TW202416270A - System and method for performing encrypted mixing based on big number format and additive homomorphism - Google Patents

Abstract

A system and a method for performing encrypted mixing based on big number format and additive homomorphism are provided. The method includes: performing a preprocessing-operation by a second-voice-information-processing-unit to obtain a voice-information-preprocessing-result, and storing the voice-information-preprocessing-result in a big number format; performing an encryption-operation on the voice-information-preprocessing-result by an encryption-and-transmission-unit to obtain an voice-information-encrypted-result in the big number format; performing an additive-homomorphism-operation on the voice-information-encrypted-result by a mixing-unit to obtain a mixed-ciphertext in the big number format; performing a decryption-operation on the mixed-ciphertext by a decryption-unit to obtain mixed-voice-information in the big number format; and performing a post-processing-operation on the mixed-voice-information by a first-voice-information-processing-unit to obtain a mixed-voice-information-post-processing-result.

Description

System and method for executing encrypted mixing based on large number type and additive homomorphism

The present invention relates to a system and method for performing encrypted mixing based on large number types and addition homomorphism.

At present, the general method of encrypted mixing is that after the user device performs voice encryption, the encrypted voice is transmitted to the server, and the server performs decryption and mixing. Then, the server encrypts the mixing result and transmits it to the user device, so that the user device can perform decryption and playback. In other words, in the general method of encrypted mixing, the server will perform decryption and obtain the plaintext voice information. If the server is monitored by a third party, this practice will cause information security risks.

The system for performing encryption mixing based on large number type and addition homomorphism includes a user device and a server. The user device includes a decryption unit, a first voice information processing unit, a second voice information processing unit and an encryption and transmission unit. The server includes a mixing unit, wherein the server is communicatively connected to the user equipment, wherein the second voice information processing unit performs a pre-processing operation to obtain a voice information pre-processing result, and stores the voice information pre-processing result in a large number form; the encryption and transmission unit performs an encryption operation on the voice information pre-processing result to obtain a voice information encryption result in a large number form; the mixing unit performs an addition homomorphic operation on the voice information encryption result to obtain a ciphertext mixture in a large number form; the decryption unit performs a decryption operation on the ciphertext mixture to obtain a mixed voice information in a large number form; and the first voice information processing unit performs a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result.

The method of performing encrypted mixing based on large number form and additive homomorphism of the present invention includes: the second voice information processing unit performs a pre-processing operation to obtain a voice information pre-processing result, and stores the voice information pre-processing result in a large number form; the encryption and transmission unit performs an encryption operation on the voice information pre-processing result to obtain a voice information encryption result in a large number form; the mixing unit performs an additive homomorphic operation on the voice information encryption result to obtain a ciphertext mixing in a large number form; the decryption unit performs a decryption operation on the ciphertext mixing to obtain a mixed voice information in a large number form; and the first voice information processing unit performs a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result.

FIG1 is a schematic diagram of a system 10 for performing encrypted mixing based on large number type and additive homomorphic execution according to an embodiment of the present invention. The system 10 may include a plurality of user devices 100 and a server 200. It should be noted that the present invention does not limit the number of user devices 100. The user devices 100 and the server 200 may support voice transmission based on IP (VoIP, Voice over IP).

The user device 100 (or server 200) has necessary components for running the user device 100 (or server 200), such as a processing unit (such as a processor but not limited thereto), a communication unit (such as various communication chips, Bluetooth chips, WiFi chips, etc. but not limited thereto), and a storage unit (such as a removable random access memory, a flash memory, a hard disk, etc. but not limited thereto). The server 200 can be (respectively) communicatively connected to each user device 100. For example, the server 200 can be communicatively connected to each user device 100 via the Internet 300.

The user equipment 100 may include a receiving unit 110 and a speaking unit 120. In more detail, the receiving unit 110 may include a sound receiving unit 111, a decryption unit 112, and a first voice information processing unit 113. In addition, the speaking unit 120 may include a recording unit 121, a second voice information processing unit 122, and an encryption and transmission unit 123. In this embodiment, the user equipment 100 may include an input and output device (not shown). The input and output device is, for example, a microphone or a speaker, which is used for inputting or outputting voice. On the other hand, the server 200 may include a sending and receiving unit 210 and a mixing unit 220.

