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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26 views

Secure storage of sensitive data [closed]

I don't like using a throwaway but somewhat need to. I'm seeking advice regarding a cryptographic implementation. I have a server that needs to be able to process, manage and hand data back to a user ...
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1answer
43 views

Encrypt a file for multiple persons with different keys?

I thought a problem and want to ask if there's a more elegant solution. The scenario: A company with a fileserver, which hosts encrypted documents. The files need to be accessible by about a dozen ...
0
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1answer
48 views

Why does rsyncrypto require a public key during decryption?

I recently came across a project called rsyncrypto that sacrifices some security so that you can have rsync-friendly files. My understanding is that it works by generating a symmetric key for each ...
0
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1answer
84 views

Encryption of exe file

I recently started learning cryptography. I have learned some basic stuff. I'm also started learning about pc security, so I was wondering how do hackers use cryptography for bypassing antivirus ...
2
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1answer
47 views

What is the right notion of security to use for file encryption?

It seems that several file encryption systems do NOT use authenticated encryption. (E.g. gpg --symmetric and boxcryptor as far as I can determine). I understand that this is generally considered ...
2
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1answer
50 views

How to securely store data? / How to securely encrypt a file? [closed]

How do I safely encrypt a file? or formulated differentely: How do I safely store the data of my application in a file? Note: Using established tools isn't an option for this. The tasks need to be ...
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1answer
49 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. ...
1
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1answer
41 views

Given an encrypted file, what are possible ways to find its encryption algorithm?

Given an encrypted file, what are possible ways to find its encryption algorithm? Heuristic ways are okay as well.
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3answers
46 views

Question about decryption

I have a question about decryption. Let's say I have a bunch of files that are encrypted. Someone gains access to those files, and finds out that he already has one of them, unencrypted. My question ...
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1answer
245 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 ...
-1
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1answer
284 views

Decrypted RSA 64 bit encryption using modulus and private exponent. Got gobbledygook [Verify] [closed]

As part of an experiment, I was given a .enc RSA (encrypted) file that was most likely generated using openssl. I had the public key, I factored it, obtained the private exponent, and decrypted the ...
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0answers
136 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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1answer
2k 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 ...
1
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1answer
140 views

ccrypt and its security

I would like to know how secure is ccrypt to encrypt files (like images, videos and other non-plain text data) using single password of 20+ chars length. It uses Rijndael with 256-bit block size and ...
2
votes
1answer
515 views

Is CAST5 still a secure algorithm to use?

I just installed GnuPG for Windows. The documentation says the default symmetric cipher is CAST5. In PGP also, default cipher was CAST5. Is CAST5 secure to use? Any known attacks reported on this ...
2
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2answers
100 views

Does key derivation with known parameters add any security?

First up: this is a question about a concept that I try to wrap my head around; it is not about the specific implementation. Anyway… I have the following scenario (simplified to show the problem I ...
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votes
4answers
531 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? ...
0
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1answer
181 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 ...
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3answers
109 views

Loss of data due to encryption

Could any kind of encryption method (AES, etc.) lead to data loss like in lossy compression? I'm interested if data (lossy compressed, lossless compressed, uncompressed) that is encrypted and ...
1
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0answers
130 views

RSA or Paillier is good? [closed]

I want to implement file storage in cloud using homomorphic encryption. I want to use paillier encryption. Can you suggest the drawback of RSA to store and retrieving the files. Then only i can use ...
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2answers
204 views

Sharing an encrypted file between a group of people

Is there any way to share an encrypted file with a group? In the other words, can I encrypt a file with a public key so that each person in a group decrypt it with his/her private key? Is there any ...
0
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1answer
414 views

Java: 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 ...
2
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2answers
2k 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 ...
2
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4answers
459 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 ...
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1answer
64 views

Data I/O operations for encrypted files

I need to implement a simple approach on a Linux system to encrypt/decrypt data and I would appreciate any feedback from you. Basically, I need to change a bit the behavior of the functions ...
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2answers
570 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 ...
2
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1answer
70 views

Encrypted files in an encrypted partition or folder

Recently I started wondering about multiple encryption and found pages upon pages of posts and debates about the security of cascades. Now, don’t worry – I'm not looking for someone to discuss a ...
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3answers
264 views

Encrypting text file line by line with stable encryption

I want to store files in a secure manner (i.e. no one should be able to decrypt the contents of the file without the secret key) but I also want a diff tool to be able to show me which lines changed ...
3
votes
1answer
197 views

When is it safe to not use authenticated encryption?

