Using CryptoAPI to resolve X509 certificates and P12 certificates

Read into a CER file, CertCreateCertificateContext generate Cert_context. Cert_context there is a cert_info,cert_info in this data structure that has a subjectpublickeyinfo, Subjectpublickeyinfo is a data segment of the Publickey_info type , which holds the ID of the algorithm and the DER encoded public key. With this der Code, we can use other tools (such as OpenSSL) to parse the parameters of the public key. Unfortunately, the interfaces defined by CryptoAPI cannot handle DER encoding directly, and they must be repackaged into CryptoAPI PublicKeyBlob of their own definition. What should I do?

First Use Cryptacqiurecontext (...). Newkeyset) to create a new container, the container name can be used on its own. Then, with Cryptimportpublickeyinfo () to the subjectpublickeyinfo just got into the built container, and then with the CryptExportKey (... PUBLICKEYBLOB) The public key is exported, and the PublicKeyBlob is generally supported by the Cryptapi interface.

I. Analysis of X509 certificate

1. Read the certificate data from the certificate file on disk
unsigned char* pbx509data; Certificate data
unsigned long Ulx509datalen; Certificate Data length

2. Get Certcontext
Pccert_context Pcertcontext = CertCreateCertificateContext (x509_asn_encoding, Pbx509data, UlX509DataLen);

3. Obtaining Certificate Information
pcertcontext->pcertinfo->dwversion; Certificate version number
Crypt_integer_blob Snblob = pcertcontext->pcertinfo->serialnumber; Certificate SN
Cert_name_blob Issuerblob = pcertcontext->pcertinfo->issuer; Certificate issuer
Cert_name_blob Subjectblob = pcertcontext->pcertinfo->subject; Certificate subject
Certificate Valid Starting Date
SYSTEMTIME SysTime;
memset (&systime, 0, sizeof (sysTime));
FileTimeToSystemTime (&pcertcontext->pcertinfo->notbefore, &systime);
Char sztime[128] = {0};
sprintf_s (Sztime, +, "%d%d months%d days%d:%d:%d", Systime.wyear, Systime.wmonth, Systime.wday, Systime.whour, Systime.wminute, Systime.wsecond);
Certificate Valid Expiration date
memset (&systime, 0, sizeof (sysTime));
FileTimeToSystemTime (&pcertcontext->pcertinfo->notafter, &systime);
memset (sztime, 0, sizeof (sztime));
sprintf_s (Sztime, +, "%d%d months%d days%d:%d:%d", Systime.wyear, Systime.wmonth, Systime.wday, Systime.whour, Systime.wminute, Systime.wsecond);

4. Create a temporary key container
Hcryptprov Htmpprov = NULL;
if (rcrypt_failed (CryptAcquireContext (&htmpprov, "My_temporary_container", NULL, Prov_rsa_aes, CRYPT_NEWKEYSET) ))//null means using the system default CSP
{
if (rcrypt_failed (CryptAcquireContext (&htmpprov, "My_temporary_container", NULL, Prov_rsa_aes, 0))// Null means using the system default CSP
{
Certfreecertificatecontext (Pcertcontext);
return nte_fail;
}
}

5. Import the public key into the container to get the public key handle
Hcryptkey HKey = NULL;
Cert_public_key_info Certpubkeyinfo = pcertcontext->pcertinfo->subjectpublickeyinfo;
Cryptimportpublickeyinfo (Htmpprov, x509_asn_encoding| Pkcs_7_asn_encoding, &certpubkeyinfo, &hkey);

6. Export the public key (preferably with two call methods)
unsigned char* pBuf = NULL;
unsigned long ulbuflen = 0;
CryptExportKey (HKey, 0, PublicKeyBlob, 0, PBuf, &ulbuflen);
PBuf = new unsigned char[ulbuflen];
memset (pBuf, 0, Ulbuflen);
CryptExportKey (HKey, 0, PublicKeyBlob, 0, PBuf, &ulbuflen);

7. Get Public key information
unsigned char* p = pBuf + sizeof (PUBLICKEYSTRUC);
(* (rsapubkey*) p). Bitlen; Public key modulo length (in bits)
(* (rsapubkey*) p). Pubexp; E of the public key (note byte order)
p + = sizeof (Rsapubkey); N of public key (note byte order)

