KR20060123653A - Secure data transfer - Google Patents

Abstract

The invention concerns secure data transfer from a first radio communication device of a first party to a second radio communication device. A random first symmetric key is generated at the first terminal device. User data of the first terminal device is encrypted with the first symmetric key. The first symmetric key is encrypted with a public key of a third party. The encrypted first symmetric key is sent from the first terminal device to the second terminal device via a transfer device. The encrypted first symmetric key is decrypted at the second terminal device by utilizing a secret key associated with the public key and comprised in a security device of the third party. The encrypted user data is sent from the first terminal device to the second terminal device via the transfer device. The encrypted user data is decrypted at the second terminal device with the first symmetric key.

Description

Secure Data Transfer {SECURE DATA TRANSFER}

The present invention relates to secure data transmission. In particular, the present invention provides a secured data transmission in an improved novel manner from a first wireless communication device of a first party to a second wireless communication device, in which case the data transmission is overseeed by the transmitting device of the second party. It is about providing.

Radio communication devices such as mobile phones have been rapidly integrating a wider variety of applications in recent years. Applications such as address book, calendar, and notebooks are common. Typically, various messaging services, such as email and short message services, will be performed using modern wireless communication devices. As a result, a typical wireless communication device will contain more personal user data such as archived messages, address book entries, calendar entries. Typically, user data is stored on a SIM-card (identity module) and / or in a storage device of a wireless communication device such as a memory chip.

In addition, user data is typically private and contains very sensitive information such as credit card numbers and the like. Thus, user data needs to be protected against unauthorized access. If the wireless communication device is damaged or broken, this wireless communication device must be replaced with a new device at the service point. In this case, user data is typically transferred or recovered from the damaged or failed device to a new device. Such data recovery or transmission is typically witnessed by personnel at the point of service, ie, someone other than the owner of the device. As a result, it is necessary to ensure that user data to be recovered cannot be accessed by service point personnel, either intentionally or accidentally.

Typically, software currently used by service point devices scrambles the user data to be transmitted so that the user data cannot be opened by normal personal computer software. However, this prior art protection is typically fragile and easily broken.

Accordingly, there is a need for a more secure solution that can provide secure data transfer from a first wireless communication device to a second wireless communication device.

A first aspect of the invention is a method for providing secure data transmission from a first wireless communication device of a first party to a second wireless communication device when the data transmission is witnessed by the transmitting device of the second party. In the method, a first symmetric key is randomly generated at the first wireless communication device. Then, the user data of the first wireless communication device in the first wireless communication device is encrypted with the generated first symmetric key. The term "symetric key" refers to a key used in symmetric cryptographic systems, where the same key is used by both the transmitter encrypting the message and the receiver decrypting the message.

According to the present invention, the generated first symmetric key in the first wireless communication device is encrypted with a public key of a third party. The encrypted first symmetric key is then transmitted from the first wireless communication device to the second wireless communication device via a transmitting device. The term "public key" is an encryption key used in an asymmetric system, where a transmitter uses a public key to encrypt a message, and a receiver uses a secret or private key associated with the public key to decrypt the message. use. As the terms mean, the public key is typically publicly available to everyone, while the secret key is only available to the owner of the secret key.

According to the present invention, further, the received encrypted first symmetric key at the second wireless communication device is decrypted by using a secret key associated with the public key and included in the security device of the third party, wherein the security The device is coupled to the second wireless communication device. The encrypted user data is transmitted from the first wireless communication device to the second wireless communication device via the transmitting device, and the received encrypted user data is transmitted to the second wireless communication device with the decrypted first symmetric key. Decrypted at

In an embodiment according to an aspect of the present invention, the received encrypted first symmetric key is first decrypted at the second wireless communication device by randomly generating a second symmetric key at the second wireless communication device. A request message is then generated at the second wireless communication device, wherein the request message includes the generated second symmetric key and the received encrypted first symmetric key, and the request message is the public key. Encrypted. The request message is then sent from the second wireless communication device to the secure device. The received request message is decrypted at the secure device with the secret key to obtain the second symmetric key and the encrypted first symmetric key. Then, the obtained encrypted first symmetric key is further decrypted at the secure device with the secret key to obtain the first symmetric key. A response message is generated at the secure device, the response message includes the obtained first symmetric key, and the response message is encrypted with the obtained second symmetric key. The response message is sent from the secure device to the second wireless communication device. The received response message is decrypted at the second wireless communication device with the generated second symmetric key to obtain the decrypted first symmetric key.

