CN105530100A - A VoLTE secure communication method - Google Patents

Abstract

The invention discloses a VoLTE secure communication method, which realizes end-to-end secure communication of VoLTE communication nodes by simultaneously using a symmetric encryption algorithm RC4 and an asymmetric encryption algorithm RSA; where the high-efficiency symmetric encryption algorithm RC4 is used to encrypt call voice data; using The asymmetric encryption algorithm RSA digitally signs and verifies the call voice data to confirm the reliability of the data source; while the symmetric encryption key is encrypted by the public key of the asymmetric encryption algorithm RSA and then negotiated with the receiver to ensure voice encryption Key security. The encryption key for each voice session is randomly generated and destroyed after the session ends. The proposed VoLTE secure communication method comprehensively and efficiently realizes the confidential transmission, authentication, signature and key negotiation of both sides of VoLTE communication, and takes into account the requirements of VoLTE voice transmission on transmission speed, voice quality and security.

Description

A VoLTE secure communication method

technical field

The invention relates to a VoLTE secure communication method to realize end-to-end voice encryption of voice on VoLTE, and belongs to the technical field of mobile communication security.

Background technique

At present, the 4G system in China and even the world has been relatively perfect, and the IMS operation voice network based on packet domain information transmission is gradually starting. The many advantages of packet domain information transmission make the transition from traditional telephone network to IP network a trend. If VoLTE is to be applied to people's daily call services in the future, the first consideration is its communication security. When the user equipment needs to access the IMS service network, it first needs to perform identity authentication. This authentication is based on a process called "IMS Authentication and Key Agreement" (IMSAKA). Since the SIP protocol itself lacks mandatory confidentiality and integrity protection, the IMS system requires user equipment to accept mandatory integrity protection when accessing the service network, and the key generated after IMSAKA negotiation is used for Establish this security association. After analysis, it is found that the security protection mechanism of the IMS network can well resist the registration hijacking attack, but the denial of service attack (DoS attack) may occur due to the lack of message security protection in the discovery process of the user in the P-CSCF. Therefore, the IMS The network has a certain ability to resist most of the existing attacks, but there are still relatively large security risks.

Because when the user accesses the packet domain, it needs to go through the IMSAKA key distribution process, and this process requires two independent authentications and network key distribution between the user equipment and the IMS network, and there are loopholes in it, which may lead to masquerading attacks. To solve this problem, we must optimize the existing key agreement mechanism. At present, in the end-to-end voice transmission process, it can be directly encrypted based on symmetric cipher. However, the disadvantage of the symmetric encryption algorithm is that the sending and receiving ends need to conduct key agreement before communication to ensure that the same key is used for encryption and decryption. Based on the above problems, Diffie and Hellman proposed the system of public key cryptography. Since the public key algorithm is mostly based on some computational complexity problems, many of which come from knowledge such as number theory, the algorithm realization of these problems often involves the operation of modulus multiplication or exponential operation, so compared with the traditional block cipher encryption method requires more computing resources. It can be seen from this that it is not a good method to use the public key algorithm to encrypt the voice data in the case of network voice transmission, which requires high real-time performance.

Based on the analysis of issues such as processing efficiency and security in the above technical methods, the present invention proposes a new VoLTE secure communication method, which involves symmetric encryption algorithms, asymmetric encryption algorithms, digital signature algorithms, and the like.

Symmetric encryption algorithm refers to the encryption algorithm that uses the same key for encryption and decryption. It requires the sender and receiver to agree on a key before secure communication. The security of the symmetric algorithm depends on the key. Leaking the key means that anyone can decrypt the messages they send or receive, so the secrecy of the key is very important.

The basic process of asymmetric encryption algorithm to realize the exchange of confidential information is: Party A generates a pair of keys and discloses one of them as a public key to other parties; Encrypted and then sent to Party A; Party A then uses another private key saved by itself to decrypt the encrypted information. Party A can only use its private key to decrypt any information encrypted by its public key, and the asymmetric encryption algorithm has better confidentiality.

