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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Backing up sensitive data - pitfalls and best practices

Obviously, securely backing up sensitive data is a challenge. A remote backup is important for surviving a variety of disasters. What are some of the "gotcha's" lurking out there, and what best ...
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What are best practices to adhering to HIPAA encryption requirements?

As HIPAA's language is somewhat vague when it comes to actual technical requirements, what are best practices for PHI encryption for HIPAA compliance? I've seen varying levels at different ...
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where to store a key for encryption

I am looking for a way to store a key used for password encryption. I am using a mysql db which would store a user name and an encrypted password that would be encrypted using ...
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5answers
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Why should one not use SSL? [duplicate]

I see a lot of posts all over the web asking whether or not they should be using SSL to secure their website, or if it's really necessary to do so when the content of their site does not contain or ...
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symmetric encryption session keys in SSL/TLS

This question concerns the session send and receive keys used in SSL/TLS protocol. my understanding is that this key uses symmetric encryption (DES, AES, BlowFish, etc.) I'm wondering, if ...
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How to secure a WiFi network?

What do I have to do to secure a WiFi network? Is there any best practices? I have been recommended to use WPA2 encryption on the router, is that enough? What can I do to improve the security even ...
18
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Multi-boot with full hard drive encryption and pre-boot authentication

How would I set up a multiboot system which supports full hard drive encryption and pre-boot authentication. I have a system with Ubuntu, Windows 7, Windows XP, and I would like to install Red Hat. ...
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2answers
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How does a crypter for bypassing antivirus detection work?

I am talking about crypters used to encrypt files like viruses and keyloggers for the sole purpose of bypassing antivirus detection. How do they work?
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Is AES encrypting a password with itself more secure than SHA1?

This isn't really a practical question, but more a question of curiosity. I heard a CS professor recommend stepping up from md5ing passwords not to SHA1, but to AES encrypting the password using ...
17
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Are URLs viewed during HTTPS transactions to one or more websites from a single IP distinguishable?

For example, say the following are HTTPS URLs to two websites by one IP over 5 mins: "A.com/1", "A.com/2", "A.com/3", "B.com/1", "B.com/2". Would monitoring of packets reveal: nothing, reveal only ...
17
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Understanding 2048 bit SSL and 256 bit encryption

On DigiCert's page, they advertise a 2048 bit SSL with a 256 bit encryption: http://www.digicert.com/256-bit-ssl-certificates.htm What exactly is the difference here and why are two encryption bits ...
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What key exchange mechanism should be used in TLS?

There are many key exchange mechanisms that can be used in TLS. Among them are RSA, ECDH_ECDSA, ECDHE_ECDSA, ECDH_RSA, ECDHE_RSA and others. Which of these are more cryptographically secure and can be ...
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How would you store a 4 digit pin code securely in the database?

I'm familiar with password hashing, using salts, bcrypt etc. But it doesn't seem like this would work to store a 4 digit pin code since the attacker could try all 10,000 combinations quite quickly. ...
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2answers
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Is “real salt” the same as “initialization vectors”?

In the question about real vs. fake salt, the answers describe how real salt 'perturbs the encryption algorithm.' I know roughly how initialization vectors work; is this the same concept, or something ...
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4answers
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IPsec (Internet Protocol Security) facts

Internet Protocol Security (IPsec) is a successor of the ISO standard Network Layer Security Protocol (NLSP). What are the advantages, disadvantages, other interesting facts regarding the protocol?
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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 ...
16
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3answers
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Is it safe to write the salt AND/OR the IV at the beggining of an encrypted file?

I want to encrypt a file with AES in CBC mode (maybe another mode is better for file encryption...I don't know, but suggestions are welcome!). What I usually do is that I first write a few random ...
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2answers
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Is 7-Zip's AES encryption just as secure as TrueCrypt's version?

The main difference being TrueCrypt creates containers and 7-Zip encrypts the file itself, so file sizes can be guessed. Now let's just talk about the strength and breakability of the encryption. ...
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2answers
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Digital Certificate deployment: using two certs for each user?

At a large enterprise environment I have come across a deployment approach for Digital Certificates where each user is issued two (2) key pairs: One for signing documents, emails, etc. that is ...
16
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1answer
559 views

Doing a dictionary attack on RSA if you have the public key?

I'm trying to learn exactly how RSA works. Currently I have a very, very simplictic overview that goes like this. Having the public key allows you to encrypt things. Encrypting the same message ...
16
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2answers
899 views

Homomorphic encryption used for e-voting?

I was reading wikipedia about homomorphic encryptions, and one part got me a bit confused: "The homomorphic property of various cryptosystems can be used to create secure voting systems, ..." ...
15
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6answers
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How do I prevent copying of my PDF files?

One time while I was printing my documents at a copy center, I saw they dragged-and-dropped my PDFs from my flash drive to their desktop. How do I protect my files without using password? Is there a ...
15
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Encryption and compression of Data

If we want both encryption and compression during transmission then what will be the most preferable order. Encrypt then compress Compress then encrypt
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Asymmetric vs Symmetric Encryption

I am currently taking a principles of information security class. While talking about different encryption methods a large number of my classmates seem to believe that Asymmetric Encryption is better ...
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In what ways does Full or Partial Homomorphic Encryption benefit the cloud?

Can someone explain, in plain English, the practical ways FHE and PHE can be leveraged in the cloud? Some interesting (and confusing) links include this Microsoft Research PDF and this wiki entry. ...
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The aescrypt implementation hashes a password 8192 times to generate the key. Is this necessary?

