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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11
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Native rsync protocol security

Is the native rsync protocol (port 873) secure? Does it encrypt data or credentials? I'm planning on using rsync to store encrypted files in the cloud, I'm wondering whatever the password is ...
35
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3answers
2k views

Am I wrong to believe that passwords should never be recoverable (one way hash)?

I recently forgot my password for our cable provider online account, only to discover that they sent it to us via plain text in an email. I quickly sent an email to customer support asking them if ...
13
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8answers
4k views

Is Steganography a safe method to store secret data?

I want to put some parts of my secret data into specific file with Steganography method. Is this method as safe as other encryption methods like RSA or SHA?
3
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3answers
1k views

AES for key encryption

Is AES a good choice for protecting a key stored on the computer of a user of my application? I have seen threads on hashing passwords that suggest using slow algorithms for defending against brute ...
3
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3answers
1k views

RSA Key Pair generation with Javascript

I need to generate a RSA key pair with Javascript. This key pair will be used for encrypting a one time blob of data (20-100kb), then discarded. This data can be reduced to a couple of hundred kb or ...
6
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2answers
488 views

NSA crypto Suite B - historical

I'm looking for information on what NSA suggested for use in commercial systems in past times. 90's and early 2000's. I'm mainly interested in PKI and symmetric cyphers for SSL and file/disk ...
4
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2answers
7k views

What password-based encryption to use with standard Java 6?

Which password-based encryption method should I use in Java 6? It should be as strong as possible, but work with the default security policy file (not the export restricted one which you have to ...
10
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7answers
43k views

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 ...
4
votes
1answer
571 views

Is this security/encryption scheme secure?

I'm rolling my own, personal threetags.com-style 'encrypted data in the cloud' webapp (I didn't like the UI, and lack of non-browser client). However, I have absolutely no experience with security ...
7
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2answers
2k views

SSL Session resumption and IDs

Some sites, as seen in the report for www.mbank.com.pl [ssllabs.com] or report for aliorbank.pl [ssllabs.com] do not support "Session resumption", either because IDs are assigned but not accepted ...
9
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2answers
5k views

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 ...
11
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2answers
3k views

Which cipher suites with AES cipher provide forward secrecy?

Does standard AES with RSA (reported by Opera as TLS v1.0 256 bit AES (1024 bit RSA/SHA)) provide perfect forward secrecy? Which SSL3.0 and TLS1.0 ciphers do provide forward secrecy? Which ciphers ...
13
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2answers
913 views

Storing sensitive information securely

I know there have been a few questions about this already, but I just wanted to know if anyone can take a look at my design plans to see if there are any gaping security holes. I am in the process of ...
2
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4answers
485 views

Hash/Digest of string; multiple clients and reverse lookup must be impossible

Ok so i need a technique (could be a system or just an algorithm) to generate a hash/digest of a string on a client app without me (admin of a server app) being able to determine what the original ...
23
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7answers
36k 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 ...
5
votes
3answers
12k views

Which type of encryption algorithms android supports, and which would be better?

I read this documentation, and I have written an algo to encrypt and decrypt a string. But I don't know how many types of algorithms android supports. Regarding DES and AES (As wiki documentation) ...
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2answers
9k views

What are private key cryptography and public key cryptography, and where are they useful?

I don't understand the real world usage scenarios of these cryptography methods. Can any one please explain how they work, with examples and also their usage in the real world?
12
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4answers
535 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 ...
7
votes
2answers
745 views

Encryption Algorithms with an error code for wrong password

I am looking for an encryption algorithm that would allow me to know if the password supplied is the correct one or not. This question can be considered as a follow-up for Q. In particular the answer ...
6
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2answers
2k views

Export laws on the cloud (key size)

Do the U.S. export laws around AES-256 apply to applications hosted in the cloud?
6
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2answers
726 views

How do I use Skein's Stream Cipher?

I understand the NIST hash function competition candidate Skein comes with a built-in block cipher, Threefish, that is turned into a stream cipher by using Unique Block Iteration chaining (is that ...
11
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5answers
622 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 ...
4
votes
4answers
330 views

Data categorization: Critical or not

I need to provide two means for securing data within my application. First is using the Operating System sandboxing model (I am talking about Mobile Phones OS) and the second using the OpenSSL AES ...
7
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3answers
2k views

Is this prime number large enough / too large for a Diffie-Hellman for AES-256?

I'm using a Diffie-Hellman key exchange to encrypt data using AES-256. The prime number I'm using is the one from the 8192bit group specified in RFC 3526 (page 6). Page 7 suggests that, with a 620 ...
14
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6answers
1k views

How can the impact of cold boot attacks be minimized?

Short of powering down and maintaining physical security for sufficient time, what are effective strategies for keeping keys from being disclosed by cold-boot attacks, and can anything be done without ...
2
votes
2answers
207 views

Which private-key encryption should I use for server to server communication?

I am tempted to write my own which covers: Checksum to ensure data is not tampered with. Long and multiple rotating keys so that it is (practically) impossible to decrypt. Will use /dev/random for ...
11
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2answers
5k views

For LUKS: The most preferable and safest cipher?

