internal static EncryptionInfo ReadFile(FileStream dataStream)
{
EncryptionInfo ret;
var bytes = new byte[8];
dataStream.Read(bytes, 0, 8);
var majorVersion = BitConverter.ToInt16(bytes, 0);
var minorVersion = BitConverter.ToInt16(bytes, 2);
if ((minorVersion == 2 || minorVersion == 3) && majorVersion <= 4) // minorVersion==1 is RC4, not supported.
{
ret = new EncryptionInfoBinary();
}
else if (majorVersion == 4 && minorVersion == 4)
{
ret = new EncryptionInfoAgile();
}
else
{
throw (new NotSupportedException("Unsupported encryption format"));
}
ret.MajorVersion = majorVersion;
ret.MinorVersion = minorVersion;
ret.Read(dataStream);
return(ret);
}
private byte[] EncryptDataAgile(byte[] data, EncryptionInfoAgile encryptionInfo, HashAlgorithm hashProvider)
{
var ke = encryptionInfo.KeyEncryptors[0];
RijndaelManaged aes = new RijndaelManaged();
aes.KeySize = ke.KeyBits;
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.Zeros;
int pos = 0;
int segment = 0;
//Encrypt the data
var ms = new MemoryStream();
ms.Write(BitConverter.GetBytes(data.LongLength), 0, 8);
while (pos < data.Length)
{
var segmentSize = (int)(data.Length - pos > 4096 ? 4096 : data.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv = hashProvider.ComputeHash(ivTmp);
EncryptAgileFromKey(ke, ke.KeyValue, data, pos, segmentSize, iv, ms);
pos += segmentSize;
segment++;
}
ms.Flush();
return(ms.ToArray());
}
// Set the dataintegrity
private void SetHMAC(EncryptionInfoAgile ei, HashAlgorithm hashProvider, byte[] salt, byte[] data)
{
var iv = GetFinalHash(hashProvider, ei.KeyEncryptors[0], BlockKey_HmacKey, ei.KeyData.SaltValue);
var ms = new MemoryStream();
EncryptAgileFromKey(ei.KeyEncryptors[0], ei.KeyEncryptors[0].KeyValue, salt, 0L, salt.LongLength, iv, ms);
ei.DataIntegrity.EncryptedHmacKey = ms.ToArray();
var h = GetHmacProvider(ei.KeyEncryptors[0], salt);
var hmacValue = h.ComputeHash(data);
ms = new MemoryStream();
iv = GetFinalHash(hashProvider, ei.KeyEncryptors[0], BlockKey_HmacValue, ei.KeyData.SaltValue);
EncryptAgileFromKey(ei.KeyEncryptors[0], ei.KeyEncryptors[0].KeyValue, hmacValue, 0L, hmacValue.LongLength, iv, ms);
ei.DataIntegrity.EncryptedHmacValue = ms.ToArray();
}
internal static EncryptionInfo ReadBinary(byte[] data)
{
var majorVersion = BitConverter.ToInt16(data, 0);
var minorVersion = BitConverter.ToInt16(data, 2);
EncryptionInfo ret;
if ((minorVersion == 2 || minorVersion == 3) && majorVersion <= 4) // minorVersion==1 is RC4, not supported.
{
ret = new EncryptionInfoBinary();
}
else if (majorVersion == 4 && minorVersion==4)
{
ret = new EncryptionInfoAgile();
}
else
{
throw (new NotSupportedException("Unsupported encryption format"));
}
ret.MajorVersion = majorVersion;
ret.MinorVersion = minorVersion;
ret.Read(data);
return ret;
}
internal static EncryptionInfo ReadBinary(byte[] data)
{
var majorVersion = BitConverter.ToInt16(data, 0);
var minorVersion = BitConverter.ToInt16(data, 2);
EncryptionInfo ret;
if ((minorVersion == 2 || minorVersion == 3) && majorVersion <= 4) // minorVersion==1 is RC4, not supported.