I'm considering encrypting some small files (hundreds of kb apiece) using the aescrypt reference implementation. Looking at the source, it seems that the encryption key is derived from the IV and the ...
15
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3answers
398 views

Storing passwords in reversible form - a genuine use-case

What's wrong with you, you crazy fool, you're not supposed to be able to retrieve a password in plain text! I know. Hear me out. Assume I've got a service that's similar to Mint.com. For those that ...
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Which Instant Messaging services use or allow secure protocols, and what do those protocols cover?

We all know there's a myriad of Instant Messaging (IM) services out there. But, which of these services uses or permits protocols that actually secure your communications? For those that do, what ...
15
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Encryption and the “security time decay” of prior encrypted data

This question is on the assumption that any data once encrypted, may (eventually) be decrypted through Brute force (compute power/time) Exploits in the cryptography used Theft of private keys ...
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Principle of asymmetric algorithm in plain english

I was giving a presentation to my colleagues about cryptography basics in which I explained about asymmetric algorithm and its use. One of the common question from the audience about asymmetric ...
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8answers
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Are there any systems out there that use a one-time pad?

I'm still new to information security, but I have read a bit about the one-time pad. The point that sticks out to me the most is that it is supposedly unbreakable. Has this method of encryption ever ...
14
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4answers
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Future proof encryption possible in theory?

Let's say I have a message that I want to keep safe for the next 100 years. Is it theoretically possible? Let's say the message is unique (raw picture data, raw video video data, raw text data) and ...
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Is it possible to decrypt a satellite TV signal without using a smart card?

And if it is possible, why has it been decided to keep using a smart card for this task? I will be grateful if you can provide some practical examples on how to bypass the use of a smart card (if ...
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In PGP, why not just encrypt message with recipient's public key? Why the meta-encryption?

It's described very well by this diagram. It seems like the process used is convoluted and more round-about than it needs to be. Why is an intermediate random key generated for the payload's ...
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Why not RSA-encrypt the entire document?

I have recently learned of a way for person B to verify that a document sent from person A is indeed from person A. Person A gives Person B his public RSA key. This must be done reliably. Person A ...
14
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Primary Key as Salt?

Is it okay to use the primary key as the salt in a Users table? The only disadvantage that I can see is if the PK changes (unlikely), then the passwords break. What are your thoughts?
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Forced into using a static IV (AES)

We've had to extend our website to communicate user credentials to a suppliers website (in the query string) using AES with a 256-bit key, however they are using a static IV when decrypting the ...
14
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Is TrueCrypt safe enough to store clear-text-passwords?

The reason: I want to be able to use a portable USB drive to access my passwords on any machine and OS. TrueCrypt seems to be the only program that has sufficient support on all major platforms. So I ...
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9answers
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Encrypting email for gmail

My friend who is an accountant was asking me what the best way to exchange documents with clients. He was trying to tell me that just sending via email was sufficient and I told him he was insane. I ...
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4answers
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Doubling up or cycling encryption algorithms

I've occasionally read the suggestion to enhance security by either doubling up on encryption algorithms (encrypt a message once with one algorithm, then encrypt the ciphertext again with a different ...
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Flaw in encryption through pseudorandom number stream (from gpg documentation)

I was reading PGP docs and came upon a part written by Phil Zimmermann (PGP's creator) that piqued my curiosity: When I was in college in the early 70s, I devised what I believed was a brilliant ...
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How does non-ephemeral Diffie-Hellman key exchange become compromised in SSL when the RSA private key is leaked?

From my understanding, one of the major reasons we recommend Diffie-Hellman Ephemeral (e.g. DHE or ECDHE) over non-ephemeral DH, for SSL / TLS, is that compromise of the RSA private key (i.e. private ...
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What are the realistic, and most secure crypto for Symmetric, Asymmetric, Hash, Message Authentication Code ciphers?

I'm interested in updating this two pronged question for 2011: What cryptology is most appropriate for low-powered devices (such as a cellphone), and yet still effective? What cryptology is most ...
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For users that does not use PGP, what would be the other channel to securely send them a document?

I would like to send a document that is confidential to users that have no clue what PGP is (so no point in teaching them how to install it etc...) via email. The real question is how to do that? ...
13
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3answers
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How secure is aSSL (javascript)? Does it effectively mimic SSL?

Some of you may be familiar with the aSSL project, which uses AJAX/PHP to mimic the SSL protocol. It uses RSA 512 or 1024 for the keys, and AES for the actual data. It looks impressive to me in ...
13
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7answers
943 views

Has cryptography reached the development level where social engineering is the only reliable method of attack?

Note that for the purpose of this question, "social engineering" means extracting information from humans, be your methods compliant with Geneva Conventions or not. Simply put: Do cryptographic ...
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How should passwords be stored if they must be recoverable?

By "encrypting" passwords you are violating CWE-257: Storing Passwords in a Recoverable Format. But this is exactly what the French government wants. They want to be able to obtain the passwords of ...
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Does the haystack theory work

The haystack theory is the recommendation to put repeated characters in your password in order to make it harder for brute force to reveal. Does this have any mathematical basis? Or is it snake oil?
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SQL field level encryption, how safe is it?

I am considering encrypting my database and/or encrypting only certain columns in a few tables. Is it worth the time? I mean, how much of a burden would it be on someone if they were to get a hold of ...
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stronger encryption for SSH keys

I configured my server to encrypt user passwords using 500,000 rounds of SHA-512. The question is, how does the standard AES-128-CBC encrypted SSH private key stack up to that, provided the same (or ...