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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90
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11answers
13k views

Technology that can survive a “Rubber-Hose attack”

In the documentary film Citizenfour, Edward Snowden says about documents: I'm comfortable in my technical ability to protect [documents]. I mean you could literally shoot me or torture me and ...
44
votes
3answers
9k views

What security scheme is used by PDF password encryption, and why is it so weak?

Many PDFs are distributed as encrypted PDFs to lock out some of their functionality (eg printing, writing, copying). However, PDF cracking software is available online, which usually cracks the PDF ...
41
votes
3answers
6k views

Why would an encrypted file be ~35% larger than an unencrypted one?

According to the ownCloud documentation, if you enable encryption, file sizes can be ~35% larger than their unencrypted forms. From my understanding of encryption, the file sizes should be ...
30
votes
5answers
46k views

How secure is a Windows password protected zip file?

I need to send some sensitive information to a client. I thought I would email a password protected zip file I created using Windows XP and then call them with the password. Presuming I pick a good ...
25
votes
6answers
3k views

Do spaces in a passphrase really add any more security/entropy?

I often see passphrase suggestions written as a sentence, with spaces. In that format are they more susceptible to a dictionary attack because each word is on it's own as opposed to a large unbroken ...
21
votes
3answers
2k views

Would it be plausible to write your own anti-crypto-ransomware tool? [closed]

Question After reading about how basic ransomware targets and encrypts your files. I was wondering if it would be plausible to write your own script to try and detect such activities? Initial ...
18
votes
2answers
25k views

Brute Forcing Password to a Truecrypt-encrypted file with Partial Knowledge

A while back, I encrypted a few files with Truecrypt, and stored the password in my head. Now I need to access it again, the password isn't working. I'm sure most of it is right, but I'm off by one or ...
16
votes
8answers
24k views

Does password protecting an archived file actually encrypt it?

For example if I use WinRAR to encrypt a file and put a password on the archive how secure is it? I keep a personal journal and am thinking of doing this, or is there a better way? It's just one huge ...
15
votes
6answers
20k views

How secure is NTFS encryption?

How secure is the data in a encrypted NTFS folder on Windows (XP, 7)? (The encryption option under file|folder -> properties -> advanced -> encrypt.) If the user uses a decent password, can this ...
14
votes
4answers
5k views

VeraCrypt/TruCrypt - I can't understand why you'd want to create a “hidden” volume…?

I can't think of a reason as to why you'd want to create a hidden volume in VeraCrypt. It says because "you may be asked to hand the information," but why would I need to hand it over? Nobody has any ...
14
votes
4answers
7k views

What are you doing when you move your mouse randomly during a truecrypt volume creation?

Is that called a 'round' every time you move your mouse when creating a new volume? I'm talking about the screen with the random numbers during the volume creation process. What is the purpose of ...
14
votes
5answers
9k views

Encrypting files in a windows environment

We have certain client data which must be encrypted at all times. The part we have been struggling with is encrypting files on network shares. Currently we have network folders encrypted using PGP ...
12
votes
5answers
7k views

How can I decrypt data with Java, without hard-coding the key?

I hope this is not a chicken-egg problem or reinventing the wheel but here goes. I have a Java application that needs to access a password protected file (actually during the application startup). The ...
12
votes
4answers
114k views

How to recover a lost zip file password

I have some files I was given by my teacher at University, I could chase him up, but I may as well try getting blood from a stone, his response rate isn't great and I completed my degree a year ago! ...
12
votes
4answers
686 views

Encrypting data by parts vs encrypting the whole data

Suppose I have a file with records, and I have two options to encrypt it: encrypt the file as a whole encrypt each record separately and store them together. Which way is generally preferable and ...
11
votes
6answers
11k views

Good file encryption tools [closed]

Could you please help me find a good file encryption tool? The target OS is Linux, but tools for Windows are welcome, too. FOSS tools are preferred. The tool must be reliable both for the recovery of ...
11
votes
5answers
779 views

Security of using passwords or even passphrases to encrypt files

Is it ever appropriate to use real-world passwords to encrypt files to be sent via unsecure means. By real world, I mean a password that is memorable and memorisable by a mere person? I am implying ...
11
votes
2answers
4k views

How to encrypt data on the server?

