diff --git a/rostests/winetests/crypt32/cert.c b/rostests/winetests/crypt32/cert.c
index e66b62101bc..a22ec7cf1f7 100644
--- a/rostests/winetests/crypt32/cert.c
+++ b/rostests/winetests/crypt32/cert.c
@@ -662,6 +662,10 @@ static void testDupCert(void)
         CertFreeCertificateContext(context);
     }
     CertCloseStore(store, 0);
+
+    SetLastError(0xdeadbeef);
+    context = CertDuplicateCertificateContext(NULL);
+    ok(context == NULL, "Expected context to be NULL\n");
 }
 
 static BYTE subjectName3[] = { 0x30, 0x15, 0x31, 0x13, 0x30, 0x11, 0x06,
diff --git a/rostests/winetests/crypt32/encode.c b/rostests/winetests/crypt32/encode.c
index 9c35de1f01c..5c681b638cc 100644
--- a/rostests/winetests/crypt32/encode.c
+++ b/rostests/winetests/crypt32/encode.c
@@ -808,7 +808,7 @@ static void test_encodeName(DWORD dwEncoding)
     attrs[0].pszObjId = "bogus";
     attrs[0].dwValueType = CERT_RDN_PRINTABLE_STRING;
     attrs[0].Value.cbData = sizeof(commonName);
-    attrs[0].Value.pbData = (BYTE *)commonName;
+    attrs[0].Value.pbData = commonName;
     rdn.cRDNAttr = 1;
     rdn.rgRDNAttr = attrs;
     ret = pCryptEncodeObjectEx(dwEncoding, X509_NAME, &info,
@@ -861,7 +861,7 @@ static void test_encodeName(DWORD dwEncoding)
      "Expected E_INVALIDARG, got %08x\n", GetLastError());
     /* Test a more complex name */
     rdn.cRDNAttr = sizeof(rdnAttrs) / sizeof(rdnAttrs[0]);
-    rdn.rgRDNAttr = (PCERT_RDN_ATTR)rdnAttrs;
+    rdn.rgRDNAttr = rdnAttrs;
     info.cRDN = 1;
     info.rgRDN = &rdn;
     buf = NULL;
@@ -993,6 +993,13 @@ static void test_encodeUnicodeName(DWORD dwEncoding)
 static void compareNameValues(const CERT_NAME_VALUE *expected,
  const CERT_NAME_VALUE *got)
 {
+    if (expected->dwValueType == CERT_RDN_UTF8_STRING &&
+        got->dwValueType == CERT_RDN_ENCODED_BLOB)
+    {
+        win_skip("Can't handle CERT_RDN_UTF8_STRING\n");
+        return;
+    }
+
     ok(got->dwValueType == expected->dwValueType,
      "Expected string type %d, got %d\n", expected->dwValueType,
      got->dwValueType);
@@ -1149,7 +1156,7 @@ static void test_decodeName(DWORD dwEncoding)
     if (ret)
     {
         rdn.cRDNAttr = sizeof(decodedRdnAttrs) / sizeof(decodedRdnAttrs[0]);
-        rdn.rgRDNAttr = (PCERT_RDN_ATTR)decodedRdnAttrs;
+        rdn.rgRDNAttr = decodedRdnAttrs;
         compareNames(&info, (CERT_NAME_INFO *)buf);
         LocalFree(buf);
     }
@@ -1977,10 +1984,10 @@ static void test_encodeBits(DWORD dwEncoding)
         if (buf)
         {
             ok(bufSize == bits[i].encoded[1] + 2,
-             "Got unexpected size %d, expected %d\n", bufSize,
+             "%d: Got unexpected size %d, expected %d\n", i, bufSize,
              bits[i].encoded[1] + 2);
             ok(!memcmp(buf, bits[i].encoded, bits[i].encoded[1] + 2),
-             "Unexpected value\n");
+             "%d: Unexpected value\n", i);
             LocalFree(buf);
         }
     }
@@ -2962,7 +2969,7 @@ static void test_encodeCertToBeSigned(DWORD dwEncoding)
     ext.pszObjId = oid_subject_key_identifier;
     ext.fCritical = FALSE;
     ext.Value.cbData = sizeof(octetCommonNameValue);
-    ext.Value.pbData = (BYTE *)octetCommonNameValue;
+    ext.Value.pbData = octetCommonNameValue;
     info.cExtension = 1;
     info.rgExtension = &ext;
     ret = pCryptEncodeObjectEx(dwEncoding, X509_CERT_TO_BE_SIGNED, &info,
diff --git a/rostests/winetests/crypt32/msg.c b/rostests/winetests/crypt32/msg.c
index e8e7eb31747..495f2f07216 100644
--- a/rostests/winetests/crypt32/msg.c
+++ b/rostests/winetests/crypt32/msg.c
@@ -182,7 +182,7 @@ static void test_msg_get_param(void)
     ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, NULL, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     /* For this (empty) message, the type isn't set */
     ok(value == 0, "Expected type 0, got %d\n", value);
@@ -193,7 +193,7 @@ static void test_msg_get_param(void)
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     /* For explicitly typed messages, the type is known. */
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == CMSG_DATA, "Expected CMSG_DATA, got %d\n", value);
     for (i = CMSG_CONTENT_PARAM; i <= CMSG_CMS_SIGNER_INFO_PARAM; i++)
@@ -208,7 +208,7 @@ static void test_msg_get_param(void)
      NULL);
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == CMSG_ENVELOPED, "Expected CMSG_ENVELOPED, got %d\n", value);
     for (i = CMSG_CONTENT_PARAM; i <= CMSG_CMS_SIGNER_INFO_PARAM; i++)
@@ -223,7 +223,7 @@ static void test_msg_get_param(void)
      NULL);
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == CMSG_HASHED, "Expected CMSG_HASHED, got %d\n", value);
