Encryption is the process of transforming plaintext using a cipher to make it unreadable to anyone except those possessing the key.

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What's the advantage of using PBKDF2 vs SHA256 to generate an AES encryption key from a passphrase?

I'm looking at two comprable pieces of software which need to encrypt data on disk using a passphrase. One uses PBKDF2 to generate the encryption key from a passphrase, while the other uses two rounds ...
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What is the DUKPT Key Derivation Function?

I'm tasked with decrypting ciphertext acquired from an encrypted card reader. The card reader utilizes DUKPT(derived unique key per transaction) scheme and 3DES encryption. I don't have a problem with ...
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What does “key with length of x bits” mean?

I'd like to know what it means to say "the cryptosystem C uses keys with a length of x bits". I do not understand what the bits length means... doesn't it depend on the encoding? The same word encodes ...
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What are the main security considerations that must be taken into account if you intend on creating a (localised) whistleblower website?

Also: Is it something that can be achieved with limited funds? I ask because I am intrigued by the obstacles that are in place.
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Is RedPhone a secure and secret way to communicate?

RedPhone provides end-to-end encryption for your calls, securing your conversations so that nobody can listen in. But really, how is the probability that a voice conversation is wiretapped still? ...
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Reason for writing Self-Decrypting Virus

What is the rationale behind writing a self-decrypting virus? By this I mean a virus that has it's payload encrypted, decrypts at runtime and runs it. How does this protect the virus from antivirus ...
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How can I encrypt a file with .NET and have the same file size of the original file?

I'm using .NET and I've written an awesome routine (xD) that encrypts and decrypts a file using AES256 CBC. It works perfectly, but now they told me that the encrypted file must be of the same size of ...
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Encryption decryption time

Does the encryption / decryption time of rsa algorithm vary significantly with a change in key length? For example, is there a noticeable difference in encryption/decryption time between 512 bit and ...
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Is 1024bit Diffie Hellman key exchange secure?

My system uses AES-256, 4096bit RSA CA key and 2048bit RSA keys for servers together with SHA-256 signing. Does using 1024bit DH key exchange lower its security? I read on one mailing list that ...
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How does a weakness in a random number generator lead to a compromise of the entire cryptographic process?

In the news, there are several articles (here, here, and the technical point of view) which have to do with a weakness in a random number generator. The question is somewhat twofold. What symptoms do ...
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How does the padding scheme impact the security of encryption

After digging a little deeper into cryptography I am wondering what impact the different padding schemes do have an the security of an encryption algorithm. Lets take AES-128 in CBC mode as an ...
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Why can't I use the same key for encryption and MAC?

I wrote a simple file encryption program as an example of how to do encryption correctly, but after reading a questions about encryption + MAC, I think I made a mistake by using the same key for both. ...
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Is TDEA (TripleDES) invulnerable to the weak keys of DES?

The key space of DES includes some keys that are weak, which results in a ciphertext that is extra vulnerable to cryptanalysis. Is TDEA (also known as TripleDES) invulnerable to those weak keys? Or, ...
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When brute-forcing DES, does knowing something about the plaintext help?

Data Encryption Standard (Wikipedia) I know that with brute force there are 2^56 possible keys to check (56 bits, each either a 1 or 0). But let's say I know the message itself is only made up of ...
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Securing a prediction about a future event

I want to make a prediction about a future event, but only reveal that prediction after the event occurs lest knowledge of my prediction affect the outcome. For example, suppose Alice predicts that ...
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How do I encrypt the source and destination IP address, along with various parts of an email?

If the subject makes no sense to you, that's fine, it makes no sense to me. I've been tasked with securing emails sent from some devices, and I'm looking for advice on intelligent questions to ask to ...
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How would you analyze an image to find out if there are scripts embedded in it?

How would you analyze an image to find out if there are scripts or possible malware embedded in it? What tools / methods to use?
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Question about dictionary attacks on GnuPG symmetric encryption

They say algorithms like AES can't practically be broken given a long enough key length (> 128 bits). If I use GnuPG to encrypt a file using AES: gpg -c --cipher-algo AES secretfile it asks me for a ...
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Suitable cipher for SMS encryption

I would like to create application for encrypting SMS messages. After long enough discussions I decided to use symmetric encryption, since handling public/private keys issue is too difficult for most ...
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AES using derived keys / IVs. Does it introduce a weakness?

I'm looking for an efficient way to encrypt multiple fields in a database with AES using a single global key, used throughout a large web application. Obviously in order to re-use this key, a unique ...
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How do I ensure data encryption on Samba transmission on *NIX systems?

I have a heterogeneous system (both MS and *nix) that communicates with CIFS/SMB. How can I ensure proper data encryption at the application layer?
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Is it possible to prevent a physical attack on full disk encryption?

I've been researching into some methods to ensure that disk encryption keys can't be stolen, and one that I've come across is called TRESOR. With this kernel patch, you can create a partition that is ...
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Is “Why Should You Avoid AES In MySQL?” true?

From a 2012 Smashing Magazine article quite a bold statement is made to avoid AES in MySQL itself. Or as they put it "Why Should You Avoid AES In MySQL?". However, if you search for SQL encryption, ...
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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 ...
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Do I need to password-protect an “Electronic Copy” of health information given to a patient on e-media?