I have some data on the server (running Linux) which needs to be encrypted (company policy). This data is being served by an application running on this machine. Now I consider a few possibilities: ...
11
votes
6answers
462 views

How to protect against adversaries snatching booted laptops to defeat full disk encryption?

I read an article describing how FBI agents snatched Ross Ulbricht's laptop while it was running to defeat full-disk encryption: Two plainclothes FBI agents, one male and one female, walked up ...
11
votes
4answers
9k views

What's the standard way to encrypt a file with a public key in Java?

I'm writing a client app in Java that sends encrypted data back to the server. All clients have my RSA public key. Is there a standard way to encrypt a given file with it to send it back to the ...
10
votes
4answers
4k views

Is Changing a File Type and Name an Effective Security Solution?

Is renaming folders & files and changing file types an effective solution for file security of a PC? I am an application programmer and have an extensive background in it. I have written a ...
10
votes
2answers
4k views

After How Much Data Encryption (AES-256) we should change key?

Considering AES-256 encryption, what is the maximum amount of data should be encrypted with one key? Does Block cipher modes/IV/counters also governs the limit? If say the maximum amount is 50GB, ...
9
votes
3answers
385 views

Linux Plausibly Deniable File System

Is there any way to encrypt a linux filesystem in such a way to maintain plausible deniability? E.g. "Hidden OS support," the way Truecrypt and Veracrypt work, they only support Windows OS due to low ...
8
votes
3answers
2k views

time to crack file-encryption password - more than just iteration

I have often seen that takes x amount of time to crack a certain length password. But this just seems to be the amount of time it takes to iterate through all the possibilities. What about the time it ...
8
votes
3answers
379 views

How can I allow acces to encrypted data if only 2 out of 3 users provide a secret?

I want to encrypt data, but make sure that no single user can decrypt the data. Further, it is important not to require ALL users to be present to decrypt. This will allow for some flexibility and ...
8
votes
2answers
6k views

Simple way to encrypt files on Linux and decrypt on Windows?

We are in need of an encryption process for backups of very valuable data. This data will be stored on a distributed filesystem, so even with permissions set right, its not out of reach that this data ...
8
votes
4answers
6k views

How secure are the password files used by Password Safe and Password Gorilla?

Password Safe and Password Gorilla are both programs to manage passwords. Both store a list of user passwords in a file, which is encrypted using a master password. They use the same file format, so ...
7
votes
7answers
4k views

Are there any “real world” implementations of secret-sharing encryption schemes?

Imagine something like TrueCrypt where user A can decrypt his files, or any 3 of the 10 directors in his organization can decrypt user A's files. As I understand it this is similar to the way the ...
7
votes
10answers
7k views

How can I share files with other individuals using the cloud in a secure way?

I would like to use a dropbox because it is easy and convenient. But I want to encrypt the files with the public key of the intended recipient, so he will be the only one who can access the data in ...
7
votes
3answers
508 views

Secure cleaning of deleted files

So I know how to secure delete files. But at our company, we have a laptop which had many important documents, which now have been deleted, but not in a secure way. We can't perform a full format of ...
7
votes
4answers
5k views

when people say a file has a checked md5 hash, what exactly does that mean?

ok I was just reading this site: http://www.zdnet.com/blog/bott/stay-safe-online-5-secrets-every-pc-and-mac-owner-should-know/3542?pg=4&tag=mantle_skin;content and thought of something I always ...
7
votes
7answers
2k views

Verify the password of an encrypted file without waiting for complete decryption

I am currently working on an application that encrypts files with AES 256. The problem is that I want the user to see whether the password is wrong before the file is decrypted. For example if you ...
7
votes
3answers
2k views

Is ENCFS secure for encrypting Dropbox?

