AT9614U1 - DEVICE FOR CREATING DIGITAL SIGNATURES - Google Patents

Abstract

For secure creation of digital signatures and / or secure authentication of users with a smart card, a device is plugged into a computer and entered the PIN. The computer operating system activates the autorun function of a read drive (1) of the device and loads an http responder program (4, 21) into the computer. A standard http protocol sends a signature request (23) containing all signature data to the http responder (4, 21) which sends it to the interface memory area (5) of a read / write drive (2) of the device writes which is read by the internal software (6) of the device that interprets the data and checks the admissibility of the command based on configuration data (7). If necessary, the signature request is then forwarded to the chip card via a chip card read / write device (9) and the signature created by the card is written to the interface memory area (5) from where it is output from the http responder (21) and the application (22) as an http answer (26).

Description

2 AT 009 614 U1

The invention relates to a method for the secure creation of digital signatures and / or for the secure authentication of users by means of a special device connected to a computer, as well as this device. The cryptographic keys and algorithms required for the signature / authentication are stored on a special chip card, which is connected by means of a chip card reader which is preferably integrated in the device. The device further preferably has an actuating device, by means of which the user must confirm safety-critical operations such as, for example, creation of signatures, access to restricted-access areas of the chip card or the device, etc, prior to their execution. These operations are performed only when the actuator has previously been operated. Furthermore, the programming of the device prevents so-called denial-of-service attacks.

Many applications in computer networks and on the Internet, such as Internet banking or Internet auctions require the secure authentication of users and / or data. For this purpose, software-based methods such as user name with password or PIN combined with encrypted transmission (for example SSL) are mostly used today. In the case of increased security requirements, transaction numbers (TAN) are usually used in addition. From a cryptographic point of view, these are so-called one-time codes and therefore only apply to one transaction at a time. All of these methods are based on software implementations. They are therefore only on the assumption that the user's computer is free of unauthorized programs (such as Trojans or viruses), which spy out the data for user identification and - unnoticed by the user - can transmit to attackers. Furthermore, these methods require that the user does not - more or less consciously - pass on his identification data to unauthorized persons. Both conditions are not given today in practice. Almost daily, new Trojans are known that exploit vulnerabilities in operating systems and spy out specific identification data. Criminal organizations use "phishing emails" to lure unsuspecting users into their identification data and attack their accounts.

As a countermeasure to these threats, smart card-based authentication and digital signature techniques have been developed in recent years. With these methods, the cryptographic keys required for the signature are stored securely in a chip card for readout. To perform a signature, the user must enter a PIN, which is checked by the card itself. The data to be signed are transferred to the card and signed there. Based on such a map, secure authentication methods can be developed that solve a majority of the above problems. However, at the same time they are throwing up a series of new difficulties.

In order to use a chip card to use, the use of a card reader for smart cards is necessary. The card readers are divided into security classes, higher classes mean higher security. The currently available on the market chip card readers can be divided into three classes.

A class 1 card reader serves only as a channel to the card. There is no interference of the card reader in the transparent card access from the PC instead. Each command is thus forwarded directly to the card. The card reader may have a keyboard and a display, but this is not under the exclusive control of the smart card reader, so the keyboard or the display can be remotely controlled from the PC.

A class 2 card reader has a keyboard that can be placed under the exclusive control of the card reader at least temporarily, i. the PC can not " hear " the data entered there.

A Class 3 card reader has a keyboard and a generally alphanumeric display that can be placed under the exclusive control of the card reader, at least in part, so that the PC can not hear the keystrokes and can not influence the display outputs , The keyboard and the display are then controlled exclusively by the firmware of the card reader. Class 3 card readers are used to use the GeldKarte on the Internet or to view and confirm HBCI transfer details.

A major weakness of smart card-based authentication schemes is that the card's PIN is safe from attack only when using class 2 or 3 smart card readers. In the other case, the PIN could be intercepted by Trojans or viruses in the user's computer and the card in the reader could be misused by means of the intercepted PIN. Furthermore, the user must be instructed to never enter his PIN on the keyboard of his computer, but only on the keyboard of the card reader. Both aspects are a problem in practical operation and therefore relativize the security advantage gained by the chip card implementation.

