1

[版主，我在将这个问题压缩到字数限制时遇到了问题，请见谅。]

用例是在 Linux 服务器上使用 OpenSSL 使用 384 位椭圆曲线数字服务器算法 (ECDSA) 对许可证（纯文本）文件进行签名，数字签名的验证在客户的 Windows 桌面操作系统（Windows ) .NET 框架。

许可证文件和 Base 64 编码数字签名通过电子邮件发送给客户（不在共享公司网络上）。客户正在运行 C# 编写的 .NET Framework（Windows 版）应用程序并验证许可证和数字签名以解锁付费功能。

现在，我说的是 Linux，但下面给出的示例服务器端代码还不是 Linux 脚本语言。我正在使用在 Windows 8 上运行的 VBA 进行原型设计，最终我将转换为 Linux 脚本语言，但暂时请耐心等待。

关键是我使用的是 OpenSSL 控制台命令，而不是针对任何 OpenSSL 软件开发工具包（C++ 头文件等）进行编译。

一个棘手的部分（也许是开始代码审查的最佳位置）是从 DER 文件中挖掘出构成公钥的 X 和 Y 坐标。DER 密钥文件是使用抽象语法符号 (ASN1) 的二进制编码文件，那里有免费的 GUI 程序，例如Code Project ASN1。易于检查的编辑器，这里是公钥文件的屏幕截图

在此处输入图像描述

幸运的是，OpenSSL 有自己的内置 ASN1 解析器，因此将相同的详细信息写入控制台，如下所示

C:\OpenSSL-Win64\bin\openssl.exe asn1parse -inform DER -in n:\ECDSA\2017-11-03T193106\ec_pubkey.der
    0:d=0  hl=2 l= 118 cons: SEQUENCE
    2:d=1  hl=2 l=  16 cons: SEQUENCE
    4:d=2  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
   13:d=2  hl=2 l=   5 prim: OBJECT            :secp384r1
   20:d=1  hl=2 l=  98 prim: BIT STRING

因此，在偏移量 20 处有 98 个字节包含 X 和 Y 坐标，在字节 20 处是一个标记（0x03），指示后面有一个字符串，在字节 21 处是长度，98（任何低于 127 的长度只需要一个字节）。所以实际上真正的 98 字节数据从 byte 22 开始，所以我总共读取了 100 个字节（98+2）。在字节 22 处是 0x00，这就是BIT STRINGS 的开始方式（参见第 5 点）。在字节 23 处是0x04，表示 X 和 Y 都遵循这称为未压缩形式（可以给出 X 值并计算 Y，在这种情况下使用 0x02 或 0x03）。在 0x04 之后是 X 和 Y 坐标，每个 48 个字节，因为一个字节中有 8 位，8*48=384。

因此，人们挖掘出两个（X 和 Y）非常长的十六进制数字作为字符串。下一个难题是创建适合 C# 代码的 Xml 文件。关键类是 C# 的 ECDsaCng，导入方法是 FromXmlString，它期望文件实现标准 Rfc4050。C# 的 ECDsaCng 导入的 Xml 文件要求 X 和 Y 是十进制而不是十六进制，所以我们必须编写另一个函数来转换，我从另一个Stack Overflow 问题中提取的另一种语言翻译。

这是 VBA 代码（有很多），您需要更改它将写入其工作文件的位置。要运行的两个代码块是EntryPoint1_RunECDSAKeyGenerationBatch_RunOnce和EntryPoint2_RunHashAndSignBatch

应视为已安装 OpenSSL，我的版本在 C:\OpenSSL-Win64\

完整的VBA 代码在这里，因为 SO 有 30000 个字符的限制。给出了可能的罪魁祸首代码

Option Explicit
Option Private Module

'******* Requires Tools->References to the following libraries
'* Microsoft ActiveX Data Objects 6.1 Library           C:\Program Files (x86)\Common Files\System\ado\msado15.dll
'* Microsoft Scripting Runtime                          C:\Windows\SysWOW64\scrrun.dll
'* Microsoft XML, v.6.0                                 C:\Windows\SysWOW64\msxml6.dll
'* Windows Script HostObject Model                      C:\Windows\SysWOW64\wshom.ocx
'* Microsoft VBScript Regular Expressions 5.5           C:\Windows\SysWOW64\vbscript.dll\3