I've encrypted my dropbox-folder with encfs according to a few tutorials I found on the web, advocating this approach. But I've found the following critical statement concerning encfs'security in ...
7
votes
2answers
3k views

Microsoft Office 2013 File Encryption

To what extent can the native file encryption provided by Microsoft Office 2013 (Word, Powerpoint, Excel, etc.) be relied upon to maintain the confidentiality of documents, especially within the ...
7
votes
1answer
135 views

Encrypting individual files on OS X

I am about to go paperless, and I want to protect the documents that I scan. The use case is that I'll be scanning paper documents, encrypting each file, and storing them locally and on various backup ...
6
votes
6answers
728 views

Applying file deltas to an encrypted file

I am developing software that will be used for data backup. The server will run on Linux. Security in transportation is not an issue (HTTPS or SSH), but the data must be stored encrypted on the ...
6
votes
3answers
595 views

Encrypted password inside compressed archive

File compression utilities like Winrar or ZIP or 7zip encrypt the password and store it inside the archive. How safe is that? I mean you are giving away the archive with the password inside,it's not ...
6
votes
4answers
5k views

TrueCrypt -vs- MacOS encrypted sparse image - equally secure? Other alternatives?

I'm currently trying to find my personal best solution for storing passwords and other sensible data. Recently I've used 1Password on iPhone and Mac but I'm not really satisfied with its predefined ...
6
votes
7answers
1k views

How do I secure patient data cheaply in a small doctor's office?

I am a single practitioner with 3 work stations and a server. What is the best cost effective way to secure my data and I suppose encrypt it. The gov't wants us to prevent any unsecure access to ...
6
votes
2answers
4k views

Security of Microsoft OneDrive

A friend asked about putting some of his data on Microsoft's OneDrive. I did some research, and what I learned seems very surprising. It appears that all the user data on MS OneDrive is store ...
6
votes
1answer
248 views

John McAfee's Explanation of iOS Hack

I'm referring to this YouTube video, and further comment from John: I hope everyone knows that the Apple explanation was VASTLY dumbed down for the press. I know the A7 system chip well, ...
6
votes
1answer
271 views

Could a consumer-friendly PGP-like file encryption application theoretically be secure?

In a situation where there are desktop and mobile clients, and a central public key repository to and from which the desktop and mobile clients automatically upload and download public keys as needed, ...
6
votes
1answer
327 views

Should an app remove or encrypt locally stored user data after a user logs out?

I’ve been poking around in the Application Support folder of a popular app, trying to extract some chat logs. (By “popular”, I mean that most people reading this will have heard of it. I’m not sure if ...
6
votes
2answers
237 views

Decrypting arbitrary offset of encrypted file

I want to store encrypted files on some storage backend that allows me to fetch bytes X through Y of the encrypted file. I can obviously decrypt the entire file locally and send it back to the client. ...
5
votes
2answers
1k views

Designing a cryptographic file-sharing protocol

As a learning project, I am trying to implement a secure way to share files with a friend over dropbox. (I am not looking for existing software, I am doing this in order to learn how to do this ...
5
votes
1answer
5k views

Why is GPG file encryption so much slower than other AES implementations?

Correct me if I'm wrong: When encrypting a file, GPG creates a one-off AES encryption key and encrypts that key using RSA. This is supposedly to take advantage of AES's superior performance when ...
5
votes
4answers
843 views

Is Encrpyting Home Sufficient?

I currently have a fully encrypted Windows System, and I'm looking at switching to Ubuntu. Is encrypting my home directory (with ecryptfs) sufficient? On windows this would be problematic due to ...
5
votes
3answers
2k views

Single File Encryption in a Windows Environment

Would it be correct to assume that encrypting a single file in a Windows environment, for example a simple text file containing login credentials for a variety of accounts, is inherently insecure? It ...
5
votes
3answers
1k views

Will editing a Word file from a mounted Truecrypt volume leave any trace behind on the host computer?

I've heard that even if you have a Word document encrpyted (just using the built in Word encryption tools) and are editing it, it can still leave behind remnants of a file on the local computer in ...
5
votes
1answer
355 views

What is the impact of RSA key's size on CPU load?

I use ssh connection encrypted and compressed. If I use small RSA keys or very big RSA keys, what is impact on CPU load for compression, for decompression and on bandwidth (encrypted file size) ?