Security method for transferring shared keys

The present invention relates to a system and procedure for preventing the theft and hacking of a user's computer device at the user's discretion, and more particularly to a security system for preventing the use of a personal computer by an unauthorized person.

To protect your sensitive data or prevent unauthorized persons from using your computer, such as personal computers, portable computers, or other handheld computers, from becoming the target of hackers and thieves. The password is used for. Such passwords are used in conjunction with encryption and authentication keys used to establish secure communication between computers. Today, it is possible to install programs on your computer that encrypt sensitive data so that it cannot be read by anyone without an unlock key. However, the key needs to be memorized somewhere, and if this key is not complicated, it will be detected.

Despite the constant development of new technologies, passwords remain the most popular security tool, and are also the most abused and often the easiest for attackers to crack. Passwords represent some sort of security paradox. The best passwords are the hardest to guess, long and random. Unfortunately, these passwords are also the hardest to remember. Also, most experts strongly recommend that you use different passwords for email, e-commerce, or other accounts and change them on a regular basis. As a result, most people choose a password that is easy to guess, or write it down in a place where it can be copied or stolen.

The answer to this conundrum is to use password safes. These programs provide space to store long, complex, or random passwords, and then encrypt them to prevent them from being stolen. Some password safes even generate random passwords. But those passwords are on disk and also require a password to start the software.

Security in cryptography and transmission by user authentication, device authentication or data authentication can be achieved using Public Key Infrastructure (PKI). In PKI encryption, the user has a pair of keys, a public key and a private key. As their names suggest, private keys are kept privately and public keys are distributed to other users. The owner of the private key does not share the private key with anyone else. Individual users' public and private keys are associated through complex mathematical structures so that one key is tightly linked to the other. This relationship is crucial for the functioning of public / private key-based encryption.

The public key is used as the basis for encrypting the message, while the private key is required by the recipient to decrypt the encrypted message. Only the person who brings the private key can decrypt the message. Even the person who did the encryption may not be able to decrypt the freshly encrypted message because he does not know the private key.

Digital signatures generally use two different keys. One key is to create a digital signature or transform the data into a form that is incomprehensible at first glance. The other is to verify the digital signature or restore the message to its original form. Computer devices and software that utilize these two types of keys are often referred to as "asymmetric cryptosystems."

Asymmetric cryptosystem keys for digital signatures are known only to the signer and are called private keys used to create digital signatures, and public keys commonly known to more people and used to verify digital signatures. It is called. The recipient must have the corresponding public key to verify that the digital signature belongs to the signer. If many people need to verify the signer's digital signature, the public key will be given to all of them, perhaps by publishing it in an online repository or directory where they can easily obtain the key. Must be distributed.

The pair of keys is mathematically associated, but it is computationally impossible to derive the other from one key if the asymmetric cryptosystem is designed and implemented securely for digital signatures. is there.

Many people know the public key of a given signer and use it to verify the signature, but they cannot discover the signer's private key and use it to forge a digital signature.

<p> Therefore, a main object of the present invention is to provide a security system based on a public key infrastructure (PKI) that prevents unauthorized persons from using the main computer device owned by an authorized user. That is.</p>

<p> Therefore, the present invention relates to a security system that prevents unauthorized persons from using a main computer device such as a personal computer owned by an authorized user. This system is a part of the main computer device. There is a removable security part that can be removed from it by the authorized person, at least including a removable main private key and PC public key, and a non-removable part of the main computer device, at least This PC private key and extractable main public key pair, including the PC security area containing the PC private key and extractable main public key, are exposed with the removable main private key and PC public key pair, respectively. Configure the Key Infrastructure (PKI), both the removable security part and the PC security area, the already removed security part is inserted into the remote computer device, and the removable security part and the PC security area It includes processing means that allow authorized users to access the data stored in the main computer device by performing mutual authentication.</p>

With reference to FIG. 1, the main principle of the present invention is to use the removable security portion 10 and the PC security area 12 in combination. The removable security portion 10 is unique in the computer device to which it is connected. Without this removable security piece 10, all devices contained or connected to it, such as computer devices and memory, hard disks, and various peripherals, cannot be used. This part can be a keyboard key, or an integrated mouse button, a block containing a small information display area or LED area or a PCMCIA card. In the latter case, one of the PCMCIA slots cannot be used for other purposes. Another feature, PC Security Area 12, is any part of the computer equipment hardware / firmware, including the operating system and installed applications. Generally, this PC security area is contained on the motherboard of the computer device or other required board or card of the computer device and cannot be removed.

The removable security part 10 includes a processor 14, which can be a microprocessor with an integrated communication port, and a memory 16 (which may be an integrated memory within the processor 14) protected against external reads. Includes PKI Checker 18, a software application used by Processor 14 to encrypt or authenticate data sent to PC Security Area 12. The protected memory 16 stores a removable main private key 20, a PC public key (computer device public key) 22, and another key or password 24.

