ファイルからテキストを読み取り、暗号化して文字列形式で関数に渡そうとしています。後で私もそれを解読したいと思います。
次のことを試しましたが、暗号化は行われませんでした。簡単な暗号化アルゴリズムを提案できる人はいますか?
fileStream = store.OpenFile(strFilePath, FileMode.Open, FileAccess.Read);
strEncryptedFileStream = Encoding.Unicode.GetBytes(fileStream.ToString()).ToString();
AESを使用します。これはヘルパークラスです。「単純な」暗号化、つまり簡単に破られる暗号化を使用しても意味がありません。人々がそれを破ることができるようにしたいか、そうでないかのどちらかです。よく知られており、テスト済みの暗号化標準を選択してください。
必要に応じて以下の例を変更できる場合があります。
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Diagnostics;
namespace Common.Cryptography
{
/// <summary>
/// AES is a symmetric 256-bit encryption algorthm.
/// Read more: http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
/// </summary>
public static class AES
{
private const string _SALT = "g46dzQ80";
private const string _INITVECTOR = "OFRna74m*aze01xY";
private static byte[] _saltBytes;
private static byte[] _initVectorBytes;
static AES()
{
_saltBytes = Encoding.UTF8.GetBytes(_SALT);
_initVectorBytes = Encoding.UTF8.GetBytes(_INITVECTOR);
}
/// <summary>
/// Encrypts a string with AES
/// </summary>
/// <param name="plainText">Text to be encrypted</param>
/// <param name="password">Password to encrypt with</param>
/// <param name="salt">Salt to encrypt with</param>
/// <param name="initialVector">Needs to be 16 ASCII characters long</param>
/// <returns>An encrypted string</returns>
public static string Encrypt(string plainText, string password, string salt = null, string initialVector = null)
{
return Convert.ToBase64String(EncryptToBytes(plainText, password, salt, initialVector));
}
/// <summary>
/// Encrypts a string with AES
/// </summary>
/// <param name="plainText">Text to be encrypted</param>
/// <param name="password">Password to encrypt with</param>
/// <param name="salt">Salt to encrypt with</param>
/// <param name="initialVector">Needs to be 16 ASCII characters long</param>
/// <returns>An encrypted string</returns>
public static byte[] EncryptToBytes(string plainText, string password, string salt = null, string initialVector = null)
{
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
return EncryptToBytes(plainTextBytes, password, salt, initialVector);
}
/// <summary>
/// Encrypts a string with AES
/// </summary>
/// <param name="plainTextBytes">Bytes to be encrypted</param>
/// <param name="password">Password to encrypt with</param>
/// <param name="salt">Salt to encrypt with</param>
/// <param name="initialVector">Needs to be 16 ASCII characters long</param>
/// <returns>An encrypted string</returns>
public static byte[] EncryptToBytes(byte[] plainTextBytes, string password, string salt = null, string initialVector = null)
{
int keySize = 256;
byte[] initialVectorBytes = string.IsNullOrEmpty(initialVector) ? _initVectorBytes : Encoding.UTF8.GetBytes(initialVector);
byte[] saltValueBytes = string.IsNullOrEmpty(salt) ? _saltBytes : Encoding.UTF8.GetBytes(salt);
byte[] keyBytes = new Rfc2898DeriveBytes(password, saltValueBytes).GetBytes(keySize / 8);
using (RijndaelManaged symmetricKey = new RijndaelManaged())
{
symmetricKey.Mode = CipherMode.CBC;
using (ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initialVectorBytes))
{
using (MemoryStream memStream = new MemoryStream())
{
using (CryptoStream cryptoStream = new CryptoStream(memStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
return memStream.ToArray();
}
}
}
}
}
/// <summary>
/// Decrypts an AES-encrypted string.
/// </summary>
/// <param name="cipherText">Text to be decrypted</param>
/// <param name="password">Password to decrypt with</param>
/// <param name="salt">Salt to decrypt with</param>
/// <param name="initialVector">Needs to be 16 ASCII characters long</param>
/// <returns>A decrypted string</returns>
public static string Decrypt(string cipherText, string password, string salt = null, string initialVector = null)
{
byte[] cipherTextBytes = Convert.FromBase64String(cipherText.Replace(' ','+'));
return Decrypt(cipherTextBytes, password, salt, initialVector).TrimEnd('\0');
}
/// <summary>
/// Decrypts an AES-encrypted string.
/// </summary>
/// <param name="cipherText">Text to be decrypted</param>
/// <param name="password">Password to decrypt with</param>
/// <param name="salt">Salt to decrypt with</param>
/// <param name="initialVector">Needs to be 16 ASCII characters long</param>
/// <returns>A decrypted string</returns>
public static string Decrypt(byte[] cipherTextBytes, string password, string salt = null, string initialVector = null)
{
int keySize = 256;
byte[] initialVectorBytes = string.IsNullOrEmpty(initialVector) ? _initVectorBytes : Encoding.UTF8.GetBytes(initialVector);
byte[] saltValueBytes = string.IsNullOrEmpty(salt) ? _saltBytes : Encoding.UTF8.GetBytes(salt);
byte[] keyBytes = new Rfc2898DeriveBytes(password, saltValueBytes).GetBytes(keySize / 8);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
using (RijndaelManaged symmetricKey = new RijndaelManaged())
{
symmetricKey.Mode = CipherMode.CBC;
using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initialVectorBytes))
{
using (MemoryStream memStream = new MemoryStream(cipherTextBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(memStream, decryptor, CryptoStreamMode.Read))
{
int byteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
return Encoding.UTF8.GetString(plainTextBytes, 0, byteCount);
}
}
}
}
}
}
}
コード内で暗号化を行うものはありません。Unicode に変換しているだけです。
C# での暗号化の良い例を示すこの質問を見ることができます。
メソッド Enconding は、テキスト エンコーディング (UTF-8、ANSI など...) に関するもので、暗号化アルゴリズムを使用する必要があります。これを行うにはいくつかの方法があります。簡単な例では、XOR 暗号化を使用します。
これを参照してください：
string XorEncryptDecryptText(string stringText, string stringKey){
// Variable that receives the result of processode encryption.
string stringNewText = "";
// First we take the difference in size of the two strings.
int diff = (stringText.Length - stringKey.Length);
// If the size difference that we put stringKey with the same size as the XOR stringText that no errors occur.
if (diff > 0){
// We calculate the rest and the amount of times we repeat the stringKey to equal sizes.
int cont = (int)diff / stringKey.Length;
int resto = diff % stringKey.Length;
string stringKeyAux = stringKey;
// At this point the stringText concatenate the stringKey to be equal sizes.
for (int i = 0; i < cont; i++){
stringKeyAux += stringKey;
}
for (int i = 0; (i < resto); i++){
stringKeyAux += stringKey[i];
}
stringKey = stringKeyAux;
}
// At this point piece of code is done the process of XOR.
for (int i = 0; i < stringText.Length; i++){
int charValue = Convert.ToInt32(stringText[i]);
int charKey = Convert.ToInt32(stringKey[i]);
charValue ^= charKey;
stringNewText += char.ConvertFromUtf32(charValue);
}
return stringNewText;}
string XOREncriptDecriptFile(string FileName, string stringKey){
string stringAux = System.IO.File.ReadAllLines(FileName);
return XorEncryptDecryptText(stringAux, stringKey);}
このコードはhttp://julioborges.p.ht/?p=769に基づいています。
セキュリティを強化するには、smdragerの回答を使用します