WO2007048301A1

WO2007048301A1 - A encryption method for ngn service

Info

Publication number: WO2007048301A1
Application number: PCT/CN2006/001922
Authority: WO
Inventors: Cheng Chen
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-10-24
Filing date: 2006-08-01
Publication date: 2007-05-03
Also published as: CN1956443A

Abstract

A encryption method for NGN service in the network communication technology, both parties end-to-end negotiate the encryption parameter on the bearing network, encrypt the transmission for the specific portion of the transferring media flow according to the negotiated the encryption parameter, it is advantageous for the compatible interconnection between the different devices as well as large-scale commercial operation. By the end-to-end negotiation function supporting the encryption parameter, the present invention may flexibly negotiate the parameters including whether supporting the negotiation function, the negotiation algorithm, the cryptographic key and the encryption object and the like between the media devices using IP bearing, the soft switching control devices and the like do not need to control such negotiation course, increase the adaptability of the encryption transmission, also improve the service security of IP network.

Description

Encryption method for NGN service

Technical field

The present invention relates to the field of network communication technologies, and in particular, to an encryption method for an NGN service.

Background of the invention

NGN (Next Generation Network) is a packet-based network that can provide telecommunication services and utilizes multiple broadband capabilities and QoS (Quality of Service) guarantees. The typical networking application is shown in Figure 1, where softswitch is The device responsible for call control; the media gateway is responsible for TDM-IP (Time Division Multiple Access Internet Protocol) bearer media conversion device; MRS (Media Resource Server) is to provide functions such as playback, number collection, multi-party conference; NGN business;

These devices are connected to the IP network and communicate with each other via IP bearer media. The main media message format is:

IP protocol part UDP (User Datagram Protocol) protocol part ~~ RTP (Real-Time Transport Protocol) protocol part - voice data part.

User service information transmitted over an IP network includes voice, video, data, and in-band signaling such as DTMF (Dual Tone Multi-Frequency). Since the IP network is more likely to be intercepted and stolen than the information on the TDM network, there is a great security risk in transmitting user service information directly on the IP network. There are two aspects to this security risk: on the one hand, the user's voice, video, and data information may be monitored; on the other hand, the user's confidential information is stolen, such as the user's telephone bank account number and password being stolen. Even a dedicated IP network, such as a network management device connected to an IP network, can steal confidential information from users.

Therefore, in order to ensure the security of NGN service transmission, it is necessary to provide an encrypted transmission function for the NGN user's service information. The existing technologies for encrypted transmission mainly include the following three types:

The first is IPSec (IP Encryption Protocol) encrypted transmission technology:

IPSec encryption technology is a universal encryption transmission technology on IP networks. It encrypts all the content above the IP protocol layer. The encryption algorithm and key can be configured on the device or exchanged by IKE (key exchange) protocol. Key, see definition in protocols such as RFC2401;

Since this encryption technology is a pure IP transport layer encryption, not an encryption technology specifically for NGN services, the IPSec encryption transmission technology has the following disadvantages -

1. It is necessary to encrypt all the data above the entire IP protocol layer. The amount of data encrypted and decrypted is huge, and the system processing capability is very high. After the IPSec encryption process, the system performance is reduced by at least half;

2. Calls on the same IP address always use the same key and encryption algorithm, which is not secure enough. In view of the above IPSec encryption transmission technology, at present, another transmission technology that only encrypts user data is proposed:

This technology only encrypts user service data, and voice messages in the following formats:

The IP protocol part - the UDP protocol part - the RTP protocol part - the voice data part,

Only the "voice data part" is encrypted, and the encryption algorithm is fixed on the NGN device; the encryption key can be dynamically allocated, and the soft exchange is passed to the encryption device when the call is established.

Taking the communication between the media gateway and the IP terminal as an example, the process is as shown in FIG. 2. At the beginning of the call, the softswitch generates a key, and when the media resource is allocated by the H.248 protocol to control the media gateway, the encryption key is also specified. The default encryption algorithm encrypts all data; then, during the call setup with the IP terminal, the IP terminal is also notified of the encryption key, generally using the SIP (Session Initiation Protocol) protocol; after the call is established, both the media gateway and the IP terminal are obtained. The key, you can encrypt and decrypt the media stream.

