-
-
Save davidsheardown/6781a4c45eaf85917392678d7c3993d6 to your computer and use it in GitHub Desktop.
| public static void Main(string[] args) | |
| { | |
| var content = "Example test"; | |
| var key = "E546C8DF278CD5931069B522E695D4F2"; | |
| var encrypted = EncryptString(content, key); | |
| Console.WriteLine(encrypted); | |
| var decrypted = DecryptString(encrypted, key); | |
| Console.WriteLine(decrypted); | |
| Console.ReadLine(); | |
| } | |
| public static string EncryptString(string text, string keyString) | |
| { | |
| var key = Encoding.UTF8.GetBytes(keyString); | |
| using (var aesAlg = Aes.Create()) | |
| { | |
| using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV)) | |
| { | |
| using (var msEncrypt = new MemoryStream()) | |
| { | |
| using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)) | |
| using (var swEncrypt = new StreamWriter(csEncrypt)) | |
| { | |
| swEncrypt.Write(text); | |
| } | |
| var iv = aesAlg.IV; | |
| var decryptedContent = msEncrypt.ToArray(); | |
| var result = new byte[iv.Length + decryptedContent.Length]; | |
| Buffer.BlockCopy(iv, 0, result, 0, iv.Length); | |
| Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length); | |
| return Convert.ToBase64String(result); | |
| } | |
| } | |
| } | |
| } | |
| public static string DecryptString(string cipherText, string keyString) | |
| { | |
| var fullCipher = Convert.FromBase64String(cipherText); | |
| var iv = new byte[16]; | |
| var cipher = new byte[16]; | |
| Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length); | |
| Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length); | |
| var key = Encoding.UTF8.GetBytes(keyString); | |
| using (var aesAlg = Aes.Create()) | |
| { | |
| using (var decryptor = aesAlg.CreateDecryptor(key, iv)) | |
| { | |
| string result; | |
| using (var msDecrypt = new MemoryStream(cipher)) | |
| { | |
| using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)) | |
| { | |
| using (var srDecrypt = new StreamReader(csDecrypt)) | |
| { | |
| result = srDecrypt.ReadToEnd(); | |
| } | |
| } | |
| } | |
| return result; | |
| } | |
| } | |
| } |
You need some modification on DecryptString
- Change >> var cipher = new byte[16]; to >> var cipher = new byte[fullCipher.Length - iv.Length];
2 . and instead of Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length); use
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, fullCipher.Length - iv.Length);
following is the complete working code if loner the length of string
public string DecryptString(string cipherText, string keyString)
{
var fullCipher = Convert.FromBase64String(cipherText);
var iv = new byte[16];
var cipher = new byte[fullCipher.Length - iv.Length]; //changes here
Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
// Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, fullCipher.Length - iv.Length); // changes here
var key = Encoding.UTF8.GetBytes(keyString);
using (var aesAlg = Aes.Create())
{
using (var decryptor = aesAlg.CreateDecryptor(key, iv))
{
string result;
using (var msDecrypt = new MemoryStream(cipher))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
{
result = srDecrypt.ReadToEnd();
}
}
}
return result;
}
}
}
yes it works. thx Pardeep
Receiving below error when "using (var encryptor = aesAlg.CreateEncryptor(_key, aesAlg.IV))" is executed in EncryptString function.
Error Message: ArgumentException: Specified key is not a valid size for this algorithm. Parameter name: rgbKey
Can anyone help?
Receiving below error when "using (var encryptor = aesAlg.CreateEncryptor(_key, aesAlg.IV))" is executed in EncryptString function.
Error Message: ArgumentException: Specified key is not a valid size for this algorithm. Parameter name: rgbKeyCan anyone help?
Same same
Use this as encryption key: "E546C8DF278CD5931069B522E695D4F2".
It will work for me now after updating key.
The key sizes need to be 128, 192 or 256 bits. Since the code above reads bytes from a UTF8 string min key length is 16 characters, 24 and 32 chars lengths will also work. Anything else will throw an exception
FYI I think Ln56 has a bug, perhaps it should be
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, **cipher**.Length);otherwise it won't work when you encrypt larger strings