mirror of
https://github.com/SabreTools/NDecrypt.git
synced 2026-07-08 18:06:38 +00:00
Take advantage of Wrapper functions for NDS
This commit is contained in:
Matt Nadareski
@@ -2,20 +2,12 @@
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using System.IO;
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using System.Text;
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using SabreTools.IO.Extensions;
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using SabreTools.Models.Nitro;
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using SabreTools.Serialization.Deserializers;
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using SabreTools.Serialization.Wrappers;
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namespace NDecrypt.Core
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{
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public class DSTool : ITool
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{
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#region Encryption process variables
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private uint[] _cardHash = new uint[0x412];
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private uint[] _arg2 = new uint[3];
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#endregion
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/// <summary>
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/// Decryption args to use while processing
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/// </summary>
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@@ -35,22 +27,31 @@ namespace NDecrypt.Core
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{
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// Open the read and write on the same file for inplace processing
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using var reader = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
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using var writer = File.Open(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
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// Deserialize the cart information
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var commonHeader = Nitro.ParseCommonHeader(reader);
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if (commonHeader == null)
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var nitro = Nitro.Create(reader);
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if (nitro == null)
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{
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Console.WriteLine("Error: Not a DS or DSi Rom!");
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return false;
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}
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// Reset state variables
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_cardHash = new uint[0x412];
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_arg2 = new uint[3];
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// Ensure the secure area was read
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if (nitro.SecureArea == null)
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{
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Console.WriteLine("Error: Invalid secure area!");
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return false;
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}
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// Encrypt the secure area
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EncryptSecureArea(commonHeader, force, reader, writer);
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nitro.EncryptSecureArea(_decryptArgs.NitroEncryptionData, force);
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// Write the encrypted secure area
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using var writer = File.Open(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
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writer.Seek(0x4000, SeekOrigin.Begin);
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writer.Write(nitro.SecureArea);
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writer.Flush();
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return true;
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}
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catch
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@@ -61,123 +62,6 @@ namespace NDecrypt.Core
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}
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}
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/// <summary>
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/// Encrypt secure area in the DS/DSi file
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/// </summary>s
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/// <param name="commonHeader">CommonHeader representing the DS file header</param>
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/// <param name="force">Indicates if the operation should be forced</param>
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/// <param name="reader">Stream representing the input</param>
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/// <param name="writer">Stream representing the output</param>
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private void EncryptSecureArea(CommonHeader commonHeader, bool force, Stream reader, Stream writer)
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{
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// If we're forcing the operation, tell the user
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if (force)
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{
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Console.WriteLine("File is not verified due to force flag being set.");
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}
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// If we're not forcing the operation, check to see if we should be proceeding
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else
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{
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bool? isDecrypted = CheckIfDecrypted(reader);
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if (isDecrypted == null)
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{
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Console.WriteLine("File has an empty secure area, cannot proceed");
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return;
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}
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else if (!isDecrypted.Value)
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{
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Console.WriteLine("File is already encrypted");
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return;
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}
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}
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EncryptARM9(commonHeader, reader, writer);
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Console.WriteLine("File has been encrypted");
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}
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/// <summary>
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/// Encrypt the secure ARM9 region of the file, if possible
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/// </summary>
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/// <param name="commonHeader">CommonHeader representing the DS header</param>
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/// <param name="encrypt">Indicates if the file should be encrypted or decrypted</param>
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/// <param name="reader">Stream representing the input</param>
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/// <param name="writer">Stream representing the output</param>
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private void EncryptARM9(CommonHeader commonHeader, Stream reader, Stream writer)
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{
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// Seek to the beginning of the secure area
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reader.Seek(0x4000, SeekOrigin.Begin);
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writer.Seek(0x4000, SeekOrigin.Begin);
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// Grab the first two blocks
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uint p0 = reader.ReadUInt32();
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uint p1 = reader.ReadUInt32();
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// Perform the initialization steps
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Init1(commonHeader);
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_arg2[1] <<= 1;
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_arg2[2] >>= 1;
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Init2();
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// Ensure alignment
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reader.Seek(0x4008, SeekOrigin.Begin);
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writer.Seek(0x4008, SeekOrigin.Begin);
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// Loop throgh the main encryption step
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uint size = 0x800 - 8;
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while (size > 0)
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{
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p0 = reader.ReadUInt32();
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p1 = reader.ReadUInt32();
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Encrypt(ref p1, ref p0);
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writer.Write(p0);
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writer.Write(p1);
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size -= 8;