I have read the post Why should I use Authenticated Encryption instead of just encryption? When is it safe to not use authenticated encryption? I assumed hard drive volume encryption or per file ...
5
votes
2answers
422 views

Reusing AES-CTR Keys and IVs for File Encryption

I’m implementing some file encryption module with random-access capability and AES-CTR seems the right way to go. I understand that reusing Keys and IVs can expose the file to ‘Stream Cipher Attacks’ ...
2
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0answers
84 views

Is ecryptfs safe after unmounting but before turning off the computer

I've read that one of the vulnerabilites of ecryptfs is leaks to swap memory, and that the solution is to encrypt swap. But even if swap is encrypted, it's still open until I reboot. I've also read in ...
2
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0answers
157 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 kind of keys: RSA public/private, AES ...
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0answers
384 views

Using RSA key pair for file encryption

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 ...
1
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1answer
493 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 ...
3
votes
3answers
235 views

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: ...
3
votes
1answer
391 views

File Hash of Encrypted File

Simple question. I have a source file and I have encrypted it with a certain public key. If I take this exact same source file, encrypt it with the exact same key a few hours later would the file hash ...
3
votes
1answer
99 views

Asymmetric Cryptography Confusion - 'Sign' a file to guarantee its source

What I want to do is use asymmetric crypto to guarantee that a file comes from a source. I have software that runs on lots of wireless devices, and each of those has a license file with an encrypted ...
4
votes
2answers
401 views

Which crypto libraries/programs do we have the most confidence in? [closed]

I have recently begun studying crypto. If it's one thing I have learned it's that we should not implement our own crypto. Therefore we should look to using existing software and libraries. When I ...
2
votes
1answer
170 views

How to design a cryptographically secure file hosting service

How one would go about design 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
350 views

Testing if a password for an eCryptfs mount is valid [closed]

I'm using "eCryptfs" on several directories on my dedicated Debian server. I mount them manually via mount -t ecryptfs [dir] [mountpoint] But after some weeks ...
4
votes
1answer
401 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
1answer
270 views

How does redundancy in a file effects performance and security of encryption?

Does redundancy in a file or data effect performance and security of encryption? (for example for AES, if not for general case) Is it easier to encrypt something that has high redundancy or something ...
-1
votes
1answer
2k views

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 ...
4
votes
1answer
358 views

How does partial key escrow work?

It is being speculated that one of the ways that NSA leaker Edward Snowden may have created his "insurance policy" – distributing sensitive documents to various individuals with instructions to ...
1
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0answers
388 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 ...
-1
votes
3answers
503 views

how much is secure to encrypt a password using itself (as encryption key) for storing it on a unsecure 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 ...
3
votes
1answer
1k views

Encrypt a single file, chunk-by-chunk, each chunk using different key (AES)

Encrypt a single file, chunk-by-chunk, each chunk using different key. I am a security newbie (only took 2 security courses before) But currently I am using this encryption method for my Android ...
3
votes
4answers
763 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 ...
3
votes
3answers
257 views

Ciphers in CBC mode reveal place of change in plaintext

Theoretically, when using a symmetric block cipher in CBC mode, the current block is dependent on the previous block. Suppose one plaintext is encrypted using CBC, and then one bit of it is changed, ...
6
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1answer
325 views

Single-purpose symmetric encryption scheme for single files

I'm writing a simple password manager program that will encrypt/decrypt a single file (it's size will most likely stay under a few K). This is my initial file format design: ...