{
ret = new EncryptionInfoBinary();
}
else if (majorVersion == 4 && minorVersion == 4)
{
ret = new EncryptionInfoAgile();
}
else
{
throw (new NotSupportedException("Unsupported encryption format"));
}
ret.MajorVersion = majorVersion;
ret.MinorVersion = minorVersion;
ret.Read(data);
return(ret);
}
private FileStream EncryptDataAgile(Stream dataStream, EncryptionInfoAgile encryptionInfo, HashAlgorithm hashProvider)
{
var ke = encryptionInfo.KeyEncryptors[0];
#if Core
var aes = Aes.Create();
#else
RijndaelManaged aes = new RijndaelManaged();
#endif
aes.KeySize = ke.KeyBits;
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.Zeros;
int pos = 0;
int segment = 0;
//Encrypt the data
var fs = new FileStream(GetTempFile(), FileMode.Create);
fs.Write(BitConverter.GetBytes((ulong)dataStream.Length), 0, 8);
while (pos < dataStream.Length)
{
var segmentSize = (int)(dataStream.Length - pos > 4096 ? 4096 : dataStream.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv = hashProvider.ComputeHash(ivTmp);
EncryptAgileFromKey(ke, ke.KeyValue, dataStream, pos, segmentSize, iv, fs);
pos += segmentSize;
segment++;
}
fs.Flush();
fs.Seek(0, SeekOrigin.Begin);
return(fs);
}
private MemoryStream EncryptPackageAgile(byte[] package, ExcelEncryption encryption)
{
var xml= "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\r\n";
xml += "<encryption xmlns=\"http://schemas.microsoft.com/office/2006/encryption\" xmlns:p=\"http://schemas.microsoft.com/office/2006/keyEncryptor/password\" xmlns:c=\"http://schemas.microsoft.com/office/2006/keyEncryptor/certificate\">";
xml += "<keyData saltSize=\"16\" blockSize=\"16\" keyBits=\"256\" hashSize=\"64\" cipherAlgorithm=\"AES\" cipherChaining=\"ChainingModeCBC\" hashAlgorithm=\"SHA512\" saltValue=\"\"/>";
xml += "<dataIntegrity encryptedHmacKey=\"\" encryptedHmacValue=\"\"/>";
xml += "<keyEncryptors>";
xml += "<keyEncryptor uri=\"http://schemas.microsoft.com/office/2006/keyEncryptor/password\">";
xml += "<p:encryptedKey spinCount=\"100000\" saltSize=\"16\" blockSize=\"16\" keyBits=\"256\" hashSize=\"64\" cipherAlgorithm=\"AES\" cipherChaining=\"ChainingModeCBC\" hashAlgorithm=\"SHA512\" saltValue=\"\" encryptedVerifierHashInput=\"\" encryptedVerifierHashValue=\"\" encryptedKeyValue=\"\" />";
xml += "</keyEncryptor></keyEncryptors></encryption>";
var encryptionInfo = new EncryptionInfoAgile();
encryptionInfo.ReadFromXml(xml);
var encr = encryptionInfo.KeyEncryptors[0];
var rnd = RandomNumberGenerator.Create();
var s = new byte[16];
rnd.GetBytes(s);
encryptionInfo.KeyData.SaltValue = s;
rnd.GetBytes(s);
encr.SaltValue = s;
encr.KeyValue = new byte[encr.KeyBits / 8];
rnd.GetBytes(encr.KeyValue);
//Get the passwork key.
