我的目标是使用 Microsoft CNG 为证书填充主题密钥标识符扩展 (2.5.29.14)。我以前使用 Microsoft CAPI 做过，但我使用的功能是：
CryptHashPublicKeyInfo
https://msdn.microsoft.com/en-us/library/windows/desktop/aa380204(v=vs.85).aspx
现在已经贬值了。CNG没有这种方法。但是，上面链接中对 CryptHashPublicKeyInfo 的描述说他们对公钥信息进行了 SHA1 哈希处理。因此，我在 CryptHashPublicKeyInfo (CAPI) 中的相同数据上对 CNG 中的公钥字节进行了 SHA1 哈希，这两个哈希是不同的。我需要解决这个差异。需要明确的是，我的逻辑是在来自同一个 CSR 的同一个公钥上运行的。
RFC 5280 中的详细信息似乎证实了微软所说的： https ://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.2
(1) keyIdentifier 由 BIT STRING subjectPublicKey 的值（不包括标签、长度和未使用的位数）的 160 位 SHA-1 哈希组成。
库珀等人。标准跟踪 [第 28 页] RFC 5280 PKIX 证书和 CRL 配置文件
2008 年 5 月(2) The keyIdentifier is composed of a four-bit type field with the value 0100 followed by the least significant 60 bits of the SHA-1 hash of the value of the BIT STRING subjectPublicKey (excluding the tag, length, and number of unused bits).
^我猜微软正在做案例#1。
这是我的 CAPI 代码：
//depreciated (CAPI)
//get data for subject key identifier
//get length
HCRYPTPROV hHashProv = NULL;
if (!CryptHashPublicKeyInfo(
hHashProv,
CALG_SHA1, //sha1
0,
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
&serverCertInfo.SubjectPublicKeyInfo,
NULL,
&dwSubjectKeyIdentifier
))
{
throw std::runtime_error("Unable to get length of public key info hash");
}
//alocate data buffer
pbSubjectKeyIdentifier = (LPBYTE)LocalAlloc(0, dwSubjectKeyIdentifier);
//fill data buffer with subject key identifier
if (!CryptHashPublicKeyInfo(
hHashProv,
CALG_SHA1, //sha1
0,
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
&serverCertInfo.SubjectPublicKeyInfo,
pbSubjectKeyIdentifier,
&dwSubjectKeyIdentifier
))
{
throw std::runtime_error("Unable to fill public key info hash");
}
CRYPT_DATA_BLOB skiBlob;
skiBlob.cbData = dwSubjectKeyIdentifier;
skiBlob.pbData = pbSubjectKeyIdentifier;
//encode subject key identifier extension
LPBYTE pbEncodeSKI = NULL;
DWORD dwEncodedSKI;
if (!CryptEncodeObject(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_KEY_IDENTIFIER,
(void*)&skiBlob,
NULL,
&dwEncodedSKI
))
{
throw std::runtime_error("Unable to get length to encode extension: subject key identifier");
}
pbEncodeSKI = (LPBYTE)LocalAlloc(0, dwEncodedSKI);
if (!CryptEncodeObject(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_KEY_IDENTIFIER,
(void*)&skiBlob,
pbEncodeSKI,
&dwEncodedSKI
))
{
throw std::runtime_error("Unable to encode extension: subject key identifier");
}
这会在扩展中产生这个值（证书请求中的相同公钥）：9d77f29e4fa15e46237d59a7c00efde9d286b9dc
这是我的 CNG 代码：
NTSTATUS statusBCryptOpenAlgorithmProvider;
NTSTATUS statusBCryptHash;
BCRYPT_ALG_HANDLE hHashAlg;
LPBYTE pbHash;
DWORD dwHash = 20;
LPSTR lpstrPublicKeyEncoded;
DWORD dwPublicKeyEncoded;
CRYPT_DATA_BLOB skiBlob;
if (!CryptBinaryToStringA(
infoPublicKey.PublicKey.pbData,
infoPublicKey.PublicKey.cbData,
CRYPT_STRING_BINARY,
NULL,
&dwPublicKeyEncoded
))
{
throw std::runtime_error("Error getting length of encoded binary string (CryptBinaryToString)");
}
lpstrPublicKeyEncoded = (LPSTR)LocalAlloc(0, dwPublicKeyEncoded);
if (!CryptBinaryToStringA(
infoPublicKey.PublicKey.pbData,
infoPublicKey.PublicKey.cbData,
CRYPT_STRING_BINARY,
lpstrPublicKeyEncoded,
&dwPublicKeyEncoded
))
{
LocalFree(lpstrPublicKeyEncoded);
throw std::runtime_error("Error encoding binary string (CryptBinaryToString)");
}
statusBCryptOpenAlgorithmProvider = BCryptOpenAlgorithmProvider(
&hHashAlg,
BCRYPT_SHA1_ALGORITHM,
MS_PRIMITIVE_PROVIDER,
0
);
if (0 != statusBCryptOpenAlgorithmProvider)
{
LocalFree(lpstrPublicKeyEncoded);
throw std::runtime_error("Error opening SHA1 algorithm provider (BCryptOpenAlgorithmProvider)");
}
pbHash = (LPBYTE)LocalAlloc(0, dwHash);
statusBCryptHash = BCryptHash(
hHashAlg,
NULL,
0,
(BYTE*)lpstrPublicKeyEncoded,
dwPublicKeyEncoded,
pbHash,
dwHash
);
if (0 != statusBCryptHash)
{
LocalFree(lpstrPublicKeyEncoded);
BCryptCloseAlgorithmProvider(hHashAlg, 0);
LocalFree(pbHash);
throw std::runtime_error("Error hashing public key (BCryptHash)");
}
skiBlob.pbData = pbHash;
skiBlob.cbData = dwHash;
BCryptCloseAlgorithmProvider(hHashAlg, 0);
LocalFree(pbHash);
LocalFree(lpstrPublicKeyEncoded);
//encode subject key identifier extension
LPBYTE pbEncodeSKI = NULL;
DWORD dwEncodedSKI;
if (!CryptEncodeObject(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_KEY_IDENTIFIER,
(void*)&skiBlob,
NULL,
&dwEncodedSKI
))
{
throw std::runtime_error("Unable to get length to encode extension: subject key identifier");
}
pbEncodeSKI = (LPBYTE)LocalAlloc(0, dwEncodedSKI);
if (!CryptEncodeObject(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_KEY_IDENTIFIER,
(void*)&skiBlob,
pbEncodeSKI,
&dwEncodedSKI
))
{
throw std::runtime_error("Unable to encode extension: subject key identifier");
}
这会产生这个 SKI 值（不同）： 210816297e8e76879f99ec4762452b5d38967b5b
任何线索我在 CNG 代码示例中做错了什么？显然有一个神奇的调用序列，但我不知道它是什么。