In an embodiment of the first aspect of the invention, first authentication information is enclosed in the first symmetric key in the first wireless communication device. Second authentication information is enclosed in the request message at the second wireless communication device. Before generating the response message, at the secure device, it is verified whether the received first authentication information matches the received second authentication information.

In an embodiment of the first aspect of the present invention, password information of the first party is used as the first and second authentication information. In another embodiment of the present invention, identity information associated with the first party is used as the first and second authentication information.

A second aspect of the present invention is a system for providing secure data transmission between wireless communication devices. The system includes a first wireless communication device of a first party having user data to be transmitted. The first wireless communication device includes a first key generator for randomly generating a first symmetric key, and user data encryption means for encrypting the user data with the generated first symmetric key. The system further includes a second wireless communication device that receives user data to be transmitted. The system further includes a second party's transmitting device linking the first and second wireless communication devices with each other and witnessing the data transmission.

According to a second aspect of the invention, the first wireless communication device further comprises key encryption means for encrypting the first symmetric key with a public key of a third party. The system further comprises a secure device of the third party coupled to the second wireless communication device and including a secret key associated with the public key. The second wireless communication device includes key decrypting means for decrypting the encrypted first symmetric key by using a secret key included in the security device, wherein the encrypted first symmetric key is passed through the transmitting device. 1 received from a wireless communication device. The second wireless communication device further comprises user data decrypting means for decrypting the encrypted user data with the decrypted first symmetric key, wherein the encrypted user data is received from the first wireless communication device via the transmitting device. It became.

In an embodiment of the second aspect of the present invention, the key decryption means comprises a second key generator for randomly generating a second symmetric key. The key decryption means generates a request message comprising the generated second symmetric key and the received encrypted first symmetric key, encrypts the request message with the public key, and sends the request message to the secure device. Request message means for transmitting. The secure device decrypts the received request message with a secret key to obtain a second symmetric key and the encrypted first symmetric key, and further decrypts the obtained encrypted first symmetric key with the secret key to generate the first symmetric key. Obtain a symmetric key, generate a response message including the obtained first symmetric key, encrypt the response message with the obtained second symmetric key, and send the response message to the second wireless communication device Reply message means. The key decryption means further comprises response message decrypting means for decrypting the received response message with the generated second symmetric key to obtain the first symmetric key.

In an embodiment of the second aspect of the present invention, the first wireless communication device comprises first authentication means for enclosing first authentication information to the first symmetric key. The second wireless communication device further comprises second authentication means for enclosing second authentication information in the request message. The security device further comprises verification means for verifying that the received first authentication information matches the received second authentication information before generating the response message.

In an embodiment of the second aspect of the invention, the wireless communication device is connected to the secure device via a mobile telecommunication network.

A third aspect of the invention is a wireless communication device comprising key decrypting means for decrypting a first symmetric key encrypted using a secret key included in a security device connected to the wireless communication device, the encrypted first symmetric key Was received from the additional wireless communication device via the transmitting device. The wireless communication device further comprises user data decrypting means for decrypting encrypted user data with the decrypted first symmetric key, wherein the encrypted user data has been received from the further wireless communication device via the transmitting device.

A fourth aspect of the invention provides a request message encrypted with a public key, the first symmetric key and a second symmetric key, encrypted with a public key, received from a wireless communication device, and included in a security device and associated with the public key. Decrypts the received request message to obtain the second symmetric key and the encrypted first symmetric key, and further decrypts the obtained encrypted symmetric key with the secret key to obtain the first symmetric key; A response message means for generating a response message comprising the obtained first symmetric key, encrypting the response message with the obtained second symmetric key, and sending the response message to the wireless communication device. Device.

The present invention allows significantly safe data transmission from the first wireless communication device of the first party to the second wireless communication device when the data transmission is witnessed by the second party. In particular, the present invention ensures that user data to be transmitted from the first wireless communication device to the second wireless communication device cannot be accessed by the service point personnel.

The accompanying drawings, which are provided to provide a better understanding of the invention and are included to constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

1 is a schematic representation illustrating a method according to an embodiment of the invention.

2 is a block diagram illustrating a system in accordance with an embodiment of the invention.

Embodiments of the present invention will now be described in detail, examples of which are illustrated in the accompanying drawings.

1 shows an exemplary embodiment of the method of the invention. In step 1, a random first symmetric key is generated at the first wireless communication device. Then, user data of the first wireless communication device is encrypted with the generated first symmetric key at the first wireless communication device (step (2)). The user data is encrypted, for example, in one data block or on a file-by-file basis.

