WO2021237388A1 - Methods for encrypting and decrypting group message, and method for transmitting message - Google Patents

Abstract

Disclosed in the present invention are methods for encrypting and decrypting a group message, and a method for transmitting a message. The present invention not only encrypts a message by means of an electronic device before transmitting the message, but also further encrypts a public key, so that a server cannot identify the encrypted public key, thereby reducing the leakage risk of third-party data.

Description

Method for encrypting and decrypting group messages and transmitting messages Technical field

The present invention relates to a method for encrypting and decrypting messages and transmitting messages, in particular to a method for encrypting and decrypting group messages and transferring messages.

Background technique

With the popularity of the Internet, various instant messaging systems have been widely used, such as Line, Wechat, and even social networking sites. Finally, they are developing platforms in the field of instant messaging, such as Facebook’s Messager. However, The general instant messaging system platform is mostly an open communication platform and cannot restrict users of the communication platform. Although the open communication platform has extremely low restrictions on users, it has a high degree of freedom for users.

Among the existing instant messaging technologies, one of them uses cloud, mobile communication devices, and push broadcasting technologies to provide a single-level internal message exchange service within the organization. Official document). Therefore, the cloud push method of instant messaging technology is to solve the problem of "known person-to-person instant messaging systems are not suitable for groups/companies." Share the message in it" effect. Another existing instant messaging technology uses cloud technology for computer and mobile communication devices to exchange messages, and can only provide a fixed single dynamic message, which means that the problem it faces is "inability to distinguish between public and private uses." In this way, if you want to distinguish between public and private use, you need to set up different accounts or groups. For example, the use of official documents is on Facebook at Work, and the use of private documents is on Facebook. The technical effect of distinguishing between public and private uses is "providing a method suitable for four different situations, all with a fixed single dynamic message providing a single level of organization to share messages in it".

However, the aforementioned two instant messaging system platforms still cannot satisfy the groups with privacy needs, and cannot provide specific private conversation messages for the groups with privacy needs, so there is still room for improvement. In view of this, an instant messaging system platform for enterprise internal use was invented. Even if the main purpose is to use instant messaging internally in the enterprise, it still fails to provide an effective means of message encryption. Furthermore, for the encryption of messages in a specific encrypted group, most of the existing instant messaging platforms use transparent encryption methods. Encryption processing through the server does not exclude the server’s role in encryption processing, and the general encryption method is to encrypt through the server, and the client does not provide an effective encryption method, and the message will still be retrieved by interested parties during the transmission process. As a result, internal business secrets of the enterprise were leaked by interested parties.

Based on the above-mentioned problems, the present invention provides a method for encrypting and decrypting group messages and transmitting messages. The electronic device itself provides encryption and decryption methods, and makes the server unable to identify, thereby eliminating the server and the transmission process from being leaked. Messages further increase the security of group communication.

Summary of the invention

The main purpose of the present invention is to provide a method for encrypting and decrypting group messages and transmitting messages, which uses the electronic device used by the user to directly encrypt and decrypt, and make the server unable to identify, so as to improve the security of the communication process and the message itself .

In order to achieve the above objective, the present invention discloses a method for transmitting messages, which is applied to a first electronic device, a second electronic device, a data server and a communication group server. The first electronic device is based on a first electronic device. The account logs in to the communication group server, the second electronic device logs in to the communication group server according to a second account in order to receive the invitation of the first electronic device, and the first electronic device logs in to the communication group server according to a group data corresponding to the communication group server Generate a first device key and a first public key, the second electronic device generates a second device key and a second public key according to the group data, and the first electronic device generates a corresponding group according to the group data The group key is used to encrypt the first public key to correspondingly generate a first encryption key, and the first electronic device records a corresponding first code and the previously obtained first encryption key in the data server , And the first electronic device further obtains the second public key transmitted from the second electronic device through the communication group server, and the first electronic device encrypts the second public key according to the group key to generate a second encryption key The first electronic device records a second code and a second encryption key corresponding to the second electronic device in the data server. Based on the above-mentioned conditions, the method for transmitting messages of the present invention first uses the first electronic device according to the first account number Download the first encryption key from the data server, whereby the first electronic device generates a group key according to the first device key and the first encryption key, and then encrypts a first message according to the group key , And generate a first encrypted message, followed by the first electronic device uploading the first encrypted message to the communication group server according to the first account; the second electronic device downloading the second encryption key from the data server according to the second account and downloading the second encryption key from the communication The group server downloads the first encrypted message, and the second electronic device generates a group key according to the second device key and the second encryption key, whereby the second electronic device decrypts the first encrypted message according to the group key, The second electronic device restores the first message and displays it, that is, the second electronic device decodes the first encrypted message of the first electronic device, and thus displays it on the second electronic device. In this way, the security of the communication process and the message itself is increased and improved.

