Crypt.h

/*
    SPDX-License-Identifier: MIT
    Copyright © 1991-2022 Amebis
    Copyright © 2016 GÉANT
*/
 
#pragma once
 
#include "Common.h"
#include <assert.h>
#include <WinCrypt.h>
#include <algorithm>
#include <string>
#include <vector>
 
 
template<class _Traits, class _Ax>
static DWORD CertGetNameStringA(_In_ PCCERT_CONTEXT pCertContext, _In_ DWORD dwType, _In_ DWORD dwFlags, _In_opt_ void *pvTypePara, _Out_ std::basic_string<char, _Traits, _Ax> &sNameString)
{
    // Query the final string length first.
    DWORD dwSize = ::CertGetNameStringA(pCertContext, dwType, dwFlags, pvTypePara, NULL, 0);
 
    // Allocate buffer on heap to format the string data into and read it.
    std::unique_ptr<char[]> szBuffer(new char[dwSize]);
    dwSize = ::CertGetNameStringA(pCertContext, dwType, dwFlags, pvTypePara, szBuffer.get(), dwSize);
    sNameString.assign(szBuffer.get(), dwSize - 1);
    return dwSize;
}
 
template<class _Traits, class _Ax>
static DWORD CertGetNameStringW(_In_ PCCERT_CONTEXT pCertContext, _In_ DWORD dwType, _In_ DWORD dwFlags, _In_opt_ void *pvTypePara, _Out_ std::basic_string<wchar_t, _Traits, _Ax> &sNameString)
{
    // Query the final string length first.
    DWORD dwSize = ::CertGetNameStringW(pCertContext, dwType, dwFlags, pvTypePara, NULL, 0);
 
    // Allocate buffer on heap to format the string data into and read it.
    std::unique_ptr<wchar_t[]> szBuffer(new wchar_t[dwSize]);
    dwSize = ::CertGetNameStringW(pCertContext, dwType, dwFlags, pvTypePara, szBuffer.get(), dwSize);
    sNameString.assign(szBuffer.get(), dwSize - 1);
    return dwSize;
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL WINAPI CertGetCertificateContextProperty(_In_ PCCERT_CONTEXT pCertContext, _In_ DWORD dwPropId, _Out_ std::vector<_Ty, _Ax> &aData)
{
    BYTE buf[WINSTD_STACK_BUFFER_BYTES];
    DWORD dwSize = WINSTD_STACK_BUFFER_BYTES;
 
    // Try with the stack buffer first.
    if (CertGetCertificateContextProperty(pCertContext, dwPropId, buf, &dwSize)) {
        // Copy from stack.
        aData.assign((const _Ty*)buf, (const _Ty*)buf + (dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        return TRUE;
    } else if (GetLastError() == ERROR_MORE_DATA) {
        aData.resize((dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        if (CertGetCertificateContextProperty(pCertContext, dwPropId, (BYTE*)aData.data(), &dwSize))
            return TRUE;
    }
 
    return FALSE;
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL CryptGetHashParam(_In_ HCRYPTHASH hHash, _In_ DWORD dwParam, _Out_ std::vector<_Ty, _Ax> &aData, _In_ DWORD dwFlags)
{
    BYTE buf[WINSTD_STACK_BUFFER_BYTES];
    DWORD dwSize = WINSTD_STACK_BUFFER_BYTES;
 
    // Try with the stack buffer first.
    if (CryptGetHashParam(hHash, dwParam, buf, &dwSize, dwFlags)) {
        // Copy from stack.
        aData.assign((const _Ty*)buf, (const _Ty*)buf + (dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        return TRUE;
    } else if (GetLastError() == ERROR_MORE_DATA) {
        aData.resize((dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        if (CryptGetHashParam(hHash, dwParam, (BYTE*)aData.data(), &dwSize, dwFlags))
            return TRUE;
    }
 
    return FALSE;
}
 
template<class T>
static _Success_(return != 0) BOOL CryptGetHashParam(_In_ HCRYPTHASH hHash, _In_ DWORD dwParam, _Out_ T &data, _In_ DWORD dwFlags)
{
    DWORD dwSize = sizeof(T);
    return CryptGetHashParam(hHash, dwParam, (BYTE*)&data, &dwSize, dwFlags);
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL CryptGetKeyParam(_In_ HCRYPTKEY hKey, _In_ DWORD dwParam, _Out_ std::vector<_Ty, _Ax> &aData, _In_ DWORD dwFlags)
{
    BYTE buf[WINSTD_STACK_BUFFER_BYTES];
    DWORD dwSize = WINSTD_STACK_BUFFER_BYTES;
 