var hashProvider = GetHashProvider(encryptionInfo.KeyEncryptors[0]);
var baseHash = GetPasswordHash(hashProvider, encr.SaltValue, encryption.Password, encr.SpinCount, encr.HashSize);
var hashFinal = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
hashFinal = FixHashSize(hashFinal, encr.KeyBits / 8);
var encrData = EncryptDataAgile(package, encryptionInfo, hashProvider);
/**** Data Integrity ****/
var saltHMAC=new byte[64];
rnd.GetBytes(saltHMAC);
SetHMAC(encryptionInfo,hashProvider,saltHMAC, encrData);
/**** Verifier ****/
encr.VerifierHashInput = new byte[16];
rnd.GetBytes(encr.VerifierHashInput);
encr.VerifierHash = hashProvider.ComputeHash(encr.VerifierHashInput);
var VerifierInputKey = GetFinalHash(hashProvider, encr, BlockKey_HashInput, baseHash);
var VerifierHashKey = GetFinalHash(hashProvider, encr, BlockKey_HashValue, baseHash);
var KeyValueKey = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
var ms = new MemoryStream();
EncryptAgileFromKey(encr, VerifierInputKey, encr.VerifierHashInput, 0, encr.VerifierHashInput.Length, encr.SaltValue, ms);
encr.EncryptedVerifierHashInput = ms.ToArray();
ms = new MemoryStream();
EncryptAgileFromKey(encr, VerifierHashKey, encr.VerifierHash, 0, encr.VerifierHash.Length, encr.SaltValue, ms);
encr.EncryptedVerifierHash = ms.ToArray();
ms = new MemoryStream();
EncryptAgileFromKey(encr, KeyValueKey, encr.KeyValue, 0, encr.KeyValue.Length, encr.SaltValue, ms);
encr.EncryptedKeyValue = ms.ToArray();
xml = encryptionInfo.Xml.OuterXml;
var byXml = Encoding.UTF8.GetBytes(xml);
ms = new MemoryStream();
ms.Write(BitConverter.GetBytes((ushort)4), 0, 2); //Major Version
ms.Write(BitConverter.GetBytes((ushort)4), 0, 2); //Minor Version
ms.Write(BitConverter.GetBytes((uint)0x40), 0, 4); //Reserved
ms.Write(byXml,0,byXml.Length);
var doc = new CompoundDocument();
//Add the dataspace streams
CreateDataSpaces(doc);
//EncryptionInfo...
doc.Storage.DataStreams.Add("EncryptionInfo", ms.ToArray());
//...and the encrypted package
doc.Storage.DataStreams.Add("EncryptedPackage", encrData);
ms = new MemoryStream();
var e=doc.Save();
ms.Write(e,0,e.Length);
return ms;
}
private MemoryStream EncryptPackageAgile(byte[] package, ExcelEncryption encryption)
{
var xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\r\n";
xml += "<encryption xmlns=\"http://schemas.microsoft.com/office/2006/encryption\" xmlns:p=\"http://schemas.microsoft.com/office/2006/keyEncryptor/password\" xmlns:c=\"http://schemas.microsoft.com/office/2006/keyEncryptor/certificate\">";
xml += "<keyData saltSize=\"16\" blockSize=\"16\" keyBits=\"256\" hashSize=\"64\" cipherAlgorithm=\"AES\" cipherChaining=\"ChainingModeCBC\" hashAlgorithm=\"SHA512\" saltValue=\"\"/>";
xml += "<dataIntegrity encryptedHmacKey=\"\" encryptedHmacValue=\"\"/>";
xml += "<keyEncryptors>";
xml += "<keyEncryptor uri=\"http://schemas.microsoft.com/office/2006/keyEncryptor/password\">";
xml += "<p:encryptedKey spinCount=\"100000\" saltSize=\"16\" blockSize=\"16\" keyBits=\"256\" hashSize=\"64\" cipherAlgorithm=\"AES\" cipherChaining=\"ChainingModeCBC\" hashAlgorithm=\"SHA512\" saltValue=\"\" encryptedVerifierHashInput=\"\" encryptedVerifierHashValue=\"\" encryptedKeyValue=\"\" />";
xml += "</keyEncryptor></keyEncryptors></encryption>";
var encryptionInfo = new EncryptionInfoAgile();
encryptionInfo.ReadFromXml(xml);
var encr = encryptionInfo.KeyEncryptors[0];
var rnd = RandomNumberGenerator.Create();
var s = new byte[16];
rnd.GetBytes(s);
encryptionInfo.KeyData.SaltValue = s;
rnd.GetBytes(s);
encr.SaltValue = s;
encr.KeyValue = new byte[encr.KeyBits / 8];
rnd.GetBytes(encr.KeyValue);
//Get the passwork key.