Private fso As New Scripting.FileSystemObject
Private Const sOPENSSL_BIN As String = "C:\OpenSSL-Win64\bin\openssl.exe"  '* installation for OpenSSL
Private msBatchDir As Variant '* hold over so we can sign multiple times

Private Function ExportECDSAToXml(ByVal sPublicKeyFile As String, ByVal sXmlFile As String) As Boolean

    '* C#'s ECDsaCng class has a FromXmlString method which imports public key from a xml file Rfc4050
    '* In this subroutine we use OpenSSL's asn1parse command to determine where the X and Y coordinates
    '* are to be found, we dig them out and then markup an Xml file

    '* sample output

    '<ECDSAKeyValue xmlns="http://www.w3.org/2001/04/xmldsig-more#">
    '  <DomainParameters>
    '    <NamedCurve URN="urn:oid:1.3.132.0.34" />
    '  </DomainParameters>
    '  <PublicKey>
    '    <X Value="28988690734503506507042353413239022820576378869683128926072865549806544603682841538004244894267242326732083660928511" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
    '    <Y Value="26760429725303641669535466935138151998536365153900531836644163359528872675820305636066450549811202036369304684551859" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
    '  </PublicKey>
    '</ECDSAKeyValue>


    Dim sAS1ParseCmd As String
    sAS1ParseCmd = sOPENSSL_BIN & " asn1parse -inform DER -in " & sPublicKeyFile

    Dim eAS1ParseStatus As WshExecStatus, sAS1ParseStdOut As String, sAS1ParseStdErr As String
    eAS1ParseStatus = RunShellAndWait(sAS1ParseCmd, sAS1ParseStdOut, sAS1ParseStdErr)
    Debug.Print sAS1ParseStdOut

    '* sample output from standard out pipe is given blow.
    '* we need to dig into the BIT STRING which is the final item
    '* we need offset and length which is always 20 and 98 for 384 bit ECDSA
    '* but I have written logic in case we want to upgrade to 512 or change of curve etc.
    '    0:d=0  hl=2 l= 118 cons: SEQUENCE
    '    2:d=1  hl=2 l=  16 cons: SEQUENCE
    '    4:d=2  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
    '   13:d=2  hl=2 l=   5 prim: OBJECT            :secp384r1
    '   20:d=1  hl=2 l=  98 prim: BIT STRING



    Dim vOutputSplit As Variant
    vOutputSplit = VBA.Split(sAS1ParseStdOut, vbNewLine)

    '* remove the traling blank line
    If Trim(vOutputSplit(UBound(vOutputSplit))) = "" Then ReDim Preserve vOutputSplit(0 To UBound(vOutputSplit) - 1)

    '* final line should be the long bit string, i.e. contain 'BIT STRING'
    Debug.Assert StrComp("BIT STRING", Right$(Trim(vOutputSplit(UBound(vOutputSplit))), 10)) = 0

    '* use regular expression to dig out offset and length
    Dim lOffset As Long, lLength As Long
    RegExpOffsetAndLengthFromASN1Parse Trim(vOutputSplit(UBound(vOutputSplit))), lOffset, lLength

    Dim abytes() As Byte
    Dim asHexs() As String  '* for debugging

    '* read in the whole file into a byte array
    ReadFileBytesAsBytes sPublicKeyFile, abytes

    '* for debugging create an array of hexadecimals
    ByteArrayToHexStringArray abytes, asHexs


    Dim bitString() As Byte
    '* need extra 2 bytes because of leading type and length bytes
    CopyArraySlice abytes, lOffset, lLength + 2, bitString()

    '* some asserts which pin down structure of the bytes
    Debug.Assert bitString(0) = 3  '* TAG for BIT STRING
    Debug.Assert bitString(1) = lLength

    '* From Point 5 at http://certificate.fyicenter.com/2221_View_Website_Server_Certificate_in_Google_Chrome.html
    '* "ASN.1 BIT STRING value is stored with DER encoding as the value itself with an extra leading byte of 0x00. "
    Debug.Assert bitString(2) = 0

