diff --git a/reactos/dll/win32/advapi32/sec/misc.c b/reactos/dll/win32/advapi32/sec/misc.c
index 554511b29ea..0b9b303ba5f 100644
--- a/reactos/dll/win32/advapi32/sec/misc.c
+++ b/reactos/dll/win32/advapi32/sec/misc.c
@@ -2,7 +2,7 @@
  * COPYRIGHT:       See COPYING in the top level directory
  * PROJECT:         ReactOS system libraries
  * FILE:            lib/advapi32/sec/misc.c
- * PURPOSE:         Miscellaneous security functions
+ * PURPOSE:         Miscellaneous security functions (some ported from Wine)
  */
 
 #include <advapi32.h>
@@ -10,6 +10,122 @@
 #define NDEBUG
 #include <debug.h>
 
+/* Needed for LookupAccountNameW implementation from Wine */
+
+typedef struct _AccountSid {
+    WELL_KNOWN_SID_TYPE type;
+    LPCWSTR account;
+    LPCWSTR domain;
+    SID_NAME_USE name_use;
+} AccountSid;
+
+static const WCHAR Account_Operators[] = { 'A','c','c','o','u','n','t',' ','O','p','e','r','a','t','o','r','s',0 };
+static const WCHAR Administrator[] = {'A','d','m','i','n','i','s','t','r','a','t','o','r',0 };
+static const WCHAR Administrators[] = { 'A','d','m','i','n','i','s','t','r','a','t','o','r','s',0 };
+static const WCHAR ANONYMOUS_LOGON[] = { 'A','N','O','N','Y','M','O','U','S',' ','L','O','G','O','N',0 };
+static const WCHAR Authenticated_Users[] = { 'A','u','t','h','e','n','t','i','c','a','t','e','d',' ','U','s','e','r','s',0 };
+static const WCHAR Backup_Operators[] = { 'B','a','c','k','u','p',' ','O','p','e','r','a','t','o','r','s',0 };
+static const WCHAR BATCH[] = { 'B','A','T','C','H',0 };
+static const WCHAR Blank[] = { 0 };
+static const WCHAR BUILTIN[] = { 'B','U','I','L','T','I','N',0 };
+static const WCHAR Cert_Publishers[] = { 'C','e','r','t',' ','P','u','b','l','i','s','h','e','r','s',0 };
+static const WCHAR CREATOR_GROUP[] = { 'C','R','E','A','T','O','R',' ','G','R','O','U','P',0 };
+static const WCHAR CREATOR_GROUP_SERVER[] = { 'C','R','E','A','T','O','R',' ','G','R','O','U','P',' ','S','E','R','V','E','R',0 };
+static const WCHAR CREATOR_OWNER[] = { 'C','R','E','A','T','O','R',' ','O','W','N','E','R',0 };
+static const WCHAR CREATOR_OWNER_SERVER[] = { 'C','R','E','A','T','O','R',' ','O','W','N','E','R',' ','S','E','R','V','E','R',0 };
+static const WCHAR DIALUP[] = { 'D','I','A','L','U','P',0 };
+static const WCHAR Digest_Authentication[] = { 'D','i','g','e','s','t',' ','A','u','t','h','e','n','t','i','c','a','t','i','o','n',0 };
+static const WCHAR DOMAIN[] = {'D','O','M','A','I','N',0};
+static const WCHAR Domain_Admins[] = { 'D','o','m','a','i','n',' ','A','d','m','i','n','s',0 };
+static const WCHAR Domain_Computers[] = { 'D','o','m','a','i','n',' ','C','o','m','p','u','t','e','r','s',0 };
+static const WCHAR Domain_Controllers[] = { 'D','o','m','a','i','n',' ','C','o','n','t','r','o','l','l','e','r','s',0 };
+static const WCHAR Domain_Guests[] = { 'D','o','m','a','i','n',' ','G','u','e','s','t','s',0 };
+static const WCHAR Domain_Users[] = { 'D','o','m','a','i','n',' ','U','s','e','r','s',0 };
+static const WCHAR Enterprise_Admins[] = { 'E','n','t','e','r','p','r','i','s','e',' ','A','d','m','i','n','s',0 };
+static const WCHAR ENTERPRISE_DOMAIN_CONTROLLERS[] = { 'E','N','T','E','R','P','R','I','S','E',' ','D','O','M','A','I','N',' ','C','O','N','T','R','O','L','L','E','R','S',0 };
+static const WCHAR Everyone[] = { 'E','v','e','r','y','o','n','e',0 };
+static const WCHAR Group_Policy_Creator_Owners[] = { 'G','r','o','u','p',' ','P','o','l','i','c','y',' ','C','r','e','a','t','o','r',' ','O','w','n','e','r','s',0 };
+static const WCHAR Guest[] = { 'G','u','e','s','t',0 };
+static const WCHAR Guests[] = { 'G','u','e','s','t','s',0 };
+static const WCHAR INTERACTIVE[] = { 'I','N','T','E','R','A','C','T','I','V','E',0 };