The present invention provides an embodiment, the content of which is that when the first electronic device does not read the first code, the first encryption key cannot be downloaded, and when the second electronic device does not read the second code, Unable to download the second encryption key.

The present invention provides an embodiment, the content of which is that the method of the present invention further includes: connecting the second electronic device to reply to the first message, thereby generating a second message according to the first message, and connecting the second electronic device according to the group key The second message is encrypted to generate a second encrypted message, whereby the second electronic device uploads the second encrypted message to the communication group server according to the second account; then, the first electronic device downloads the second encrypted message from the communication group server Then, the first electronic device decrypts the second encrypted message according to the group key to restore the second message in the first electronic device.

The present invention provides an embodiment, the content of which is that a first electronic device generates a first device key and a first public key according to an asymmetric cryptographic algorithm, and a second electronic device generates a second device secret according to an asymmetric cryptographic algorithm. Key and the second encryption key.

The present invention provides an embodiment, the content of which is that the message delivery method further includes the step of transferring the first device key and the first public key to a third electronic device. Bar code and temporarily store the first device key and the first public key corresponding to the encryption group on the server, then the third electronic device obtains authorization information according to the first barcode, and then the third electronic device obtains authorization information from the server according to the authorization information Download and restore the first device key and the first public key, and then the third electronic device joins the encryption group and encrypts the first public key according to the encryption group to generate the first encryption key and record the first public key The third electronic device and the first encryption key are on the server, thus completing the transfer of the first device key and the first public key to the third electronic device.

The present invention provides an embodiment, the content of which is that the first electronic device obtains a first barcode according to the communication group server and temporarily stores the first device key and the first public key in the data server. The first electronic device Encrypting the first device key and the first public key to generate a first encrypted data, which is temporarily stored in the data server.

The present invention provides an embodiment, the content of which is that the method for transferring messages further includes the step of transferring the second device key and the second public key to the fourth electronic device, and the second electronic device first obtains it according to the encryption group A second barcode and temporarily store the first device key and the first public key corresponding to the encryption group in the server, connect the fourth electronic device to obtain authorization information according to the second barcode, and then the fourth electronic device automatically according to the authorization information The server downloads and restores the second device key and the second public key, and then the fourth electronic device joins the encryption group and encrypts the second public key according to the encryption group to generate the second encryption key and record the The fourth electronic device and the second encryption key are in the server.

The present invention provides an embodiment. In the step in which the second electronic device obtains a second barcode according to the communication group server and temporarily stores the second device key and the second public key in the data server, the second electronic device The second device key and the second public key are encrypted to generate a second encrypted data, which is temporarily stored in the data server.

The present invention provides an embodiment, the content of which is that the communication group server and the data server are the same server.

In order to achieve the above objective, the present invention also discloses a method for encrypting group messages, which is applied to an electronic device to store an encryption key to a data server according to an account, and the encryption key corresponds to the device key of the electronic device. In the method of encrypting group messages of the present invention, the electronic device first downloads the encryption key according to the account number, the connected electronic device decrypts the encryption key according to the device key to generate a group key, and then the electronic device according to the group key Encrypt a message to generate an encrypted message. In this way, the reliability of encrypted messages is improved.

The present invention provides another embodiment. In the step of decrypting according to a device key and the encryption key, the electronic device further decrypts according to an asymmetric cryptographic algorithm to generate the group key.

The present invention provides another embodiment. In the step of decrypting according to a device key and the encryption key, the encrypted message is further generated according to an Advanced Encryption Standard (AES) algorithm.

In order to achieve the above objective, the present invention also discloses a method for decrypting group messages, which is applied to an electronic device to store an encryption key to a data server according to an account, and the encryption key corresponds to a device of the electronic device In the method for decrypting group messages of the present invention, the electronic device first downloads the encryption key according to the account number, and the connected electronic device decrypts the encryption key according to the device key to generate a group key; the electronic device according to the group The group key decrypts an encrypted message to generate a decrypted message. In this way, the security of group messages is improved.

The present invention provides another embodiment, the content of which is that in the step of decrypting according to a device key and the encryption key, the electronic device further decrypts according to an asymmetric cryptographic algorithm to generate the group key.

The present invention provides another embodiment, the content of which is that in the step of generating and displaying a decrypted message according to the group key and an encrypted message, the encrypted message is further generated according to an Advanced Encryption Standard (AES) algorithm.