    '* 0x04 means by x and y values follow, i.e. uncompressed
    '* (instead of just one from which the other can be derived, leading with 0x02 or 0x03)
    '* https://en.bitcoin.it/wiki/Elliptic_Curve_Digital_Signature_Algorithm
    Debug.Assert bitString(3) = 4
    'Stop



    Dim x() As Byte
    Dim y() As Byte

    '* slice out the 48 bits for nopth x and y
    '* why 48?  because 48*8=384 bits(change for 512)
    CopyArraySlice bitString, 4, 48, x()
    CopyArraySlice bitString, 52, 48, y()

    '* convert bytes to hex string for x coord
    Dim sHexX As String
    sHexX = ByteArrayToHexString(x(), "")

    Debug.Print "sHexX:" & sHexX

    '* convert bytes to hex string for y coord
    Dim sHexY As String
    sHexY = ByteArrayToHexString(y(), "")

    Debug.Print "sHexY:" & sHexY

    '* convert hexadeciumal to plain decimal
    '* as Xml file requires it
    Dim sDecX As String
    sDecX = HexToDecimal(sHexX)

    Debug.Print "sDecX:" & sDecX

    '* convert hexadeciumal to plain decimal
    '* as Xml file requires it
    Dim sDecY As String
    sDecY = HexToDecimal(sHexY)

    Debug.Print "sDecY:" & sDecY


    '* create the xml file from a template
    Dim dom2 As MSXML2.DOMDocument60
    Set dom2 = New MSXML2.DOMDocument60
    dom2.LoadXML ECDSAXml(sDecX, sDecY)
    Debug.Assert dom2.parseError.ErrorCode = 0


    dom2.Save sXmlFile

    Debug.Print dom2.XML
    Set dom2 = Nothing


    Debug.Assert CreateObject("Scripting.FileSystemObject").FileExists(sXmlFile)


End Function

这是 VBA 即时窗口的输出，它说明了控制台命令和运行响应EntryPoint1_RunECDSAKeyGenerationBatch_RunOnce。

创建批处理目录：n:\ECDSA\2017-11-03T193106
C:\OpenSSL-Win64\bin\openssl.exe ecparam -genkey -name secp384r1 -out n:\ECDSA\2017-11-03T193106\ec_key.pem

C:\OpenSSL-Win64\bin\openssl.exe ec -pubout -outform DER -in n:\ECDSA\2017-11-03T193106\ec_key.pem -out n:\ECDSA\2017-11-03T193106\ec_pubkey.der
C:\OpenSSL-Win64\bin\openssl.exe ec -pubout -outform PEM -in n:\ECDSA\2017-11-03T193106\ec_key.pem -out n:\ECDSA\2017-11-03T193106\ec_pubkey.pem

C:\OpenSSL-Win64\bin\openssl.exe ec -noout -text -in n:\ECDSA\2017-11-03T193106\ec_key.pem -out n:\ECDSA\2017-11-03T193106\ec_key.txt

私钥：（384 位）
私人：
    00:98:78:0d:c7:29:10:1c:9f:4d:75:b2:95:01:01:
    a9:d2:36:72:0d:77:6a:5c:57:8d:51:a0:53:27:05:
    9b:22:1c:c9:0a:1e:e1:27:06:92:c1:6c:2a:c4:bb:
    46:91:98:f6
酒馆：
    04:bd:4a:38:04:69:d5:ba:fa:11:27:0f:a8:ef:70:
    3f:11:8d:e0:0f:e7:fd:26:ac:4d:40:32:7a:b5:9c:
    97:71:c1:80:72:1b:42:25:f8:a4:49:4d:8f:89:bf:
    1b:e9:6c:8c:f3:0b:02:db:89:b3:f7:92:e8:c4:a6:
    ce:04:88:10:51:cc:17:0b:b8:9c:9a:a6:3d:fd:ec:
    d4:99:c3:31:6b:22:1d:b6:41:fa:3c:0e:51:fe:86:
    67:bb:7e:86:ce:06:6c
ASN1 OID：secp384r1
NIST 曲线：P-384