A digital signature is a digital string that only the sender of the message can produce and cannot be forged by others. This digital string is also an effective proof of the authenticity of the message sent by the sender. The digital signature should have the following characteristics: the recipient can confirm or verify the signature of the sender, and no one can forge it. Digital signature is an encryption process, and digital signature verification is a decryption process. Digital signatures can ensure the integrity of information transmission, authenticate the identity of the sender, and prevent the occurrence of repudiation.

Contents of the invention

Technical problem: The present invention provides a VoLTE secure communication method that can further ensure the speed, quality and security of voice information transmission.

Technical solution: The VoLTE secure communication method of the present invention uses the symmetric encryption algorithm RC4 to encrypt the call voice data, and uses the asymmetric encryption algorithm RSA to digitally sign and verify the call voice data; the symmetric encryption key is passed through the asymmetric encryption algorithm The RSA public key is encrypted and then negotiated with the receiver.

Further, the concrete steps of the inventive method are as follows:

(1) The sender prepares the voice data information to be transmitted, performs digest calculation on the voice data information, obtains a message digest, then encrypts the message digest with an RSA private key to obtain a digital signature, and sends the digital signature attached to the voice data message;

(4) The sender generates a symmetric encryption key at random, and encrypts the voice data information with the digital signature with the symmetric encryption algorithm RC4 to form ciphertext;

(5) The sender encrypts the randomly generated symmetric encryption key with the RSA public key of the receiver, and transmits the encrypted key together with the ciphertext to the receiver;

(6) The recipient receives the ciphertext and the encrypted key, first decrypts the encrypted key with the RSA private key to obtain the symmetric encryption key, and then uses the symmetric encryption key to perform RC4 decryption on the ciphertext , get voice data information with digital signature;

(8) the receiver decrypts the digital signature in the voice data information obtained by deciphering the step (6) with the RSA public key of the sender, and obtains an information summary;

(9) the receiving party calculates the voice data information with digital signature obtained in the step (6) with the same abstract calculation method as step (1), to obtain a new information abstract;

(10) The receiver compares the new information summary with the information summary obtained by decrypting the step (8), if they are consistent, it means that the received voice information has not been tampered with, then trust the voice information and obtain its content, otherwise block The voice message.

Further, in the method of the present invention, the symmetric encryption key will be destroyed after the call ends.

Beneficial effect: compared with the prior art, the present invention has the following advantages:

In a voice communication system, the amount of communication voice data is generally relatively large, and the requirement for time delay is also high. By adopting the highly efficient symmetric encryption RC4 algorithm to encrypt communication voice data, it can better meet the requirements of VoLTE voice. The encryption key for each voice data encryption is encrypted and negotiated with the asymmetric RSA algorithm, which makes better use of the flexible and convenient features of asymmetric encryption and decryption.

The proposed VoLTE secure communication method comprehensively uses symmetric and asymmetric encryption and decryption methods, efficiently realizes the confidential transmission, authentication, signature and key negotiation of both sides of VoLTE communication, and takes into account the impact of VoLTE voice transmission on transmission speed and voice quality. and security requirements.

Description of drawings

FIG. 1 is an overall block diagram of a VoLTE secure communication method.

detailed description

The present invention will be further described below in conjunction with embodiment and accompanying drawing. VoLTE is an IP-based voice communication based on LTE mobile communication technology, and it is an important voice communication method in the future. It must first complete the access of the IMS protocol and the establishment of the basic communication link, and then realize the end-to-end voice data transmission.

According to Fig. 1, we describe the implementation process of the secure communication method on VoLTE. First, based on the VoLTE protocol, the sender is A and the receiver is B. The sender and receiver need to implement VoLTE IMS access and basic communication link establishment first. Its implementation steps are as follows:

(1) The sender A completes the two-way authentication with the service network through IMSAKA.