FIG. 2 is an operation flow chart of each unit of the system 10 shown in FIG. 1 . Please refer to FIG. 1 and FIG. 2 at the same time. In step S201, the recording unit 121 can receive voice information through the input-output device. In detail, the user can operate the user device 100 to input the voice information (in the form of an analog signal) to the recording unit 121. Then, the recording unit 121 can convert the voice information in the form of an analog signal into the voice information in the form of a digital signal, and send the voice information (in the form of a digital signal) to the second voice information processing unit 122. It should be noted here that the voice information may include (multiple) voice samples. The user can use the input-output device to set the number of bits of the voice sample. The number of bits is, for example, 8 bits or 16 bits, but the present invention is not limited to this.

In step S202, the second voice information processing unit 122 may perform a pre-processing operation to obtain a voice information pre-processing result, and store the voice information pre-processing result in a large number format. Specifically, the second voice information processing unit 122 may perform a voice information segmentation operation on the voice information to obtain a voice information segmentation result, and perform a voice information upward shift operation on the voice information segmentation result to obtain a voice information upward shift result. The voice information upward shift operation may be related to the number of bits of the voice sample. In detail, the second voice information processing unit 122 may perform a voice information segmentation operation on the voice information according to each voice sample. Then, if the number of bits of the voice sample is bits, the second voice information processing unit 122 can add each voice sample in the voice information to In other words, since each voice sample in the voice information (in the form of digital signal) obtained by the second voice information processing unit 122 from the recording unit 121 in the aforementioned step S201 may be a negative number, the second voice information processing unit 122 may add each voice sample in the voice information to the value of , so that each voice sample must be a positive number. Furthermore, the second voice information processing unit 122 can add an overflow buffer to the voice information upward shift result to obtain the voice information pre-processing result. The overflow buffer can be related to the number of bits (of the voice sample). For example, the second voice information processing unit 122 can use the following formula 1 to obtain the number of bits (length) of the overflow buffer. Finally, the second voice information processing unit 122 can merge these voice samples, store the voice information pre-processing result in a large number format, and send the voice information pre-processing result to the encryption and transmission unit 123. ……… (Formula 1) Where k is the number of tracks before mixing.

It should be noted that in the above formula 1 (Number of tracks before mixing) may mean the number of user devices 100 shown in FIG. 1. Further, in this embodiment, the server 200 may inform each user device 100 of the number of user devices 100 in advance, so that the second voice information processing unit 122 may use the above The operation of adding the overflow buffer code in step S202 is performed.

In step S203, the encryption and transmission unit 123 may perform an encryption operation on the voice information pre-processing result (stored in a large number format) to obtain a voice information encryption result in a large number format. Specifically, the encryption and transmission unit 123 may perform an encryption operation on the voice information pre-processing result using the Paillier algorithm. Then, the encryption and transmission unit 123 may transmit the voice information encryption result to the transceiver unit 210. Specifically, the encryption and transmission unit 123 may transmit the voice information encryption result to the transceiver unit 210 of the server 200 through the Internet 300 according to the UDP/RTP transmission protocol.

In step S204, the transceiver unit 210 may disassemble the UDP/RTP transport protocol packet according to the UDP/RTP transport protocol to obtain the aforementioned voice information encryption result, and send the voice information encryption result to the mixing unit 220.

In step S205, the mixing unit 220 can perform an addition homomorphic operation on the voice information encryption result to obtain a ciphertext mixture in a large number format. Specifically, the mixing unit 220 can use the Payet algorithm to perform an addition homomorphic operation on the voice information encryption result. In other words, the server 200 of the present invention does not need to perform decryption, but only needs to add ciphertexts to obtain the ciphertext mixture. Then, the sending and receiving unit 210 can package the ciphertext mixture into the format of the UDP/RTP transmission protocol, and transmit the ciphertext mixture to the receiving unit 111 via the Internet 300.

In step S206 , after the sound receiving unit 111 receives the packet, the sound receiving unit 111 may unpack the packet using the UDP/RTP transmission protocol to obtain the ciphertext audio mixture. Then, the sound receiving unit 111 may transmit the ciphertext audio mixture to the decryption unit 112 .

In step S207, the decryption unit 112 may perform a decryption operation on the ciphertext mixture to obtain the mixed voice information in a large number format. Specifically, the decryption unit 112 may perform a decryption operation on the ciphertext mixture using the Payet algorithm. In detail, the decryption unit 112 may perform a decryption operation on the ciphertext mixture using the Payet algorithm key to obtain the mixed voice information, and send the mixed voice information to the first voice information processing unit 113.