+static const WCHAR LOCAL[] = { 'L','O','C','A','L',0 };
+static const WCHAR LOCAL_SERVICE[] = { 'L','O','C','A','L',' ','S','E','R','V','I','C','E',0 };
+static const WCHAR NETWORK[] = { 'N','E','T','W','O','R','K',0 };
+static const WCHAR Network_Configuration_Operators[] = { 'N','e','t','w','o','r','k',' ','C','o','n','f','i','g','u','r','a','t','i','o','n',' ','O','p','e','r','a','t','o','r','s',0 };
+static const WCHAR NETWORK_SERVICE[] = { 'N','E','T','W','O','R','K',' ','S','E','R','V','I','C','E',0 };
+static const WCHAR NT_AUTHORITY[] = { 'N','T',' ','A','U','T','H','O','R','I','T','Y',0 };
+static const WCHAR NT_Pseudo_Domain[] = { 'N','T',' ','P','s','e','u','d','o',' ','D','o','m','a','i','n',0 };
+static const WCHAR NTML_Authentication[] = { 'N','T','M','L',' ','A','u','t','h','e','n','t','i','c','a','t','i','o','n',0 };
+static const WCHAR NULL_SID[] = { 'N','U','L','L',' ','S','I','D',0 };
+static const WCHAR Other_Organization[] = { 'O','t','h','e','r',' ','O','r','g','a','n','i','z','a','t','i','o','n',0 };
+static const WCHAR Performance_Log_Users[] = { 'P','e','r','f','o','r','m','a','n','c','e',' ','L','o','g',' ','U','s','e','r','s',0 };
+static const WCHAR Performance_Monitor_Users[] = { 'P','e','r','f','o','r','m','a','n','c','e',' ','M','o','n','i','t','o','r',' ','U','s','e','r','s',0 };
+static const WCHAR Power_Users[] = { 'P','o','w','e','r',' ','U','s','e','r','s',0 };
+static const WCHAR Pre_Windows_2000_Compatible_Access[] = { 'P','r','e','-','W','i','n','d','o','w','s',' ','2','0','0','0',' ','C','o','m','p','a','t','i','b','l','e',' ','A','c','c','e','s','s',0 };
+static const WCHAR Print_Operators[] = { 'P','r','i','n','t',' ','O','p','e','r','a','t','o','r','s',0 };
+static const WCHAR PROXY[] = { 'P','R','O','X','Y',0 };
+static const WCHAR RAS_and_IAS_Servers[] = { 'R','A','S',' ','a','n','d',' ','I','A','S',' ','S','e','r','v','e','r','s',0 };
+static const WCHAR Remote_Desktop_Users[] = { 'R','e','m','o','t','e',' ','D','e','s','k','t','o','p',' ','U','s','e','r','s',0 };
+static const WCHAR REMOTE_INTERACTIVE_LOGON[] = { 'R','E','M','O','T','E',' ','I','N','T','E','R','A','C','T','I','V','E',' ','L','O','G','O','N',0 };
+static const WCHAR Replicators[] = { 'R','e','p','l','i','c','a','t','o','r','s',0 };
+static const WCHAR RESTRICTED[] = { 'R','E','S','T','R','I','C','T','E','D',0 };
+static const WCHAR SChannel_Authentication[] = { 'S','C','h','a','n','n','e','l',' ','A','u','t','h','e','n','t','i','c','a','t','i','o','n',0 };
+static const WCHAR Schema_Admins[] = { 'S','c','h','e','m','a',' ','A','d','m','i','n','s',0 };
+static const WCHAR SELF[] = { 'S','E','L','F',0 };
+static const WCHAR Server_Operators[] = { 'S','e','r','v','e','r',' ','O','p','e','r','a','t','o','r','s',0 };
+static const WCHAR SERVICE[] = { 'S','E','R','V','I','C','E',0 };
+static const WCHAR SYSTEM[] = { 'S','Y','S','T','E','M',0 };
+static const WCHAR TERMINAL_SERVER_USER[] = { 'T','E','R','M','I','N','A','L',' ','S','E','R','V','E','R',' ','U','S','E','R',0 };
+static const WCHAR This_Organization[] = { 'T','h','i','s',' ','O','r','g','a','n','i','z','a','t','i','o','n',0 };
+static const WCHAR Users[] = { 'U','s','e','r','s',0 };
+
+static const AccountSid ACCOUNT_SIDS[] = {
+    { WinNullSid, NULL_SID, Blank, SidTypeWellKnownGroup },
+    { WinWorldSid, Everyone, Blank, SidTypeWellKnownGroup },
+    { WinLocalSid, LOCAL, Blank, SidTypeWellKnownGroup },
+    { WinCreatorOwnerSid, CREATOR_OWNER, Blank, SidTypeWellKnownGroup },
+    { WinCreatorGroupSid, CREATOR_GROUP, Blank, SidTypeWellKnownGroup },
+    { WinCreatorOwnerServerSid, CREATOR_OWNER_SERVER, Blank, SidTypeWellKnownGroup },
+    { WinCreatorGroupServerSid, CREATOR_GROUP_SERVER, Blank, SidTypeWellKnownGroup },