Description of the drawings

Figure 1A is a partial flowchart of an embodiment of the present invention;

FIG. 1B is a partial flowchart of an embodiment of the present invention;

2 is a schematic diagram of a system of a first encryption key according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a second encryption key system according to an embodiment of the present invention;

4 is a schematic diagram of a system for encrypting messages by a first electronic device according to an embodiment of the present invention;

4B is a schematic diagram of a system for decrypting messages by a second electronic device according to an embodiment of the present invention;

5A is a schematic diagram of a system for encrypting messages by a second electronic device according to an embodiment of the present invention;

5B is a schematic diagram of a system for decrypting messages by the first electronic device according to an embodiment of the present invention;

Figure 6 is a flowchart of the encrypted group message of the present invention;

Fig. 7 is a flowchart of decrypting group messages according to the present invention;

8A is a partial flowchart of the replacement of the first electronic device to the third electronic device according to the present invention;

8B is a partial flowchart of the replacement of the first electronic device to the third electronic device according to the present invention;

FIG. 9 is a schematic diagram of a system of a first encryption key according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a second encryption key system according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a system for encrypting messages according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a system for decrypting messages according to an embodiment of the present invention;

13A is a partial flowchart of the replacement of the second electronic device to the fourth electronic device according to the present invention;

13B is a partial flowchart of the replacement of the second electronic device to the fourth electronic device according to the present invention;

FIG. 14 is a schematic diagram of a system of a first encryption key according to an embodiment of the present invention;

15 is a schematic diagram of a second encryption key system according to an embodiment of the present invention;

FIG. 16 is a schematic diagram of a system for encrypting messages according to an embodiment of the present invention; and

FIG. 17 is a schematic diagram of a system for decrypting messages according to an embodiment of the present invention.

Description of Reference Signs: 1 group system; 2 group system; 10 data server; 12 key list; 20 first electronic device; 22 first device key; 24 first public key; 30 second electronic device; 32 Second device key; 34 second public key; 40 communication group server; 40A encryption group; 50 multifunction server; 50A encryption group; 60 third electronic device; 62 third device key; 64 third public key Key; 70 fourth electronic device; 72 fourth device key; 74 fourth public key; D1 first encrypted data; D2 second encrypted data; device1 first code; device2 second code; key1 first encryption key; key2 second encryption key; keyg group key; M1 first message; M12 first encrypted message; M2 second message; M22 second encrypted message; QR1 first barcode; QR2 second barcode; S10-S120 steps; Steps S210-S230; Steps S310-S330; Steps S410-S560; Steps S610-S760.

Detailed ways

In order to enable those skilled in the art to have a better understanding and understanding of the characteristics of the present invention and the effects achieved, the present invention will be described in detail below with embodiments and drawings.

In view of the influence of the prior art positioning technology on reliability, the present invention proposes a method for encrypting and decrypting group messages and transferring messages to solve the problem of message reliability caused by the prior art.

In the following, the characteristics, the structure and the method of the method for encrypting and decrypting group messages and transmitting messages of the present invention will be further explained:

First, please refer to the flowchart of an embodiment of the present invention shown in FIG. 1A. A method of message delivery of the present invention includes the following steps:

Step S10: The first electronic device downloads the first encryption key from the data server according to the first account number;

Step S20: The first electronic device decrypts the first encryption key according to the first device key to obtain the group key;

Step S30: The first electronic device encrypts the first message according to the group key to generate the first encrypted message;

Step S40: The first electronic device uploads the first encrypted message to the communication group server according to the first account;

Step S50: The second electronic device downloads the second encryption key from the data server and downloads the first encrypted message from the communication group server according to the second account number;

Step S60: The second electronic device decrypts the second encryption key according to the second device key to obtain the group key;

Step S70: The second electronic device decrypts the first encrypted message according to the group key to restore the first message in the second electronic device.

Please also refer to the system schematic diagrams of an embodiment of the present invention shown in FIGS. 2 to 4B. The group system 1 used in the method of transmitting messages of the present invention includes a data server 10, a first electronic device 20, a second electronic device 30, and a communication group server 40. In this embodiment, the first electronic device 20 Log in to the communication group server 40 according to a first account A1, the first account A1 of the first electronic device 20 is stored in the communication group server 40, and the first account A1 acts as a manager in a communication group 40A and is managed by the first The electronic device 20 invites the second electronic device 30 to log in to the communication group server according to a second account A2, and the first account A1 is a communication group G1 in the communication group server 40 as a manager.