     for (i = CMSG_CONTENT_PARAM; i <= CMSG_CMS_SIGNER_INFO_PARAM; i++)
@@ -238,7 +238,7 @@ static void test_msg_get_param(void)
      NULL);
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == CMSG_SIGNED, "Expected CMSG_SIGNED, got %d\n", value);
     for (i = CMSG_CONTENT_PARAM; i <= CMSG_CMS_SIGNER_INFO_PARAM; i++)
@@ -254,7 +254,7 @@ static void test_msg_get_param(void)
      NULL);
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == CMSG_ENCRYPTED, "Expected CMSG_ENCRYPTED, got %d\n", value);
     CryptMsgClose(msg);
@@ -262,7 +262,7 @@ static void test_msg_get_param(void)
     msg = CryptMsgOpenToDecode(PKCS_7_ASN_ENCODING, 0, 1000, 0, NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToDecode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_TYPE_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %x\n", GetLastError());
     ok(value == 1000, "Expected 1000, got %d\n", value);
     CryptMsgClose(msg);
@@ -830,7 +830,7 @@ static void test_hash_msg_get_param(void)
     ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, NULL, &size);
     ok(ret, "CryptMsgGetParam failed: %08x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %08x\n", GetLastError());
     ok(value == 0, "Expected version 0, got %d\n", value);
     /* As usual, the type isn't available. */
@@ -1116,11 +1116,10 @@ static void test_signed_msg_open(void)
     signer.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
     U(signer.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonName);
-    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData =
-     (BYTE *)encodedCommonName;
+    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData = encodedCommonName;
     U(signer.SignerId).IssuerSerialNumber.SerialNumber.cbData =
      sizeof(serialNum);
-    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = serialNum;
     msg = CryptMsgOpenToEncode(PKCS_7_ASN_ENCODING, 0, CMSG_SIGNED, &signInfo,
      NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToEncode failed: %x\n", GetLastError());
@@ -1211,7 +1210,7 @@ static void test_signed_msg_update(void)
     ok(!ret && (GetLastError() == NTE_BAD_KEYSET ||
      GetLastError() == NTE_NO_KEY),
      "Expected NTE_BAD_KEYSET or NTE_NO_KEY, got %x\n", GetLastError());
-    ret = CryptImportKey(signer.hCryptProv, (LPBYTE)privKey, sizeof(privKey),
+    ret = CryptImportKey(signer.hCryptProv, privKey, sizeof(privKey),
      0, 0, &key);
     ok(ret, "CryptImportKey failed: %08x\n", GetLastError());
     /* The final update should be able to succeed now that a key exists, but
@@ -1630,7 +1629,7 @@ static void test_signed_msg_encoding(void)
         return;
     }
 
-    ret = CryptImportKey(signer.hCryptProv, (LPBYTE)privKey, sizeof(privKey),
+    ret = CryptImportKey(signer.hCryptProv, privKey, sizeof(privKey),
      0, 0, &key);
     ok(ret, "CryptImportKey failed: %08x\n", GetLastError());
 
@@ -1664,7 +1663,7 @@ static void test_signed_msg_encoding(void)
     certInfo.Issuer.cbData = 0;
     signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
     U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
-    U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).KeyId.pbData = serialNum;
     msg = CryptMsgOpenToEncode(PKCS_7_ASN_ENCODING, 0, CMSG_SIGNED, &signInfo,
      NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToEncode failed: %x\n", GetLastError());
@@ -1814,7 +1813,7 @@ static void test_signed_msg_get_param(void)
     ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, NULL, &size);
     ok(ret, "CryptMsgGetParam failed: %08x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %08x\n", GetLastError());
     ok(value == CMSG_SIGNED_DATA_V1, "Expected version 1, got %d\n", value);
     /* But for this message, with no signers, the hash and signer aren't
@@ -1892,11 +1891,10 @@ static void test_signed_msg_get_param(void)
     signer.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
     U(signer.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonName);
-    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData =
-     (BYTE *)encodedCommonName;
+    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData = encodedCommonName;
     U(signer.SignerId).IssuerSerialNumber.SerialNumber.cbData =
      sizeof(serialNum);
-    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = serialNum;
     ret = pCryptAcquireContextA(&signer.hCryptProv, cspNameA, NULL,
      PROV_RSA_FULL, CRYPT_NEWKEYSET);
     if (!ret && GetLastError() == NTE_EXISTS)
@@ -1910,7 +1908,7 @@ static void test_signed_msg_get_param(void)
      * are used and no additional CMS fields are used.