    // Try with the stack buffer first.
    if (CryptGetKeyParam(hKey, dwParam, buf, &dwSize, dwFlags)) {
        // Copy from stack.
        aData.assign((const _Ty*)buf, (const _Ty*)buf + (dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        return TRUE;
    } else if (GetLastError() == ERROR_MORE_DATA) {
        aData.resize((dwSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        if (CryptGetKeyParam(hKey, dwParam, (BYTE*)aData.data(), &dwSize, dwFlags))
            return TRUE;
    }
 
    return FALSE;
}
 
template<class T>
static BOOL CryptGetKeyParam(_In_ HCRYPTKEY hKey, _In_ DWORD dwParam, _Out_ T &data, _In_ DWORD dwFlags)
{
    DWORD dwSize = sizeof(T);
    return CryptGetKeyParam(hKey, dwParam, (BYTE*)&data, &dwSize, dwFlags);
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL CryptExportKey(_In_ HCRYPTKEY hKey, _In_ HCRYPTKEY hExpKey, _In_ DWORD dwBlobType, _In_ DWORD dwFlags, _Out_ std::vector<_Ty, _Ax> &aData)
{
    DWORD dwKeyBLOBSize = 0;
 
    if (CryptExportKey(hKey, hExpKey, dwBlobType, dwFlags, NULL, &dwKeyBLOBSize)) {
        aData.resize((dwKeyBLOBSize + sizeof(_Ty) - 1) / sizeof(_Ty));
        if (CryptExportKey(hKey, hExpKey, dwBlobType, dwFlags, aData.data(), &dwKeyBLOBSize))
            return TRUE;
    }
 
    return FALSE;
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL CryptEncrypt(_In_ HCRYPTKEY hKey, _In_opt_ HCRYPTHASH hHash, _In_ BOOL Final, _In_ DWORD dwFlags, _Inout_ std::vector<_Ty, _Ax> &aData)
{
    DWORD
        dwDataLen = (DWORD)(aData.size()     * sizeof(_Ty)),
        dwBufLen  = (DWORD)(aData.capacity() * sizeof(_Ty)),
        dwEncLen  = dwDataLen,
        dwResult;
 
    if (dwBufLen) {
        aData.resize(dwBufLen);
        if (CryptEncrypt(hKey, hHash, Final, dwFlags, (BYTE*)aData.data(), &dwEncLen, dwBufLen)) {
            // Encryption succeeded.
            assert(dwEncLen <= dwBufLen);
            if (dwEncLen < dwBufLen)
                aData.resize((dwEncLen + sizeof(_Ty) - 1) / sizeof(_Ty));
            return TRUE;
        } else
            dwResult = GetLastError();
    } else if (CryptEncrypt(hKey, NULL, Final, dwFlags, NULL, &dwEncLen, 0)) {
        // CryptEncrypt() always succeeds for output data size queries.
        // dwEncLen contains required output data size. Continue as if the buffer was to small. Actually, the output buffer _was_ too small!
        dwResult = ERROR_MORE_DATA;
    } else
        dwResult = GetLastError();
 
    if (dwResult == ERROR_MORE_DATA) {
        // Encrypted data will be longer. Reserve more space and retry.
        aData.resize(((dwBufLen = dwEncLen) + sizeof(_Ty) - 1) / sizeof(_Ty));
        dwEncLen = dwDataLen;
        if (CryptEncrypt(hKey, hHash, Final, dwFlags, (BYTE*)aData.data(), &dwEncLen, dwBufLen)) {
            // Encryption succeeded.
            assert(dwEncLen <= dwBufLen);
            if (dwEncLen < dwBufLen)
                aData.resize((dwEncLen + sizeof(_Ty) - 1) / sizeof(_Ty));
            return TRUE;
        }
    } else {
        // Resize back to data length.
        aData.resize((dwDataLen + sizeof(_Ty) - 1) / sizeof(_Ty));
    }
 
    return FALSE;
}
 
template<class _Ty, class _Ax>
static _Success_(return != 0) BOOL CryptDecrypt(_In_ HCRYPTKEY hKey, _In_opt_ HCRYPTHASH hHash, _In_ BOOL Final, _In_ DWORD dwFlags, _Inout_ std::vector<_Ty, _Ax> &aData)
{
    DWORD dwDataLen = (DWORD)(aData.size() * sizeof(_Ty));
 