Following the above, the first electronic device 20 generates a first device key 22 and a first public key 24 according to a group data GD1 of the communication group G1, and the second electronic device 30 generates a second device key according to the group data GD1 The device key 32 and a second public key 34, so the first electronic device 20 encrypts the first public key 24 according to a group key keyg corresponding to the group data GD1 to generate a first encryption key Key1, and An electronic device 20 obtains the second public key 34 of the second electronic device 30 through the communication group server 40, that is, the second electronic device 30 transmits the second public key 34 to the first electronic device 20 through the communication group server 40, The first electronic device 20 encrypts the second public key 34 according to the group key keyg to generate a second encryption key Key2, where the group data GD1 is the communication group 40A corresponding to the group communication server 40, so this implementation The key mentioned in the example is the application communication group 40A and cannot be used in other groups to enhance security. Both the first encryption key Key1 and the second encryption key Key2 correspond to the group key keyg.

Furthermore, in this embodiment, storing data and group broadcasting messages are performed on different servers, that is, the data server 10 and the group communication server 40 are distinguished, so the data server 10 and the communication group server 40 are distinguished. The data server 10 stores a first encryption key Key1 and a second encryption key Key2. The first encryption key key1 and the second encryption key key2 are respectively connected (or bound) with a first code device1 and a second code device2, The first code device1 and the second code device2 are codes corresponding to the first electronic device 20 and the second electronic device 30 respectively. Therefore, they are uploaded to the data server 10 through the first electronic device 20 so that the data server 10 records the first electronic device The first code device1 and the first encryption key key1 corresponding to 30, and the data server 10 records the second code device2 and the second encryption key key2 corresponding to the second electronic device 30. The first device key 22 and the first public key 24 are generated by the first electronic device 20 according to an asymmetric encryption algorithm, and the second device key 32 and the second public key 34 are generated by the second electronic device 30 according to The asymmetric encryption algorithm is generated, for example, the RSA encryption algorithm, so the first device key 22 is matched to the first public key 24, and the second device key 32 is matched to the second public key 34.

In step S10, as shown in FIG. 4, the first account A1 of the first electronic device 20 is in the communication group server 40, and a data download request is made to download the first encryption key key1 previously stored in the data server 10. The data server 10 allows the first electronic device 20 to download the first encryption key key1 in the internal storage space of the first electronic device 20 according to the first code device1. In step S20, as shown in FIG. 4, the first electronic device 20 decrypts the first encryption key Key1, so that the first electronic device 20 obtains the group key keyg corresponding to the communication group 40A, and then in step S30 Here, the first electronic device 20 encrypts a first message M1 to be transmitted by the first electronic device 20 according to the group key keyg, thereby generating a first encrypted message M12.

In step S40, as shown in FIG. 4, the first electronic device 20 uploads the first encrypted message M12 to the communication group 40A. In step S50, as shown in FIG. 5, the second electronic device 30 makes a data download request for the second encryption key key2 to the data server 10, so that the data server 10 downloads the second encryption key key2 according to the second code device2 , While allowing the second electronic device 30 to download the first encrypted message M12 from the communication group 40A, and then in step S60, the second electronic device 30 decrypts according to the second device key 32 and the second encryption key key2, thereby obtaining Corresponding to the group key keyg of the communication group 40A, the second electronic device 30 uses the group key keyg to decrypt the encrypted message M12 in step S70 to restore the first encrypted message M12 to the first message M1. In the second electronic device 30, the second electronic device 30 can display the first message M1 instead of the first encrypted message M12.

It can be seen from the above that the method of transmitting messages of the present invention allows the server to no longer interpret or recognize the messages transmitted by the first electronic device 20 to the second electronic device 30, thereby avoiding the leakage of information by third parties, and because the process of message transmission is Encrypting messages further improves the reliability of message delivery.

As shown in FIG. 1B, the method for transferring messages of the present invention can also be applied to the transfer process of the reply message of the second electronic device 30. Therefore, according to node A, the steps of the method of the present invention are further continued to step S150, that is to say, this The invented method of delivering messages also includes:

Step S80: the second electronic device generates a second message according to the first message;

Step S90: The second electronic device encrypts the second message according to the second device key and the second encryption key to generate a second encrypted message;

Step S100: the second electronic device uploads the second encrypted message to the communication group server according to the second account;

Step S110: the first electronic device downloads the second encrypted message from the communication group server; and

Step S120: The first electronic device decrypts the second encrypted message according to the first device key and the first encryption key to restore the second message in the first electronic device.

In step S110, the second electronic device 30 generates a corresponding reply message according to the first message M1, that is, correspondingly generates a second message M2, and then, in step S120, the second electronic device 30 generates a corresponding response message according to the second device key 32 The group key keyg generated by decrypting with the second encryption key key2 is used to encrypt the second message M2, wherein the second electronic device 30 can download the second encryption key key2 again from the data server 10, and execute the first The second encryption key key2 is decrypted to obtain the group key keyg, and the second message M2 is encrypted to generate the corresponding second encrypted message M22, or the second electronic device 30 according to the second device key 32 The second encryption key key2 downloaded in the previous step S70 is directly used for decryption to obtain the group key keyg, and then the second message M2 is encrypted.

