误解 CSR 和 X.509 的功能

Question

在花了两天时间搜索并找到我的问题的答案后，才意识到这些答案只会带来更多我无法解决的问题，我决定在这里寻求帮助，希望我没有错过我所了解的信息正在寻找某个地方。

我刚刚开始了一个项目，在开始与该客户合作之前，我必须与该客户交换X.509 证书。 我已经很好地理解了 X.509 证书的制作方式和原因：

• 使用私钥制作 CSR；
• 此 CSR 包含数字身份和从私钥中提取的公钥；
• CSR 是自签名的或发送给 CA，CA 使用自己的私钥对其进行签名，以验证发送者的身份；
• CA 发回符合 X.509 标准的证书，证明您没有伪造身份，因此 X.509 中包含的公钥是可靠的。

因此，X.509 证书是一种与他人交换您的公钥以对抗潜在的中间人攻击的方法。 使用OpenSSL，我已经能够单独模拟这些操作，以了解这些步骤的功能。

我的第一个问题是，当我使用私钥 (privateKey.pem) 创建 CSR，然后检查此私钥是否与 CSR 匹配时，不匹配 >.
然后我使用不同的私钥（signingPrivateKey.pem）对 CSR 进行自签名，再次检查 X.509 证书是否与私钥匹配，仍然不匹配（这似乎很正常，因为 CSR两者都没有，但两者都应该匹配，不是吗？）。

这里是 OpenSSL 命令：

@echo off

echo "Generates private key and puts it in SigningPrivateKey.pem"
echo.
openssl genrsa -out SigningPrivateKey.pem 1024

echo "Generates private key and puts it in privateKey.pem, then create CSR"
echo.
openssl req -newkey rsa:1024 -keyout privateKey.pem -out CSR_TEST.csr -nodes


echo "Checks if CSR and privateKey matches
echo.
openssl x509 -noout -modulus -in CSR_TEST.csr | openssl md5
openssl rsa -noout -modulus -in privateKey.pem | openssl md5

echo "Self sign CSR with private key"
echo.
openssl x509 -in CSR_TEST.csr -out CSR_TEST.pem -req -signkey 
SigningPrivateKey.pem -days 1

echo. "Checks again if certificate and private key matches
openssl x509 -noout -modulus -in CSR_TEST.pem | openssl md5
openssl rsa -noout -modulus -in privateKey.pem | openssl md5  

这是总结的输入：

stdin = d41d8....8427e  
stdin = f3213....4538c  
Signature ok  
stdin = 82baf...a0863  
stdin = f3213...4538c

我的第二个问题是验证 X.509 的方法。 假设我设法从输入私钥制作了 X.509 证书，并且提取的公钥与之匹配。我将其发送给我的客户，后者将证书发送给。 我们怎么知道这个 X.509 是可靠的？我在某处读到我们需要用 CA 的公钥“取消签名”X.509 证书，并将输出与散列证书进行比较，但似乎每个人都说 X .509 证书是自给自足的，它本身就证明了您的身份。我们只需要使用 OpenSSL 命令检查其真实性吗？ 请在这一点上减轻我的负担。

感谢您花时间阅读和理解我的问题，我再次希望我不是唯一一个面临这些问题的人，并且这篇文章将对其他人有所帮助。 抱歉，我还不允许在这篇文章中添加更多链接，否则我会更准确。

Answer 1

企业社会责任/关键比较

$ openssl req -in test.csr -modulus -noout | openssl md5
(stdin)= 76d44c1a05f535f5e78a648b41bdaf73
$ openssl rsa -in test.key -modulus -noout | openssl md5
(stdin)= 76d44c1a05f535f5e78a648b41bdaf73

您在 CSR 上使用了openssl x509。他们不一样。而且您显然在通过 MD5 运行之前没有查看输出：

$ openssl x509 -in test.csr -modulus -noout
unable to load certificate
139958187611800:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:701:Expecting: TRUSTED CERTIFICATE

你还没有把它做成证书，所以x509命令不起作用。

在您制作证书并再次检查后，您会得到不同的答案，因为您使用了-signkey。 documentation 表示 -signkey 用作自签名密钥，这意味着它替换原始请求中的公钥。如果您使用-signkey privateKey.pem，您的命令应该显示对齐。

诚信

每个 X.509 证书都包含提供的数据（包括公钥）和签名。对于“真正的”CA，通常会有一条说明（授权信息访问扩展）说明如何找到 CA 的证书。无论您是手头有它还是必须从互联网上检索它，都可以使用签名证书中的公钥来验证原始证书中的数据是否没有更改。

签名 CA 本身有一个证书，因此您可以进一步证明它没有被更改。

最终您将获得根/自签名证书。要么你已经拥有它并认为它是可信的，要么你没有，你称整个事情为恶意。

对于不属于您的内置信任库的自签名证书，唯一可以真正验证的是它在创建后没有被修改。这样做的唯一安全好处是否认：如果有人编辑了您创建的证书并添加了一个扩展名，该扩展名的意思是“你妈妈是个臭驴推销员！”你可以证明自签名是无效的。