    if (CryptDecrypt(hKey, hHash, Final, dwFlags, (BYTE*)aData.data(), &dwDataLen)) {
        // Decryption succeeded.
        aData.resize((dwDataLen + sizeof(_Ty) - 1) / sizeof(_Ty));
        return TRUE;
    }
 
    return FALSE;
}
 
 
namespace winstd
{
 
    class cert_context : public dplhandle<PCCERT_CONTEXT, NULL>
    {
        WINSTD_DPLHANDLE_IMPL(cert_context, NULL)
 
    public:
        virtual ~cert_context()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CertCreateCertificateContext"))
        bool create(_In_  DWORD dwCertEncodingType, _In_  LPCBYTE pbCertEncoded, _In_  DWORD cbCertEncoded) noexcept
        {
            handle_type h = CertCreateCertificateContext(dwCertEncodingType, pbCertEncoded, cbCertEncoded);
            if (h != invalid) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        bool operator==(_In_ const handle_type &other) const noexcept
        {
            // TODO: [Crypto] Make constant time.
            return
                m_h == other ||
                m_h->cbCertEncoded == other->cbCertEncoded && memcmp(m_h->pbCertEncoded, other->pbCertEncoded, m_h->cbCertEncoded) == 0;
        }
 
        bool operator!=(_In_ const handle_type &other) const noexcept
        {
            return !operator==(other);
        }
 
        bool operator<(_In_ const handle_type &other) const noexcept
        {
            // TODO: [Crypto] Make constant time.
            const int r = memcmp(m_h->pbCertEncoded, other->pbCertEncoded, std::min<DWORD>(m_h->cbCertEncoded, other->cbCertEncoded));
            return r < 0 || r == 0 && m_h->cbCertEncoded < other->cbCertEncoded;
        }
 
        bool operator>(_In_ const handle_type &other) const noexcept
        {
            // TODO: [Crypto] Make constant time.
            const int r = memcmp(m_h->pbCertEncoded, other->pbCertEncoded, std::min<DWORD>(m_h->cbCertEncoded, other->cbCertEncoded));
            return r > 0 || r == 0 && m_h->cbCertEncoded > other->cbCertEncoded;
        }
 
        bool operator<=(_In_ const handle_type &other) const noexcept
        {
            return !operator>(other);
        }
 
        bool operator>=(_In_ const handle_type &other) const noexcept
        {
            return !operator<(other);
        }
 
    protected:
        void free_internal() noexcept override
        {
            CertFreeCertificateContext(m_h);
        }
 
        handle_type duplicate_internal(_In_ handle_type h) const noexcept override
        {
            return CertDuplicateCertificateContext(h);
        }
    };
 
    class cert_chain_context : public dplhandle<PCCERT_CHAIN_CONTEXT, NULL>
    {
        WINSTD_DPLHANDLE_IMPL(cert_chain_context, NULL)
 
    public:
        virtual ~cert_chain_context()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CertGetCertificateChain"))
        bool create(_In_opt_ HCERTCHAINENGINE hChainEngine, _In_ PCCERT_CONTEXT pCertContext, _In_opt_ LPFILETIME pTime, _In_opt_ HCERTSTORE hAdditionalStore, _In_ PCERT_CHAIN_PARA pChainPara, _In_ DWORD dwFlags, __reserved LPVOID pvReserved = NULL) noexcept
        {
            handle_type h;
            if (CertGetCertificateChain(hChainEngine, pCertContext, pTime, hAdditionalStore, pChainPara, dwFlags, pvReserved, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
    protected:
        void free_internal() noexcept override
        {
            CertFreeCertificateChain(m_h);
        }
 
        handle_type duplicate_internal(_In_ handle_type h) const noexcept override
        {
            return CertDuplicateCertificateChain(h);
        }
    };
 
    class cert_store : public handle<HCERTSTORE, NULL>
    {
        WINSTD_HANDLE_IMPL(cert_store, NULL)
 
