encryption-symmetric

Differences Between Rijndael and AES

I'm investigating encryption algorithms - can someone give me a quick rundown of the differences between Rijndael and AES? ...

Should one use Cryptographic message syntax (CMS) for this task?

Hello, I've the task to transfer small binary messages (1 or 2 kb long) between a desktop application and mobile devices. The messages should be encrypted asymmetrically (RSA for instance). From what I've learned one should use a hybrid cryptosystem for this kind of task: Generate random symmetric key Encrypt plain text with symmetric...

Can Derby / JavaDB _really_ encrypt with Triple DES rather than (plain) DES?

It seems to be confusing Triple-DES (>128bit) with plain DES (64bit). I'm trying to encrypt a Derby database with Triple DES (or DESede) using Java 1.5 I found this discussion forum message about a problem with JDK 1.5 by chance and so checked to make sure that it really was using DESede and not plain DES. When I created the database wi...

Preventing MITM attacks on server

Hello, Two clients Alice and Bob use a server to login and exchange messages through the server. On login, they both send their public keys to be stored on the server. When Alice wants to speak to Bob, she enrypts a symmetric key with Bob's public key and sends it to Bob through the server. How can I make sure that the server doesn't...

Securely Storing Optional Entropy While Using DPAPI

So I am trying to store the symmetric key using DPAPI. All is well and great, but what to do with the entropy? This answered question here really doesn't provide enough insight. It seems like a slippery slope - I could use the machine store to store the entropy but then what prevents someone from getting at that as well? Note: I am stori...

Diffie-Hellman in Silverlight

I am trying to devise a security scheme for encrypting the application level data between a silverlight client, and a php webservice that I created. Since I am dealing with a public website the information I am pulling from the service is public, but the information I'm submitting to the webservice is not public. There is also a back end...

BAD_UID error while exporting key in CryptoAPI

Hi all, I am writing a test application for Microsoft CryptoAPI. I want to export the secret key of one party using the public key of the second party, and then import that secret key as the second party's secret key (this sets up a shared secret key for communication). Here is my code: if(!CryptExportKey(encryptT->hSymKey, decryptT->hP...

Safe non-tamperable URL component in Perl using symmetric encryption?

OK, I'm probably just having a bad Monday, but I have the following need and I'm seeing lots of partial solutions but I'm sure I'm not the first person to need this, so I'm wondering if I'm missing the obvious. $client has 50 to 500 bytes worth of binary data that must be inserted into the middle of a URL and roundtrip to their customer...

AES / Rijndael Test Vectors : what padding mode?

So I've been looking at these test vectors for the Known Answer Test for AES / Rijndael (with 128-bit block) in CBC mode, and I wonder: what kind of padding do they use? PKCS7? ...

How to authenticate client based on possession of symmetric key?

Our clients call our web service over SSL and authenticate themselves with a username and password. Our server then generates a symmetric key and sends it back to the client. Then, the client establishes a TCP connection to our server, and sends a login message. At this point, I want to authenticate the client. My idea is to have the c...

PyCrypto problem using AES+CTR

Hi, I'm writing a piece of code to encrypt a text using symmetric encryption. But it's not coming back with the right result... from Crypto.Cipher import AES import os crypto = AES.new(os.urandom(32), AES.MODE_CTR, counter = lambda : os.urandom(16)) encrypted = crypto.encrypt("aaaaaaaaaaaaaaaa") print crypto.decrypt(encrypted) Here,...

Getting 'BadPaddingException: pad block corrupted' in AES/CBC/PKCS5Padding

My constants public static final String AES_ALGORITHM_MODE_PADDING = "AES/CBC/PKCS5Padding"; public static final String AES = "AES"; public static final String PROVIDER = "BC"; Encryption Cipher aesCipher = Cipher.getInstance(AES_ALGORITHM_MODE_PADDING, PROVIDER); SecretKeySpec aeskeySpec = new SecretKeySpec(rawAesKey, AES);...

Static or random IV for a license file

I have made a small program that will allow me to send licenses in encrypted form to users. At the moment I have An RSA private key that encrypts my AES key A single AES/CBC key that encrypts the data An RSA public key Both the AES and public key are hard coded onto the device. How should I deal with the IV when a license is reque...

AES key finding from encrypted and plaintext data

If I have a plaintext message M along with its encrypted equivalent E, and I know that it has been encrypted with a 256-bit AES key, is there a way to work out the key? Are there ways to do it, if M is long enough? ...

Differences between CAPICOM TripleDES and System.Security.Cryptography TripleDES

I'm trying to move away from using CAPICOM since I can no longer use it (64-bit Windows 7 machine). The existing code for using TripleDES is like this: EncryptedDataClass cryptic = new EncryptedDataClass(); cryptic.Algorithm.Name = CAPICOM_ENCRYPTION_ALGORITHM.CAPICOM_ENCRYPTION_ALGORITHM_3DES; cryptic.SetSecret(secretKey, CAPICOM_SECR...

Using Rijndael encryption for large files

Hi there! I'm in a situation where I need to encrypt / decrypt a file of n length securely, ideally using Rijndael, but definitely at 256bit encryption. I've played around with encryption before and have encrypted/decrypted strings and byte arrays quite happily. However, because I don't know the size of the file (and it's very feasible...

Calculation of encrypted file size does not match true size.

I have the need to calculate the size of a file I am encrypting using Rijndael. According to other answers on this site, and on google, the following is the correct way of calculating encrypted data length: EL = UL + (BS - (UL Mod BS) Mod BS) Where: EL = Encrypted Length UL = Unencrypted Length BS = Block Size In my instance, the u...

Proper password storage and retrieval for service accounts?

Most of the information that I found and read about properly storing passwords in a database say that I should Hash the password clear text with a unique salt value for each user and then store that hash in the database. But this process doesn't work for my needs... I have a windows service written in C# that needs to connect to other r...

Simple XOR a message (Javascript/Tcl)?

I need the username/password to be scrambled at the client-side before sending it over via HTTP GET/POST. And the server will decode it with Tcl, before the checks against database. Currently I'm thinking about using JavaScript for the client-side. Java Applet will also do. Is there any way, that I can easily achieve it, using Simple X...

SQL Encrypted Columns in WHERE Clause

Hi I am looking to apply SQL column level encryption using symmetric keys. The initial steps needed to create the Database Master Key, Certificates and Symmetric Keys seems straight forward and I have tested encrypting/decrypting data using Symmetric Keys successfully. However, once the data is encrypted I don't know how best to query...