var hashProvider = GetHashProvider(encryptionInfo.KeyEncryptors[0]);
var baseHash = GetPasswordHash(hashProvider, encr.SaltValue, encryption.Password, encr.SpinCount, encr.HashSize);
var hashFinal = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
hashFinal = FixHashSize(hashFinal, encr.KeyBits / 8);
var encrData = EncryptDataAgile(package, encryptionInfo, hashProvider);
/**** Data Integrity ****/
var saltHMAC = new byte[64];
rnd.GetBytes(saltHMAC);
SetHMAC(encryptionInfo, hashProvider, saltHMAC, encrData);
/**** Verifier ****/
encr.VerifierHashInput = new byte[16];
rnd.GetBytes(encr.VerifierHashInput);
encr.VerifierHash = hashProvider.ComputeHash(encr.VerifierHashInput);
var VerifierInputKey = GetFinalHash(hashProvider, encr, BlockKey_HashInput, baseHash);
var VerifierHashKey = GetFinalHash(hashProvider, encr, BlockKey_HashValue, baseHash);
var KeyValueKey = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
var ms = new MemoryStream();
EncryptAgileFromKey(encr, VerifierInputKey, encr.VerifierHashInput, 0, encr.VerifierHashInput.Length, encr.SaltValue, ms);
encr.EncryptedVerifierHashInput = ms.ToArray();
ms = new MemoryStream();
EncryptAgileFromKey(encr, VerifierHashKey, encr.VerifierHash, 0, encr.VerifierHash.Length, encr.SaltValue, ms);
encr.EncryptedVerifierHash = ms.ToArray();
ms = new MemoryStream();
EncryptAgileFromKey(encr, KeyValueKey, encr.KeyValue, 0, encr.KeyValue.Length, encr.SaltValue, ms);
encr.EncryptedKeyValue = ms.ToArray();
xml = encryptionInfo.Xml.OuterXml;
var byXml = Encoding.UTF8.GetBytes(xml);
ms = new MemoryStream();
ms.Write(BitConverter.GetBytes((ushort)4), 0, 2); //Major Version
ms.Write(BitConverter.GetBytes((ushort)4), 0, 2); //Minor Version
ms.Write(BitConverter.GetBytes((uint)0x40), 0, 4); //Reserved
ms.Write(byXml, 0, byXml.Length);
var doc = new CompoundDocument();
//Add the dataspace streams
CreateDataSpaces(doc);
//EncryptionInfo...
doc.Storage.DataStreams.Add("EncryptionInfo", ms.ToArray());
//...and the encrypted package
doc.Storage.DataStreams.Add("EncryptedPackage", encrData);
ms = new MemoryStream();
var e = doc.Save();
ms.Write(e, 0, e.Length);
return(ms);
}
/// <summary>
/// Validate the password
/// </summary>
/// <param name="key">The encryption key</param>
/// <param name="encryptionInfo">The encryption info extracted from the ENCRYPTIOINFO stream inside the OLE document</param>
/// <returns></returns>
private bool IsPasswordValid(HashAlgorithm sha, EncryptionInfoAgile.EncryptionKeyEncryptor encr)
{
var valHash = sha.ComputeHash(encr.VerifierHashInput);
//Equal?
for (int i = 0; i < valHash.Length; i++)
{
if (encr.VerifierHash[i] != valHash[i])
{
return false;
}
}
return true;
}
/// <summary>
/// Create the hash.