      */
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, &value, &size);
     ok(ret, "CryptMsgGetParam failed: %08x\n", GetLastError());
     ok(value == CMSG_SIGNED_DATA_V1, "expected version 1, got %d\n", value);
     /* Apparently the encoded signer can be retrieved.. */
@@ -1936,7 +1934,7 @@ static void test_signed_msg_get_param(void)
      */
     signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
     U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
-    U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).KeyId.pbData = serialNum;
     ret = pCryptAcquireContextA(&signer.hCryptProv, cspNameA, NULL,
      PROV_RSA_FULL, CRYPT_NEWKEYSET);
     if (!ret && GetLastError() == NTE_EXISTS)
@@ -1947,7 +1945,7 @@ static void test_signed_msg_get_param(void)
      CMSG_CRYPT_RELEASE_CONTEXT_FLAG, CMSG_SIGNED, &signInfo, NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToEncode failed: %x\n", GetLastError());
     size = sizeof(value);
-    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, (LPBYTE)&value, &size);
+    ret = CryptMsgGetParam(msg, CMSG_VERSION_PARAM, 0, &value, &size);
     ok(value == CMSG_SIGNED_DATA_V3, "expected version 3, got %d\n", value);
     /* Even for a CMS message, the signer can be retrieved.. */
     ret = CryptMsgGetParam(msg, CMSG_ENCODED_SIGNER, 0, NULL, &size);
@@ -2528,7 +2526,7 @@ static void test_decode_msg_get_param(void)
         signer.dwVersion = CMSG_SIGNED_DATA_V3;
         signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
         U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
-        U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
+        U(signer.SignerId).KeyId.pbData = serialNum;
         signer.HashAlgorithm.pszObjId = oid_rsa_md5;
         CryptMsgGetParam(msg, CMSG_CMS_SIGNER_INFO_PARAM, 0, buf, &size);
         compare_cms_signer_info((CMSG_CMS_SIGNER_INFO *)buf, &signer);
diff --git a/rostests/winetests/crypt32/protectdata.c b/rostests/winetests/crypt32/protectdata.c
index 30b55b4b942..97b08c510fb 100644
--- a/rostests/winetests/crypt32/protectdata.c
+++ b/rostests/winetests/crypt32/protectdata.c
@@ -69,11 +69,16 @@ static void test_cryptprotectdata(void)
     /* without entropy */
     SetLastError(0xDEADBEEF);
     protected = pCryptProtectData(&plain,desc,NULL,NULL,NULL,0,&cipher);
-    ok(protected, "Encrypting without entropy.\n");
-    r = GetLastError();
-    ok(r == ERROR_SUCCESS ||
-       r == ERROR_IO_PENDING, /* win2k */
-       "Expected ERROR_SUCCESS or ERROR_IO_PENDING, got %d\n",r);
+    ok(protected ||
+     broken(!protected), /* Win9x/NT4 */
+     "Encrypting without entropy.\n");
+    if (protected)
+    {
+        r = GetLastError();
+        ok(r == ERROR_SUCCESS ||
+           r == ERROR_IO_PENDING, /* win2k */
+           "Expected ERROR_SUCCESS or ERROR_IO_PENDING, got %d\n",r);
+    }
 
     cipher_entropy.pbData=NULL;
     cipher_entropy.cbData=0;
@@ -81,7 +86,9 @@ static void test_cryptprotectdata(void)
     /* with entropy */
     SetLastError(0xDEADBEEF);
     protected = pCryptProtectData(&plain,desc,&entropy,NULL,NULL,0,&cipher_entropy);
-    ok(protected, "Encrypting with entropy.\n");
+    ok(protected ||
+     broken(!protected), /* Win9x/NT4 */
+     "Encrypting with entropy.\n");
 
     cipher_no_desc.pbData=NULL;
