AES algorithm supports , , and bit encryption. We can also see in the above code that we used initialization vector IV which is of 16 bytes in size, the block size of the algorithm.
IV is optional. Now, we are going to write the following code in the Main method that is inside the Program. In the given code, we are using a hardcoded value as a key but in real time, we can get a key at runtime and also, we can use the optional initialization vector IV as per the complexity we need. In this article, we learned how to use a symmetric key for encryption and decryption in C. If you want to securely encrypt anything, you don't want to create your own encryption algorithms.
There are lots of ways to encrypt data and most of them are wrong. Stick to proven methods that have been rigorously tested.
Fortunately, we have several such algorithms available in. NET right out of the box, so we don't have to look to far. When we encrypt lots of data such as a file we typically use a symmetric algorithm. In cryptography when we use the term symmetric we mean that the same credentials that are used to encrypt the data are used to decrypt the data. A common example of this is when you password protect a zip archive. You use a password when you lock the archive and you must use the same password to unlock the archive.
If you lose or forget the password, you can't access the archive any more. It is heavily tested and relied upon by our government. It is definitely good enough for us and it is part of the. Start off by creating a new console project. Before we get into the details of encryption, let's get some basic functionality working. We simply want to copy the input file to the output file without making any changes to it.
This way, we know we have something working that we can build on. In the above code, that we require two arguments be provided. If not, we return with a friendly tip. Otherwise, we get the source file name as the first argument and the destination file name as the second argument. You might want to add some code to make sure the source file exists, but I'm going to skip that so we can focus on the core mechanics.
If you are not familiar with the using statement, you may want to look that up. In C that is a way to cleanup objects when we are done with them. It is particularly useful for file operations. The real work is the five lines of code that start on line 19 with the using statement.
We open our source file for reading line 19 and we create our destination file for writing line We get a stream for each file and simply copy the contents of one file to the other using the CopyTo method line If you are following along, this is a good time to make sure you can get this working and that you can create the target file identical to the source. Since we are already copying files using Stream objects, we use the CryptoStream API to add encryption to the existing operation.
The only thing we did here was add a few lines of code lines 22, 23, 24 and made a slight alteration to the stream copy line OK, MessageBoxIcon. Information ;. Show cert. Error ;. Encrypt Encoding. Text , true ;. ToBase64String cipherData ;. Show ex. Message, ex. ToString ,. We create an instance of the XStore class. This represents an X. We set the store location that exists in the current windows user that the application runs under.
The OpenFlags enumeration specifies the way to open the X. We create an instance of XCertificate2Collection and name it certCollection that defines a collection that stores XCertificate objects.
We fill this collection with the certificates in the store we open earlier. We create another instance of XCertificate2Collection and name it foundCollection that will store the found X Certificates with our search criteria. We fill this collection with X Certificates that are not expired in our store.
Create an XStore object and initialize it to open the current user store. Initialize an XCertificate2Collection with all of the certificates in the store. Enumerate through the certificates in the store and find the certificate with the appropriate name. Find the specified element in the XmlDocument object and create a new XmlElement object to represent the element you want to encrypt. In this example, the "creditcard" element is encrypted. Create a new instance of the EncryptedXml class and use it to encrypt the specified element using the X.
The Encrypt method returns the encrypted element as an EncryptedData object. Replace the element from the original XmlDocument object with the EncryptedData element. Save the XmlDocument object. This example assumes that a file named "test. It also assumes that "test.
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