    public:
        virtual ~cert_store()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CertOpenStore"))
        bool create(_In_ LPCSTR lpszStoreProvider, _In_ DWORD dwEncodingType, _In_opt_ HCRYPTPROV_LEGACY hCryptProv, _In_ DWORD dwFlags, _In_opt_ const void *pvPara) noexcept
        {
            handle_type h = CertOpenStore(lpszStoreProvider, dwEncodingType, hCryptProv, dwFlags, pvPara);
            if (h != invalid) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        __declspec(deprecated("Use CertOpenSystemStore"))
        bool create(_In_opt_ HCRYPTPROV_LEGACY hCryptProv, _In_z_ LPCTSTR szSubsystemProtocol) noexcept
        {
            handle_type h = CertOpenSystemStore(hCryptProv, szSubsystemProtocol);
            if (h != invalid) {
                attach(h);
                return true;
            } else
                return false;
        }
 
    protected:
        void free_internal() noexcept override
        {
            CertCloseStore(m_h, 0);
        }
    };
 
    class crypt_prov : public handle<HCRYPTPROV, NULL>
    {
        WINSTD_HANDLE_IMPL(crypt_prov, NULL)
 
    public:
        virtual ~crypt_prov()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CryptAcquireContext"))
        bool create(_In_opt_z_ LPCTSTR szContainer, _In_opt_z_ LPCTSTR szProvider, _In_ DWORD dwProvType, _In_ DWORD dwFlags = 0) noexcept
        {
            handle_type h;
            if (CryptAcquireContext(&h, szContainer, szProvider, dwProvType, dwFlags)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
    protected:
        void free_internal() noexcept override
        {
            CryptReleaseContext(m_h, 0);
        }
    };
 
    class crypt_hash : public dplhandle<HCRYPTHASH, NULL>
    {
        WINSTD_DPLHANDLE_IMPL(crypt_hash, NULL)
 
    public:
        virtual ~crypt_hash()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CryptCreateHash"))
        bool create(_In_ HCRYPTPROV  hProv, _In_ ALG_ID Algid, _In_opt_ HCRYPTKEY hKey = NULL, _In_opt_ DWORD dwFlags = 0) noexcept
        {
            handle_type h;
            if (CryptCreateHash(hProv, Algid, hKey, dwFlags, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
    protected:
        void free_internal() noexcept override
        {
            CryptDestroyHash(m_h);
        }
 
        handle_type duplicate_internal(_In_ handle_type h) const noexcept override
        {
            handle_type hNew;
            return CryptDuplicateHash(h, NULL, 0, &hNew) ? hNew : invalid;
        }
    };
 
    class crypt_key : public dplhandle<HCRYPTKEY, NULL>
    {
        WINSTD_DPLHANDLE_IMPL(crypt_key, NULL)
 
    public:
        virtual ~crypt_key()
        {
            if (m_h != invalid)
                free_internal();
        }
 
        __declspec(deprecated("Use CryptGenKey"))
        bool generate(_In_ HCRYPTPROV hProv, _In_ ALG_ID Algid, _In_ DWORD dwFlags) noexcept
        {
            handle_type h;
            if (CryptGenKey(hProv, Algid, dwFlags, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        __declspec(deprecated("Use CryptImportKey"))
        bool import(_In_ HCRYPTPROV hProv, __in_bcount(dwDataLen) LPCBYTE pbData, _In_ DWORD dwDataLen, _In_ HCRYPTKEY hPubKey, _In_ DWORD dwFlags) noexcept
        {
            handle_type h;
            if (CryptImportKey(hProv, pbData, dwDataLen, hPubKey, dwFlags, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        __declspec(deprecated("Use CryptImportPublicKeyInfo"))
        bool import_public(_In_ HCRYPTPROV hCryptProv, _In_ DWORD dwCertEncodingType, _In_ PCERT_PUBLIC_KEY_INFO pInfo) noexcept
        {
            handle_type h;
            if (CryptImportPublicKeyInfo(hCryptProv, dwCertEncodingType, pInfo, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        __declspec(deprecated("Use CryptDeriveKey"))
        bool derive(_In_ HCRYPTPROV hProv, _In_ ALG_ID Algid, _In_ HCRYPTHASH hBaseData, _In_ DWORD dwFlags) noexcept
        {
            handle_type h;
            if (CryptDeriveKey(hProv, Algid, hBaseData, dwFlags, &h)) {
                attach(h);
                return true;
            } else
                return false;
        }
 
        bool create_exp1(_In_ HCRYPTPROV hProv, _In_ DWORD dwKeySpec)
        {
            if (dwKeySpec != AT_KEYEXCHANGE && dwKeySpec != AT_SIGNATURE) {
                SetLastError(ERROR_INVALID_PARAMETER);
                return false;
            }
 