In WO99 / 08415A this problem is solved in that the chip card reading unit is equipped with an actuating element (for example a key), which always has to be actuated before a signature is generated. This ensures that an unauthorized program in the user's computer can not create abusive signatures even if the PIN is known to him and the card is inserted in the reading unit.

Another problem with smart card-based implementations is the denial-of-service attacks. This refers to attacks by unauthorized programs with the aim of rendering the smart card permanently unusable. In addition to the protection by PINs or PUKs in many smart card-based applications the read and / or write access to individual files of the card is cryptographically secured, i. he depends on the authentication with a cryptographic key. In the case of PIN / PUK as well as in the case of authentication by means of a cryptographic key, the card, or specific applications of the card, is generally irreversibly blocked for any further use after a certain number of failed attempts for the code or the authentication. This mechanism is implemented in the operating system of the card and is intended to prevent the code or codes to be found on a card or the authentication key (s) by means of brute force attacks (simple trial and error). The only way to make the blocked application available to the user is to replace the card or, if provided, unlock it with a special key for a personal interview at specially equipped workstations. Both are associated with high costs. This circumstance can be exploited by attackers using the so-called " Denial of Service Attack " be exploited. In doing so, the attacker spreads a virus or other malicious software that makes smart cards unusable that are used on compromised systems by performing verification attempts with deliberately wrong PINs / PUKs or authentication attempts with deliberately wrong keys until the card is useless. Such an attack could effectively sabotard card-based systems for e-government, e-banking, e-health and the like and cause considerable damage. The use of class 2 or 3 readers or a device according to WO99 / 08415 does not solve these problems, since the PIN may possibly be protected against misuse, but a denial-of-service attack on the PUK or authentication key of the card is still possible is.

Another practical problem of smart card based systems is the driver installation associated with the card reader. Each card reader requires its own driver, which must be installed on the computer before use. This often involves technical problems, which increase costs and reduce customer acceptance.

To be able to address a chip card from a browser-based Internet application, the installation of a driver for the card reader alone is not enough. The Internet application must either use active browser components or the user must install a suitable browser plug-in 4 AT 009 614 U1. Active browser components are mostly blocked by browser security settings, while plug-in installation leads to long download times and organizational problems. Both solutions are therefore in practice associated with organizational and technical problems and thus with high costs for the application operators. Furthermore, they limit the mobility of the signature functions, since the customer can only sign on such a computer, which has the appropriate settings / installations. Therefore, such applications do not meet today's mobility requirements. The customer wants to be able to do banking from any PC (for example in the office, at home, internet cafe, hotel, ...)

For the reasons mentioned above, smart card-based authentication solutions on the mass market have not been successful so far. Although there are already smart chip cards with widespread distribution (eg in Austria e-Card in social security, Maestro card in the banking sector) and the required certificate infrastructure is available (eg A-Trust), but prevented the high cost and the lack of user-friendliness of the card reader installations As well as the highly limited mobility so far the broad application - and that despite the undoubtedly existing massive security problems in many areas of application, but especially in Internet banking.

The object of the present invention is therefore to provide a device and a method for signature creation and authentication with which the problems described above are solved. This device and method should be able to be used without the installation of drivers and without active browser content for the creation of smart card-based signatures and authentications and thus offer unlimited mobility and user comfort. Appropriate hardware and software mechanisms are designed to prevent both misuse attacks and denial-of-service attacks, providing maximum security to both the user and the application operator.

The object is achieved by a device according to the features of claim 1 and a method according to the features of claim 3. The subclaims indicate a preferred embodiment of the device according to the invention or of the method according to the invention.

