/// <summary>
/// Loads contents of encryptedInputFile to string, decrypts the string and returns decrypted string to caller.
/// </summary>
/// <param name="encryptedInputFile">Path to file containing encrypted data.</param>
/// <returns>Decrypted string.</returns>
public string Decrypt(string encryptedInputFile)
{
string encryptedString = string.Empty;
string decryptedString = string.Empty;
IStringEncryptor encryptor = new StringEncryptorTripleDES();
if (String.IsNullOrEmpty(encryptedInputFile))
{
throw new ArgumentNullException("Path to both the encrypted input file needs to be specified.");
}
if (KeyIsValid(GetStringFromByteArray(_key)) == false)
{
throw new System.Exception("Invalid length for Key.");
}
if (IVIsValid(GetStringFromByteArray(_iv)) == false)
{
throw new System.Exception("Invalid length for IV.");
}
try
{
encryptedString = File.ReadAllText(encryptedInputFile);
encryptor.Key = this.Key;
encryptor.IV = this.IV;
decryptedString = encryptor.Decrypt(encryptedString);
}
catch (System.Exception ex)
{
_msg.Length = 0;
_msg.Append("Attempt to decrypt file to string failed: Make sure you are using the same key and IV used to encryp ");
_msg.Append(encryptedInputFile);
_msg.Append("\r\n");
_msg.Append("Error Message:");
_msg.Append("\r\n");
_msg.Append(AppMessages.FormatErrorMessage(ex));
throw new System.Exception(_msg.ToString());
}
finally
{
;
}
return(decryptedString);
}
/// <summary>
/// Decrypts by loading encryptedInputFile to a string and then decrypting the string. Decrypted string is then written out as text to the outputFile.
/// </summary>
/// <param name="encryptedInputFile">Full path to file containing the encrypted data.</param>
/// <param name="outputFile">Full path to file that will contain decrypted data.</param>
/// <returns>Returns path to output file.</returns>
public string Decrypt(string encryptedInputFile, string outputFile)
{
IStringEncryptor encryptor = new StringEncryptorTripleDES();
if (String.IsNullOrEmpty(encryptedInputFile) || String.IsNullOrEmpty(outputFile))
{
throw new ArgumentNullException("Paths to both the encrypted input file and the output file need to be specified.");
}
if (KeyIsValid(GetStringFromByteArray(_key)) == false)
{
throw new System.Exception("Invalid length for Key.");
}
if (IVIsValid(GetStringFromByteArray(_iv)) == false)
{
throw new System.Exception("Invalid length for IV.");
}
try
{
string encryptedData = File.ReadAllText(encryptedInputFile);
encryptor.Key = this.Key;
encryptor.IV = this.IV;
string decryptedData = encryptor.Decrypt(encryptedData);
File.WriteAllText(outputFile, decryptedData);
}
catch (System.Exception ex)
{
_msg.Length = 0;
_msg.Append("Attempt to decrypt file ");
_msg.Append(encryptedInputFile);
_msg.Append(" failed. Verify you are using same key/iv pair used to encrypt. Error message: ");
_msg.Append("\r\n");
_msg.Append(AppMessages.FormatErrorMessage(ex));
throw new System.Exception(_msg.ToString());
}
finally
{
;
}
return(outputFile);
}