C:\OpenSSL-Win64\bin\openssl.exe asn1parse -inform DER -in n:\ECDSA\2017-11-03T193106\ec_pubkey.der
    0:d=0 hl=2 l= 118 缺点：序列          
    2:d=1 hl=2 l= 16 缺点：序列          
    4:d=2 hl=2 l= 7 prim: 对象:id-ecPublicKey
   13:d=2 hl=2 l= 5 prim: 对象:secp384r1
   20:d=1 hl=2 l= 98 prim: 位串        

sHexX:BD4A380469D5BAFA11270FA8EF703F118DE00FE7FD26AC4D40327AB59C9771C180721B4225F8A4494D8F89BF1BE96C8C
sHexY:F30B02DB89B3F792E8C4A6CE04881051CC170BB89C9AA63DFDECD499C3316B221DB641FA3C0E51FE8667BB7E86CE066C
sDecX:29134384736743232303148959866907873847020585008044539704341734517362687803911673703523083044584737202030832217844876
sDecY:37407743276271579329804703064876533532537408218368858949720169306023437854945515421210341789026319167790678153234028
<ECDSAKeyValue xmlns="http://www.w3.org/2001/04/xmldsig-more#">
          <域参数>
            <NamedCurve URN="urn:oid:1.3.132.0.34" />
          </域参数>
          <公钥>
            <X Value="28988690734503506507042353413239022820576378869683128926072865549806544603682841538004244894267242326732083660928511" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
            <Y Value="26760429725303641669535466935138151998536365153900531836644163359528872675820305636066450549811202036369304684551859" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
          </公钥>
        </ECDSAKeyValue>

这是用于运行的 VBA 即时窗口输出EntryPoint2_RunHashAndSignBatch...



    C:\OpenSSL-Win64\bin\openssl.exe dgst -sha256 -out n:\ECDSA\2017-11-03T193106\license.sha256 n:\ECDSA\2017-11-03T193106\license.txt

    SHA256(n:\ECDSA\2017-11-03T193106\license.txt)= 185f8db32271fe25f561a6fc938b2e264306ec304eda518007d1764826381969

    C:\OpenSSL-Win64\bin\openssl.exe dgst -sha256 -sign n:\ECDSA\2017-11-03T193106\ec_key.pem -out n:\ECDSA\2017-11-03T193106\license.sig n:\ECDSA\2017-11-03T193106\license.txt

    C:\OpenSSL-Win64\bin\openssl.exe base64 -in n:\ECDSA\2017-11-03T193106\license.sig -out n:\ECDSA\2017-11-03T193106\license.sigb64

    C:\OpenSSL-Win64\bin\openssl.exe dgst -sha256 -verify n:\ECDSA\2017-11-03T193106\ec_pubkey.pem -signature n:\ECDSA\2017-11-03T193106\license.sig n:\ECDSA\2017-11-03T193106\license.txt
    Verification success

接下来，我们创建一个 C# 经典控制台应用程序并粘贴以下代码以验证数字签名，记住客户将收到 base64 版本的数字签名。

using System;
using System.Diagnostics;
using System.IO;
using System.Security.Cryptography;
using System.Xml;

namespace ECDSAVerSig
{
    class Program
    {
        static Action<string> feedback { get; set; }
        static byte[] fileContents = null;
        static byte[] signatureContents = null;

        static ECDsaCng client = null;
        static HashAlgorithm hashAlgo = new SHA256Managed();

        static String parentDirectory = null;

        static void Main(string[] args)
        {

            //* the following will be different for you!!!
            //* and will need to match what was output by the VBA script
            parentDirectory = "n:\\ECDSA\\2017-11-03T193106\\";
            Debug.Assert(Directory.Exists(parentDirectory));

            feedback = Console.WriteLine; // Abstract away 

            if (LoadSignature())
            {
                VerifySignature();
            }


        }



        static private Boolean VerifySignature()
        {
            try
            {
                // a byte array to store hash value
                byte[] hashedData = null;

                Debug.Assert(fileContents[0] == 'H');
                Debug.Assert(fileContents[1] == 'e');
                Debug.Assert(fileContents[2] == 'l');
                Debug.Assert(fileContents[3] == 'l');
                Debug.Assert(fileContents[4] == 'o');
                hashedData = hashAlgo.ComputeHash(fileContents);
                //'* hard coded check of "Hello" hash 
                Debug.Assert(hashedData[0] == 0x18);
                Debug.Assert(hashedData[1] == 0x5f);

