如何确保证书没有被更改？
How to make sure certificate is not changed?
我想到了一个问题。
只有当系统中安装了证书时，是否有任何通用的方法来制作应用程序 运行。而我想要这样的证书由我的自签名证书颁发和验证？
我可以通过它的名称从存储中获取证书，但是如何确保这样的证书是由我的自签名证书签名的，并且没有人颁发过同名证书并替换了证书中的证书本地存储？
或者换句话说，如何确保在本地存储中签署证书的证书不是伪造的？
如果问题不正确或不明确，我很抱歉，但我很乐意就此问题提供帮助。
确实是个好问题。
最终用户总是有可能使用您的主题名称创建一个有效的证书链，作为颁发者，另一个用于颁发者证书，一直到根。
他们不能做的是用颁发者证书的私钥签署这些证书。
因此，下面的代码从当前用户的个人证书库中加载应用程序证书，然后从资源中加载颁发者的颁发者证书，并验证安装在客户端机器上的应用程序证书上的签名颁发者证书的 public 密钥。
在我的源代码中，颁发者证书使用密钥 IssuerCertificate
添加到资源中
我其实很喜欢提出这样的解决方案。
在代码中我提到了编码 ASN.1。 Check it here如果你需要
static void Main(string[] args)
{
string expectedSubjectName = "My Application";
X509Certificate2 issuerCertificate = new X509Certificate2(Resource1.IssuerCertificate);
string expectedIssuerName = issuerCertificate.Subject;
bool result = VerifyCertificateIssuer(expectedSubjectName, expectedIssuerName, issuerCertificate);
}
private static void ThrowCertificateNotFoundException(string expectedSubjectName, string expectedIssuerName, bool isThumbprintMismatch)
{
if (isThumbprintMismatch)
{
// Notification for possible certificate forgery
}
throw new SecurityException("A certificate with subject name " + expectedSubjectName + " issued by " + expectedIssuerName + " is required to run this application");
}
private static X509Certificate2 GetCertificate(string expectedSubjectName, string expectedIssuerName)
{
X509Store personalCertificateStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
personalCertificateStore.Open(OpenFlags.ReadOnly);
X509CertificateCollection certificatesBySubjectName = personalCertificateStore.Certificates.Find(X509FindType.FindBySubjectName, expectedSubjectName, true);
if (certificatesBySubjectName.Count == 0)
{
ThrowCertificateNotFoundException(expectedSubjectName, expectedIssuerName, false);
}
X509Certificate2 matchingCertificate = null;
foreach (X509Certificate2 certificateBySubjectName in certificatesBySubjectName)
{
if (certificateBySubjectName.Issuer == expectedIssuerName)
{
matchingCertificate = certificateBySubjectName;
break;
}
}
if (matchingCertificate == null)
{
ThrowCertificateNotFoundException(expectedSubjectName, expectedIssuerName, false);
}
return matchingCertificate;
}
private static bool VerifyCertificateIssuer(string expectedSubjectName, string expectedIssuerName, X509Certificate2 issuerCertificate)
{
X509Certificate2 matchingCertificate = GetCertificate(expectedSubjectName, expectedIssuerName);
X509Chain chain = new X509Chain();
chain.Build(matchingCertificate);
// bool x = Encoding.ASCII.GetString(chain.ChainElements[1].Certificate.RawData) == Encoding.ASCII.GetString(issuerCertificate.RawData);
byte[] certificateData = matchingCertificate.RawData;
MemoryStream asn1Stream = new MemoryStream(certificateData);
BinaryReader asn1StreamReader = new BinaryReader(asn1Stream);
// The der encoded certificate structure is like this:
// Root Sequence
// Sequence (Certificate Content)
// Sequence (Signature Algorithm (like SHA256withRSAEncryption)
// Sequence (Signature)
// We need to decode the ASN.1 content to get
// Sequence 0 (which is the actual certificate content that is signed by the issuer, including the sequence definition and tag number and length)
// Sequence 2 (which is the signature. X509Certificate2 class does not give us that information. The year is 2015)
// Read the root sequence (ignore)
byte leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
ReadDataLength(asn1StreamReader);
// Save the current position because we will need it for including the sequence header with the certificate content
int sequence0StartPosition = (int)asn1Stream.Position;
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence0ContentLength = ReadDataLength(asn1StreamReader);
int sequence0HeaderLength = (int)asn1Stream.Position - sequence0StartPosition;
sequence0ContentLength += sequence0HeaderLength;
byte[] sequence0Content = new byte[sequence0ContentLength];
asn1Stream.Position -= 4;
asn1StreamReader.Read(sequence0Content, 0, sequence0ContentLength);
// Skip sequence 1 (signature algorithm) since we don't need it and assume that we know it because we own the issuer certificate
// This sequence, containing the algorithm used during the signing process IS HIDDEN FROM US BY DEFAULT. The year is 2015.
