.NET provides high-level level classes for various encryption algorithms, both symmetric and asymmetric. Advanced Encryption Standard (AES) is one of the symmetric encryption algorithms that allows both parties, sender, and receiver, to use the same key to encrypt and decrypt data.
AES was developed by two Belgian cryptographers, Vincent Rijmen and Jan Daemen. In 2001, AES was selected as a standard for encryption by the U. S. National Institute of Standards and Technology (NIST). AES supports 128, 192, and 256 bits key sizes and 128 bits sizes.
AesManaged class is a managed implementation of the AES algorithm. This article demonstrates the use AesManaged class to apply an AES algorithm to encrypt and decrypt data in .NET and C#.
The following steps are required to encrypt data using AesManaged.
Step 1
Create AesManaged,
AesManagedaes=newAesManaged();Step 2
Create Encryptor,
ICryptoTransformencryptor=aes.CreateEncryptor(Key,IV);Step 3
Create MemoryStream,
MemoryStreamms=newMemoryStream();Step 4
Create CryptoStream from MemoryStream and Encrypter and write it.
using(CryptoStreamcs=newCryptoStream(ms,encryptor,CryptoStreamMode.Write)){//CreateStreamWriterandwritedatatoastreamusing(StreamWritersw=newStreamWriter(cs))sw.Write(plainText);encrypted=ms.ToArray();}The complete code is listed in Listing 1. To test the code, create a .NET Core project in Visual Studio and copy and paste the code.
usingSystem;usingSystem.IO;usingSystem.Security.Cryptography;classManagedAesSample{publicstaticvoidMain(){Console.WriteLine("Entertextthatneedstobeencrypted..");stringdata=Console.ReadLine();EncryptAesManaged(data);Console.ReadLine();}staticvoidEncryptAesManaged(stringraw){try{//CreateAesthatgeneratesanewkeyandinitializationvector(IV).//Samekeymustbeusedinencryptionanddecryptionusing(AesManagedaes=newAesManaged()){//Encryptstringbyte[]encrypted=Encrypt(raw,aes.Key,aes.IV);//PrintencryptedstringConsole.WriteLine($"Encrypteddata:{System.Text.Encoding.UTF8.GetString(encrypted)}");//decryptthebytestoastring.stringdecrypted=Decrypt(encrypted,aes.Key,aes.IV);//Printdecryptedstring.ItshouldbesameasrawdataConsole.WriteLine($"Decrypteddata:{decrypted}");}}catch(Exceptionexp){Console.WriteLine(exp.Message);}Console.ReadKey();}staticbyte[]Encrypt(stringplainText,byte[]Key,byte[]IV){byte[]encrypted;//CreateanewAesManaged.using(AesManagedaes=newAesManaged()){//CreateencryptorICryptoTransformencryptor=aes.CreateEncryptor(Key,IV);//CreateMemoryStreamusing(MemoryStreamms=newMemoryStream()){//CreatecryptostreamusingtheCryptoStreamclass.Thisclassisthekeytoencryption//andencryptsanddecryptsdatafromanygivenstream.Inthiscase,wewillpassamemorystream//toencryptusing(CryptoStreamcs=newCryptoStream(ms,encryptor,CryptoStreamMode.Write)){//CreateStreamWriterandwritedatatoastreamusing(StreamWritersw=newStreamWriter(cs))sw.Write(plainText);encrypted=ms.ToArray();}}}//Returnencrypteddatareturnencrypted;}staticstringDecrypt(byte[]cipherText,byte[]Key,byte[]IV){stringplaintext=null;//CreateAesManagedusing(AesManagedaes=newAesManaged()){//CreateadecryptorICryptoTransformdecryptor=aes.CreateDecryptor(Key,IV);//Createthestreamsusedfordecryption.using(MemoryStreamms=newMemoryStream(cipherText)){//Createcryptostreamusing(CryptoStreamcs=newCryptoStream(ms,decryptor,CryptoStreamMode.Read)){//Readcryptostreamusing(StreamReaderreader=newStreamReader(cs))plaintext=reader.ReadToEnd();}}}returnplaintext;}}Listing 1.
The output looks like the following, where you can type any text that will be encrypted and decrypted.
References
- https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
- https://docs.microsoft.com