It can be seen that although the above technology for encrypting and transmitting user data is different from IPSec encryption technology, each call can use a different encryption key, the security is improved, and only the data portion is encrypted, and the amount of encryption is reduced. However, the following still exists. Disadvantages:

1. Only use a fixed encryption algorithm, requiring all devices in the system to use the same encryption algorithm, which is not secure enough;

2. Encrypt each data packet in the call media stream, which requires high processing power of the system, and cannot select some key information to be encrypted. The amount of data encrypted and decrypted is large, and the system processing capability is high;

3. The encryption process is controlled by softswitch. Softswitch is required to understand the encryption capabilities of different media gateways and IP terminal devices, which increases the complexity of softswitches. Moreover, IP terminals are diverse and difficult to be completely unified.

Currently, the third method provided is the RTP (Real-Time Transport Protocol) encryption method defined by RFC3711.

SRTP is an end-to-end encryption and authentication method for voice services carried by RTP. It uses the AES (Advanced Data Encryption Algorithm) encryption algorithm to encrypt the message content and supports authentication at the RTP protocol layer.

The shortcomings of the prior art 3 are basically the same as those of the prior art 2. The fixed encryption algorithm requires that all the systems support the decryption algorithm to be used; each message is encrypted, the amount of encryption is large, and the efficiency is affected.

Therefore, it is necessary to provide a method for more effectively ensuring the security of NGN service transmission.

Summary of the invention

In view of the above problems in the prior art, the object of the present invention is to provide an encryption method for an NGN service. The two parties encrypt the encryption parameters end-to-end on the IP bearer network, and encrypt the media stream by using encryption parameters supported by both ends. Transmission improves the security of network transmission.

The object of the invention is achieved by the following technical solutions - An encryption method for an NGN service, including:

The encryption parameters are negotiated end-to-end between IP devices, and the parts of the media stream that need to be encrypted are encrypted and transmitted according to the encryption parameters confirmed by negotiation.

The encryption method specifically includes:

A. The calling party initiates encryption parameter negotiation;

B. After receiving the above negotiation, the called party selects the encryption parameter supported by the local end and returns to the calling party;

C. The calling party confirms the encryption parameter selected by the called party, and the encryption negotiation is successful, and the specific part of the media stream is encrypted and transmitted by using the negotiated encryption parameter.

The step A further includes: before initiating the encryption parameter negotiation:

The calling party configures or uses the key exchange protocol. IKE sets the key a used to encrypt the key information in the signaling during the encryption negotiation process and the encryption algorithm a of the key a.

The step A further includes:

The calling party allocates IP resources for the calling service and reserves the encrypted resources.

The step A further includes: the softswitch receives the encrypted parameter negotiation message of the calling party, and transparently transmits the message to the called party, and the softswitch does not participate in the negotiation process.

The encryption parameter in the negotiation of the encryption parameter initiated by the calling party in the step A is a plurality of encryption parameter sequences that can be selected by the called party.

The encryption parameters include: acknowledgment encryption, acknowledgment not encryption, encryption algorithm, key, and/or encryption object. The encryption method further includes:

D. Determine whether the calling party requests to modify the encryption parameter, and then re-initiate the encryption parameter negotiation process.

The encryption method further includes:

If the renegotiation is unsuccessful, the original negotiated encryption parameters are retained.

It can be seen from the technical solution provided by the present invention that the present invention can flexibly negotiate whether to support the encryption function, the encryption algorithm, the key, and the encryption object between the media devices using the IP bearer by supporting the end-to-end negotiation function of the encryption parameters. Control parameters such as encryption parameters and softswitches do not need to control this negotiation process, which increases the flexibility of encrypted transmission and improves the service security of the IP network.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic diagram of networking of a prior art NGN network;

2 is a flow chart showing another operation of an encryption method in the prior art; Figure 3 is a flow chart showing the operation of the method of the present invention.

Mode for carrying out the invention

The core idea of the present invention is to provide an NGN service encryption method, which encrypts the end-to-end negotiation of the IP bearer network, whether encryption, encryption algorithm, key and encrypted object, and increases the reliability and flexibility of encryption.

The present invention provides an NGN service encryption method, which is described by taking a media gateway and an IP terminal as an example. The method is applicable to communication between devices in the NGN and IMS domains that carry IP media over the IP interface. The operation flow of the method is as shown in FIG. 3, and specifically includes the following steps: Step 10: The encryption algorithm a and the key a of the configuration key are used to encrypt the encryption key in the call negotiation process. '

Configure the encryption algorithm a and key a on the media gateway and IP terminal, or use RFC2409

IKE (key exchange) protocol negotiation key a.