Then in step S130, the second electronic device 30 uploads the second encrypted message M22 to the communication group 40A of the communication group server 40, so that the first electronic device 20 is connected to the communication group 40A from the communication group server 40 in step S140. Download the second encrypted message M22 to the internal storage space of the device. Continuing, in step S150, the first electronic device 20 decrypts the second encrypted message M22 according to the group key keyg generated by decrypting the first device key 22 and the first encryption key key1 to restore the second encrypted message M22. Message M2, where the first electronic device 20 can download the first encryption key key1 again from the data server 10, and perform the decryption of the first encryption key key1 again to obtain the group key keyg, and the second encrypted message M22 encrypts to restore the corresponding second message M2, or the first electronic device 20 directly uses the first encryption key key1 downloaded in the previous step S20 to decrypt according to the first device key 22 to obtain the group The group key keyg further decrypts the second encrypted message M22.

Please refer to the flowchart shown in FIG. 6 for encrypting group messages of the present invention. As shown in the figure, the method for encrypting group messages of the present invention includes the following steps:

Step S210: the electronic device downloads the encryption key stored in the server;

Step S220: Decrypt the encryption key according to the device key to obtain the group key;

Step S230: Generate an encrypted message according to the group key and the group message, and send it to an encrypted group.

4, when the first electronic device 20 wants to encrypt the first message M1, it needs to download the first encryption key key1 originally uploaded to the data server 10 or the multifunction server 50, because the first encryption key key1 is not generated by the data server 10 or the multi-function server 50, so the data server 10 or the multi-function server 50 cannot decrypt the first encryption key key1, and only the first electronic device 20 can decrypt the first encryption key key1. Therefore, in step S220 In step S230, the first electronic device 20 performs decryption to obtain the group key keyg corresponding to the encrypted group 40. In step S230, the first electronic device 20 pairs the group message (that is, the first The message M1) is encrypted, and the corresponding first encrypted message M12 is generated and uploaded to the corresponding encrypted group.

In the above embodiment, the first electronic device 20 sends a group message to the encrypted group. If the second electronic device 30 sends a group message to the encrypted group, the above steps S210 to S230 are also followed.

Please refer to the flowchart shown in FIG. 7 for the decryption of group messages of the present invention. The method for decrypting group messages of the present invention includes the following steps:

Step S310: an electronic device downloads an encryption key stored in a server;

Step S320: Decrypt the encryption key according to a device key to obtain a group key;

Step S330: Generate a decrypted message according to the group key and an encrypted message and display it on the electronic device.

4B, when the second electronic device 30 wants to decrypt the first encrypted message M12, it needs to download the second encryption key key2 originally uploaded to the data server 10. Because the second encryption key key2 is not used by the data server 10 or the multifunction It is encrypted by the server 50, so the data server 10 cannot decrypt the second encryption key key2. Only the second electronic device 30 can decrypt the second encryption key key2. Therefore, in step S220, the second electronic device 30 performs Decryption to generate a group key keyg corresponding to the encrypted group. In step S230, the second electronic device 30 decrypts the first encrypted message M12 according to the group key keyg, and restores it to the corresponding first message M1 (ie, group message), so that the second electronic device 30 can display the first message M1 instead of displaying the encrypted first encrypted message M12.

In the above embodiment, the second electronic device 30 wants to restore the encrypted message of the encrypted group. If the first electronic device 20 wants to restore the encrypted message of the encrypted group, the steps S310 to S330 are also followed.

In addition, when the first electronic device 20 and the second electronic device 30 are not registered in the key list 12, the first electronic device 20 and the second electronic device 30 cannot encrypt the sent group message or cannot decrypt the encrypted message. Therefore, when the first electronic device 20 and the second electronic device 30 are not registered in the key list 12, it is displayed that the messages in the encrypted group are all encrypted group messages and are displayed as unrecognizable garbled characters.

The following embodiments further illustrate that the communication group server 40 and the data server 10 are combined into a multifunctional server 50, and the first electronic device 20 and the second electronic device 30 log in to the multifunctional server with the first account A1 and the second account A2, respectively. The user of the first electronic device 20 replaces the electronic device to rejoin the encryption group 50A, and holds the description of the key related to the first electronic device 20 again.