I'm about to encrypt two of my hard drives using LUKS, since I can't really do it myself I use the guide on the Arch Linux wiki (which can be found here). In an example in the guide the cipher ...
1
vote
1answer
119 views

Challenge Response across several hops

This is a follow-up question to "When should I use Message layer encryption vs transport layer encryption". I need to send a certificate from the mobile phone to the server. Regardless of all the ...
1
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1answer
640 views

Nonce construction for CTR mode (Mcrypt)

Edit: I'll put up this more clearly. By the most simplest form, I'm asking that if I AES encrypt in CTR more with Mcrypt (using PHP), can I create the "IV" by just simply reading 16 bytes from ...
13
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3answers
1k views

What's the mathematical model behind the security claims of symmetric ciphers and digest algorithms?

Why can SHA-1 be considered a secure hash function? That's something I still wonder about. I understand the concepts of why modern asymmetric algorithms are deemed to be secure. They are founded on ...
230
votes
7answers
176k views

RSA vs. DSA for SSH authentication keys

When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type). What is the difference between RSA and DSA ...
1
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2answers
201 views

TCrypto - Comments about design decisions I made?

I have pushed some code to GitHub to demonstrate the usage of symmetric key encryption in PHP. It is a small key-value storage library and it (optionally) offers ability to encrypt the stored ...
4
votes
1answer
421 views

Asynchonous Linear Feedback Shift Register : test vectors

Well I've been working on coding LFSR structures for my research projects. Being able to find sources on the subject, I've been able to test a single LFSR with different initialisation and TAP ...
5
votes
1answer
950 views

Is the DES “mangler” function invertible?

The DES symmetric cipher is based on a Feistel network operating repeated on 32-bit halves of the 64-bit block. The usage of Feistel means that the "mangler" function used does not need to be ...
12
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6answers
2k views

Identity-Based Encryption - how secure is it?

I was always taught never to invent my own crypto algorithm, and never to trust someone who has a proprietary algorithm. I'm looking at Voltage SecureMail, which uses IBE (identity-based encryption) ...
11
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4answers
2k views

Using computer random number generators to produce keys, it is secure?

Does generating an encryption key using the random number generator on one's computer present a security risk? If so how might that risk be mitigated, specifically when generating RSA key pairs in ...
12
votes
5answers
4k views

Use RSA keypair for PGP encryption and decryption

Is there a way that I can use a RSA keypair with PGP? What I mean is that I have 2048 length keypair and i want to use that to encrypt and decrypt data. But all I have found is that the PGP uses some ...
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3answers
419 views

Would this kind of encryption be good at anything?

I have put much thought into this very simple algorithm and I have no clue if it was thought before... But I think it should have. I also know nothing about other encryption algorithms so I can't tell ...
4
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2answers
3k views

mysql AES_ENCRYPT key length

AES_ENCRYPT uses a 128 bit long key to encrypt the data, but how does mysql handle longer or shorter keys? I found out that pycrypto for instances recomend to transform the key by using md5 sha1 sha2, ...
-1
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1answer
169 views

Theorical question on encryption methods [duplicate]

Possible Duplicate: Encryption strategies for multi users access in production systems I would like to develop a service on wich clients would connect and retrieve informations. These ...
31
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2answers
8k views

Web Application encryption key management

In a nutshell, let's consider a web application which stores some information in a database as encrypted data. While I'm purposely trying to keep this some what generic, here are some assumptions: ...
8
votes
4answers
4k views

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 ...
7
votes
1answer
271 views

Collision attacks on OCB?

I've been looking into the OCB cipher mode and everything I hear sounds good. I was planning on implementing it. Everything except for this lone voice, that is: Collision attacks on OCB: We ...
4
votes
3answers
233 views

Choosing an authenticated encryption cipher mode without associated data

In the application I'm writing there is need for a huge amount of private data transfer on the order of eighty gigabytes, but there is no public data. I'm looking especially to gain ...
6
votes
1answer
2k views

What is the purpose of AEAD?

I think I need to correct some misunderstandings I have about AEAD. What is associated data used for in authenticated encryption?
5
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2answers
232 views

OMAC: multiplication in a finite field - how can I compute the correct polynomial

From The EAX Mode of Operation: We explain the notation used in the definition of OMAC. The value of iL (line 40: i an integer in {2, 4} and L ∈ {0, 1}n) is the n-bit string that is obtained by ...
3
votes
1answer
129 views

What is the benefit to using a two-pass AE scheme rather than one-pass?

What benefit is gained using a two-pass AE or AEAD scheme rather than a one-pass? Two-pass is roughly half the speed.
4
votes
2answers
147 views

A method for securely sharing centrally-stored documents among a changing set of users?

I believe it's possible to meet these requirements only if a third party is involved in a manual process. For example: Each user is given the same public key The private key resides offline at a ...
2
votes
1answer
379 views

Secure implementations of G2/G3/G4 cellular technology

It appears that GSM is like any other technology, and is only as secure as its implementation. What implementations are known to be secure or insecure due to a fault on the implementor's side, or due ...
6
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1answer
3k views

Is this how to implement CTR around a system that only implements CBC, CFB, CTS, ECB and OFB?

The encryption library in my programming language does not support CTR, though it supports CBC, CFB, CTS, ECB and OFB. I'm assuming it is theoretically possible to securely implement CTR around one ...