            // Generate the private key.
            handle_type h;
            if (CryptGenKey(hProv, dwKeySpec, CRYPT_EXPORTABLE, &h)) {
                // Export the private key, we'll convert it to a private exponent of one key.
                std::vector<BYTE, sanitizing_allocator<BYTE>> key_blob;
                if (CryptExportKey(h, 0, PRIVATEKEYBLOB, 0, key_blob)) {
                    CryptDestroyKey(h);
 
                    // Get the byte length of the key.
                    size_t
                        size_key   = *reinterpret_cast<DWORD*>(&key_blob[12])/8,
                        size_prime = size_key/2;
 
                    // Modify the Exponent in Key BLOB format
                    // Key BLOB format is documented in SDK
 
                    // Convert pubexp in rsapubkey to 1
                    LPBYTE ptr = &key_blob[16];
                    *reinterpret_cast<DWORD*>(ptr) = 1;
                    ptr += sizeof(DWORD);
 
                    // Skip modulus, prime1, prime2
                    ptr += size_key;
                    ptr += size_prime;
                    ptr += size_prime;
 
                    // Convert exponent1 to 1
                    ptr[0] = 1;
                    memset(ptr + 1, 0, size_prime - 1);
                    ptr += size_prime;
 
                    // Convert exponent2 to 1
                    ptr[0] = 1;
                    memset(ptr + 1, 0, size_prime - 1);
                    ptr += size_prime;
 
                    // Skip coefficient
                    ptr += size_prime;
 
                    // Convert privateExponent to 1
                    ptr[0] = 1;
                    memset(ptr + 1, 0, size_key - 1);
 
                    // Import the exponent-of-one private key.
                    if (CryptImportKey(hProv, key_blob.data(), static_cast<DWORD>(key_blob.size()), 0, 0, &h)) {
                        attach(h);
                        return true;
                    }
                } else
                    CryptDestroyKey(h);
            }
 
            return false;
        }
 
    protected:
        void free_internal() noexcept override
        {
            CryptDestroyKey(m_h);
        }
 
        handle_type duplicate_internal(_In_ handle_type h) const noexcept override
        {
            handle_type hNew;
            return CryptDuplicateKey(h, NULL, 0, &hNew) ? hNew : invalid;
        }
    };
 
    #pragma warning(push)
    #pragma warning(disable: 26432) // Copy constructor and assignment operator are also present, but not detected by code analysis as they are using base type source object reference.
    class data_blob : public DATA_BLOB
    {
    public:
        data_blob() noexcept
        {
            cbData = 0;
            pbData = NULL;
        }
 
        data_blob(_In_count_(size) BYTE *data, _In_ DWORD size) noexcept
        {
            cbData = size;
            pbData = data;
        }
 
        data_blob(_In_ const DATA_BLOB &other)
        {
            cbData = other.cbData;
            if (cbData) {
                pbData = static_cast<BYTE*>(LocalAlloc(LMEM_FIXED, other.cbData));
                if (!pbData) throw win_runtime_error("LocalAlloc failed.");
                memcpy(pbData, other.pbData, other.cbData);
            } else
                pbData = NULL;
        }
 
        data_blob(_Inout_ data_blob &&other) noexcept
        {
            cbData = other.cbData;
            pbData = other.pbData;
            other.cbData = 0;
            other.pbData = NULL;
        }
 
        virtual ~data_blob()
        {
            if (pbData != NULL)
                LocalFree(pbData);
        }
 
        data_blob& operator=(_In_ const DATA_BLOB &other)
        {
            if (this != &other) {
                cbData = other.cbData;
                if (pbData)
                    LocalFree(pbData);
                if (cbData) {
                    pbData = static_cast<BYTE*>(LocalAlloc(LMEM_FIXED, other.cbData));
                    if (!pbData) throw win_runtime_error("LocalAlloc failed.");
                    memcpy(pbData, other.pbData, other.cbData);
                } else
                    pbData = NULL;
            }
 
            return *this;
        }
 
        data_blob& operator=(_Inout_ data_blob &&other) noexcept
        {
            if (this != &other) {
                cbData = other.cbData;
                if (pbData)
                    LocalFree(pbData);
                pbData = other.pbData;
                other.cbData = 0;
                other.pbData = NULL;
            }
 
            return *this;
        }
 
        DWORD size() const noexcept
        {
            return cbData;
        }
 
        const BYTE* data() const noexcept
        {
            return pbData;
        }
 
        BYTE* data() noexcept
        {
            return pbData;
        }
    };
    #pragma warning(pop)
 