/// This method is written with the help of Lyquidity library, many thanks for this nice sample
/// </summary>
/// <param name="password">The password</param>
/// <param name="encryptionInfo">The encryption info extracted from the ENCRYPTIOINFO stream inside the OLE document</param>
/// <param name="blockKey">The block key appended to the hash to obtain the final hash</param>
/// <returns>The hash to encrypt the document</returns>
private byte[] GetPasswordHashAgile(string password, EncryptionInfoAgile.EncryptionKeyEncryptor encr, byte[] blockKey)
{
try
{
var hashProvider = GetHashProvider(encr);
var hash = GetPasswordHash(hashProvider, encr.SaltValue, password, encr.SpinCount, encr.HashSize);
var hashFinal = GetFinalHash(hashProvider, encr, blockKey, hash);
return FixHashSize(hashFinal, encr.KeyBits / 8);
}
catch (Exception ex)
{
throw (new Exception("An error occured when the encryptionkey was created", ex));
}
}
private HMAC GetHmacProvider(EncryptionInfoAgile.EncryptionKeyEncryptor ei, byte[] salt)
{
switch (ei.HashAlgorithm)
{
case eHashAlogorithm.RIPEMD160:
return new HMACRIPEMD160(salt);
case eHashAlogorithm.MD5:
return new HMACMD5(salt);
case eHashAlogorithm.SHA1:
return new HMACSHA1(salt);
case eHashAlogorithm.SHA256:
return new HMACSHA256(salt);
case eHashAlogorithm.SHA384:
return new HMACSHA384(salt);
case eHashAlogorithm.SHA512:
return new HMACSHA512(salt);
default:
throw(new NotSupportedException(string.Format("Hash method {0} not supported.",ei.HashAlgorithm)));
}
}
private HashAlgorithm GetHashProvider(EncryptionInfoAgile.EncryptionKeyEncryptor encr)
{
HashAlgorithm hashProvider;
switch (encr.HashAlgorithm)
{
case eHashAlogorithm.MD5:
return new MD5CryptoServiceProvider();
case eHashAlogorithm.RIPEMD160:
return new RIPEMD160Managed();
case eHashAlogorithm.SHA1:
return new SHA1CryptoServiceProvider();
case eHashAlogorithm.SHA256:
return new SHA256CryptoServiceProvider();
case eHashAlogorithm.SHA384:
return new SHA384CryptoServiceProvider();
case eHashAlogorithm.SHA512:
return new SHA512CryptoServiceProvider();
default:
throw new NotSupportedException(string.Format("Hash provider is unsupported. {0}", encr.HashAlgorithm));
}
}
private byte[] GetFinalHash(HashAlgorithm hashProvider, EncryptionInfoAgile.EncryptionKeyEncryptor encr, byte[] blockKey, byte[] hash)
{
//2.3.4.13 MS-OFFCRYPTO
var tempHash = new byte[hash.Length + blockKey.Length];
Array.Copy(hash, tempHash, hash.Length);
Array.Copy(blockKey, 0, tempHash, hash.Length, blockKey.Length);
var hashFinal = hashProvider.ComputeHash(tempHash);
return hashFinal;
}
readonly byte[] BlockKey_HmacValue = new byte[] { 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, 0x33 }; //MSOFFCRYPTO 2.3.4.14 section 5
private void DecryptAgile(EncryptionInfoAgile encryptionInfo, string password, long size, FileStream fs, Stream outputStream)
{
if (encryptionInfo.KeyData.CipherAlgorithm == eCipherAlgorithm.AES)
{
var encr = encryptionInfo.KeyEncryptors[0];
var hashProvider = GetHashProvider(encr);
var baseHash = GetPasswordHash(hashProvider, encr.SaltValue, password, encr.SpinCount, encr.HashSize);
//Get the keys for the verifiers and the key value
var valInputKey = GetFinalHash(hashProvider, encr, BlockKey_HashInput, baseHash);
var valHashKey = GetFinalHash(hashProvider, encr, BlockKey_HashValue, baseHash);
var valKeySizeKey = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
//Decrypt
encr.VerifierHashInput = DecryptAgileFromKey(encr, valInputKey, encr.EncryptedVerifierHashInput, encr.SaltSize, encr.SaltValue);