// What should have been done for real is, to get the algorithm ID (hash algorithm and asymmetric algorithm) and to use those
// algorithms during the verification process
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence1ContentLength = ReadDataLength(asn1StreamReader);
byte[] sequence1Content = new byte[sequence1ContentLength];
asn1StreamReader.Read(sequence1Content, 0, sequence1ContentLength);
// Read sequence 2 (signature)
// The actual signature of the certificate IS HIDDEN FROM US BY DEFAULT. The year is 2015.
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence2ContentLength = ReadDataLength(asn1StreamReader);
byte unusedBits = asn1StreamReader.ReadByte();
sequence2ContentLength -= 1;
byte[] sequence2Content = new byte[sequence2ContentLength];
asn1StreamReader.Read(sequence2Content, 0, sequence2ContentLength);
// At last, we have the data that is signed and the signature.
bool verificationResult = ((RSACryptoServiceProvider)issuerCertificate.PublicKey.Key)
.VerifyData
(
sequence0Content,
CryptoConfig.MapNameToOID("SHA256"),
sequence2Content
);
return verificationResult;
}
private static byte[] ReadTagNumber(byte leadingOctet, BinaryReader inputStreamReader)
{
List<byte> byts = new List<byte>();
byte temporaryByte;
if ((leadingOctet & 0x1F) == 0x1F) // More than 1 byte is used to specify the tag number
{
while (((temporaryByte = inputStreamReader.ReadByte()) & 0x80) > 0)
{
byts.Add((byte)(temporaryByte & 0x7F));
}
byts.Add(temporaryByte);
}
else
{
byts.Add((byte)(leadingOctet & 0x1F));
}
return byts.ToArray();
}
private static int ReadDataLength(BinaryReader inputStreamReader)
{
byte leadingOctet = inputStreamReader.ReadByte();
if ((leadingOctet & 0x80) > 0)
{
int subsequentialOctetsCount = leadingOctet & 0x7F;
int length = 0;
for (int i = 0; i < subsequentialOctetsCount; i++)
{
length <<= 8;
length += inputStreamReader.ReadByte();
}
return length;
}
else
{
return leadingOctet;
}
}
private static byte[] GetTagNumber(byte leadingOctet, BinaryReader inputStreamReader, ref int readBytes)
{
List<byte> byts = new List<byte>();
byte temporaryByte;
if ((leadingOctet & 0x1F) == 0x1F) // More than 1 byte is used to specify the tag number
{
while (((temporaryByte = inputStreamReader.ReadByte()) & 0x80) > 0)
{
readBytes++;
byts.Add((byte)(temporaryByte & 0x7F));
}
byts.Add(temporaryByte);
}
else
{
byts.Add((byte)(leadingOctet & 0x1F));
}
return byts.ToArray();
}
我想到了一个问题。 只有当系统中安装了证书时，是否有任何通用的方法来制作应用程序 运行。而我想要这样的证书由我的自签名证书颁发和验证？
我可以通过它的名称从存储中获取证书，但是如何确保这样的证书是由我的自签名证书签名的，并且没有人颁发过同名证书并替换了证书中的证书本地存储？
或者换句话说，如何确保在本地存储中签署证书的证书不是伪造的？
如果问题不正确或不明确，我很抱歉，但我很乐意就此问题提供帮助。
确实是个好问题。
最终用户总是有可能使用您的主题名称创建一个有效的证书链，作为颁发者，另一个用于颁发者证书，一直到根。
他们不能做的是用颁发者证书的私钥签署这些证书。
因此，下面的代码从当前用户的个人证书库中加载应用程序证书，然后从资源中加载颁发者的颁发者证书，并验证安装在客户端机器上的应用程序证书上的签名颁发者证书的 public 密钥。
在我的源代码中，颁发者证书使用密钥 IssuerCertificate
添加到资源中我其实很喜欢提出这样的解决方案。
在代码中我提到了编码 ASN.1。 Check it here如果你需要
static void Main(string[] args)
{
string expectedSubjectName = "My Application";
X509Certificate2 issuerCertificate = new X509Certificate2(Resource1.IssuerCertificate);
string expectedIssuerName = issuerCertificate.Subject;
bool result = VerifyCertificateIssuer(expectedSubjectName, expectedIssuerName, issuerCertificate);
}
private static void ThrowCertificateNotFoundException(string expectedSubjectName, string expectedIssuerName, bool isThumbprintMismatch)
{
if (isThumbprintMismatch)
{
// Notification for possible certificate forgery
}
throw new SecurityException("A certificate with subject name " + expectedSubjectName + " issued by " + expectedIssuerName + " is required to run this application");
}
private static X509Certificate2 GetCertificate(string expectedSubjectName, string expectedIssuerName)
{
X509Store personalCertificateStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
personalCertificateStore.Open(OpenFlags.ReadOnly);
X509CertificateCollection certificatesBySubjectName = personalCertificateStore.Certificates.Find(X509FindType.FindBySubjectName, expectedSubjectName, true);
if (certificatesBySubjectName.Count == 0)
{
ThrowCertificateNotFoundException(expectedSubjectName, expectedIssuerName, false);
}
X509Certificate2 matchingCertificate = null;
foreach (X509Certificate2 certificateBySubjectName in certificatesBySubjectName)
{
if (certificateBySubjectName.Issuer == expectedIssuerName)
{
matchingCertificate = certificateBySubjectName;
break;
}
}
if (matchingCertificate == null)
{
ThrowCertificateNotFoundException(expectedSubjectName, expectedIssuerName, false);
}
return matchingCertificate;
}