(2) A establishes communication with CSCF-A.

(3) Receiver B completes the two-way authentication with the service network through IMSAKA.

(4) B establishes communication with CSCF-B.

(5) A sends a session invitation request to CSCF-A.

(6) CSCF-A routes to CSCF-B by checking the relevant fields of the SIP request.

(7) CSCF-B sends a session invitation request to B.

(8) B confirms the session invitation request, and the call is established.

Next, establish a secure communication method:

(1) The sender A generates a random encryption key;

(2) The sender A performs digest calculation on the voice data information to obtain the message digest;

(3) The sender A encrypts the information summary with the RSA private key to obtain a digital signature, and attaches it to the voice data information;

(4) The sender A randomly generates a key, and encrypts the voice data information to be sent with the symmetric encryption algorithm RC4 to form a ciphertext;

(5) The sender A encrypts the previously randomly generated key with the RSA public key of the receiver, and transmits the encrypted key together with the ciphertext to the receiver;

(6) Receiver B receives the ciphertext and the encrypted key, first decrypts the encrypted key with the RSA private key, and obtains the symmetric encryption key;

(7) The receiver B uses the symmetric encryption key to decrypt the ciphertext by RC4 to obtain the plaintext voice data information;

(8) Receiver B decrypts the digital signature with the sender's RSA public key to obtain a message digest;

(9) Receiver B uses the same digest algorithm to calculate the plaintext to obtain a new message digest;

(10) Receiver B compares the new message digest with the received message digest, and if they are consistent, it means that the received voice message has not been tampered with.

(11) After the call ends, the symmetric encryption key used to encrypt voice data will be destroyed;

In this way, the voice information is encrypted and transmitted from the sender to the receiver based on VoLTE, effectively ensuring the security of the session.

The foregoing embodiments are only preferred implementations of the present invention. It should be pointed out that those skilled in the art can make several improvements and equivalent replacements without departing from the principle of the present invention. Technical solutions requiring improvement and equivalent replacement all fall within the protection scope of the present invention.

Claims (3)

1. A VoLTE secure communication method is characterized in that, the method uses symmetric encryption algorithm RC4 to encrypt call voice data, and simultaneously uses asymmetric encryption algorithm RSA to carry out digital signature and verification to call voice data; the key of symmetric encryption is passed The public key of the asymmetric encryption algorithm RSA is encrypted and then negotiated with the receiver. 2. A kind of VoLTE safe communication method as claimed in claim 1, is characterized in that, the specific steps of the method are as follows: (1) The sender prepares the voice data information to be transmitted, performs digest calculation on the voice data information, obtains a message digest, then encrypts the message digest with an RSA private key to obtain a digital signature, and sends the digital signature attached to the voice data message; (4) The sender generates a symmetric encryption key at random, and encrypts the voice data information with the digital signature with the symmetric encryption algorithm RC4 to form ciphertext; (5) The sender encrypts the randomly generated symmetric encryption key with the RSA public key of the receiver, and transmits the encrypted key together with the ciphertext to the receiver; (6) The recipient receives the ciphertext and the encrypted key, first decrypts the encrypted key with the RSA private key to obtain the symmetric encryption key, and then uses the symmetric encryption key to perform RC4 decryption on the ciphertext , get voice data information with digital signature; (8) the receiver decrypts the digital signature in the voice data information obtained by deciphering the step (6) with the RSA public key of the sender, and obtains an information summary; (9) the receiving party calculates the voice data information with digital signature obtained in the step (6) with the same abstract calculation method as step (1), to obtain a new information abstract; (10) The receiver compares the new information summary with the information summary obtained by decrypting the step (8), if they are consistent, it means that the received voice information has not been tampered with, then trust the voice information and obtain its content, otherwise block The voice message. 3. A VoLTE secure communication method according to claim 1 or 2, wherein the symmetric encryption key will be destroyed after the call ends.