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-1

In order to stop speculations, decrypting altered encrypted file using AESCrypt results in 'Message has been altered and should not be trusted' dialog box coming from reliable HMAC computation and is forbidding decryption. The software is also using random salt, contrary to VSEncryptor, for example.


0

Thank you everyone for the feedback. In summary, the title question, is FDE for a server in a secure data center pointless? The answer is not necessarily as there could be scenarios where one would want the additional protection on the physical devices. For instance protection during destruction, protection from the host country, or protection in case of ...


0

DSA is a signature algorithm; its keys are not usable for asymmetric encryption. In the OpenPGP format, algorithms for encryption are RSA and El-Gamal. Normally, when you create your keypair, you are actually producing several key pairs: a "master" key, and some "sub-keys" for signing and for encrypting. The master key signs the sub-keys. When you say that ...


0

I think your main problem would be to implement the Format-Preserving encryption in the database. You could simply use AES on the field. See for example the encryption functions supported by MySQL. For a 20-byte input, aes_encrypt() output would be 32 binary characters (AES works on 16-byte blocks). You can get closer (25) with the less-secure (and ...


1

Torrent clients offer encryption of traffic using RC4, and people consider this, like, very safe to hide traffic information from ISP. People are wrong to do so, but not because RC4 is even remotely the weak point. Simply knowing which IPs you're connecting to allows precise determination of the torrent you are downloading by an opponent who simply ...


1

Quote: " . . .they have done little to nothing to actually reduce risk associated with unencrypted data. . ." Ok, yeah, I think you are right. The simple answer is "it is pointless", but "it is also NOT pointless." Which is why, and forgive me for saying this, I think you may be barking up the wrong tree. Let me explain. The full disk encryption (FDE) does ...


1

If you are executing the code in an extension, it is run in a separate context (for security reasong) and it can be made to run without the code/key being concealed to the called webpage (which is a bit different than the web page not being able to detect that you used some script within the page). For example, GreaseMonkey is designed for doing this kind ...


0

I still think, the problem is not yet addressed. Which is the asset you are trying to protect? the password or the password hash? Is it the stored password / password hash or while transit? Some disconnects / or clarity requirements I go to amazon.com, and am asked for my credentials. With the login page, amazon sends a guid: ...


2

Your scheme would not work as it is, because the Amazon server has not authenticated you when you arrive on the login page yet. So it must let your client browser decide how to create a unique guid. If the server tried to calculate a unique guid based on known attributes such as your IP address or browser fingerprint, you would be unable to connect from ...


6

Consider what you mean by 'secure' data center. Generally, I don't consider anything secure against a determined and well-resourced attacker. True, having 18" of reinforced concrete, double man-traps, and armed security provides a fair amount of protection, but it's rare that this protection is all just for you. In most co-location facilities, the only ...


1

Not surely. It depends on, against what you want to defend yourself. Some examples: If you live in a country, where the government can confiscate your server to analyze its content and then use it against you, or your employer. If you are the owner of the server, but won't give the possibility of your employee/collegues having physical access to it, that ...


6

There are attacks on the firmware of hard disks. Googling for hard drive firmware attack will return some results about what the NSA does or can do, which probably isn't very relevant to you; but even hobbyists are able to modify the firmware of drives. This guy even installed a linux kernel on his hard disk - no, it wasn't the PC that ran linux, the hard ...


1

As long as the data travels inside a properly configured SSL/TLS connections, there is no security issue regarding the increase amount of data sent through the internet, the only downside would be an increased load on your server. If you cannot trust local storage, then fetching the data from the server when it is required seems the best option from a ...


12

If the decryption key is stored in plain on the very same media as the encrypted data, then the encryption is pointless. If you have a set of rules, which require data to be encrypted, but permit storing the key in plain on the very same media, then the rules are flawed. If you ever face such a flawed set of rules, you should point out the flaw. If the key ...


54

Two generic things you apparently have missed: In case of disk failure, having the data encrypted at rest solves the issue of having potentially sensitive data on a media you can't access any more. It makes disposing of faulty drives easier and cheaper (and it's one less problem) Full disk encryption also makes it harder for an attacker to retrieve data ...


0

The problem with a browser extension approach is that many users would be either unwilling or enable to install it (eg logged in at their place of work they would not be able to install extensions). You also have to securely distribute the extension which is a problem itself. One online banking approach I have seen the bank puts a custom browser bin/exe ...


2

I'm not fully sure if this paper about time-lock encryption has been inspired by this discussion but it would be the most formal solution to the question "How to build time-lock encryption?", which is a reformulation of "How to protect data so that it can only be decrypted after a specific date?" But now let's get into the details on how this works. One ...