+    { WinNtAuthoritySid, NT_Pseudo_Domain, NT_Pseudo_Domain, SidTypeDomain },
+    { WinDialupSid, DIALUP, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinNetworkSid, NETWORK, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinBatchSid, BATCH, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinInteractiveSid, INTERACTIVE, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinServiceSid, SERVICE, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinAnonymousSid, ANONYMOUS_LOGON, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinProxySid, PROXY, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinEnterpriseControllersSid, ENTERPRISE_DOMAIN_CONTROLLERS, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinSelfSid, SELF, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinAuthenticatedUserSid, Authenticated_Users, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinRestrictedCodeSid, RESTRICTED, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinTerminalServerSid, TERMINAL_SERVER_USER, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinRemoteLogonIdSid, REMOTE_INTERACTIVE_LOGON, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinLocalSystemSid, SYSTEM, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinLocalServiceSid, LOCAL_SERVICE, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinNetworkServiceSid, NETWORK_SERVICE, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinBuiltinDomainSid, BUILTIN, BUILTIN, SidTypeDomain },
+    { WinBuiltinAdministratorsSid, Administrators, BUILTIN, SidTypeAlias },
+    { WinBuiltinUsersSid, Users, BUILTIN, SidTypeAlias },
+    { WinBuiltinGuestsSid, Guests, BUILTIN, SidTypeAlias },
+    { WinBuiltinPowerUsersSid, Power_Users, BUILTIN, SidTypeAlias },
+    { WinBuiltinAccountOperatorsSid, Account_Operators, BUILTIN, SidTypeAlias },
+    { WinBuiltinSystemOperatorsSid, Server_Operators, BUILTIN, SidTypeAlias },
+    { WinBuiltinPrintOperatorsSid, Print_Operators, BUILTIN, SidTypeAlias },
+    { WinBuiltinBackupOperatorsSid, Backup_Operators, BUILTIN, SidTypeAlias },
+    { WinBuiltinReplicatorSid, Replicators, BUILTIN, SidTypeAlias },
+    { WinBuiltinPreWindows2000CompatibleAccessSid, Pre_Windows_2000_Compatible_Access, BUILTIN, SidTypeAlias },
+    { WinBuiltinRemoteDesktopUsersSid, Remote_Desktop_Users, BUILTIN, SidTypeAlias },
+    { WinBuiltinNetworkConfigurationOperatorsSid, Network_Configuration_Operators, BUILTIN, SidTypeAlias },
+    { WinNTLMAuthenticationSid, NTML_Authentication, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinDigestAuthenticationSid, Digest_Authentication, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinSChannelAuthenticationSid, SChannel_Authentication, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinThisOrganizationSid, This_Organization, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinOtherOrganizationSid, Other_Organization, NT_AUTHORITY, SidTypeWellKnownGroup },
+    { WinBuiltinPerfMonitoringUsersSid, Performance_Monitor_Users, BUILTIN, SidTypeAlias },
+    { WinBuiltinPerfLoggingUsersSid, Performance_Log_Users, BUILTIN, SidTypeAlias },
+};
+
 /* Interface to ntmarta.dll ***************************************************/
 
 NTMARTA NtMartaStatic = { 0 };
@@ -984,20 +1100,42 @@ LookupAccountSidW (
 /******************************************************************************
  * LookupAccountNameA [ADVAPI32.@]
  *
- * @unimplemented
+ * @implemented
  */
 BOOL STDCALL
 LookupAccountNameA (LPCSTR SystemName,
                     LPCSTR AccountName,
-		    PSID Sid,
-		    LPDWORD SidLength,
-		    LPSTR ReferencedDomainName,
-		    LPDWORD hReferencedDomainNameLength,
-		    PSID_NAME_USE SidNameUse)
+                    PSID Sid,
+                    LPDWORD SidLength,