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}
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// Replace the header explicitly
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reader.Seek(0x4000, SeekOrigin.Begin);
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writer.Seek(0x4000, SeekOrigin.Begin);
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p0 = reader.ReadUInt32();
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p1 = reader.ReadUInt32();
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if (p0 == 0xE7FFDEFF && p1 == 0xE7FFDEFF)
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{
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p0 = Constants.MAGIC30;
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p1 = Constants.MAGIC34;
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}
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Encrypt(ref p1, ref p0);
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Init1(commonHeader);
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Encrypt(ref p1, ref p0);
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writer.Write(p0);
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writer.Write(p1);
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}
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/// <summary>
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/// Perform an encryption step
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/// </summary>
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/// <param name="arg1">First unsigned value to use in encryption</param>
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/// <param name="arg2">Second unsigned value to use in encryption</param>
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private void Encrypt(ref uint arg1, ref uint arg2)
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{
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uint a = arg1;
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uint b = arg2;
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for (int i = 0; i < 16; i++)
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{
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uint c = _cardHash[i] ^ a;
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a = b ^ Lookup(c);
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b = c;
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}
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arg2 = a ^ _cardHash[16];
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arg1 = b ^ _cardHash[17];
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}
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#endregion
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#region Decrypt
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@@ -189,22 +73,30 @@ namespace NDecrypt.Core
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{
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// Open the read and write on the same file for inplace processing
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using var reader = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
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using var writer = File.Open(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
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// Deserialize the cart information
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var commonHeader = Nitro.ParseCommonHeader(reader);
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if (commonHeader == null)
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var nitro = Nitro.Create(reader);
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if (nitro == null)
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{
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Console.WriteLine("Error: Not a DS or DSi Rom!");
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return false;
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}
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// Reset state variables
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_cardHash = new uint[0x412];
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_arg2 = new uint[3];
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// Ensure the secure area was read
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if (nitro.SecureArea == null)
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{
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Console.WriteLine("Error: Invalid secure area!");
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return false;
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}
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// Decrypt the secure area
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DecryptSecureArea(commonHeader, force, reader, writer);
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nitro.DecryptSecureArea(_decryptArgs.NitroEncryptionData, force);
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// Write the decrypted secure area
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using var writer = File.Open(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
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writer.Seek(0x4000, SeekOrigin.Begin);
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writer.Write(nitro.SecureArea);
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writer.Flush();
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return true;
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}
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@@ -216,115 +108,6 @@ namespace NDecrypt.Core
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}
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}
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/// <summary>
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/// Decrypt secure area in the DS/DSi file
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/// </summary>s
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/// <param name="commonHeader">CommonHeader representing the DS file header</param>
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/// <param name="force">Indicates if the operation should be forced</param>
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/// <param name="reader">Stream representing the input</param>
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/// <param name="writer">Stream representing the output</param>
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private void DecryptSecureArea(CommonHeader commonHeader, bool force, Stream reader, Stream writer)
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{
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// If we're forcing the operation, tell the user
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if (force)
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{
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Console.WriteLine("File is not verified due to force flag being set.");
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}
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// If we're not forcing the operation, check to see if we should be proceeding
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else
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{
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bool? isDecrypted = CheckIfDecrypted(reader);
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if (isDecrypted == null)
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{
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Console.WriteLine("File has an empty secure area, cannot proceed");
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return;
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}
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else if (isDecrypted.Value)
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{
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Console.WriteLine("File is already decrypted");
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return;
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}
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}
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DecryptARM9(commonHeader, reader, writer);
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Console.WriteLine("File has been decrypted");
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}
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/// <summary>
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/// Decrypt the secure ARM9 region of the file, if possible
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/// </summary>
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/// <param name="commonHeader">CommonHeader representing the DS header</param>
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/// <param name="">Indicates if the file should be encrypted or decrypted</param>
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/// <param name="reader">Stream representing the input</param>
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/// <param name="writer">Stream representing the output</param>
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private void DecryptARM9(CommonHeader commonHeader, Stream reader, Stream writer)
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{
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// Seek to the beginning of the secure area
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reader.Seek(0x4000, SeekOrigin.Begin);
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writer.Seek(0x4000, SeekOrigin.Begin);
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// Grab the first two blocks
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uint p0 = reader.ReadUInt32();
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uint p1 = reader.ReadUInt32();
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// Perform the initialization steps
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Init1(commonHeader);