22

This message is Google trying to push people nilly-willy into the 21st century of cryptography. So they point and mock when they see "RC4" or "SHA-1". This does not mean that such algorithms can be broken immediately. Only that Google would find the world a better place (or possibly a googler place) if everybody were using algorithms more to their liking, ...


0

On IE-8 after you have browsed to an https site you can select File->Properties and it will show the type of encryption being used. For Firefow click the lock icon to the left of the URL and select More Information.


-1

If I understood it well the end issue is to protect data from being recovered from deleted temp files. To address this problem use tools to shred the temp file and or folder instead of shift+delete. Deleting a files is nothing more than unlinking the address of the file from filesystem. Unless the contents of the location are over-written it is possible to ...


2

Whats wrong? The waring you are getting is about "Mixed-Mode" which is basically when some parts of a site are sent over HTTPS and others are sent over HTTP. Some people down play this as unimportant because "The important data is encrypted" and while in a sense they are correct it can still be a security risk. Browser generally flag it for two reason: ...


2

(Moved from comment to answer) On Firefox, I found 2 Security Warnings in the Console: Loading mixed (insecure) display content "http://julian.referata.com/w/images/background-normal.png" on a secure page Loading mixed (insecure) display content "http://juliancubillos.com/favicon.ico" on a secure page They are most likely the reason why a warning sign is ...


2

I just did a small audit if your site, here are my findings. ssllabs test report grade A which is good a curl -vvv https://www.jcwiki.website/wiki/Main_Page | grep "http:" yielded no results, also good. Opening the site in Google Chrome (Version 42.0.2311.152) incognito window yields a mixed content warning. I checked the development tools and the reason ...


3

Nope. Cryptowall encrypts all your data using AES, with a randomly generated key. That key is encrypted with an RSA public key, for which the bot controller holds the private key. When you pay the ransom, they decrypt the AES key using their private RSA key, which allows them to decrypt all your files. This particular type of malware is particularly ...


0

It depends on a lot of things. Let's consider a message encrypted by OpenPGP, the most used encryption standard. By default, it includes in plain text a field containing the key ID the message has been encrypted to. However, note that the OpenPGP standard allows for this field to be empty i.e. containing a key ID = 0x0. So the correct answer to your ...


0

The only way you could match a encrypted text to the key-pair it is used with would be to own the private key and successfully decipher the message. Apart from this, there is no telltale sign as to which public key has been used to, as any message could have been used for encryption. Though, the protocol could tell you. For example, the OpenPGP protocol ...


1

Did you look at RSAKeyPairGenerator(doc)(source) from BouncyCastle? It generates an RSA keypair and encodes it. I bet you can create a keypair object, fill it with your values and call the encoding function to get a file gpg will accept. EDIT: So I've used openssl to generate an RSA keypair and export the values of its components: openssl genrsa -out ...


0

It could be possible to build a blockchain based system that gives every block in the future additional payload that the miner of that block has to solve. Every block could create a private key for a public key that's known in advance. You encrypt your message with a symmetric key and then encrypt that key with the known public keys of the next 10000 ...


0

Encrypt with a one-time XOR pad and have some kind of automation to send the cipher stream at the appointed hour. One time XOR pads are completely resistant to pattern attacks because there's no pattern. For this to succeed you must produce the key yourself and not share it with anyone build tamper-proof timed delivery automation conceal the true ...


4

How does work exactly the hybrid encryption RSA with AES? The long-term RSA keypair is used to exchange a temporary "session" key which is used to encrypt the traffic with AES. This can either be direct (i.e. generate key, encrypt with RSA public key, send to server, decrypt with RSA private key) or via a secondary key exchange mechanism (e.g. ...


0

You could generate a certificate on first run and then use certificate/public key pinning within the app to verify that it is connecting to the right server. This will enable you to use HTTPS over SSL/TLS. Apparently lots of existing apps use self-signed certificates. You could perhaps display the details of the certificate it receives of the first ...


0

Ultimately, the second law of thermodynamics gets in your way. Look at your plaintext as a closed system; it can only ever increase in entropy. Encrypting information increases its entropy, but having the key compensates for it. The total entropy of key+ciphertext is the same as the entropy of the plain text. When you destroy the key, the overall entropy ...


4

If the only trusted party is yourself, and you can't guarantee being available when the message contents are to be made public, then what you can do instead is to build a device (physical or virtual) that will automatically make the key public at the required time, and then hide the device. An easy way would be to buy a virtual server from Amazon or any of ...


