diff --git a/reactos/dll/win32/advapi32/misc/logon.c b/reactos/dll/win32/advapi32/misc/logon.c
index 68f6b30449d..6f14106f02d 100644
--- a/reactos/dll/win32/advapi32/misc/logon.c
+++ b/reactos/dll/win32/advapi32/misc/logon.c
@@ -666,7 +666,7 @@ LogonUserW (LPWSTR lpszUsername,
       DPRINT ("SamGetUserSid() failed\n");
       RtlAllocateAndInitializeSid (&SystemAuthority,
 				   5,
-				   SECURITY_NT_NON_UNIQUE_RID,
+				   SECURITY_NT_NON_UNIQUE,
 				   0x12345678,
 				   0x12345678,
 				   0x12345678,
diff --git a/reactos/dll/win32/advapi32/sec/sid.c b/reactos/dll/win32/advapi32/sec/sid.c
index f82ef5b5060..f53e8cbabe1 100644
--- a/reactos/dll/win32/advapi32/sec/sid.c
+++ b/reactos/dll/win32/advapi32/sec/sid.c
@@ -31,6 +31,63 @@ typedef struct _ACEFLAG
    DWORD value;
 } ACEFLAG, *LPACEFLAG;
 
+typedef struct _MAX_SID
+{
+    /* same fields as struct _SID */
+    BYTE Revision;
+    BYTE SubAuthorityCount;
+    SID_IDENTIFIER_AUTHORITY IdentifierAuthority;
+    DWORD SubAuthority[SID_MAX_SUB_AUTHORITIES];
+} MAX_SID;
+
+typedef struct WELLKNOWNSID
+{
+    WCHAR wstr[2];
+    WELL_KNOWN_SID_TYPE Type;
+    MAX_SID Sid;
+} WELLKNOWNSID;
+
+static const WELLKNOWNSID WellKnownSids[] =
+{
+    { {0,0}, WinNullSid, { SID_REVISION, 1, { SECURITY_NULL_SID_AUTHORITY }, { SECURITY_NULL_RID } } },
+    { {'W','D'}, WinWorldSid, { SID_REVISION, 1, { SECURITY_WORLD_SID_AUTHORITY }, { SECURITY_WORLD_RID } } },
+    { {0,0}, WinLocalSid, { SID_REVISION, 1, { SECURITY_LOCAL_SID_AUTHORITY }, { SECURITY_LOCAL_RID } } },
+    { {'C','O'}, WinCreatorOwnerSid, { SID_REVISION, 1, { SECURITY_CREATOR_SID_AUTHORITY }, { SECURITY_CREATOR_OWNER_RID } } },
+    { {'C','G'}, WinCreatorGroupSid, { SID_REVISION, 1, { SECURITY_CREATOR_SID_AUTHORITY }, { SECURITY_CREATOR_GROUP_RID } } },
+    { {0,0}, WinCreatorOwnerServerSid, { SID_REVISION, 1, { SECURITY_CREATOR_SID_AUTHORITY }, { SECURITY_CREATOR_OWNER_SERVER_RID } } },
+    { {0,0}, WinCreatorGroupServerSid, { SID_REVISION, 1, { SECURITY_CREATOR_SID_AUTHORITY }, { SECURITY_CREATOR_GROUP_SERVER_RID } } },
+    { {0,0}, WinNtAuthoritySid, { SID_REVISION, 0, { SECURITY_NT_AUTHORITY }, { } } },
+    { {0,0}, WinDialupSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_DIALUP_RID } } },
+    { {'N','U'}, WinNetworkSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_NETWORK_RID } } },
+    { {0,0}, WinBatchSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_BATCH_RID } } },
+    { {'I','U'}, WinInteractiveSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_INTERACTIVE_RID } } },
+    { {'S','U'}, WinServiceSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_SERVICE_RID } } },
+    { {'A','N'}, WinAnonymousSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_ANONYMOUS_LOGON_RID } } },
+    { {0,0}, WinProxySid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_PROXY_RID } } },
+    { {'E','D'}, WinEnterpriseControllersSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_ENTERPRISE_CONTROLLERS_RID } } },
+    { {'P','S'}, WinSelfSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_PRINCIPAL_SELF_RID } } },
+    { {'A','U'}, WinAuthenticatedUserSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_AUTHENTICATED_USER_RID } } },
+    { {'R','C'}, WinRestrictedCodeSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_RESTRICTED_CODE_RID } } },
+    { {0,0}, WinTerminalServerSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_TERMINAL_SERVER_RID } } },
+    { {0,0}, WinRemoteLogonIdSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_REMOTE_LOGON_RID } } },
+    { {'S','Y'}, WinLocalSystemSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_LOCAL_SYSTEM_RID } } },
+    { {'L','S'}, WinLocalServiceSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_LOCAL_SERVICE_RID } } },
+    { {'N','S'}, WinNetworkServiceSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_NETWORK_SERVICE_RID } } },
+    { {0,0}, WinBuiltinDomainSid, { SID_REVISION, 1, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID } } },
+    { {'B','A'}, WinBuiltinAdministratorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS } } },
+    { {'B','U'}, WinBuiltinUsersSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_USERS } } },
+    { {'B','G'}, WinBuiltinGuestsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_GUESTS } } },
+    { {'P','U'}, WinBuiltinPowerUsersSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_POWER_USERS } } },
+    { {'A','O'}, WinBuiltinAccountOperatorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ACCOUNT_OPS } } },
+    { {'S','O'}, WinBuiltinSystemOperatorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_SYSTEM_OPS } } },
+    { {'P','O'}, WinBuiltinPrintOperatorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_PRINT_OPS } } },
+    { {'B','O'}, WinBuiltinBackupOperatorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_BACKUP_OPS } } },
+    { {'R','E'}, WinBuiltinReplicatorSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_REPLICATOR } } },
+    { {'R','U'}, WinBuiltinPreWindows2000CompatibleAccessSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_PREW2KCOMPACCESS } } },
+    { {'R','D'}, WinBuiltinRemoteDesktopUsersSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_REMOTE_DESKTOP_USERS } } },
+    { {'N','O'}, WinBuiltinNetworkConfigurationOperatorsSid, { SID_REVISION, 2, { SECURITY_NT_AUTHORITY }, { SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_NETWORK_CONFIGURATION_OPS } } },
+};
+
 static const SID sidWorld = { SID_REVISION, 1, { SECURITY_WORLD_SID_AUTHORITY} , { SECURITY_WORLD_RID } };
 