encr.VerifierHash = DecryptAgileFromKey(encr, valHashKey, encr.EncryptedVerifierHash, encr.HashSize, encr.SaltValue);
encr.KeyValue = DecryptAgileFromKey(encr, valKeySizeKey, encr.EncryptedKeyValue, encr.KeyBits / 8, encr.SaltValue);
if (IsPasswordValid(hashProvider, encr))
{
var ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacKey, encryptionInfo.KeyData.SaltValue);
var key = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacKey, encryptionInfo.KeyData.HashSize, ivhmac);
ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacValue, encryptionInfo.KeyData.SaltValue);
var value = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacValue, encryptionInfo.KeyData.HashSize, ivhmac);
var hmca = GetHmacProvider(encr, key);
var startPos = fs.Position;
fs.Seek(0, SeekOrigin.Begin);
var v2 = hmca.ComputeHash(fs);
fs.Seek(startPos, SeekOrigin.Begin);
for (int i = 0; i < v2.Length; i++)
{
if (value[i] != v2[i])
{
throw (new Exception("Dataintegrity key missmatch"));
}
}
int pos = 0;
uint segment = 0;
while (pos < size)
{
var segmentSize = (int)(size - pos > 4096 ? 4096 : size - pos);
var bufferSize = (int)(fs.Length - pos > 4096 ? 4096 : fs.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv = hashProvider.ComputeHash(ivTmp);
var buffer = new byte[bufferSize];
fs.Read(buffer, 0, bufferSize);
//Array.Copy(encryptedData, pos, buffer, 0, bufferSize);
var b = DecryptAgileFromKey(encr, encr.KeyValue, buffer, segmentSize, iv);
outputStream.Write(b, 0, b.Length);
pos += segmentSize;
segment++;
}
outputStream.Flush();
}
else
{
throw (new SecurityException("Invalid password"));
}
}
}
private byte[] EncryptDataAgile(byte[] data, EncryptionInfoAgile encryptionInfo, HashAlgorithm hashProvider)
{
var ke = encryptionInfo.KeyEncryptors[0];
RijndaelManaged aes = new RijndaelManaged();
aes.KeySize = ke.KeyBits;
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.Zeros;
int pos=0;
int segment=0;
//Encrypt the data
var ms = new MemoryStream();
ms.Write(BitConverter.GetBytes(data.LongLength), 0, 8);
while (pos < data.Length)
{
var segmentSize = (int)(data.Length - pos > 4096 ? 4096 : data.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv=hashProvider.ComputeHash(ivTmp);
EncryptAgileFromKey(ke, ke.KeyValue, data, pos, segmentSize, iv, ms);
pos += segmentSize;
segment++;
}
ms.Flush();
return ms.ToArray();
}
private void EncryptAgileFromKey(EncryptionInfoAgile.EncryptionKeyEncryptor encr, byte[] key, byte[] data, long pos, long size, byte[] iv,MemoryStream ms)
{
var encryptKey = GetEncryptionAlgorithm(encr);
encryptKey.BlockSize = encr.BlockSize << 3;
encryptKey.KeySize = encr.KeyBits;
encryptKey.Mode = encr.ChiptherChaining==eChainingMode.ChainingModeCBC ? CipherMode.CBC : CipherMode.CFB;
encryptKey.Padding = PaddingMode.Zeros;
ICryptoTransform encryptor = encryptKey.CreateEncryptor(
FixHashSize(key, encr.KeyBits / 8),
FixHashSize(iv, 16, 0x36));
CryptoStream cryptoStream = new CryptoStream(ms,
encryptor,
CryptoStreamMode.Write);
var cryptoSize = size % encr.BlockSize == 0 ? size : (size + (encr.BlockSize - (size % encr.BlockSize)));
var buffer = new byte[size];
Array.Copy(data, pos, buffer, 0, size);
cryptoStream.Write(buffer, 0, (int)size);
while (size % encr.BlockSize != 0)
{
cryptoStream.WriteByte(0);
size++;
}
}
private byte[] DecryptAgileFromKey(EncryptionInfoAgile.EncryptionKeyEncryptor encr, byte[] key, byte[] encryptedData, long size, byte[] iv)
{
SymmetricAlgorithm decryptKey = GetEncryptionAlgorithm(encr);
decryptKey.BlockSize = encr.BlockSize << 3;
decryptKey.KeySize = encr.KeyBits;