4

No. SHA-256 is hashing not encryption. It's irreversible. You may however be able to try all available inputs and see if any of your known hashes matches one of the computed hashes. There is no other way than this "brute force" approach.


0

Like others said, one cannot provide decryption by a specific date, but by a specific effort. As for a single purpose algorithm the effort is strongly related to the interest of the partys trying to unlock it earlier and thus quite unknown. So the best solution may involve linking the puzzle to a much larger and inert interest. The most feasable that came ...


2

You can not securely use encrypted virtual machines without full disk encryption on the host. While the virtual machine is running, the host stores memory chunks, log data, configurations, and loads of other files on disk, leaving permanent forensic trail of a live decrypted virtual machine. File and project names will almost certainly be recoverable. If ...


0

I wrote a series of stored procedures (specifically for MySQL vs. MSSQL) that might be of interest. You can view it at sqlSec. Keep in mind that it is more a proof of concept using stored procedures to rotate symmetric encryption keys but does provide a transparent encryption/decryption procedure examples in the readme.


2

You have a few options, and it'd probably be best to do at least the first two: Encrypt your host operating system's drive using BitLocker or doxbox. When installing your guest operating system, do the same thing inside the guest. VirtualBox and other VM hosts provide the option to encrypt the virtual drive. All drive contents are encrypted before written ...


1

I am sorry if I am missing something simple in your question. Why not just store the image on an encrypted drive? You could store the image or the entire VirtualBox folder on the encrypted disk so that way you need the key to be able to access it.


1

These are two separate concepts, and I'll attempt to make an analogy. Imagine access control mechanisms are like locking windows and doors in a house. You have to make sure that all of them are locked down to create a secure house, but breaking them is still possible for entry. For some things in the house this level of security is all you need. But ...


4

Encryption is used to provide confidentiality of data that may or will be accessed by an untrusted entity. Access control is used to limit or otherwise control an entity's access to an object. Asking "when do we use them" is an open question. Access controls can be anything from a padlock on a gate to a permission set on a filesystem. They can be simple or ...


3

Encryption mechanisms can be used to achieve specific outcomes: Making some data illegible, with the ability for specific individuals to retransform it into a legible format later: this can be used to implement confidentiality within some technical limitations Providing an authentic signature related to a specific blob of data: this can be used to provide ...


2

Approaching your second question, rather than using a different crypto algorithm, you can replace gpg in symmetric mode with openssl: echo "plain text" | openssl enc -aes-128-cbc -nosalt -pass pass:secret Beware: For sample purposes, I am providing the passphrase in the command line. See PASS PHRASE ARGUMENTS in openssl(1) for better ways of providing ...


7

The whole point of all encryption is that it's safe for the attacker to get your ciphertext, because they don't have the key. This is true for public-key encryption as well; it's perfectly safe for you to broadcast your ciphertext to the world, and certificates aren't related to that in any way. The reason you use certificates in public-key cryptography is ...


3

This in an interesting problem; with only symmetric encryption, how do you secure a communication channel (ensuring both privacy and authentication)? Researchers have been working on the problem for centuries and the best solution they've come up with is: Public Keys! That's a tongue-in-cheek way of saying that authentication is a fundamental problem in ...


-1

There's no reason why this construction should be insecure except for standard chosen-plain and ciphertext attacks. To prevent those you still need an authentication mechanism. (like AES-GCM or Poly-1305). As practical construction I'd suggest you using an offset. Hence you would use the first few bits from the PBKDF to derive a key for authentication and ...


9

By using PBKDF2 that way, what you are really doing is turning PBKDF2 into a stream cipher. The three main problems with this idea are: Use of PBKDF2 as a stream cipher has not been thoroughly investigated. It may be fine. Or not. Security properties of PBKDF2 have been analyzed for mostly short outputs only, and then, only as a KDF. If you reuse the same ...


1

Yes. Because of known-plaintext-attacks, a adversiary that can find out the plaintext, could use that to find out the hash to decrypt ciphertexts that the adversiary does not have the plaintext to. AES is specifically built to prevent a attacker from finding out the key, even if he knows both the plaintext and ciphertext. If you want to gain performance ...


5

In addition to the encryption initialization vector (IV), the symmetric key derivation uses a random salt to protect against offline dictionary or rainbow table attacks. Specifically, the Iterated and Salted S2K (String-to-Key) packet contains an 8-byte salt.


16

Use secret sharing to split a private encryption key into N parts, parameterized to allow reconstruction of the key with K or more parts, where K <= N. Best done using CRM, as described on the following page: http://en.wikipedia.org/wiki/Secret_sharing Then send each part to independent services that agree to publish at a given date in the future. Up ...



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