Please refer to FIGS. 8A and 8B, which are flowcharts of replacing the first electronic device to the third electronic device according to the present invention. The method of transmitting messages of the present invention further includes a step flow of replacing the first electronic device, including the following steps:

Step S410: The first electronic device downloads the first encryption key from the data server according to the first account number;

Step S420: The first electronic device decrypts the first encryption key according to the first device key to obtain the group key;

Step S430: The first electronic device encrypts the first message according to the group key to generate the first encrypted message;

Step S440: the first electronic device uploads the first encrypted message to the communication group server according to the first account;

Step S450: The second electronic device downloads the second encryption key from the data server and downloads the first encrypted message from the communication group server according to the second account number;

Step S460: The second electronic device decrypts the second encryption key according to the second device key to obtain the group key;

Step S470: The second electronic device decrypts the first encrypted message according to the group key to restore the first message in the second electronic device;

Step S480: the second electronic device generates a second message according to the first message;

Step S490: The second electronic device encrypts the second message according to the group key obtained by the second device key and the second encryption key to generate a second encrypted message;

Step S500: the second electronic device uploads the second encrypted message to the communication group server according to the second account;

Step S510: The first electronic device downloads the second encrypted message from the communication group server;

Step S520: The first electronic device decrypts the second encrypted message according to the group key obtained by the first device key and the first encryption key, so as to restore the second message in the first electronic device;

Step S530: The first electronic device obtains the first barcode according to the encryption group and temporarily stores the first device key and the first public key corresponding to the encryption group in the server;

Step S540: The third electronic device obtains the authorization information according to the first barcode and joins the encryption group;

Step S550: The third electronic device downloads and restores the first device key and the first public key from the server according to the authorization information; and

Step S560: The third electronic device encrypts the first public key according to the encryption group to generate a first encryption key and records the third electronic device with the first encryption key on the server.

Please refer to FIGS. 9 to 12 together, which are schematic diagrams of a system according to another embodiment of the present invention. The difference between FIGS. 2 to 4B and FIGS. 9 to 12 is that FIGS. 9 to 12 further include a third electronic device 60.

Steps S410 to S520 have been disclosed in steps S10 to S120 of the above-mentioned embodiment, so they will not be repeated. Since the first electronic device 20 sends the first encrypted message M12, the user of the first electronic device 20 will The third electronic device 60 is replaced by the third electronic device 60. Therefore, in step S530, as shown in FIG. The first device key 22 and the first public key 24 for encryption and decryption purposes will be temporarily stored to the multifunctional server 50, where the first electronic device 20 further encrypts the first device key 22 and the first public key 24, thus A corresponding first encrypted data D1 is generated, so that the multifunctional server 50 does not recognize the first device key 22 and the first public key 24, thereby avoiding the problem of server-side leakage.

In step S540, as shown in FIG. 15, the third electronic device 60 reads the first barcode QR1, for example: using a built-in camera to capture the image of the first barcode QR1, thereby obtaining a temporary third device key 62 and the third public key 64 are added to the encryption group 50A, so the third public key 64 is encrypted to generate a third encryption key key3 and upload it to the key list 12, which is to temporarily authorize the third electronic device 60 to use Corresponding to the encryption and decryption of the encryption group 50A; in step S550, as shown in FIG. 16, the third electronic device 60 downloads the temporarily stored first encrypted data D1 from the multifunction server 50, and the third electronic device 60 targets the first The encrypted data D1 is decrypted to restore the first device key 22 and the first public key 24 in the third electronic device 60, and then in step S560, the restored first public key 24 is encrypted to generate the corresponding The first encryption key key1 of the third electronic device 60 is uploaded to the key list 12 of the multifunction server 50. In this way, in the key list 12, the first encryption key key1 is changed to correspond to the third electronic device 60, wherein, since the third electronic device 60 replaces the first electronic device 20 as the manager of the encryption group 50A, step In S560, the complete asymmetric encryption key of the first device key 22 and the first public key 24 has been obtained by the third electronic device 60, so the encryption process can be directly performed.

Please refer to FIG. 13A and FIG. 13B, which are flowcharts of replacing the second electronic device to the fourth electronic device. As shown in the figure, the method of transmitting messages of the present invention further includes a step flow of replacing the second electronic device, and the steps include:

Step S610: The first electronic device downloads the first encryption key to the data server according to the first account number;

Step S620: The first electronic device decrypts the first encryption key according to the first device key to obtain the group key;

Step S630: The first electronic device encrypts the first message according to the group key to generate the first encrypted message;

Step S640: the first electronic device uploads the first encrypted message to the communication group server according to the first account;

Step S650: The second electronic device downloads the second encryption key from the data server and downloads the first encrypted message from the communication group server according to the second account.