In step 3, the generated first symmetric key is encrypted with a third party's public key at the first wireless communication device. The public key is previously obtained and embedded in the first wireless communication device in an integrity protected manner, so that an attacker cannot change or replace the public key. Alternatively, the public key may come from outside while for example initiating data transfer. If the public key comes from outside, the public key may be accompanied by a certificate chain, so that the first wireless communication device can verify the legitimacy of the public key before accepting the public key. Alternatively, if the public key from outside is not accompanied by an authentication chain, the first wireless communication device shows the user a fingerprint print of the public key and before the user uses the public key. Requires accepting the public key.

In step 4, first authentication information is enclosed in the first symmetric key in the first wireless communication device. The first authentication information may be, for example, password information by the first party. The password may for example be entered during or before the data transfer. Alternatively or additionally, the first authentication information may be identity information associated with the first party, such as, for example, the MSISDN-number (mobile subscriber international ISDN number) of the first wireless communication device. The MSISDN-number of the current subscriber identity module (SIM) of the first wireless communication device may be stored as authentication information, for example previously read and used for future data transfer. In another embodiment of the present invention, the authentication information may be omitted. For example, if the keyboard of the first wireless communication device is broken, the authentication information may be omitted. A copy of the encrypted first symmetric key may then be stored with the encrypted user data in the first wireless communication device. If the transmission process fails or is subsequently interrupted for some reason, then the encrypted first symmetric key can be easily recovered.

The encrypted first symmetric key is transmitted from the first wireless communication device to the second wireless communication device via a transmitting device (step 5). The received encrypted first symmetric key is then decrypted at the second wireless communication device by using a secret key associated with the public key and included in the secure device of the third party. Wherein the secure device is connected to the second wireless communication device. In the embodiment of the invention shown in FIG. 1, this is done by first randomly generating a second symmetric key in the second wireless communication device (step 6).

Then, in step 7, a request message is generated at the second wireless communication device, the request message includes the generated second symmetric key and the received encrypted first symmetric key, and the request The message is encrypted with the public key. Second authentication information is enclosed in the request message at the second wireless communication device (step 8). The second authentication information must be the same as the previous first authentication information input. In other words, if a password is required, for example, the first party or the user of the wireless communication device must enter the same password as the previous password. However, if no first authentication information is enclosed, the second authentication information will also be omitted. Then, the request message is sent from the second wireless communication device to the secure device (step 9).

In step 10, the secure device decrypts the received request message with the secret key to obtain the second symmetric key and the encrypted first symmetric key. Then, in step 11, the secure device obtains the first symmetric key by further decrypting the obtained encrypted first symmetric key with the secret key. Before generating the response message, at the secure device, verify that the received first authentication information matches the received second authentication information (step 12).

In step 13, a response message is generated at the secure device, the response message includes the obtained first symmetric key, and the response message is encrypted with the obtained second symmetric key. The response message is sent from the secure device to the second wireless communication device (step 14). If, as in the embodiment of the invention shown in FIG. 1, the authentication information is used, the secure device will then forget this transaction. If no authentication information is used, the secure device will refuse to record the encrypted first symmetric key and decrypt the encrypted first symmetric key again. In any case, the secure device may store the response message, for example in a public repository, for some time to retrieve the response message if the initial transmission of the response message fails for some reason.

In step 15, the received response message at the second wireless communication device is decrypted with the generated second symmetric key to obtain the decrypted first symmetric key. The decrypted first symmetric key is stored in a file on the second wireless communication device in case the transmission process fails or is interrupted for some reason such as a lack of power. If part of the user data being recovered must be subject to an access control policy set by someone other than the first party, for example, copyrighted content or confidential business to which the user data should not be transmitted. If so, the decrypted first symmetric key is stored in the second wireless communication device in a secure manner.

The encrypted user data is then transmitted from the first wireless communication device to the second wireless communication device via the transmitting device (step 16). Finally, in step 17, the received encrypted user data is decrypted at the second wireless communication device with the decrypted first symmetric key. After the data transmission is successfully performed, the second wireless communication device deletes the first and second symmetric keys. Correspondingly, if the transmitting device has a copy of the encrypted user data, the transmitting device will now also delete it. In other embodiments, additional information may be included with the encrypted first symmetric key, request message, and response message. For example, if the secure device holds a record of the encrypted first symmetric key, an expiration date can be included that the secure device can use to determine how long to retain the record of the encrypted first symmetric key.