Similarly, PC security area 12 is a software application used to encrypt or authenticate data sent to processor 26, which communicates with processor 14 through a communication port, and removable security portion 10. Includes a PKI checker 28 and a protected memory 30 that can also be integrated within the processor 26. The protected memory 30 stores an extractable main public key 32 (the public key of the removable security portion 10), a PC private key 34, and another key or password 36.

Mutual authentication with PC Security Area 12 is automatic as described below when the removable security part 10 previously removed from the computer device by an authorized user is repositioned in the correct location within the computer device. Is done. When this check is complete, the processor 26 can initiate access to the PC system 38 via an I / O bus for the OS or application password that checks the application's authentication or encryption. At this moment, either processor 14 or 26 can help perform encryption or authentication. Further, the computer apparatus system 38 can open communication to the processor 26 to identify an external user such as a remote user.

The protected memory 16 of the removable security portion 10 includes a set of storage, which is illustrated in more detail in FIG. This storage stores either key, which can be the key itself, a complete certificate containing these keys, or a password area.

That is, the storage area stores the following items. -Removable main private key 40, which is a unique private key for identifying the removable security part 10. Similar to sequence numbers, but much more complex and hard to read. This private key 40 identifies itself to the connected computer device and is removable security to allow the computer device to send encrypted messages that can only be decrypted by this private key 40 to this part. Used by part 10. -The main PC public key 42, which is used to encrypt messages sent to the PC security area 12, such as requesting permission to use security part 10 in this environment, which is compatible with computer devices. This key is also used to authenticate messages from PC Security Area 12. A shared private key 44, which is a private key generated by the user and sent to other security parts authorized on this computer device for certain applications, as described below. -Local PC public key 46, which is the PC public key used to identify the removable security part 10 on a computer device different from the computer device to which this security part 10 belongs. A removable local private key 48, which is a unique private key for identifying a removable security part on a computer device that is different from the computer device to which this security part belongs. This key, along with the local PC public key, forms a set of keys corresponding to possible guest computers, as described below. These keys can be duplicated so that many computer devices can be connected. · Main password area 50 that stores passwords required for local connection to the main computer unit or for remote connection. Local password area 52 used in guest mode when a removable security part is allowed on other computer equipment, as described below. Authorized users may wish to keep all their passwords on a removable security area rather than on the computer device itself. -Application private key 54, which is a key that can be used for certain applications, such as building a secure IPSec tunnel. This key can also be used to perform PKI procedures for encryption and / or authentication. A number of such fields are available in the removable security part.

The protected memory 30 of the PC security area 12 includes functions similar to those contained in the removable security portion 10. The public key of the removable security part 10 and the extractable main public key 56 used by the computer device to send the encrypted message decrypted by the removable security part 10.<u style="single">A PC private key 58 that authenticates the removable security part 10 in pairs with the main PC public key 42, along with a pair of the removable main private key 40 and the extractable main public key 56.</u>The PC public key 60, which is the public key of the computer device used by the computer device to send the encrypted message to another external device. This key may be the same as the main PC public key 42 of the removable security portion 10. In fact, it is the same if the removable security part 10 is the one that corresponds to the computer device (the main computer device that has the main security part). Temporary (TEMP) that can store the temporary key used to store the private key when other removable security parts are placed on the main computer device, as described below. ) Key area 62. Shared public key 64, which is the public key sent to other removable security parts located on the main computer device, as described below. PC password area 66, including PC passwords that can be exchanged for or updated with passwords stored in the main password area 50 of removable security portion 10.

The computer equipment system 38 checks the login password by comparison of what is stored in the PC password area 66 or main password area 50 when the removable security part 10 is recognized. Includes OS logon 68, which is a logon. This includes the application logon 70 used when the application requires a password in the main password area 50 in the removable security part 10, and the application secret also in the removable security part 10. Contains a PKI application 72 that uses key 54.

FIG. 3 shows a case where another removable security part is used together with the main computer device instead of the removable security part 10. In such cases, the first step is to insert a removable main security portion into the main computer equipment. The removable security part is mentioned earlier, thanks to the pair of removable main private key 40 and extractable main public key 56 on the one hand, and the pair of main PC public key 42 and PC private key 58 on the other hand. You will be authenticated as if.

Next, the shared private key 44 in the memory 16 of the removable security portion 10 is copied to the temporary key area 62 of the memory 30 in the PC security area. The removable security portion 10 can then be removed from the computer device and replaced with a removable guest security portion. Of course, the identity of the guest security part of the latter is checked by a server that stores the corresponding public key using an external sequence number. The key in the temporary key area 62 is then loaded into the removable local private key 74 in memory 76 of the removable guest security portion. Therefore, the removable local private key 74 of the removable guest security portion matches the shared public key 64 of the computer device and can communicate with each other.