The device according to the invention - hereinafter also referred to collectively as a signature dongle - is an integrated system consisting of the following components: A chip card read / write device, preferably an actuating element for preventing the misuse of the PIN, PUK and / or the authentication key of the chip card , an interface for connection to a computer by means of a standard provided in the operating system of the computer protocol (eg USB), as well as suitable software components that prevent denial of service attacks on the one hand and on the other hand allow the connection to computer applications without driver installation and active browser components ,

In a variant of the invention, the chip card read-write unit can also be connected via a cable.

For a better understanding of the invention will be described with reference to the accompanying drawings, in which Fig. 1 shows the scheme of a preferred device according to the invention and Fig. 2 illustrates the sequence of a preferred method according to the invention.

Fig. 1 shows the schematic structure of the signature dongle. The signature dongle includes a smart card reader / writer 9 and an actuator 8. The signature dongle simulates two drives to the computer, namely a CD-ROM drive 1 for read-out and a removable drive 2 for read / write operations. The connection is made via a standard protocol, preferably a USB interface 3. The simulated CD-ROM drive 1 contains a program, the so-called http responder 4, which is intended for execution on the computer. The simulated removable medium contains an interface memory area 5, which serves for data exchange between signature dongle and computer, a table with configuration data 7, which serves to prevent denial of service attacks, and an internal software 6 for controlling the functions of the signature dongle and the Actuator 8, taking into account the configuration data 7 and the communication between the memory area 5 and chip card reading / writing device 9.

2 shows the sequence of a signature creation. From a technical point of view, there is no difference between the secure authentication of a user and the signing of data. In the first case, the login form is simply signed. In the following, therefore, we will only consider the case of creating a signature. To perform a signature, the application 22 of the computer prompts the user to plug in the signature dongle and asks for the PIN to be entered. After connecting the signature dongle to the interface 1 of the computer, the operating system automatically activates the autorun function of the CD-ROM drive simulated by the signature dongle. As a result, the http responder program 4 stored on the signature dongle is automatically loaded into the computer and started there. 21. In the presence of the http responder program 21, the application 22 can recognize that the signature dongle has been inserted. The application 22 sends a signature request 23 to the http responder 21 via the standard http protocol. This request contains all the data required for the signature, including the PIN. The http responder 21 writes the data 24 required for the execution of the signature into the interface memory area 5 of the removable disk 2 simulated by the signature dongle. The internal software 6 of the signature dongle reads this memory area and interprets the data. It checks on the basis of the configuration data 7 whether the desired command for this card is permissible at all and, if so, whether a confirmation of the user via the actuating element 8 is required. If a confirmation of the user is required, this must be requested via the http responder 21. The internal software 6 writes this request in the interface memory area 5, from where it is read by the http responder 21 and a corresponding request is displayed on the computer. The internal software 6 forwards the signature request via the card reading / writing device 9 to the chip card only after confirmation of the user by the actuating element 8. The signature created by the card is again written to the interface memory area 5, from where it is read out by the http responder 21. 25. The application 22 receives the signature as http response 26 from the http responder.

The protocol parameters such as port, URL, message structure and protocol for the communication between http responder 21 and application 22 are given by the implementation of the http responder 21 and must be complied with by all applications which want to use functions of the signature dongle. This creates a quasi-protocol standard for signatures.

The extension of the signature dongle to new, previously unsupported chip cards is done by adjusting the HTTP responder software 4 in the simulated CD-ROM drive 1 of the signature dongle.

The http responder 21 may be programmed to automatically terminate when the signature dongle 27 is removed from the computer.