                //* the following is consistently wrong though it is my best guess
                Boolean verified = client.VerifyHash(hashedData, signatureContents); //<-- Help required here StackOverflowers

                feedback("Verification:" + verified);

                if (verified)
                {
                    feedback("Hooray you got this 384 bit ECDSA code working! You absolute star!");
                } else
                {
                    feedback("Oh dear, still does not work.  Please keep twiddling.");

                }
                Debug.Assert(verified);

                return true;

            }
            catch (XmlException ex)
            {
                feedback("Problem with verification (Xml parse error):" + ex.ToString());
                return false;
            }
            catch (Exception ex)
            {
                feedback("Problem with verification :" + ex.ToString());
                return false;
            }
        }

        static private Boolean LoadSignature()
        {

            client = new ECDsaCng();
            try
            {

                System.Xml.XmlDocument dom = new System.Xml.XmlDocument();

                dom.Load(Path.Combine(parentDirectory,"ec_pubkey.xml"));

                string xml = dom.OuterXml;
                feedback(xml);
                client.FromXmlString(xml, ECKeyXmlFormat.Rfc4050);

                fileContents = System.IO.File.ReadAllBytes(Path.Combine(parentDirectory, "license.txt"));

                string base64SignatureContents = System.IO.File.ReadAllText(Path.Combine(parentDirectory, "license.sigB64"));
                signatureContents = Convert.FromBase64String(base64SignatureContents); 


                byte[] hashedData = hashAlgo.ComputeHash(fileContents);
                //'* hard coded check of "Hello" hash
                Debug.Assert(hashedData[0] == 0x18);
                Debug.Assert(hashedData[1] == 0x5f);


                return true;
            }
            catch (XmlException ex)
            {
                feedback("Problem with reading digital signature (Xml parse error):" + ex.ToString());
                return false;
            }

            catch (Exception ex)
            {
                feedback("Problem with reading digital signature:" + ex.ToString());
                return false;
            }
        }
    }
}

我已经三次检查了这段代码。我已将许可证文件设为非常短的“Hello”并检查了字节和编码。我也检查了哈希值。我不知道下一步该做什么。请协助。提前致谢

4

1 回答 1

2

假设您正确执行了其他所有操作 - 问题是openssl 和 .NET 生成的签名格式不同。openssl 产生（和预期）的签名（惊喜！）再次被 ASN.1 编码。跑

openssl.exe asn1parse -in license.sig -inform DER

你会看到

0:d=0  hl=2 l= 101 cons: SEQUENCE
2:d=1  hl=2 l=  49 prim: INTEGER           :F25556BBB... big number here
53:d=1  hl=2 l=  48 prim: INTEGER          :3E98E7B376624FF.... big number

所以它又是两个数字的序列，（基于0的）索引1处的字节是总长度，索引3处的字节是第一个数字的长度，然后是第一个数字，在那个字节之后是第二个数字的长度，然后是第二个数字。请注意，可能存在应该删除的可选填充（0 字节），所以不要像我模糊描述的那样实现它，而是阅读如何正确解析 ASN.1。

无论如何，.NET 期望这两个数字连接在一起，没有任何 ASN.1 内容，因此您需要再次提取它们。作为一个快速测试 - 从上面的命令输出中获取这两个数字（它们是十六进制的），连接在一起并从十六进制字符串转换为字节数组，然后在你的代码中使用signatureContents. 或者，使用此示例代码（切勿将其用于实际提取这些数字）从现有签名中提取数字（如果使用此代码您仍然得到无效签名 - 尝试上述方法，直接从 asn1parse 输出复制数据）：

// only for testing purposes
private static byte[] FromOpenSslSignature(byte[] data) {
    var rLength = data[3];
    byte[] rData = new byte[48];
    Array.Copy(data, 4 + (rLength - 48), rData, 0, 48);
    var sLength = data[5 + rLength];
    byte[] sData = new byte[48];
    Array.Copy(data, 6 + rLength + (sLength - 48), sData, 0, 48);
    return rData.Concat(sData).ToArray();
}

如果你做的一切都正确 - 签名将验证就好了。

于 2017-11-03T23:34:33.027 回答