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Decrypt(ref p1, ref p0);
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_arg2[1] <<= 1;
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_arg2[2] >>= 1;
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Init2();
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// Set the proper flags
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Decrypt(ref p1, ref p0);
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if (p0 == Constants.MAGIC30 && p1 == Constants.MAGIC34)
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{
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p0 = 0xE7FFDEFF;
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p1 = 0xE7FFDEFF;
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}
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writer.Write(p0);
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writer.Write(p1);
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// Ensure alignment
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reader.Seek(0x4008, SeekOrigin.Begin);
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writer.Seek(0x4008, SeekOrigin.Begin);
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// Loop throgh the main encryption step
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uint size = 0x800 - 8;
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while (size > 0)
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{
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p0 = reader.ReadUInt32();
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p1 = reader.ReadUInt32();
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Decrypt(ref p1, ref p0);
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writer.Write(p0);
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writer.Write(p1);
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size -= 8;
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}
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}
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/// <summary>
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/// Perform a decryption step
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/// </summary>
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/// <param name="arg1">First unsigned value to use in decryption</param>
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/// <param name="arg2">Second unsigned value to use in decryption</param>
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private void Decrypt(ref uint arg1, ref uint arg2)
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{
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uint a = arg1;
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uint b = arg2;
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for (int i = 17; i > 1; i--)
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{
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uint c = _cardHash[i] ^ a;
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a = b ^ Lookup(c);
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b = c;
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}
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arg1 = b ^ _cardHash[0];
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arg2 = a ^ _cardHash[1];
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}
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#endregion
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#region Info
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@@ -361,10 +144,6 @@ namespace NDecrypt.Core
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}
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}
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#endregion
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#region Common
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/// <summary>
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/// Determine if the current file is already decrypted or not (or has an empty secure area)
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/// </summary>
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@@ -456,87 +235,6 @@ namespace NDecrypt.Core
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return firstValue == 0xE7FFDEFF && secondValue == 0xE7FFDEFF;
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}
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/// <summary>
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/// First common initialization step
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/// </summary>
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/// <param name="commonHeader">CommonHeader representing the DS file</param>
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private void Init1(CommonHeader commonHeader)
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{
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Buffer.BlockCopy(_decryptArgs.NitroEncryptionData, 0, _cardHash, 0, 4 * (1024 + 18));
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_arg2 = [commonHeader.GameCode, commonHeader.GameCode >> 1, commonHeader.GameCode << 1];
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Init2();
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Init2();
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}
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/// <summary>
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/// Second common initialization step
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/// </summary>
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private void Init2()
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{
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Encrypt(ref _arg2[2], ref _arg2[1]);
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Encrypt(ref _arg2[1], ref _arg2[0]);
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byte[] allBytes =[.. BitConverter.GetBytes(_arg2[0]),
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.. BitConverter.GetBytes(_arg2[1]),
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.. BitConverter.GetBytes(_arg2[2])];
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UpdateHashtable(allBytes);
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}
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/// <summary>
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/// Lookup the value from the hashtable
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/// </summary>
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/// <param name="v">Value to lookup in the hashtable</param>
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/// <returns>Processed value through the hashtable</returns>
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private uint Lookup(uint v)
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{
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uint a = (v >> 24) & 0xFF;
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uint b = (v >> 16) & 0xFF;
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uint c = (v >> 8) & 0xFF;
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uint d = (v >> 0) & 0xFF;
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a = _cardHash[a + 18 + 0];
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b = _cardHash[b + 18 + 256];
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c = _cardHash[c + 18 + 512];
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d = _cardHash[d + 18 + 768];
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return d + (c ^ (b + a));
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}
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/// <summary>
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/// Update the hashtable
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/// </summary>
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/// <param name="arg1">Value to update the hashtable with</param>
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private void UpdateHashtable(byte[] arg1)
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{
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for (int j = 0; j < 18; j++)
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{
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uint r3 = 0;
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for (int i = 0; i < 4; i++)
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{
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r3 <<= 8;
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r3 |= arg1[(j * 4 + i) & 7];
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}
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_cardHash[j] ^= r3;
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}
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uint tmp1 = 0;
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uint tmp2 = 0;
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for (int i = 0; i < 18; i += 2)
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{
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Encrypt(ref tmp1, ref tmp2);
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_cardHash[i + 0] = tmp1;
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_cardHash[i + 1] = tmp2;
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}
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for (int i = 0; i < 0x400; i += 2)
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{
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Encrypt(ref tmp1, ref tmp2);
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_cardHash[i + 18 + 0] = tmp1;
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_cardHash[i + 18 + 1] = tmp2;
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}
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}
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#endregion
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}
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}
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