledge is it possible to make an algorithm to recreate a ...
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1answer
188 views

Hardening password-based file encryption with a synchronous stream cipher plus high-memory hashing algorithm?

So this is probably a stupid question, but I'm trying to understand why the following isn't done for at-rest files encrypted via password: generate an AES-256 key/salt/iv take the plaintext message (...
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1answer
325 views

which places are used to store the the encryption key? [duplicate]

So i have an encryption key which i will use to encrypt data or sign data with it. But in order make it possible to ensure the data integrity, i have to keep the key secret. So i thought of spliting ...
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100 views

Windows EFS Files Spontaneously Unavailable

We are trying to secure a folder with over 1 million very small text files using Windows EFS on Windows Server 2008 R2. We already have an infrastructure in place for backing up keys and data. We ...
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89 views

Is there a good way to use to find out how this was encrypted [duplicate]

Ok, so this is a very basic cryptography question. I have captured a message from an Android app to a server. I believe this app may be stealing information from the phone it is on so I'm running it ...
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1answer
475 views

Disk Encryption vs File Encryption for Embedded Linux?

The Security page for Android discusses file-based vs full-disk encryption. It discusses some rationale about why FBE in Android 7.0 is an enhancement over FDE when it come to a smartphone. But, if ...
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6answers
2k views

Downloading a file from a server with a secret: in text or binary?

Suppose, a user can click a button on a website and downloads a file with a secret. Via ajax. Is it more secure if a server generates that file and sends it as 1) zip, tar or the like -- a binary ...
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2answers
3k views

Does Wanna Cry encrypt files on network drives?

I've dealt with ransomware threats in the past, such as LOCKY that not only encrypt data it considers user documents found on the local machine, but also on any network drive to which the user has ...
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2answers
226 views

How to create a format that is very difficult to reverse engineer? [closed]

I am learning about file formats. I have an application that will do analytics and will have some personal information. I need to make it such that only some people are able to access data and even ...

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