+                    LPSTR ReferencedDomainName,
+                    LPDWORD hReferencedDomainNameLength,
+                    PSID_NAME_USE SidNameUse)
 {
-  DPRINT1("LookupAccountNameA is unimplemented\n");
-  SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-  return FALSE;
+    BOOL ret;
+    UNICODE_STRING lpSystemW;
+    UNICODE_STRING lpAccountW;
+    LPWSTR lpReferencedDomainNameW = NULL;
+
+    RtlCreateUnicodeStringFromAsciiz(&lpSystemW, SystemName);
+    RtlCreateUnicodeStringFromAsciiz(&lpAccountW, AccountName);
+
+    if (ReferencedDomainName)
+        lpReferencedDomainNameW = HeapAlloc(GetProcessHeap(), 0, *hReferencedDomainNameLength * sizeof(WCHAR));
+
+    ret = LookupAccountNameW(lpSystemW.Buffer, lpAccountW.Buffer, Sid, SidLength, lpReferencedDomainNameW,
+        hReferencedDomainNameLength, SidNameUse);
+
+    if (ret && lpReferencedDomainNameW)
+    {
+        WideCharToMultiByte(CP_ACP, 0, lpReferencedDomainNameW, *hReferencedDomainNameLength,
+            ReferencedDomainName, *hReferencedDomainNameLength, NULL, NULL);
+    }
+
+    RtlFreeUnicodeString(&lpSystemW);
+    RtlFreeUnicodeString(&lpAccountW);
+    HeapFree(GetProcessHeap(), 0, lpReferencedDomainNameW);
+
+    return ret;
 }
 
 
@@ -1006,18 +1144,71 @@ LookupAccountNameA (LPCSTR SystemName,
  *
  * @unimplemented
  */
-BOOL STDCALL
-LookupAccountNameW (LPCWSTR SystemName,
-                    LPCWSTR AccountName,
-		    PSID Sid,
-		    LPDWORD SidLength,
-		    LPWSTR ReferencedDomainName,
-		    LPDWORD hReferencedDomainNameLength,
-		    PSID_NAME_USE SidNameUse)
+BOOL WINAPI LookupAccountNameW(LPCWSTR lpSystemName, LPCWSTR lpAccountName, PSID Sid,
+                               LPDWORD cbSid, LPWSTR ReferencedDomainName,
+                               LPDWORD cchReferencedDomainName, PSID_NAME_USE peUse)
 {
-  DPRINT1("LookupAccountNameW is unimplemented\n");
-  SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-  return FALSE;
+    /* Default implementation: Always return a default SID */
+    SID_IDENTIFIER_AUTHORITY identifierAuthority = {SECURITY_NT_AUTHORITY};
+    BOOL ret;
+    PSID pSid;
+    static const WCHAR dm[] = {'D','O','M','A','I','N',0};
+    unsigned int i;
+
+    DPRINT("%s %s %p %p %p %p %p - stub\n", lpSystemName, lpAccountName,
+          Sid, cbSid, ReferencedDomainName, cchReferencedDomainName, peUse);
+
+    for (i = 0; i < (sizeof(ACCOUNT_SIDS) / sizeof(ACCOUNT_SIDS[0])); i++)
+    {
+        if (!wcscmp(lpAccountName, ACCOUNT_SIDS[i].account))
+        {
+            if (*cchReferencedDomainName)
+                *ReferencedDomainName = '\0';
+            *cchReferencedDomainName = 0;
+            *peUse = SidTypeWellKnownGroup;
+            return CreateWellKnownSid(ACCOUNT_SIDS[i].type, NULL, Sid, cbSid);
+        }
+    }
+
+    ret = AllocateAndInitializeSid(&identifierAuthority,
+        2,
+        SECURITY_BUILTIN_DOMAIN_RID,
+        DOMAIN_ALIAS_RID_ADMINS,
+        0, 0, 0, 0, 0, 0,
+        &pSid);
+
+    if (!ret)
+       return FALSE;
+
+    if (!RtlValidSid(pSid))
+    {
+       FreeSid(pSid);
+       return FALSE;
+    }
+
+    if (Sid != NULL && (*cbSid >= GetLengthSid(pSid)))
+       CopySid(*cbSid, Sid, pSid);
+    if (*cbSid < GetLengthSid(pSid))
+    {
+       SetLastError(ERROR_INSUFFICIENT_BUFFER);
+       ret = FALSE;
+    }
+    *cbSid = GetLengthSid(pSid);
+    
+    if (ReferencedDomainName != NULL && (*cchReferencedDomainName > wcslen(dm)))
+      wcscpy(ReferencedDomainName, dm);
+
+    if (*cchReferencedDomainName <= wcslen(dm))
+    {
+       SetLastError(ERROR_INSUFFICIENT_BUFFER);
+       ret = FALSE;
+    }
+
+    *cchReferencedDomainName = wcslen(dm)+1;
+
+    FreeSid(pSid);
+
+    return ret;
 }