$ openssl x509 -in test.cer -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 11195357966677484939 (0x9b5de6c15126a58b)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, OU=.NET Framework (CoreFX), CN=localhost
        Validity
            Not Before: Mar  2 01:48:00 2016 GMT
            Not After : Mar  2 01:48:00 2017 GMT
        Subject: C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, OU=.NET Framework (CoreFX), CN=localhost
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:af:81:c1:cb:d8:20:3f:62:4a:53:9e:d6:60:81:
                    75:37:23:93:a2:83:7d:48:90:e4:8a:19:de:d3:69:
                    73:11:56:20:96:8d:6b:e0:d3:da:a3:8a:a7:77:be:
                    02:ee:0b:6b:93:b7:24:e8:dc:c1:2b:63:2b:4f:a8:
                    0b:bc:92:5b:ce:62:4f:4c:a7:cc:60:63:06:b3:94:
                    03:e2:8c:93:2d:24:dd:54:6f:fe:4e:f6:a3:7f:10:
                    77:0b:22:15:ea:8c:bb:5b:f4:27:e8:c4:d8:9b:79:
                    eb:33:83:75:10:0c:5f:83:e5:5d:e9:b4:46:6d:df:
                    be:ee:42:53:9a:ef:33:ef:18:7b:77:60:c3:b1:a1:
                    b2:10:3c:2d:81:44:56:4a:0c:10:39:a0:9c:85:cf:
                    6b:59:74:eb:51:6f:c8:d6:62:3c:94:ae:3a:5a:0b:
                    b3:b4:c7:92:95:7d:43:23:91:56:6c:f3:e2:a5:2a:
                    fb:0c:14:2b:9e:06:81:b8:97:26:71:af:2b:82:dd:
                    39:0a:39:b9:39:cf:71:95:68:68:7e:49:90:a6:30:
                    50:ca:77:68:dc:d6:b3:78:84:2f:18:fd:b1:f6:d9:
                    ff:09:6b:af:7b:eb:98:dc:f9:30:d6:6f:cf:d5:03:
                    f5:8d:41:bf:f4:62:12:e2:4e:3a:fc:45:ea:42:bd:
                    88:47
                Exponent: 8589935681 (0x200000441)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
                78:A5:C7:5D:51:66:73:31:D5:A9:69:24:11:4C:9B:5F:A0:0D:7B:CB
            X509v3 Authority Key Identifier:
                keyid:78:A5:C7:5D:51:66:73:31:D5:A9:69:24:11:4C:9B:5F:A0:0D:7B:CB

            X509v3 Basic Constraints:
                CA:TRUE
    Signature Algorithm: sha256WithRSAEncryption
         77:75:6d:05:ff:a6:ad:fe:d5:b6:d4:af:b5:40:84:0c:6d:01:
         cf:6b:3f:a6:c9:73:df:d6:1f:ca:a0:a8:14:fa:1e:24:69:01:
         9d:94:b1:d8:56:d0:7d:d2:b9:5b:85:50:df:d2:08:59:53:a4:
         94:b9:9e:fc:ba:a7:98:2c:e7:71:98:4f:9d:4a:44:5f:fe:e0:
         62:e8:a0:49:73:6a:39:fd:99:4e:1f:da:0a:5d:c2:b5:b0:e5:
         7a:0b:10:c4:1b:c7:fe:6a:40:b2:4f:85:97:73:02:59:3e:60:
         b9:8d:d4:81:1d:47:d9:48:ed:f8:d6:e6:b5:af:80:a1:82:74:
         96:e2:0b:fd:24:0e:46:76:74:50:4d:4e:47:03:33:1d:64:70:
         5c:36:fb:6e:14:ba:bf:d9:cb:ee:c4:4b:33:a8:d7:b3:64:79:
         90:0f:3c:5b:ba:b6:9c:5e:45:3d:18:07:83:e2:50:80:51:b9:
         98:c0:38:e4:62:25:71:d2:ab:89:1d:89:8e:54:58:82:8c:f1:
         86:79:51:7d:28:db:ca:bf:72:e8:13:07:bf:d7:21:b7:3d:db:
         17:51:12:3f:99:d8:fc:0d:53:37:98:c4:db:d1:47:19:d5:d8:
         a8:5b:00:a1:44:a3:67:67:7b:48:89:1a:9b:56:f0:45:33:48:
         11:ba:cb:7a