decryptKey.Mode = encr.ChiptherChaining == eChainingMode.ChainingModeCBC ? CipherMode.CBC : CipherMode.CFB;
decryptKey.Padding = PaddingMode.Zeros;
ICryptoTransform decryptor = decryptKey.CreateDecryptor(
FixHashSize(key, encr.KeyBits / 8),
FixHashSize(iv, encr.BlockSize, 0x36));
MemoryStream dataStream = new MemoryStream(encryptedData);
CryptoStream cryptoStream = new CryptoStream(dataStream,
decryptor,
CryptoStreamMode.Read);
var decryptedData = new byte[size];
cryptoStream.Read(decryptedData, 0, (int)size);
return decryptedData;
}
private MemoryStream DecryptAgile(EncryptionInfoAgile encryptionInfo, string password, long size, byte[] encryptedData, byte[] data)
{
MemoryStream doc = new MemoryStream();
if (encryptionInfo.KeyData.CipherAlgorithm == eCipherAlgorithm.AES)
{
var encr = encryptionInfo.KeyEncryptors[0];
var hashProvider = GetHashProvider(encr);
var baseHash = GetPasswordHash(hashProvider, encr.SaltValue, password, encr.SpinCount, encr.HashSize);
//Get the keys for the verifiers and the key value
var valInputKey = GetFinalHash(hashProvider, encr, BlockKey_HashInput, baseHash);
var valHashKey = GetFinalHash(hashProvider, encr, BlockKey_HashValue, baseHash);
var valKeySizeKey = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
//Decrypt
encr.VerifierHashInput = DecryptAgileFromKey(encr, valInputKey, encr.EncryptedVerifierHashInput, encr.SaltSize, encr.SaltValue);
encr.VerifierHash = DecryptAgileFromKey(encr, valHashKey, encr.EncryptedVerifierHash, encr.HashSize, encr.SaltValue);
encr.KeyValue = DecryptAgileFromKey(encr, valKeySizeKey, encr.EncryptedKeyValue, encr.KeyBits / 8, encr.SaltValue);
if (IsPasswordValid(hashProvider, encr))
{
var ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacKey, encryptionInfo.KeyData.SaltValue);
var key = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacKey, encryptionInfo.KeyData.HashSize, ivhmac);
ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacValue, encryptionInfo.KeyData.SaltValue);
var value = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacValue, encryptionInfo.KeyData.HashSize, ivhmac);
var hmca = GetHmacProvider(encr, key);
var v2 = hmca.ComputeHash(data);
for (int i = 0; i < v2.Length; i++)
{
if (value[i] != v2[i])
{
throw (new Exception("Dataintegrity key missmatch"));
}
}
int pos = 0;
uint segment = 0;
while (pos < size)
{
var segmentSize = (int)(size - pos > 4096 ? 4096 : size - pos);
var bufferSize = (int)(encryptedData.Length - pos > 4096 ? 4096 : encryptedData.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv = hashProvider.ComputeHash(ivTmp);
var buffer = new byte[bufferSize];
Array.Copy(encryptedData, pos, buffer, 0, bufferSize);
var b = DecryptAgileFromKey(encr, encr.KeyValue, buffer, segmentSize, iv);
doc.Write(b, 0, b.Length);
pos += segmentSize;
segment++;
}
doc.Flush();
return doc;
}
else
{
throw (new UnauthorizedAccessException("Invalid password"));
}
}
return null;
}
// Set the dataintegrity
private void SetHMAC(EncryptionInfoAgile ei, HashAlgorithm hashProvider, byte[] salt, byte[] data)
{
var iv = GetFinalHash(hashProvider, ei.KeyEncryptors[0], BlockKey_HmacKey, ei.KeyData.SaltValue);
var ms = new MemoryStream();
EncryptAgileFromKey(ei.KeyEncryptors[0], ei.KeyEncryptors[0].KeyValue, salt, 0L, salt.LongLength, iv, ms);
ei.DataIntegrity.EncryptedHmacKey = ms.ToArray();
var h = GetHmacProvider(ei.KeyEncryptors[0], salt);
var hmacValue = h.ComputeHash(data);
ms = new MemoryStream();
iv = GetFinalHash(hashProvider, ei.KeyEncryptors[0], BlockKey_HmacValue, ei.KeyData.SaltValue);