2 illustrates an exemplary embodiment of the system of the present invention. The example embodiment shown in FIG. 2 relates to recovering user data from a first wireless communication device of a first party, where the recovery is witnessed by a second party, such as a service point personnel. The system comprises a first wireless communication device MS1 of a first party having user data to be recovered, a second wireless communication device MS2 receiving the user data to be recovered, and a second functioning as a transmitting device. A party's service device (SERV), the service device (SERV) links the first and second wireless communication devices with each other and witnesses the data recovery. The service device SERV may for example be a personal computer with suitable service software. In an exemplary embodiment of the system of the present invention shown in FIG. 2, the first and second wireless communication devices are mobile telephones. The system also includes a third party security device SEC connected to the second wireless communication device MS2 and having a secret key associated with the public key. The secure device SEC may, for example, be a server with suitable software. In the embodiment of the invention shown in FIG. 2, the second wireless communication device MS2 is connected to the security device SEC via a mobile communication network GSM. In the embodiment of the present invention shown in FIG. 2, the mobile communication network is a Global System for Mobile communication (GSM) network, but as will be apparent to those skilled in the art, a code-division multiple access (CDMA) network or a wideband code (WCDMA) Other digital mobile telecommunication networks, such as Division Multiple Access networks, may be used instead. Alternatively or additionally the second wireless communication device MS2 is connected to a secure device SEC via a switched network such as the Internet.

The first wireless communication device MS1 has a first key generator KG1 for randomly generating a first symmetric key, and user data encryption means UD-ENC for encrypting user data with the generated first symmetric key. ). The first wireless communication device MS1 further comprises key encrypting means K_ENC for encrypting the first symmetric key with the public key of the third party. The first wireless communication device MS1 further comprises first authentication means AUTH1 for enclosing first authentication information into the first symmetric key.

The second wireless communication device MS2 uses the secret key included in the security device SEC after the encrypted first symmetric key is received from the first wireless communication device via a service device SERV. Key decrypting means (K_DEC) for decrypting the encrypted first symmetric key.

The key decryption means K_DEC comprises a second key generator KG2 which randomly generates a second symmetric key. The key decryption means K_DEC generates a request message comprising the generated second symmetric key and the received encrypted first symmetric key, encrypts the request message with the public key, and encrypts the request message. Request message means REQ_MSG for transmitting to the secure device SEC. The second wireless communication device MS2 further comprises second authentication means AUTH2 for enclosing second authentication information in the request message.

The secure device (SEC) decrypts the received request message with the secret key to obtain the second symmetric key and the encrypted first symmetric key, and the obtained encryption with the secret key to obtain the first symmetric key. Decrypt the first symmetric key, generate a response message including the obtained first symmetric key, encrypt the response message with the obtained second symmetric key, and encrypt the response message in the second wireless communication device. Reply message means (RESP_MSG) for transmission. The security device SEC further comprises verification means VER for verifying that the received first authentication information matches the received second authentication information before generating the response message.

The key decryption means K_DEC includes a response message decrypting means (RESP_MSG_DEC) for decoding the received response message with the generated second symmetric key to obtain the first symmetric key. After receiving the encrypted user data from the first wireless communication device via the service device SERV, the second wireless communication device MS2 decrypts the encrypted user data with the decrypted first symmetric key. User data decrypting means (UD_DEC).

As the technology progresses, it is apparent to those skilled in the art that the basic idea of the present invention can be implemented in various ways. Accordingly, the present invention and its embodiments are not limited to the above examples, but instead may be variously modified within the scope of the claims. In particular, although embodiments relating to data recovery at service points have been described, it will be apparent to those skilled in the art that the present invention can be used in any situation where important information needs to be transmitted through an untrusted second party.

Claims (11)