和

$ openssl x509 -in alsotest.cer -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 11195357966677484939 (0x9b5de6c15126a58b)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, OU=.NET Framework (CoreFX), CN=localhost
        Validity
            Not Before: Mar  2 01:48:00 2016 GMT
            Not After : Mar  2 01:48:00 2019 GMT
        Subject: C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, OU=.NET Framework (CoreFX), CN=localhost
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:af:81:c1:cb:d8:20:3f:62:4a:53:9e:d6:60:81:
                    75:37:23:93:a2:83:7d:48:90:e4:8a:19:de:d3:69:
                    73:11:56:20:96:8d:6b:e0:d3:da:a3:8a:a7:77:be:
                    02:ee:0b:6b:93:b7:24:e8:dc:c1:2b:63:2b:4f:a8:
                    0b:bc:92:5b:ce:62:4f:4c:a7:cc:60:63:06:b3:94:
                    03:e2:8c:93:2d:24:dd:54:6f:fe:4e:f6:a3:7f:10:
                    77:0b:22:15:ea:8c:bb:5b:f4:27:e8:c4:d8:9b:79:
                    eb:33:83:75:10:0c:5f:83:e5:5d:e9:b4:46:6d:df:
                    be:ee:42:53:9a:ef:33:ef:18:7b:77:60:c3:b1:a1:
                    b2:10:3c:2d:81:44:56:4a:0c:10:39:a0:9c:85:cf:
                    6b:59:74:eb:51:6f:c8:d6:62:3c:94:ae:3a:5a:0b:
                    b3:b4:c7:92:95:7d:43:23:91:56:6c:f3:e2:a5:2a:
                    fb:0c:14:2b:9e:06:81:b8:97:26:71:af:2b:82:dd:
                    39:0a:39:b9:39:cf:71:95:68:68:7e:49:90:a6:30:
                    50:ca:77:68:dc:d6:b3:78:84:2f:18:fd:b1:f6:d9:
                    ff:09:6b:af:7b:eb:98:dc:f9:30:d6:6f:cf:d5:03:
                    f5:8d:41:bf:f4:62:12:e2:4e:3a:fc:45:ea:42:bd:
                    88:47
                Exponent: 8589935681 (0x200000441)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
                78:A5:C7:5D:51:66:73:31:D5:A9:69:24:11:4C:9B:5F:A0:0D:7B:CB
            X509v3 Authority Key Identifier:
                keyid:78:A5:C7:5D:51:66:73:31:D5:A9:69:24:11:4C:9B:5F:A0:0D:7B:CB

            X509v3 Basic Constraints:
                CA:TRUE
    Signature Algorithm: sha256WithRSAEncryption
         77:75:6d:05:ff:a6:ad:fe:d5:b6:d4:af:b5:40:84:0c:6d:01:
         cf:6b:3f:a6:c9:73:df:d6:1f:ca:a0:a8:14:fa:1e:24:69:01:
         9d:94:b1:d8:56:d0:7d:d2:b9:5b:85:50:df:d2:08:59:53:a4:
         94:b9:9e:fc:ba:a7:98:2c:e7:71:98:4f:9d:4a:44:5f:fe:e0:
         62:e8:a0:49:73:6a:39:fd:99:4e:1f:da:0a:5d:c2:b5:b0:e5:
         7a:0b:10:c4:1b:c7:fe:6a:40:b2:4f:85:97:73:02:59:3e:60:
         b9:8d:d4:81:1d:47:d9:48:ed:f8:d6:e6:b5:af:80:a1:82:74:
         96:e2:0b:fd:24:0e:46:76:74:50:4d:4e:47:03:33:1d:64:70:
         5c:36:fb:6e:14:ba:bf:d9:cb:ee:c4:4b:33:a8:d7:b3:64:79:
         90:0f:3c:5b:ba:b6:9c:5e:45:3d:18:07:83:e2:50:80:51:b9:
         98:c0:38:e4:62:25:71:d2:ab:89:1d:89:8e:54:58:82:8c:f1:
         86:79:51:7d:28:db:ca:bf:72:e8:13:07:bf:d7:21:b7:3d:db:
         17:51:12:3f:99:d8:fc:0d:53:37:98:c4:db:d1:47:19:d5:d8:
         a8:5b:00:a1:44:a3:67:67:7b:48:89:1a:9b:56:f0:45:33:48:
         11:ba:cb:7a

为了避免您的眼睛疲劳：其中一个在当前过去有到期日，另一个在当前未来有一个到期日。 （我懒得注入扩展）。

哪个是正确的？

$ openssl verify test.cer
test.cer: C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 18 at 0 depth lookup:self signed certificate
C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 10 at 0 depth lookup:certificate has expired
OK

$ openssl verify alsotest.cer
alsotest.cer: C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 18 at 0 depth lookup:self signed certificate
OK

Drat，他们都是正确的。还是他们？等等，openssl verify 不会正常检查自签名签名，因为它通常无关紧要。

$ openssl verify -check_ss_sig test.cer
test.cer: C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 18 at 0 depth lookup:self signed certificate
C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 10 at 0 depth lookup:certificate has expired
OK

$ openssl verify -check_ss_sig alsotest.cer
alsotest.cer: C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 18 at 0 depth lookup:self signed certificate
C = US, ST = Washington, L = Redmond, O = Microsoft Corporation, OU = .NET Framework (CoreFX), CN = localhost
error 7 at 0 depth lookup:certificate signature failure
140450704717464:error:04091068:rsa routines:INT_RSA_VERIFY:bad signature:rsa_sign.c:278:
140450704717464:error:0D0C5006:asn1 encoding routines:ASN1_item_verify:EVP lib:a_verify.c:218:

我们去吧。还对test.cer 进行了修改（未辞职）以延长其到期日期。