 /*
@@ -68,6 +125,57 @@ static const WCHAR SDDL_INHERITED[]          = {'I','D',0};
 static const WCHAR SDDL_AUDIT_SUCCESS[]      = {'S','A',0};
 static const WCHAR SDDL_AUDIT_FAILURE[]      = {'F','A',0};
 
+static const char * debugstr_sid(PSID sid)
+{
+    int auth = 0;
+    SID * psid = (SID *)sid;
+
+    if (psid == NULL)
+        return "(null)";
+
+    auth = psid->IdentifierAuthority.Value[5] +
+           (psid->IdentifierAuthority.Value[4] << 8) +
+           (psid->IdentifierAuthority.Value[3] << 16) +
+           (psid->IdentifierAuthority.Value[2] << 24);
+
+    switch (psid->SubAuthorityCount) {
+    case 0:
+        return wine_dbg_sprintf("S-%d-%d", psid->Revision, auth);
+    case 1:
+        return wine_dbg_sprintf("S-%d-%d-%lu", psid->Revision, auth,
+            psid->SubAuthority[0]);
+    case 2:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1]);
+    case 3:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1], psid->SubAuthority[2]);
+    case 4:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1], psid->SubAuthority[2],
+            psid->SubAuthority[3]);
+    case 5:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1], psid->SubAuthority[2],
+            psid->SubAuthority[3], psid->SubAuthority[4]);
+    case 6:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[3], psid->SubAuthority[1], psid->SubAuthority[2],
+            psid->SubAuthority[0], psid->SubAuthority[4], psid->SubAuthority[5]);
+    case 7:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu-%lu-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1], psid->SubAuthority[2],
+            psid->SubAuthority[3], psid->SubAuthority[4], psid->SubAuthority[5],
+            psid->SubAuthority[6]);
+    case 8:
+        return wine_dbg_sprintf("S-%d-%d-%lu-%lu-%lu-%lu-%lu-%lu-%lu-%lu", psid->Revision, auth,
+            psid->SubAuthority[0], psid->SubAuthority[1], psid->SubAuthority[2],
+            psid->SubAuthority[3], psid->SubAuthority[4], psid->SubAuthority[5],
+            psid->SubAuthority[6], psid->SubAuthority[7]);
+    }
+    return "(too-big)";
+}
+
 /* set last error code from NT status and get the proper boolean return value */
 /* used for functions that are a simple wrapper around the corresponding ntdll API */
 static __inline BOOL set_ntstatus( NTSTATUS status )
@@ -1020,7 +1128,36 @@ CreateWellKnownSid(IN WELL_KNOWN_SID_TYPE WellKnownSidType,
                    OUT PSID pSid,
                    IN OUT DWORD* cbSid)
 {
-    FIXME("unimplemented!\n", __FUNCTION__);
+    int i;
+    TRACE("(%d, %s, %p, %p)\n", WellKnownSidType, debugstr_sid(DomainSid), pSid, cbSid);
+
+    if (DomainSid != NULL) {
+        FIXME("Only local computer supported!\n");
+        SetLastError(ERROR_INVALID_PARAMETER);	/* FIXME */
+        return FALSE;
+    }
+
+    if (cbSid == NULL || pSid == NULL) {
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return FALSE;
+    }
+
+    for (i = 0; i < sizeof(WellKnownSids)/sizeof(WellKnownSids[0]); i++) {
+        if (WellKnownSids[i].Type == WellKnownSidType) {
+            DWORD length = GetSidLengthRequired(WellKnownSids[i].Sid.SubAuthorityCount);
+
+            if (*cbSid < length) {
+                SetLastError(ERROR_INSUFFICIENT_BUFFER);
+                return FALSE;
+            }
+
+            CopyMemory(pSid, &WellKnownSids[i].Sid.Revision, length);
+            *cbSid = length;
+            return TRUE;
+        }
+    }
+
+    SetLastError(ERROR_INVALID_PARAMETER);
     return FALSE;
 }
 