EncryptAgileFromKey(ei.KeyEncryptors[0], ei.KeyEncryptors[0].KeyValue, hmacValue, 0L, hmacValue.LongLength, iv, ms);
ei.DataIntegrity.EncryptedHmacValue = ms.ToArray();
}
readonly byte[] BlockKey_HmacValue = new byte[] { 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, 0x33 }; //MSOFFCRYPTO 2.3.4.14 section 5
private MemoryStream DecryptAgile(EncryptionInfoAgile encryptionInfo, string password, long size, byte[] encryptedData, byte[] data)
{
MemoryStream doc = new MemoryStream();
if (encryptionInfo.KeyData.CipherAlgorithm == eCipherAlgorithm.AES)
{
var encr = encryptionInfo.KeyEncryptors[0];
var hashProvider = GetHashProvider(encr);
var baseHash = GetPasswordHash(hashProvider, encr.SaltValue, password, encr.SpinCount, encr.HashSize);
//Get the keys for the verifiers and the key value
var valInputKey = GetFinalHash(hashProvider, encr, BlockKey_HashInput, baseHash);
var valHashKey = GetFinalHash(hashProvider, encr, BlockKey_HashValue, baseHash);
var valKeySizeKey = GetFinalHash(hashProvider, encr, BlockKey_KeyValue, baseHash);
//Decrypt
encr.VerifierHashInput = DecryptAgileFromKey(encr, valInputKey, encr.EncryptedVerifierHashInput, encr.SaltSize, encr.SaltValue);
encr.VerifierHash = DecryptAgileFromKey(encr, valHashKey, encr.EncryptedVerifierHash, encr.HashSize, encr.SaltValue);
encr.KeyValue = DecryptAgileFromKey(encr, valKeySizeKey, encr.EncryptedKeyValue, encr.KeyBits / 8, encr.SaltValue);
if (IsPasswordValid(hashProvider, encr))
{
var ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacKey, encryptionInfo.KeyData.SaltValue);
var key = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacKey, encryptionInfo.KeyData.HashSize, ivhmac);
ivhmac = GetFinalHash(hashProvider, encr, BlockKey_HmacValue, encryptionInfo.KeyData.SaltValue);
var value = DecryptAgileFromKey(encr, encr.KeyValue, encryptionInfo.DataIntegrity.EncryptedHmacValue, encryptionInfo.KeyData.HashSize, ivhmac);
var hmca = GetHmacProvider(encr, key);
var v2 = hmca.ComputeHash(data);
for (int i = 0; i < v2.Length; i++)
{
if (value[i] != v2[i])
{
throw (new Exception("Dataintegrity key missmatch"));
}
}
int pos = 0;
uint segment = 0;
while (pos < size)
{
var segmentSize = (int)(size - pos > 4096 ? 4096 : size - pos);
var bufferSize = (int)(encryptedData.Length - pos > 4096 ? 4096 : encryptedData.Length - pos);
var ivTmp = new byte[4 + encryptionInfo.KeyData.SaltSize];
Array.Copy(encryptionInfo.KeyData.SaltValue, 0, ivTmp, 0, encryptionInfo.KeyData.SaltSize);
Array.Copy(BitConverter.GetBytes(segment), 0, ivTmp, encryptionInfo.KeyData.SaltSize, 4);
var iv = hashProvider.ComputeHash(ivTmp);
var buffer = new byte[bufferSize];
Array.Copy(encryptedData, pos, buffer, 0, bufferSize);
var b = DecryptAgileFromKey(encr, encr.KeyValue, buffer, segmentSize, iv);
doc.Write(b, 0, b.Length);
pos += segmentSize;
segment++;
}
doc.Flush();
return(doc);
}
else
{
throw (new UnauthorizedAccessException("Invalid password"));
}
}
return(null);
}
private SymmetricAlgorithm GetEncryptionAlgorithm(EncryptionInfoAgile.EncryptionKeyEncryptor encr)
{
switch (encr.CipherAlgorithm)
{
case eCipherAlgorithm.AES:
return new RijndaelManaged();
case eCipherAlgorithm.DES:
return new DESCryptoServiceProvider();
case eCipherAlgorithm.TRIPLE_DES:
case eCipherAlgorithm.TRIPLE_DES_112:
return new TripleDESCryptoServiceProvider();
case eCipherAlgorithm.RC2:
return new RC2CryptoServiceProvider();
default:
throw(new NotSupportedException(string.Format("Unsupported Cipher Algorithm: {0}", encr.CipherAlgorithm.ToString())));
}
}