Step S660: The second electronic device decrypts the second encryption key according to the second device key to obtain the group key;

Step S670: The second electronic device decrypts the first encrypted message according to the group key to restore the first message on the second electronic device

Step S680: The second electronic device generates a second message according to the first message;

Step 690: The second electronic device encrypts the second message according to the group key obtained by the second device key and the second encryption key to generate a second encrypted message;

Step S700: the second electronic device uploads the second encrypted message to the communication group server according to the second account;

Step S710: The first electronic device downloads the second encrypted message from the communication group server;

Step S720: The first electronic device decrypts the second encrypted message according to the group key obtained by the first device key and the first encryption key, so as to restore the second message in the first electronic device;

Step S730: The second electronic device obtains the second barcode according to the encryption group and temporarily stores the second device key and the second public key corresponding to the encryption group in the server;

Step S740: the fourth electronic device obtains the authorization information according to the second barcode and joins the encryption group;

Step S750: The fourth electronic device downloads and restores the second device key and the second public key from the server according to the authorization information; and

Step S760: The fourth electronic device encrypts the second public key according to the encryption group to generate a second encryption key and records the fourth electronic device with the second encryption key on the server.

Please also refer to FIG. 14 to FIG. 17 for system schematic diagrams of another embodiment of the present invention. The difference between FIGS. 9-12 and FIGS. 14-17 is that FIGS. 9-12 replace the first electronic device 20 with the third electronic device 60, and FIGS. 14-17 replace the second electronic device 30 with the fourth electronic device 70. .

Steps S610 to S720 have been disclosed in steps S10 to S120 of the above-mentioned embodiment, so they will not be repeated. Since the second electronic device 30 decrypts the first encrypted message M12 and displays it, the use of the second electronic device 30 The user will be replaced with the fourth electronic device 70. Therefore, in step S730, the second electronic device 30 obtains a second barcode QR2 for transfer from the encryption group 50A, and the second electronic device 30 will temporarily store it The second device key 32 and the second public key 34 for encryption and decryption purposes are sent to the multifunction server 50, wherein the second electronic device 30 further encrypts the second device key 32 and the second public key 34, thereby generating a corresponding one The second encrypted data D2 prevents the multi-function server 50 from identifying the second device key 32 and the second public key 34, thereby avoiding the problem of server-side leakage.

In step S740, the fourth electronic device 70 reads the second barcode QR2, for example: using a built-in camera to capture the image of the second barcode QR2, thereby obtaining the temporary fourth device key 72 and the fourth public key 74 and join the encryption group 50A, so the fourth public key 74 is encrypted and uploaded to the key list 12, that is, the fourth electronic device 70 is temporarily authorized to use the encryption and decryption corresponding to the encryption group 50A; in step S750, The fourth electronic device 70 downloads the temporarily stored second encrypted data D2 from the multifunction server 50, and the fourth electronic device 70 decrypts the second encrypted data D2 to restore the second device key 32 and the second public key 34. In the fourth electronic device 70, in step S760, the restored second public key 34 is encrypted, thereby generating a second encryption key key2 corresponding to the fourth electronic device 70, and uploading the key to the multifunction server 50 Listing 12. In this way, in the key list 12, the second encryption key key2 is changed to correspond to the fourth electronic device 70, and since the second electronic device 30 itself is not the manager of the encryption group 50A, the fourth electronic device 70 replaces the first After the second electronic device 30 joins the encryption group 50A, the fourth electronic device 70 still needs to be encrypted by the first electronic device 20 when the second public key 34 is encrypted into the second encryption key key2.

In summary, the method for encrypting and decrypting group messages and transmitting messages of the present invention is based on the fact that after the electronic device enters the encrypted group, the group manager receives the public key from other electronic devices and encrypts it for the server to establish The corresponding key list prevents the server from reading or identifying the public key, so that the electronic device only encrypts and decrypts the group information. Furthermore, the electronic device can be encrypted according to the encryption principle of the present invention to be applied to the user to replace the electronic device.

The foregoing descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. All the equivalent changes and modifications of the shape, structure, characteristics and spirit described in the claims of the present invention shall be included in this Within the scope of protection of the invention.

Claims (15)