}
 
 
#pragma warning(push)
#pragma warning(disable: 4505) // Don't warn on unused code
 
static BOOL CertGetCertificateChain(_In_opt_ HCERTCHAINENGINE hChainEngine, _In_ PCCERT_CONTEXT pCertContext, _In_opt_ LPFILETIME pTime, _In_opt_ HCERTSTORE hAdditionalStore, _In_ PCERT_CHAIN_PARA pChainPara, _In_ DWORD dwFlags, _Reserved_ LPVOID pvReserved, _Inout_ winstd::cert_chain_context &ctx)
{
    PCCERT_CHAIN_CONTEXT pChainContext;
    BOOL bResult = CertGetCertificateChain(hChainEngine, pCertContext, pTime, hAdditionalStore, pChainPara, dwFlags, pvReserved, &pChainContext);
    if (bResult)
        ctx.attach(pChainContext);
    return bResult;
}
 
static BOOL CryptAcquireContextA(_Inout_ winstd::crypt_prov &prov, _In_opt_ LPCSTR szContainer, _In_opt_ LPCSTR szProvider, _In_ DWORD dwProvType, _In_ DWORD dwFlags)
{
    HCRYPTPROV h;
    BOOL bResult = CryptAcquireContextA(&h, szContainer, szProvider, dwProvType, dwFlags);
    if (bResult)
        prov.attach(h);
    return bResult;
}
 
static BOOL CryptAcquireContextW(_Inout_ winstd::crypt_prov &prov, _In_opt_ LPCWSTR szContainer, _In_opt_ LPCWSTR szProvider, _In_ DWORD dwProvType, _In_ DWORD dwFlags)
{
    HCRYPTPROV h;
    BOOL bResult = CryptAcquireContextW(&h, szContainer, szProvider, dwProvType, dwFlags);
    if (bResult)
        prov.attach(h);
    return bResult;
}
 
static BOOL CryptCreateHash(_In_ HCRYPTPROV hProv, _In_ ALG_ID Algid, _In_ HCRYPTKEY hKey, _In_ DWORD dwFlags, _Inout_ winstd::crypt_hash &hash)
{
    HCRYPTHASH h;
    BOOL bResult = CryptCreateHash(hProv, Algid, hKey, dwFlags, &h);
    if (bResult)
        hash.attach(h);
    return bResult;
}
 
static BOOL CryptGenKey(_In_ HCRYPTPROV hProv, _In_ ALG_ID Algid, _In_ DWORD dwFlags, _Inout_ winstd::crypt_key &key)
{
    HCRYPTKEY h;
    BOOL bResult = CryptGenKey(hProv, Algid, dwFlags, &h);
    if (bResult)
        key.attach(h);
    return bResult;
}
 
static bool CryptImportKey(_In_ HCRYPTPROV hProv, __in_bcount(dwDataLen) LPCBYTE pbData, _In_ DWORD dwDataLen, _In_ HCRYPTKEY hPubKey, _In_ DWORD dwFlags, _Inout_ winstd::crypt_key &key)
{
    HCRYPTKEY h;
    BOOL bResult = CryptImportKey(hProv, pbData, dwDataLen, hPubKey, dwFlags, &h);
    if (bResult)
        key.attach(h);
    return bResult;
}
 
static bool CryptImportPublicKeyInfo(_In_ HCRYPTPROV hCryptProv, _In_ DWORD dwCertEncodingType, _In_ PCERT_PUBLIC_KEY_INFO pInfo, _Inout_ winstd::crypt_key &key)
{
    HCRYPTKEY h;
    BOOL bResult = CryptImportPublicKeyInfo(hCryptProv, dwCertEncodingType, pInfo, &h);
    if (bResult)
        key.attach(h);
    return bResult;
}
 
static bool CryptDeriveKey(_In_ HCRYPTPROV hProv, _In_ ALG_ID Algid, _In_ HCRYPTHASH hBaseData, _In_ DWORD dwFlags, _Inout_ winstd::crypt_key &key)
{
    HCRYPTKEY h;
    BOOL bResult = CryptDeriveKey(hProv, Algid, hBaseData, dwFlags, &h);
    if (bResult)
        key.attach(h);
    return bResult;
}
 
#pragma warning(pop)