8. Cleanup work
Delete[] PBuf;
PBuf = NULL;
Cryptdestroykey (HKey);
CryptReleaseContext (Htmpprov, 0);
Certfreecertificatecontext (Pcertcontext);

Second, analytic P12 certificate

1. Read the certificate data from the certificate file on disk
unsigned char* pbp12data; Certificate data
unsigned long Ulp12datalen; Certificate Data length

2. Let the user enter the certificate password
char* szpwd; Certificate Password

3. Convert the certificate password into Unicode format (preferably with two calls)
LPWSTR Pwidechar = NULL;
int Nwidechar = 0;
Nwidechar = MultiByteToWideChar (CP_ACP, 0, Szpwd,-1, Pwidechar, Nwidechar);
Pwidechar = new Wchar[nwidechar];
memset (Pwidechar, 0, sizeof (WCHAR) *nwidechar);
MultiByteToWideChar (CP_ACP, 0, Szpwd,-1, Pwidechar, Nwidechar);

4. Import the certificate data into the temporary store
Crypt_data_blob BLOB;
memset (&blob, 0, sizeof (BLOB));
Blob.pbdata = Pbp12data;
Blob.cbdata = Ulp12datalen;
Hcertstore Hcertstore = NULL;
Hcertstore = Pfximportcertstore (&blob, Pwidechar, crypt_exportable);

5. Find the certificate in the store and get Certcontext
Pccert_context Pcertcontext = CertFindCertificateInStore (Hcertstore, x509_asn_encoding| pkcs_7_asn_encoding, 0, cert_find_any, NULL, or NULL);

6. Obtaining Certificate information
Crypt_integer_blob Snblob = pcertcontext->pcertinfo->serialnumber; Certificate SN
pcertcontext->pbcertencoded; X509 Format certificate Data
pcertcontext->cbcertencoded; X509 Format Certificate Data length

7. Get the CSP handle
Hcryptprov Hprov = NULL;
DWORD dwkeyspec = 0;
BOOL Bcallerfreeprov = FALSE;
Cryptacquirecertificateprivatekey (pcertcontext, 0, NULL, &hprov, &dwkeyspec, &bcallerfreeprov);

8. Get the key handle
Hcryptkey HKey = NULL;
Cryptgetuserkey (Hprov, Dwkeyspec, &hkey);

9. Export the private key (preferably with two call methods)
byte* pbdata = NULL;
DWORD Dwdatalen = 0;
CryptExportKey (HKey, NULL, Privatekeyblob, 0, pbdata, &dwdatalen);
Pbdata = new Byte[dwdatalen];
memset (pbdata, 0, Dwdatalen);
CryptExportKey (HKey, NULL, Privatekeyblob, 0, pbdata, &dwdatalen);

10. Get Public Private key information
BYTE *p = pbdata+ sizeof (PUBLICKEYSTRUC);
(* (rsapubkey*) p). Bitlen; Public key modulus (in bits)
(* (rsapubkey*) p). Pubexp; E of the public key (note byte order)
p + = sizeof (Rsapubkey); N of Public private key (note byte order)
p + = ((* (rsapubkey*) p). Bitlen)/8; P (note byte order) of the private key
p + = ((* (rsapubkey*) p). Bitlen)/16; Q of the private key (note byte order)
p + = ((* (rsapubkey*) p). Bitlen)/16; DP of the private key (note byte order)
p + = ((* (rsapubkey*) p). Bitlen)/16; DQ of the private key (note byte order)
p + = ((* (rsapubkey*) p). Bitlen)/16; Qu of the private key (note byte order)
p + = ((* (rsapubkey*) p). Bitlen)/16; D of the private key (note byte order)

11. Cleanup work
Delete[] pbdata;
Pbdata = NULL;
Cryptdestroykey (HKey);
CryptReleaseContext (Hprov, 0);
Certfreecertificatecontext (Pcertcontext);
CertCloseStore (Hcertstore, Cert_close_store_force_flag);
Delete[] Pwidechar;
Pwidechar = NULL;

Using CryptoAPI to resolve X509 certificates and P12 certificates