Glossary / Lexicon from abylonsoft

Definitions of terms

In the lexicon or glossary explains abylonsoft topics of general interest around the offered software products, computers and technology. The column with the letter R contains 8 entries, like for example RC4.

Column R 8 entries

RAS dial-in

The abbreviation RAS stands for Remote Access Sservice and offers from Microsoft Windows NT the possibility to access a server in a secured network from an external client via a "telephone line". The variable protocol support of TCP/IP, IPX/SPX or NetBEUI provides the user with complete file and printer access. Nowadays the VPNs (Virtuell Private Networks) are increasingly used for telework (home office). One

RC4

With RC4 from RSA Data Security Inc. a random byte sequence in the length of the data to be encrypted is generated with a pseudo-random generator depending on the password. The ciphertext results from the simple XOR link with the expanded key, similar to the One Time Pad. For decryption, this procedure is simply used again. The procedure is surprisingly simple, fast and very easy to program. According to RSA Data Security Inc., this method cannot be cracked with linear or differential cryptanalysis. However, since the end of 2013 there has been growing evidence that the NSA can decrypt RC4 encryption in real-time. For this reason, the use of RC4 has been prohibited since February 2015 for the SSL successor TSL (Transport Layer Security). As with any power encryption, there is no protection against changes. All compromised bits are also changed in the decrypted file without this having to be noticed.

see also: One Time Pad Verschlüsseln Symmetrische Verschlüsselung Asymmetrische Verschlüsselung

RFID Radio-chip-cards

RFID radio chip cards have no contacts and communicate via an electromagnetic wave. This technology is often used for automatic identification. Passive cards draw their power from the high-frequency signal of the reader. The transmission distance depends on the frequency and is normally limited to short differences of a few centimeters. In addition to chip cards, RFID transponders are also installed in labels, key fobs and numerous other products. Since 2010, RFID chips have also been integrated into German ID cards.

The RFID technology is used for electronic locks, access control, authentication, cashless payment, customer cards and also key for Windows logon or encryption in the software from abylonsoft.

The most common frequencies are 125 kHz long wave and 13.56 MHz short wave. Depending on the region and application, UHF and SHF frequencies are also used. The speed, transversion rate and range is largely dependent on the frequency. Common RFID chip cards are:

  • NXP® (13.56 MHz): MIFARE Classic®, MIFARE Ultralight®, MIFARE Plus®, MIFARE DESFire®
  • LEGIC® (13.56 MHz): LEGIC prime®, LEGIC advant®, LEGIC CTC®
  • HID® (13.56 MHz): HID iCLASS®, HID Prox®
  • HITAG® (125 kHz): Hitag 1®, Hitag 2®, Hitag S®
  • EM Microelectronic® (125 kHz): EM4200®, EM4105®, EM4150®, EM4169®, EM4450®, EM4550®, EM4205®, EM4305®

see also: Chipkarten Access Control

RSA

RSA is named after the developers Ronald Rivest, Adi Shamir and Leonard Adleman. Besides PGP, RSA is the best known method for asymmetric encryption and signature. From a key length of 2048 bits, the flagship asymmetric encryption method can still be classified as secure today. As an asymmetric procedure, RSA uses a key pair consisting of a private and a public key. Because the mathematical effort for live encryption is very high, usually only one session key is encrypted asymmetrically. The actual data is then encrypted with the symmetrical session key.

see also: Asymmetrische Verschlüsselung PGP Public Key Public Key Verfahren Signatur

RUNONCE (Registry)

In the Windows registry the key RUNONCE is offered in the path [HKCU] or [HKCU]\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. Programs can be entered here to be executed once after a Windows login. This is used, for example, by installation programs or one-time administrative tasks. After the execution the entry of operating system is deleted immediately. For this reason, this key is usually empty. There are however particularly stubborn programs, which register themselves here before each shutdown, in order to be started likewise after the restart. For the user there is no easy way to prevent this. The application abylon APP-BLOCKER monitors this folder in the registry under [HKCU] and [HKCU] and allows to prevent unwanted entries.

see also: Windows AllUser Windows User Windows Autostart Dienste Prozessliste

RUN (Registry)

With the key RUN in the Windows registry you can register applications which should be executed after the Windows logon! In contrast to the Autostart folder in the Windows Start menu, the registry entries are not so easy to find for most users. For this reason, many applications use this location to be started automatically every time they log on to Windows. Often, in the course of time, so many programs are registered here that the start time of the PC is considerably extended and the processor performance is reduced. This registry key should therefore be checked from time to time for unnecessary or unwanted entries! The software abylon APP-BLOCKER helps to monitor the autostart entries, where a distinction is made between User under HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run and AllUser under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run.

see also: Windows AllUser Windows User Autostart Dienste Prozessliste

Registry

The registry (registry database) has been added to Windows NT and has been extended until today. The registry is a database in which Windows and Windows applications store information and settings in a structured way. In contrast to the file-based storage of information in INI or XML files, access to the registry is extremely fast due to the hierarchical structure, despite the large number of data contained. The Registry is advantageous also in the network, whereby several computers can be controlled centrally over Policies. The registry database is divided into the main groups HKEY_CLASSES_ROOT, HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE and HKEY_CURRENT_CONFIG, which are comparable to folders. Below this, the data is stored in the respective subfolders and can be of the data type REG_BINARY, REG_DWORD, REG_QWORD, REG_SZ, REG_EXPAND_SZ, REG_MULTI_SZ or REG_FULL_RESOURCE_DESCRIPTOR. The individual data is accessed via the specific registry path (RegPath). Windows offers the editors regedit.exe and regedt32.exe (incl. network access). These can be started via the Windows search or execute field.

see also: Dienste Prozessliste RUN (Registry) RUNONCE (Registry)

Revocation-list

These certificate revocation lists are offered by the trust centers (CA's) and contain all invalid and revoked certificates. Certificate revocation lists are an important part of the Public Key Infrastructure.

see also: Trustcenter Certificate Certification Authority

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