A method for providing secure data transmission from a first wireless communication device of a first party to a second wireless communication device when data transmission is witnessed by the second device's transmitting device, the method comprising: Randomly generating, at the first wireless communication device, a first symmetric key; Encrypting, at the first wireless communication device, user data of the first wireless communication device with the generated first symmetric key; Encrypting, at the first wireless communication device, the generated first symmetric key with a third party's public key; Transmitting the encrypted first symmetric key from the first wireless communication device to the second wireless communication device via the transmitting device; At the second wireless communication device, decrypting the received encrypted first symmetric key using a secret key associated with the public key and included in a security device of the third party; Is connected to a second wireless communication device; Transmitting the encrypted user data from the first wireless communication device to the second wireless communication device via the transmitting device; And At the second wireless communication device, decrypting the received encrypted user data with the decrypted first symmetric key. The method of claim 1, wherein the decrypting the received encrypted first symmetric key at the second wireless communication device using a secret key associated with the public key and included in the secure device of the third party: At the second wireless communication device, randomly generating a second symmetric key; Generating, at the second wireless communication device, a request message encrypted with the public key including the generated second symmetric key and the received encrypted first symmetric key; Sending the request message from the second wireless communication device to the secure device; At the secure device, decrypting the received request message with the secret key to obtain the second symmetric key and the encrypted first symmetric key; At the secure device, further decrypting the obtained encrypted first symmetric key with the secret key to obtain the first symmetric key; Generating, at the secure device, a response message including the obtained first symmetric key and encrypted with the obtained second symmetric key; Sending the response message from the secure device to the second wireless communication device; And And at said second wireless communication device, decrypting said received response message with said generated second symmetric key to obtain said decrypted first symmetric key. The method of claim 2, Enclosing, at the first wireless communication device, first authentication information to the first symmetric key; Enclosing, at the second wireless communication device, second authentication information in the request message; And At the secure device, before performing the step of generating the response message, verifying that the received first authentication information matches the received second authentication information. Way. 4. The method of claim 3, wherein password information by the first party is used as the first and second authentication information. 4. The method of claim 3, wherein identity information associated with the first party is used as the first and second information. A system for providing secure data transmission between wireless communication devices: In addition to having user data to be transmitted, a first key generator KG1 for randomly generating a first symmetric key and user data encryption means UD_ENC for encrypting the user data with the generated first symmetric key. A first wireless communication device MS1 of a first party, wherein the first wireless communication device MS1 further comprises key encrypting means K_ENC adapted to encrypt the first symmetric key with a third party's public key. To; A second wireless communication device (MS2) adapted to receive the user data to be transmitted; A second party's transmission device (SERV) adapted to link said first and second wireless communication devices together and to witness said data transmission; And A third party secure device (SEC) coupled to the second wireless communication device and including a secret key associated with the public key, Here, the second wireless communication device MS2 is: Key decrypting means (K_DEC) adapted to decrypt the encrypted first symmetric key using the secret key included in the secure device (SEC), wherein the encrypted first symmetric key is used to identify the transmitting device (SERV). Is received from the first wireless communication device MS1 via; And User data decrypting means (UD_DEC) adapted to decrypt the encrypted user data with the decrypted first symmetric key, The encrypted user data is received from the first wireless communication device (MS1) via the transmitting device (SERV). The method of claim 6, The key decryption means K_DEC is: A second key generator KG2 for randomly generating a second symmetric key; And Generate a request message comprising the generated second symmetric key and the received encrypted first symmetric key, encrypt the request message with the public key, and send the request message to the secure device (SEC) Request message means (REQ_MSG), The secure device (SEC) is: Decrypting the received request message with the secret key to obtain the second symmetric key and the encrypted first symmetric key, and further decrypting the obtained encrypted first symmetric key with the secret key to the first symmetric key Obtain a message, generate a response message including the obtained first symmetric key, encrypt the response message with the obtained second symmetric key, and send the response message to the second wireless communication device Message means (RESP_MSG), The key decryption means K_DEC is: And a response message decoding means (RESP_MSG_DEC) configured to decrypt the received response message with the generated second symmetric key to obtain the first symmetric key. The method of claim 7, wherein The first wireless communication device MS1 is: A first authentication means (AUTH1) adapted to enclose first authentication information into the first symmetric key, The second wireless communication device MS2 is: Second authentication means AUTH2 adapted to enclose second authentication information in the request message, The secure device (SEC) is: And verifying means (VER) configured to verify whether the received first authentication information matches the received second authentication information before generating the response message. 9. A system as claimed in claim 6 or 7 or 8, wherein the second wireless communication device (MS2) is connected to the secure device (SEC) via a mobile telecommunication network. . As a wireless communication device MS2: Key decryption means (K_DEC) adapted to decrypt a first symmetric key encrypted using a secret key included in a secure device (SEC) connected to said wireless communication device (MS2), wherein said encrypted first symmetric key is transmitted. Received from the further wireless communication device MS1 via the device SERV; And User data decrypting means (UD_DEC) adapted to decrypt encrypted user data with the decrypted first symmetric key, The encrypted user data is received from the further wireless communication device (MS1) via the transmitting device (SERV). As a secure device (SEC): Receive a request message from a wireless communication device (MS2) that includes a first symmetric key and a second symmetric key encrypted with a public key, and includes the received request message in the secure device (SEC); Decrypt the secret key associated with the public key to obtain the second symmetric key and the encrypted first symmetric key, and further decrypt the obtained encrypted symmetric key with the secret key to obtain the first symmetric key; Response message means arranged to generate a response message comprising the obtained first symmetric key, to encrypt the response message with the obtained second symmetric key, and to transmit the response message to the wireless communication device MS2 And a security device (RESP_MSG).

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