I'm struggling to find good documentation regarding requirements around security and encryption of patient clinical information when delivered to a patient in electronic format. Patient portals, ...
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Reversible, recoverable user data encryption scheme

From this earlier question, I have a general need to obfuscate a set of third-party credentials stored in a user account, which are then used in an internal Winforms software client. The scheme from ...
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Data Encryption and Key Management in C#

Which route to take, what are the pros and cons, which is more secure.. Generate AES key, encrypt the data with it and then encrypt the AES key with RSA, save the encrypted data and encrypted AES ...
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Is it preferable to perform encryption using database functions or code?

Several databases I am familiar with provide functions or modules for encryption. Examples include dbms_crypto for oracle databases and built-in functions for MySQL. Most of the commonly used ...
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Optimal variable sizes in the Secure Remote Password protocol

I am implementing the Secure Remote Password protocol: U = <username> --> <-- s = <salt from passwd file> a = random() A = g^a ...
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Best practices on securely storing access tokens

What would be the best practices for storing access tokens of another api for your users? In particular I'm developing an application with some friends that let's user log into Facebook to both ...
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Can I use hardware random number generation on my computer? Am I already using it?

A lot of computer security depends on encryption: SSL connections, TCP packet sequencing, encrypted files, etc. These depend on random number generation to ensure that attackers can't guess the ...
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How can I determine the encryption strength of an SSL connection

If I've connected to a https url, how can I determine the cipher strength of the connection? My understanding is that after the asymmetric public-key handshake the information is encrypted using a ...
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Is there any asymmetrically encrypted file system?

Is there a file system providing a directory where everybody can write, but only the directory owner can read the files? In theory it could be done by encrypting using the public key while writing, ...
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Encrypting a disk that has stuff on it?

Ok, so a pretty big disk ~1-2TB (90% full, multiple partitions + 2 operating systems on it), needs to be encrypted and zeroed-out, and it's a bit too much data for backing it all up before encryption. ...
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What can one do when encryption methods fail?

I'm in search of an expert to answer my curiosity. Suppose that methods like AES/DES, SSH, PGP, RSA, etc. can be cracked or fail somehow. In other words, suppose that it's possible to determine one ...
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What common products use Public-key cryptography?

I want know what common use products are there that use public key/private key cryptography?
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Using RSA with 3DES instead of plain 3DES. Does it make sense?

I have a large legacy code. Currently it is using 3DES encryption for a network based application. It encrypts data packets with a main key. This key is used to encrypt and decrypt (symmetrical). And ...
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Is using HMAC to transmit a password OK?

I'm writing a small webapp and I don't want to transmit login passwords as cleartext. As I don't have SSL available I've written a one-time challenge system which sends a random string with the login ...
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What Partial Homomorphic Encryption implementations exist and how do I leverage them?

It appears that only Partial Homomorphic Encryption(P.H.E.) is practical for modern day (2011) use. However I'm having difficulty locating libraries (FOSS or otherwise) that enable me to leverage ...
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Why do so many embedded devices use shared keys?

Many commercially available embedded device manufactures use the same keys for all instances of their respective devices. This situation is so rampant, a project called littleblackbox has created a ...
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moving from MD5 to SHA-512

This question is more of a security policy than a technical security question. Many years ago I developed an asp.net site, implemented Forms Authentication, and stored the user passwords as MD5 ...
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At what point does adding more iterations to PBKDF2 provide no extra security?

If my true passphrase is used only to generate a hash which is used as the cipher's actual key, doesn't that mean it's possible to try and brute force the cipher itself? I know it would take an ...
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Automated encryption detection

Is there any program that, given a cipher text, it would tell me what the encryption algorithm is? What if I have the plain text? Is there something that can be done in that case?
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Most widespread use of PGP after 20 years

Phil Zimmerman released PGP (Pretty Good Privacy) on June 5, 1991. As we examine the legacy of that far-sighted and brave act 20 years later, what are the most widespread and helpful uses of PGP ...
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Securing an E-commerce site

I'm building a custom e-commerce site, and the user will input their credit card details on the site instead of being directed to the payment gateway's site. I'm confused as to what the critical ...
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Is ECDSA breakable by quantum computers?

Is ECDSA secure from quantum computers? Will quantum computers be able to calculate it's private keys from the knowledge of the public key once there are working quantum computers?
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Choosing a session ID algorithm for a client-server relationship

I am developing an application which has a client-server relationship, and I am having trouble deciding on the algorithm by which the session identifier is determined. My goal is to restrict ...
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Security of email [duplicate]

Possible Duplicate: How commonly are SSL/TLS or S/MIME used by e-mail providers? Say, Alice uses gmail and Bob uses hotmail. Alice wants to send an email to Bob. Alice goes to gmail ...
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What do key size and block size mean in cryptography?

Can some one simply explain the meanings and the difference between symmetric key and block size. Why 64 block size not safe any more and they increase it to 128 (AES,...,Serpent)? And what about key ...
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sniffing/recording GSM 3G signals

Is it possible to sniff or record and process GSM 3G signals (from some reciever) given that there is no other signals interrupting etc (the most comfortable conditions) Update (with some supporting ...