@@ -1032,7 +1169,14 @@ BOOL STDCALL
 IsWellKnownSid(IN PSID pSid,
                IN WELL_KNOWN_SID_TYPE WellKnownSidType)
 {
-    FIXME("unimplemented!\n", __FUNCTION__);
+    int i;
+    TRACE("(%s, %d)\n", debugstr_sid(pSid), WellKnownSidType);
+
+    for (i = 0; i < sizeof(WellKnownSids)/sizeof(WellKnownSids[0]); i++)
+        if (WellKnownSids[i].Type == WellKnownSidType)
+            if (EqualSid(pSid, (PSID)&(WellKnownSids[i].Sid.Revision)))
+                return TRUE;
+
     return FALSE;
 }
 
diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index 7a86b9a7587..c63d4c2c5fa 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -529,19 +529,39 @@ typedef DWORD FLONG;
 
 #define SECURITY_LOGON_IDS_RID_COUNT 0x3
 #define SID_REVISION 1
-#define DOMAIN_USER_RID_ADMIN 0x1F4L
-#define DOMAIN_USER_RID_GUEST 0x1F5L
-#define DOMAIN_GROUP_RID_ADMINS	0x200L
-#define DOMAIN_GROUP_RID_USERS	0x201L
-#define DOMAIN_ALIAS_RID_ADMINS	0x220L
-#define DOMAIN_ALIAS_RID_USERS	0x221L
-#define DOMAIN_ALIAS_RID_GUESTS	0x222L
-#define DOMAIN_ALIAS_RID_POWER_USERS	0x223L
-#define DOMAIN_ALIAS_RID_ACCOUNT_OPS	0x224L
-#define DOMAIN_ALIAS_RID_SYSTEM_OPS	0x225L
-#define DOMAIN_ALIAS_RID_PRINT_OPS	0x226L
-#define DOMAIN_ALIAS_RID_BACKUP_OPS	0x227L
-#define DOMAIN_ALIAS_RID_REPLICATOR	0x228L
+
+#define FOREST_USER_RID_MAX                     0x000001F3L
+#define DOMAIN_USER_RID_ADMIN                   0x000001F4L
+#define DOMAIN_USER_RID_GUEST                   0x000001F5L
+#define DOMAIN_USER_RID_KRBTGT                  0x000001F6L
+#define DOMAIN_USER_RID_MAX                     0x000003E7L
+
+#define DOMAIN_GROUP_RID_ADMINS                 0x00000200L
+#define DOMAIN_GROUP_RID_USERS                  0x00000201L
+#define DOMAIN_GROUP_RID_GUESTS                 0x00000202L
+
+#define DOMAIN_ALIAS_RID_ADMINS                 0x00000220L
+#define DOMAIN_ALIAS_RID_USERS                  0x00000221L
+#define DOMAIN_ALIAS_RID_GUESTS                 0x00000222L
+#define DOMAIN_ALIAS_RID_POWER_USERS            0x00000223L
+
+#define DOMAIN_ALIAS_RID_ACCOUNT_OPS            0x00000224L
+#define DOMAIN_ALIAS_RID_SYSTEM_OPS             0x00000225L
+#define DOMAIN_ALIAS_RID_PRINT_OPS              0x00000226L
+#define DOMAIN_ALIAS_RID_BACKUP_OPS             0x00000227L
+
+#define DOMAIN_ALIAS_RID_REPLICATOR             0x00000228L
+#define DOMAIN_ALIAS_RID_RAS_SERVERS            0x00000229L
+#define DOMAIN_ALIAS_RID_PREW2KCOMPACCESS       0x0000022AL
+#define DOMAIN_ALIAS_RID_REMOTE_DESKTOP_USERS   0x0000022BL
+#define DOMAIN_ALIAS_RID_NETWORK_CONFIGURATION_OPS 0x0000022CL
+#define DOMAIN_ALIAS_RID_INCOMING_FOREST_TRUST_BUILDERS 0x0000022DL
+
+#define DOMAIN_ALIAS_RID_MONITORING_USERS       0x0000022EL
+#define DOMAIN_ALIAS_RID_LOGGING_USERS          0x0000022FL
+#define DOMAIN_ALIAS_RID_AUTHORIZATIONACCESS    0x00000230L
+#define DOMAIN_ALIAS_RID_TS_LICENSE_SERVERS     0x00000231L
+#define DOMAIN_ALIAS_RID_DCOM_USERS             0x00000232L
 
 typedef enum
 {