In step S208, the first voice information processing unit 113 may perform a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result. Specifically, the first voice information processing unit 113 may perform a mixed voice information segmentation operation on the mixed voice information according to the aforementioned overflow buffer to obtain a mixed voice information segmentation result, and perform a voice information downward shift operation on the mixed voice information segmentation result to obtain a mixed voice information post-processing result. The voice information downward shift operation may be related to the number of audio tracks before mixing and the number of bits of the voice sample. In detail, if the number of bits of the voice sample (in the mixed voice information segmentation result) is bits, and is the number of tracks before mixing (as described in the above embodiment, The first voice information processing unit 113 may subtract the number of each voice sample (in the mixed voice information segmentation result) from the first voice information processing unit 113. Finally, the first voice information processing unit 113 can output the mixed voice information post-processing result through the input and output device.

FIG3 is a schematic diagram of a group encrypted mixed voice call according to an embodiment of the present invention. Please refer to FIG1, FIG2 and FIG3 at the same time. In the embodiment shown in FIG3, three users, namely, user "Xiaohua", user "Xiaoming" and user "Azhong", respectively operate user equipment 100 to perform a group encrypted mixed voice call. In other words, in the embodiment of FIG3, the above formula 1 is The value (the number of tracks before mixing, i.e., the number of user devices 100) is 3. It is assumed that each user device 100 and the server 200 shown in FIG. 3 have exchanged homomorphic encryption keys in advance, and that the number of bits of the voice sample set by each user device 100 is 8 bits.

Similar to the above-mentioned embodiment, user "Xiaohua", user "Xiaoming" and user "Azhong" can start a conversation respectively with the user equipment 100 they each own. The conversation content can be first recorded by the recording unit 121 in the speaking unit 120 to obtain a digital signal composed of a series of voice samples with a bit number of 8 bits. Then, this digital signal can be pre-processed by the second voice information processing unit 122 to obtain a voice information pre-processing result. Then, the voice information pre-processing result can be encrypted by the encryption and transmission unit 123 to obtain a voice information encryption result, and the encryption and transmission unit 123 transmits the voice information encryption result to the receiving and transmitting unit 210 of the server 200. After the transceiver unit 210 receives the voice information encryption results of each user device 100, the mixing unit 220 of the server 200 can perform an addition homomorphic operation on the voice information encryption results of each user device 100 to obtain a ciphertext mix, and then the transceiver unit 210 transmits the ciphertext mix back to the receiving unit 111 of each user device 100 used by the user "Xiaohua", the user "Xiaoming" and the user "Azhong". Then, each user device 100 can perform a decryption operation on the ciphertext mix through the decryption unit 112 to obtain a large number of mixed voice information that has not been post-processed. Finally, the first voice information processing unit 113 of each user device 100 can perform post-processing operations on the mixed voice information to obtain a mixed voice information post-processing result (capable of being output/played), and output the mixed voice information post-processing result through the input and output devices of each user device 100.

FIG. 4A is a schematic diagram of the operation of the system 10 shown in FIG. 1 during the first stage of group encrypted mixed voice calls. FIG. 4B is a schematic diagram of the operation of the system 10 shown in FIG. 1 during the second stage of group encrypted mixed voice calls. As described in the embodiment of FIG. 3 above, in the embodiments of FIG. 4A and FIG. 4B, the above formula 1 is The value (the number of tracks before mixing, i.e., the number of user devices 100) is 3, and the number of bits of the speech sample set by each user device 100 is 8 bits (i.e. value is 8).