A method for transmitting messages, the method is applied to a first electronic device, a second electronic device, a data server and a communication group server. The first electronic device logs in to the communication group server according to a first account, and the first electronic device logs into the communication group server according to a first account. An electronic device invites the second electronic device to log in to the communication group server according to a second account. The first electronic device generates a first device key and a first public key according to a group data corresponding to the communication group server. The second The electronic device generates a second device key and a second public key according to the group data, the first electronic device generates a group key corresponding to the group data, and the first electronic device encrypts the first public key according to the group key , To generate a first encryption key and record a first code and a first encryption key corresponding to the first electronic device in the data server, and the second electronic device transmits the second public key to the first electronic device via the communication group server The first electronic device encrypts the second public key according to the group key to generate a second encryption key and records a second code and a second encryption key corresponding to the second electronic device on the data server, the method includes The following steps: The first electronic device downloads the first encryption key from the data server according to the first account; The first electronic device decrypts the first encryption key according to the first device key to obtain the group key; The first electronic device encrypts a first message according to the group key to generate a first encrypted message; The first electronic device uploads the first encrypted message to the communication group server according to the first account; The second electronic device downloads the second encryption key from the data server and downloads the first encrypted message from the communication group server according to the second account; The second electronic device decrypts the second encryption key according to the second device key to obtain the group key; and The second electronic device decrypts the first encrypted message according to the group key to restore the first message in the second electronic device. 2. The method for transmitting messages according to claim 1, wherein when the first electronic device does not read the first code, the first encryption key cannot be downloaded, and when the second electronic device does not read the second code , Unable to download the second encryption key. The method for delivering messages according to claim 1, further comprising: The second electronic device generates a second message according to the first message; The second electronic device encrypts the second message according to the group key to generate a second encrypted message; The second electronic device uploads the second encrypted message to the communication group server according to the second account; The first electronic device downloads the second encrypted message from the communication group server; and The first electronic device decrypts the second encrypted message according to the group key to restore the second message in the first electronic device. 8. The method of transmitting messages according to claim 1, wherein the first electronic device further generates the first device key and the first public key according to an asymmetric cryptographic algorithm, and the second electronic device also generates the first device key and the first public key according to an asymmetric cryptographic algorithm. Method to generate the second device key and the second public key. The method for delivering messages according to claim 1, further comprising: The first electronic device obtains a first barcode from the communication group server and temporarily stores the first device key and the first public key in the data server; A third electronic device obtains authorization information according to the first barcode and logs in to the communication group server according to the first account; The third electronic device downloads and restores the first device key and the first public key from the data server according to the authorization information; and The third electronic device encrypts the first public key according to the encryption group to generate a first encryption key and records the third electronic device with the first encryption key in the data server. 5. The method for transmitting messages according to claim 5, wherein the step of obtaining a first barcode from the communication group server in the first electronic device and temporarily storing the first device key and the first public key in the data server , The first electronic device encrypts the first device key and the first public key to generate a first encrypted data, which is temporarily stored in the data server. The method for delivering messages according to claim 1, further comprising: The second electronic device obtains a second barcode from the communication group server and temporarily stores the second device key and the second public key in the data server; A fourth electronic device obtains authorization information according to the second barcode and logs in to the communication group server according to the second account; The fourth electronic device downloads and restores the second device key and the second public key from the data server according to the authorization information; and The fourth electronic device encrypts the second public key to generate a second encryption key and records the fourth electronic device with the second encryption key in the data server. 7. The method for transmitting messages according to claim 7, wherein in the step of obtaining a second barcode from the communication group server by the second electronic device and temporarily storing the second device key and the second public key in the data server, the first The two electronic devices encrypt the second device key and the second public key to generate a second encrypted data, which is temporarily stored in the data server. 8. The method for delivering messages according to claim 1, wherein the communication group server and the data server are the same server. A method for encrypting group messages. The method is applied to an electronic device storing an encryption key to a data server according to an account number. The encryption key corresponds to a public key and a group key. A device key of an electronic device, the method includes the following steps: The electronic device downloads the encryption key according to the account; The electronic device decrypts the encryption key according to the device key to obtain the group key; and The electronic device encrypts a message according to the group key to generate an encrypted message. 10. The method for encrypting group messages according to claim 10, wherein in the step of decrypting the encryption key by the electronic device according to the device key, the electronic device further decrypts according to an asymmetric cryptographic algorithm to generate the group Group key. The method for encrypting group messages according to claim 10, wherein in the step of generating an encrypted message by the electronic device encrypting a message according to the group key, further according to an Advanced Encryption Standard (AES) algorithm Generate encrypted messages. A method for decrypting group messages. The method is applied to an electronic device storing an encryption key to a data server according to an account number. The encryption key corresponds to a public key and a group key. For a device key of an electronic device, the method includes the following steps: The electronic device downloads the encryption key according to the account; The electronic device decrypts the encryption key according to the device key to obtain the group key; and The electronic device decrypts an encrypted message according to the group key and restores it to a group message. The method for decrypting group messages according to claim 13, wherein in the step of decrypting the electronic device according to the device key and the encryption key, the electronic device further decrypts according to an asymmetric cryptographic algorithm to generate the group Group key. The method for decrypting a group message as claimed in claim 13, wherein the step of generating a group message on the electronic device according to the group key and an encrypted message by the electronic device is further according to an advanced encryption standard (AES) The algorithm generates the decrypted message.

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