     cipher_no_desc.cbData=0;
diff --git a/rostests/winetests/crypt32/store.c b/rostests/winetests/crypt32/store.c
index ae2112399af..65d7f1529e7 100644
--- a/rostests/winetests/crypt32/store.c
+++ b/rostests/winetests/crypt32/store.c
@@ -1701,7 +1701,7 @@ struct EnumSystemStoreInfo
 static BOOL CALLBACK enumSystemStoreCB(const void *systemStore, DWORD dwFlags,
  PCERT_SYSTEM_STORE_INFO pStoreInfo, void *pvReserved, void *pvArg)
 {
-    struct EnumSystemStoreInfo *info = (struct EnumSystemStoreInfo *)pvArg;
+    struct EnumSystemStoreInfo *info = pvArg;
 
     info->storeCount++;
     return info->goOn;
diff --git a/rostests/winetests/crypt32/str.c b/rostests/winetests/crypt32/str.c
index 5b2e0253e95..2b30995615f 100644
--- a/rostests/winetests/crypt32/str.c
+++ b/rostests/winetests/crypt32/str.c
@@ -204,19 +204,19 @@ static void test_CertRDNValueToStrA(void)
 {
     CertRDNAttrEncoding attrs[] = {
      { "2.5.4.6", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin1), (PBYTE)bin1 }, "US" },
+       { sizeof(bin1), bin1 }, "US" },
      { "2.5.4.8", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin2), (PBYTE)bin2 }, "Minnesota" },
+       { sizeof(bin2), bin2 }, "Minnesota" },
      { "2.5.4.7", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin3), (PBYTE)bin3 }, "Minneapolis" },
+       { sizeof(bin3), bin3 }, "Minneapolis" },
      { "2.5.4.10", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin4), (PBYTE)bin4 }, "CodeWeavers" },
+       { sizeof(bin4), bin4 }, "CodeWeavers" },
      { "2.5.4.11", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin5), (PBYTE)bin5 }, "Wine Development" },
+       { sizeof(bin5), bin5 }, "Wine Development" },
      { "2.5.4.3", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin6), (PBYTE)bin6 }, "localhost" },
+       { sizeof(bin6), bin6 }, "localhost" },
      { "1.2.840.113549.1.9.1", CERT_RDN_IA5_STRING,
-       { sizeof(bin7), (PBYTE)bin7 }, "aric@codeweavers.com" },
+       { sizeof(bin7), bin7 }, "aric@codeweavers.com" },
     };
     DWORD i, ret;
     char buffer[2000];
@@ -261,19 +261,19 @@ static void test_CertRDNValueToStrW(void)
      'a','v','e','r','s','.','c','o','m',0 };
     CertRDNAttrEncodingW attrs[] = {
      { "2.5.4.6", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin1), (PBYTE)bin1 }, usW },
+       { sizeof(bin1), bin1 }, usW },
      { "2.5.4.8", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin2), (PBYTE)bin2 }, minnesotaW },
+       { sizeof(bin2), bin2 }, minnesotaW },
      { "2.5.4.7", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin3), (PBYTE)bin3 }, minneapolisW },
+       { sizeof(bin3), bin3 }, minneapolisW },
      { "2.5.4.10", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin4), (PBYTE)bin4 }, codeweaversW },
+       { sizeof(bin4), bin4 }, codeweaversW },
      { "2.5.4.11", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin5), (PBYTE)bin5 }, wineDevW },
+       { sizeof(bin5), bin5 }, wineDevW },
      { "2.5.4.3", CERT_RDN_PRINTABLE_STRING,
-       { sizeof(bin6), (PBYTE)bin6 }, localhostW },
+       { sizeof(bin6), bin6 }, localhostW },
      { "1.2.840.113549.1.9.1", CERT_RDN_IA5_STRING,
-       { sizeof(bin7), (PBYTE)bin7 }, aricW },
+       { sizeof(bin7), bin7 }, aricW },
     };
     DWORD i, ret;
     WCHAR buffer[2000];