Information in the form of a data pair from the ATR of the chip card and the safety-critical command to be blocked or to be confirmed via the actuating element 8 are stored in the configuration data 7. The ATR (Answer to Reset) identifies a series

Claims (4)

6 AT 009 614 U1 of smart cards and can therefore be used as an identification feature. The rules are currently provided by the manufacturer of the signature dongle and are used e.g. offered as a download from a website. The user of the signature dongle downloads the current configuration data to his PC and can store this data in the signature dongle using a software provided by the manufacturer of the signature dongle. The update of the rules in the configuration data can also be cryptographically secured against corruption (for example by digital signature of the rule entries). In a further embodiment of the invention, additionally or alternatively to the o.a. Blocking rules also confirmation rules are stored in the configuration data. An affirmation rule causes a user to issue a confirmation by the user to a card with a particular ATR in an attempt to authenticate read or write access to a particular cryptographically secured file. The signature dongle executes the requested access only when the user allows it by confirmation by means of the actuator 8. The individual confirmation rules specify which of the files on the card can be secured by such a user confirmation. This ensures that no software can perform authentication attempts for such secured files unnoticed by the user. For each smart card series (identified by the ATR) any number of rules can be stored. The above-mentioned problem is solved by the interaction of the described components as follows: The security of the PIN against misuse and the security of the chip card against denial of service attacks is achieved by combining the combination data 7 with the actuating element (8). The PIN is only forwarded to the card when the actuator 8 has been previously operated. This ensures that not an unauthorized computer application creates abusive signatures by means of a once entered PIN. Likewise, safety-critical commands are either not forwarded to the card depending on the configuration data or only after confirmation by the actuating element 8. The card is thus protected against deliberate destruction by e.g. deliberately wrong PUK entries safe. Using a standard interface, preferably USB, in conjunction with emulation of drives and autorun feature eliminates the need to install any software or drivers on the computer. By designing the software as an http responder, the application does not require any active components. This allows any application that adheres to the protocol of the http responder to use the functions of the signature dongle without security restrictions and without the installation of plug-ins. Claims 1. A device for the connection to a computer for the secure creation of digital signatures and / or for the secure authentication of users with the help of cryptographic keys and algorithms required for signature / authentication stored on a chip card, the device comprising a preferably integrated chip card Read-write device (9) for connecting the chip card and an interface (3) for connection to the computer by means of a standard protocol provided in the operating system of the computer, characterized in that the device comprises two drives (1, 2), a drive for read operations (1), in particular a CD-ROM drive, with an http-7 AT 009 614 U1 Responder (4) and a drive (2) for read / write operations, in particular a removable disk, with a Interface memory area (5) for data exchange between the Device and the computer, with a table with configuration data (7) in the form of data pairs from the ATR of the chip card and commands to be blocked, and with internal software (6) for controlling the functions of the device taking into account the configuration data (7) and for communication between the interface memory area (5) and the smart card reader-writer (9). 2. Device according to claim 1, characterized in that it contains an actuating element (8) and that the configuration data (7) contain data pairs from the ATR of the chip card and via the actuating element (8) to be confirmed safety-critical commands and that the internal software (6 ) controls the actuator (8) functions in consideration of the configuration data (7) controls. 3. A method for the secure creation of digital signatures and / or secure Authentication of users with a device according to claim 1 or 2, characterized in that after appropriate request of an application (22) of a computer, the device via the interface (3) the computer is plugged in and the PIN is entered, that the autorun function of the preferably simulated drive (1) for read operations is activated by the operating system of the computer and thereby the stored http responder program (4, 21) is loaded into the computer that the Application (22) via the standard HTTP protocol sends all required for the signature data including the PIN-containing signature request (23) to the HTTP responder (4, 21), which in the interface memory area (5) of the preferably simulated drive (2) for read / write operations writes that the internal software (6) of the device this memory area (5) reads out and interprets the data, in particular on the basis of the configuration data (7) checks whether the desired command for this card is allowed and if yes, that the internal software (6), the signature request via the chip card read-write device (9) to the smart card, and that the signature created by the card is again written to the interface memory area (5) from where it is read by the http responder (21) and the application (22) as http response (26). 4. The method according to claim 3, characterized in that before passing on the signature request to the smart card based on the configuration data (7) is also checked whether a confirmation of the user via the actuating element (8) is required, in which case the internal software (6) writes a corresponding request in the interface memory area (5), from where it is read by the http responder (21) and displayed on the computer, wherein the transfer may take place only after confirmation of the user by the actuator (8). For this purpose 1 sheet of drawings