///-------------------------------------------------------------------------------------------------
/// <summary> 解密一个文件流. </summary>
///
/// <remarks> Surface, 2018/9/18. </remarks>
///
/// <param name="enStream"> 加密文件的流，这个流从0位置到开始都是加密文件数据，包括前面的info信息. </param>
/// <param name="deStream"> 解密流，原始数据流（这个流从0位置开始都是有效的原始数据）. </param>
/// <param name="key"> The key. </param>
/// <param name="blockLen"> (Optional) 加密buffer长度. </param>
///
/// <returns> A CryptoFile. </returns>
///-------------------------------------------------------------------------------------------------
public static CryptoFile Decrypt(Stream enStream, Stream deStream, byte[] key, int blockLen = 4096)
{
CryptoFile cfile = new CryptoFile()
{
isCryptoFile = true, enStream = enStream, deStream = deStream
};
byte[] byheader = Encoding.UTF8.GetBytes(cfile.header);
enStream.Position = 0;
BinaryReader br = new BinaryReader(enStream);
//验证文件头是否是加密文件
for (int i = 0; i < byheader.Length; i++)
{
if (br.ReadByte() != byheader[i])
{
cfile.isCryptoFile = false;
break;
}
}
if (cfile.isCryptoFile == false)
{
return(cfile);
}
cfile.md5 = br.ReadString();
cfile.info = br.ReadString();
cfile.deStream.Position = 0;
Crypto.AESDecrypt(enStream, cfile.deStream, key, blockLen);
return(cfile);
}
///-------------------------------------------------------------------------------------------------
/// <summary> 加密一个文件流. </summary>
///
/// <remarks> Surface, 2018/9/18. </remarks>
///
/// <param name="oriStream"> 原始文件流. </param>
/// <param name="info"> 一些可以被记录的其他附加信息. </param>
/// <param name="enStream"> 加密文件的流，这个流从0位置到开始都是加密文件数据，包括前面的info信息。. </param>
/// <param name="key"> The key. </param>
/// <param name="blockLen"> (Optional) 加密buffer长度. </param>
///
/// <returns> A CryptoFile. </returns>
///-------------------------------------------------------------------------------------------------
public static CryptoFile Encrypt(Stream oriStream, string info, Stream enStream, byte[] key, int blockLen = 4096)
{
CryptoFile cfile = new CryptoFile()
{
isCryptoFile = true
};
cfile.md5 = xuexue.file.MD5Helper.MD5(oriStream);
cfile.info = info;
cfile.enStream = enStream; //设置加密流
cfile.deStream = oriStream; //原始数据流就是解密流
cfile.deStream.Position = 0;
BinaryWriter bw = new BinaryWriter(cfile.enStream);
bw.Write(Encoding.UTF8.GetBytes(cfile.header)); //先写一个文件头,这样写不带长度
bw.Write(cfile.md5); //写一个md5信息，这个自带string长度
bw.Write(cfile.info); //写一个info信息，这个自带string长度
bw.Flush();
//使用原始文件流，原始文件流的长度
Crypto.AESEncrypt(cfile.deStream, cfile.deStream.Length, enStream, key);
return(cfile);
}