Finally, the computer device stores its PC public key 60 as a local PC public key 78 in the removable guest security portion of memory 76 to complete the two-way secure link. Once this link is established, the removable guest security portion of the local password area 80 is used for the computer equipment system OS guest logon 82 through the computer equipment PC password area 66. Can be done.

Another application of the present invention is when a removable main security portion is inserted into a remote computer or guest computer device instead of being inserted into the main computer device. Figure 4 shows the process performed in such a case. In the figure, the two-way arrow represents the relationship between entities and the bus means data transfer. Note that the reference items used in Figure 2 remain the same when representing the same entity, such as a removable main security part or a different area of the PC security area of the main computer unit.

Basically, the removable security part<u style="single">10</u>And guest computer equipment security area<u style="single">84</u>The connection with is on the side of the security part, using the removable main private key 40, and the remote temporary key area 90 that stores the main public key 56'that can then extract the corresponding public key. It is done by sending to.<u style="single">Detachable main</u>Private key<u style="single">40</u>When<u style="single">Extractable main</u>Public key<u style="single">56’</u>Are generated at the same time.<u style="single">Extractable main</u>Public key<u style="single">56’</u>Can be provided to external devices without risk, even remote computer devices<u style="single">Or guest computer equipment</u>Even if you're not a well-known computer device, it's okay to give it a public key. In addition, each user can define certain rules to change both the private and public keys on a regular basis, and to change the previous public key, a new device on the other side. It can be updated with the key.

All updates or key transmissions between different entities can be done using a certificate containing the device ID and public key. These certificates are certified by a trusted entity, the Certificate Authority (CA) server. Therefore, such a CA server can be used as an authentication server. These servers, for example, know all the public keys of all the equipment of the customer, and thus can allow those keys to build secure communications with each other. It can be said that the common rule is to trust only the certificate issued by this CA.

Using this method, after cross authentication has taken place between the user security part and the remote computer device, the remote computer device will eventually accept any logon execution within this system. , You can check if the public key actually corresponds to this user. The security part of the user needs to receive the PC public key in order to communicate securely with the remote computer device. The remote computer device transfers its remote PC public key 86 (matching the remote PC private key 88) to the field in memory 16 of security portion 10, the local PC public key 46. At this stage, secure communication can be established between the guest computer device and the security part. The user can then log on as a guest to a remote computer device in the profile that allows remote connections.

One type of connection is to connect to the CA to verify the identity of the remote computer device and then do more in this environment. In that case, the remote PC public key 86 is confirmed.

The main purpose of such an interconnect is to allow the user to access the main computer device in a secure manner. The connection to the main PC security area consists of the main set of keys shown in Figure 2, the removable main private key 40 and main public key 42 on the security part side, and the extractable main computer device side. Established using main public key 56 and PC private key 58. The remote computer device deciphers the data communication between the extractable main security part and the main computer device, even if it does not know the respective public key, as it is the basic principle of PKI. It is impossible.

Finally, over this secure channel, use all passwords stored in main password area 50 and securely transfer it to PC password area 66 on the security area of the main computer unit. And you can use it as an application logon 70 for normal logon. In this case, the remote computer device is considered a local device. At this stage, a shared secret key can be exchanged to establish a secure communication channel between the main and remote computer devices, using less computational resources than PKI communication. it can.

In addition, the application can behave as already described in Figure 1. That is, the PKI application 72 can use the key stored in the application private key 54 with the help of PKI checkers existing in each security part and each security area, although not shown in FIG.

<figref num="1">FIG. 6 is a block diagram showing a security system according to the invention, having a removable security portion, a PC security area, and a link to a computer equipment system.</figref><figref num="2">FIG. 5 is a schematic diagram showing a dialogue between a removable security part, a PC security area, and a computer device system when a removable security part is connected on the main computer device.</figref><figref num="3">Demonstrates the interaction between the removable main security part, the PC security area, the removable guest security part, and the computer equipment system when a removable guest security part is connected on the main computer unit. It is a schematic diagram.</figref><figref num="4">When a removable main security part is connected on a remote computer device, the removable security part, main PC security area, guest PC security area, main computer device system, and guest computer device system It is a schematic diagram which shows the dialogue between.</figref>

Code description

10 Detachable security part 14 processor 16 Protected memory 18 PKI checker 20 Detachable main private key 22 PC public key 24 Other keys or passwords 26 processor 28 PKI checker 30 Protected memory 32 Extractable main public key 34 PC private key 36 Other keys or passwords 38 PC system