private static bool VerifyCertificateIssuer(string expectedSubjectName, string expectedIssuerName, X509Certificate2 issuerCertificate)
{
X509Certificate2 matchingCertificate = GetCertificate(expectedSubjectName, expectedIssuerName);
X509Chain chain = new X509Chain();
chain.Build(matchingCertificate);
// bool x = Encoding.ASCII.GetString(chain.ChainElements[1].Certificate.RawData) == Encoding.ASCII.GetString(issuerCertificate.RawData);
byte[] certificateData = matchingCertificate.RawData;
MemoryStream asn1Stream = new MemoryStream(certificateData);
BinaryReader asn1StreamReader = new BinaryReader(asn1Stream);
// The der encoded certificate structure is like this:
// Root Sequence
// Sequence (Certificate Content)
// Sequence (Signature Algorithm (like SHA256withRSAEncryption)
// Sequence (Signature)
// We need to decode the ASN.1 content to get
// Sequence 0 (which is the actual certificate content that is signed by the issuer, including the sequence definition and tag number and length)
// Sequence 2 (which is the signature. X509Certificate2 class does not give us that information. The year is 2015)
// Read the root sequence (ignore)
byte leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
ReadDataLength(asn1StreamReader);
// Save the current position because we will need it for including the sequence header with the certificate content
int sequence0StartPosition = (int)asn1Stream.Position;
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence0ContentLength = ReadDataLength(asn1StreamReader);
int sequence0HeaderLength = (int)asn1Stream.Position - sequence0StartPosition;
sequence0ContentLength += sequence0HeaderLength;
byte[] sequence0Content = new byte[sequence0ContentLength];
asn1Stream.Position -= 4;
asn1StreamReader.Read(sequence0Content, 0, sequence0ContentLength);
// Skip sequence 1 (signature algorithm) since we don't need it and assume that we know it because we own the issuer certificate
// This sequence, containing the algorithm used during the signing process IS HIDDEN FROM US BY DEFAULT. The year is 2015.
// What should have been done for real is, to get the algorithm ID (hash algorithm and asymmetric algorithm) and to use those
// algorithms during the verification process
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence1ContentLength = ReadDataLength(asn1StreamReader);
byte[] sequence1Content = new byte[sequence1ContentLength];
asn1StreamReader.Read(sequence1Content, 0, sequence1ContentLength);
// Read sequence 2 (signature)
// The actual signature of the certificate IS HIDDEN FROM US BY DEFAULT. The year is 2015.
leadingOctet = asn1StreamReader.ReadByte();
ReadTagNumber(leadingOctet, asn1StreamReader);
int sequence2ContentLength = ReadDataLength(asn1StreamReader);
byte unusedBits = asn1StreamReader.ReadByte();
sequence2ContentLength -= 1;
byte[] sequence2Content = new byte[sequence2ContentLength];
asn1StreamReader.Read(sequence2Content, 0, sequence2ContentLength);
// At last, we have the data that is signed and the signature.
bool verificationResult = ((RSACryptoServiceProvider)issuerCertificate.PublicKey.Key)
.VerifyData
(
sequence0Content,
CryptoConfig.MapNameToOID("SHA256"),
sequence2Content
);
return verificationResult;
}
private static byte[] ReadTagNumber(byte leadingOctet, BinaryReader inputStreamReader)
{
List<byte> byts = new List<byte>();
byte temporaryByte;
if ((leadingOctet & 0x1F) == 0x1F) // More than 1 byte is used to specify the tag number
{
while (((temporaryByte = inputStreamReader.ReadByte()) & 0x80) > 0)
{
byts.Add((byte)(temporaryByte & 0x7F));
}
byts.Add(temporaryByte);
}
else
{
byts.Add((byte)(leadingOctet & 0x1F));
}
return byts.ToArray();
}
private static int ReadDataLength(BinaryReader inputStreamReader)
{
byte leadingOctet = inputStreamReader.ReadByte();
if ((leadingOctet & 0x80) > 0)
{
int subsequentialOctetsCount = leadingOctet & 0x7F;
int length = 0;
for (int i = 0; i < subsequentialOctetsCount; i++)
{
length <<= 8;
length += inputStreamReader.ReadByte();
}
return length;
}
else
{
return leadingOctet;
}
}
private static byte[] GetTagNumber(byte leadingOctet, BinaryReader inputStreamReader, ref int readBytes)
{
List<byte> byts = new List<byte>();
byte temporaryByte;
if ((leadingOctet & 0x1F) == 0x1F) // More than 1 byte is used to specify the tag number
{
while (((temporaryByte = inputStreamReader.ReadByte()) & 0x80) > 0)
{
readBytes++;
byts.Add((byte)(temporaryByte & 0x7F));
}
byts.Add(temporaryByte);
}
else
{
byts.Add((byte)(leadingOctet & 0x1F));
}
return byts.ToArray();
}