Please refer to Figures 1, 2, 3 and 4A. The following description will be continued by taking the user "Xiaohua" as an example. As shown in Figure 4A, it is assumed that the voice information received by the recording unit 121 of the user device 100 held by the user "Xiaohua" includes 3 voice samples [11110110, 00000110, 00011110] with a bit number of 8 bits. The second voice information processing unit 122 of the user device 100 held by the user "Xiaohua" can add all the 3 voice samples. , to perform the voice information upward translation operation and obtain the voice information upward translation result (i.e., 3 voice samples [118, 134, 158]). Thus, these 3 voice samples must be positive numbers (positive integers from 0 to 255). Then, in order to avoid overflow in the subsequent (server 200) mixing process, when the second voice information processing unit 122 concatenates these 3 voice samples into a large number format, the second voice information processing unit 122 can add an overflow buffer to the voice information upward translation result to obtain the voice information pre-processing result. In detail, according to the above formula 1, since , the second voice information processing unit 122 can add an overflow buffer with a bit number (length) of 1 at the beginning of the three voice samples to obtain the voice information pre-processing result (i.e., 1110110010000110010011110), and complete the conversion of the large number format. Then, the encryption and transmission unit 123 of the user equipment 100 held by the user "Xiaohua" can perform an encryption operation (i.e., homomorphic encryption) on the voice information pre-processing result (in the large number format) to obtain the voice information encryption result in the large number format, i.e., E(1110110010000110010011110). Similarly, the user equipment 100 held by the user "Xiao Ming" and the user equipment 100 held by the user "A Zhong" can also obtain their respective voice information encryption results in the same manner as the user "Xiao Hua". Then, each user equipment 100 can transmit the voice information encryption results to the transceiver unit 210 of the server 200 respectively.

Please continue to refer to Figures 1, 2, 3, 4A and 4B. After the server 200 receives the voice information encryption result from each user device 100, the mixing unit 220 can perform an addition homomorphic operation on the voice information encryption result to obtain a ciphertext mixture (in the form of a large number), that is, E(110110100110011100100111101). Then, the transceiver unit 210 can return the ciphertext mixture to the receiver unit 111 of each user device 100. Then, the decryption unit 112 can perform a decryption operation on the ciphertext mixture to obtain the mixed voice information (in the form of a large number), that is, 110110100110011100100111101. Then, the first voice information processing unit 113 may perform a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result. Specifically, the first voice information processing unit 113 may perform a mixed voice information segmentation operation (i.e., string segmentation) on the mixed voice information according to the bit of each voice sample containing the overflow buffer code to obtain a mixed voice information segmentation result [110110100, 110011100, 100111101]. Furthermore, the first voice information processing unit 113 may perform a voice information downward translation operation on the mixed voice information segmentation result to obtain a mixed voice information post-processing result. In other words, the first voice information processing unit 113 can remove the three voice samples from the mixed voice information segmentation result. , to obtain the mixed voice information post-processing result [52, 28, -67]. Finally, the first voice information processing unit 113 can output/play the mixed voice information post-processing result through the input and output device.

FIG5 is a flow chart of a method for performing encrypted mixing based on large number form and additive homomorphism according to an embodiment of the present invention, wherein the method can be implemented by the system 10 shown in FIG1. In step S501, the second voice information processing unit performs a pre-processing operation to obtain a voice information pre-processing result, and stores the voice information pre-processing result in large number form. In step S502, the encryption and transmission unit performs an encryption operation on the voice information pre-processing result to obtain a voice information encryption result in large number form. In step S503, the mixing unit performs an additive homomorphic operation on the voice information encryption result to obtain a ciphertext mixing in large number form. In step S504, the decryption unit performs a decryption operation on the ciphertext mixture to obtain the mixed voice information in a large number format. In step S505, the first voice information processing unit performs a post-processing operation on the mixed voice information to obtain the mixed voice information post-processing result. The method has been described in the above-mentioned embodiment and will not be repeated here.

In summary, the system and method for performing encrypted mixing based on large number types and additive homomorphism of the present invention can be performed by the user equipment to perform encryption operations to obtain the voice information encryption result after the user equipment performs pre-processing operations such as voice information upward translation operation and adding overflow buffer code on the voice information. Then, the server does not need to perform decryption, but performs additive homomorphic operations on the voice information encryption result to obtain the ciphertext mixing. Finally, the user equipment can perform a decryption operation on the ciphertext mixing, and output/play it after the user equipment performs post-processing operations. In other words, since the server does not need to perform decryption, the server will not obtain the plaintext voice information. Thereby improving the security of the voice information of the user equipment.

10: System for performing encrypted mixing based on large number type and addition homomorphism 100: User equipment 110: Receiver unit 111: Radio unit 112: Decryption unit 113: First voice information processing unit 120: Speaker unit 121: Recorder unit 122: Second voice information processing unit 123: Encryption and transmission unit 200: Server 210: Transmitter and receiver unit 220: Mixer unit 300: Internet S201~S208, S501~S505: Steps

FIG. 1 is a schematic diagram of a system for executing encrypted mixing based on large number type and additive homomorphism according to an embodiment of the present invention. FIG. 2 is an operation flow chart of each unit of the system shown in FIG. 1. FIG. 3 is a schematic diagram of a group encrypted mixing call according to an embodiment of the present invention. FIG. 4A is a schematic diagram of the operation of the system shown in FIG. 1 in the first stage of a group encrypted mixing call. FIG. 4B is a schematic diagram of the operation of the system shown in FIG. 1 in the second stage of a group encrypted mixing call. FIG. 5 is a flow chart of a method for executing encrypted mixing based on large number type and additive homomorphism according to an embodiment of the present invention.

S501~S505: Steps

Claims (10)

A system for performing encrypted mixing based on large number form and additive homomorphism, comprising: A user device, comprising a decryption unit, a first voice information processing unit, a second voice information processing unit, and an encryption and transmission unit; and A server, comprising a mixing unit, wherein the server is communicatively connected to the user device, wherein The second voice information processing unit performs a pre-processing operation to obtain a voice information pre-processing result, and stores the voice information pre-processing result in large number form; The encryption and transmission unit performs an encryption operation on the voice information pre-processing result to obtain the voice information encryption result in the large number form; The mixing unit performs an additive homomorphic operation on the voice information encryption result to obtain the ciphertext mixing in the large number form; The decryption unit performs a decryption operation on the ciphertext mixture to obtain the mixed voice information in the form of a large number; The first voice information processing unit performs a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result. A system as described in claim 1, wherein the user equipment further includes an input-output device, wherein the user equipment further includes a recording unit, wherein the recording unit receives voice information through the input-output device. A system as described in claim 2, wherein the voice information includes a voice sample, wherein the second voice information processing unit performs a voice information segmentation operation on the voice information to obtain a voice information segmentation result, and performs a voice information upward translation operation on the voice information segmentation result to obtain a voice information upward translation result, wherein the voice information upward translation operation is associated with the number of bits of the voice sample. A system as described in claim 3, wherein the second voice information processing unit adds an overflow buffer to the voice information upward shift result to obtain the voice information pre-processing result, wherein the overflow buffer is associated with the bit number. A system as described in claim 4, wherein the second voice information processing unit concatenates the voice samples to form the voice information pre-processing result in the large number format. The system as described in claim 1, wherein the server further includes a transceiver unit, wherein the user equipment further includes a radio unit, wherein the encryption and transmission unit transmits the voice information encryption result to the transceiver unit; the transceiver unit transmits the ciphertext mix to the radio unit. A system as described in claim 1, wherein the first voice information processing unit performs a mixed voice information segmentation operation on the mixed voice information according to the overflow buffer code to obtain a mixed voice information segmentation result, and performs a voice information downward shift operation on the mixed voice information segmentation result to obtain the mixed voice information post-processing result, wherein the voice information downward shift operation is related to the number of audio tracks before mixing and the number of bits of the voice sample. A system as described in claim 1, wherein the user equipment further includes an input-output device, wherein the first voice information processing unit outputs the post-processing result of the mixed voice information through the input-output device. The system as described in claim 1, wherein the encryption and transmission unit uses the Paillier algorithm to perform the encryption operation on the pre-processing result of the voice information; the mixing unit uses the Paillier algorithm to perform the addition homomorphic operation on the voice information encryption result; the decryption unit uses the Paillier algorithm to perform the decryption operation on the ciphertext mixing. A method for performing encrypted mixing based on large number form and additive homomorphism is applicable to a system including a user device and a server, wherein the user device includes a decryption unit, a first voice information processing unit, a second voice information processing unit and an encryption and transmission unit, and the server includes a mixing unit, wherein the method includes: The second voice information processing unit performs a pre-processing operation to obtain a voice information pre-processing result, and stores the voice information pre-processing result in large number form; The encryption and transmission unit performs an encryption operation on the voice information pre-processing result to obtain the voice information encryption result in the large number form; The mixing unit performs an additive homomorphic operation on the voice information encryption result to obtain the ciphertext mixing in the large number form; The decryption unit performs a decryption operation on the ciphertext mixture to obtain the large-scale mixed voice information; and the first voice information processing unit performs a post-processing operation on the mixed voice information to obtain a mixed voice information post-processing result.