The key a is used to encrypt the key b information in the signaling during the encryption negotiation process. If the key and the encryption algorithm in the negotiation process are stolen, the encryption of the media stream may be cracked.

Softswitches do not participate in this encryption process.

Step 11: Start the call. When the softswitch receives the call, it notifies the media gateway to allocate the IP resource. The media gateway initiates the negotiation of the encryption parameter in the response message.

The softswitch and the media gateway generally use the H.248/MGCP (Media Gateway Control Protocol) protocol to communicate. The softswitch and the IP terminal generally use the SIP/H.323 protocol to communicate. The following uses the commonly used H.248 and SIP protocols as an example. The call setup process using these protocols follows the standard protocol.

After receiving the call, the softswitch uses the H.248 protocol to notify the media gateway to allocate IP resources, that is, assign an IP address and port number for receiving and transmitting the media stream, and the softswitch also needs to notify the media gateway to reserve the encrypted resource.

After receiving the message sent by the softswitch, the media gateway reserves the ciphering resource, sends the acknowledgment message, and initiates the ciphering parameter negotiation, which can be implemented by carrying the ciphering parameter in the SDP (Session Description Protocol) of the acknowledgment message, in the SDP protocol. The encryption parameters carried include: an encryption calculation b, a key b, and an encryption object, and the media gateway can provide a plurality of the encryption parameter sequences selectable by the other party.

The encryption algorithm may be an encryption algorithm such as RSA (Public Key Algorithm), DES (Data Encryption Standard Algorithm), AES (Advanced Data Encryption Algorithm), RC4, or the like.

The key b is generated in accordance with the requirements of the encryption algorithm.

The encryption object refers to which part of the media stream is encrypted, and may be: an encrypted 2833 message, an encrypted T38 fax data, an encrypted Modem data, an encrypted G.711 A voice code, etc., and the encrypted object may be pressed by PT. (Load type) to distinguish, the PT is a parameter that distinguishes different message types in the media stream, and different encryption objects can be identified by PT.

The key b, the field is encrypted and encrypted according to the encryption algorithm a and the key a configured in step 10. The encryption algorithm a and the encryption algorithm b may be different algorithms, and the key a and the key b should be different.

In this embodiment, the call initiated by the media gateway side is the same as the call initiated by the IP terminal. The SDP of the request message carries the encryption parameter and initiates the negotiation. The process is the same as the negotiation process initiated by the media gateway.

Step 12: After receiving the encryption parameter negotiation message of the media gateway, the softswitch transparently transmits the negotiated encryption parameter to the IP terminal.

In this process, the softswitch is only a transparent transmission parameter and does not participate in negotiation. The negotiation process is performed end-to-end between the media gateway and the IP terminal.

The media gateway uses the H.248 protocol. When the IP terminal uses the SIP protocol, the softswitch only needs to send the SDP in the H.248 protocol message to the IP terminal through the SIP protocol.

Step 13: After receiving the negotiation request message, the IP terminal selects the encryption parameter supported by the device in the encryption parameter carried in the SDP, and returns the selected encryption parameter to the softswitch in the response message through the SIP protocol.

The IP terminal selects the encryption parameter used for the current call from the request SDP according to the encryption algorithm and encryption capability supported by the device. If no encryption is used, no encryption parameter is returned. .

The encryption parameters selected by the IP terminal include: Encryption algorithm! ), key c, encrypted object. The key c and the key b may be different, and the key c herein refers to the decryption key. The key c is different from the key b, indicating that the upstream and downstream media streams of the call use different keys.

Step 14: After receiving the response message from the IP terminal, the softswitch notifies the media gateway of the negotiation result.

The softswitch confirms the negotiated encryption parameter through the Modify message of the H.248 protocol. If the media gateway accepts the negotiation result, the negotiation succeeds and sends an acknowledgement message to the softswitch. If the negotiation result is not accepted, the negotiation is unsuccessful. User service requirements, you can suspend the service or not encrypt the call.

Step 15: During the call progress, the specific part of the media stream is encrypted and decrypted according to the negotiated encryption parameters.

Step 16: During the call progress, either party can modify the encryption parameters as needed.

During the call progress, if one party requests to modify the encryption parameters, the encryption parameter negotiation process may be re-initiated. Taking the IP terminal to initiate the renegotiation as an example, if the IP terminal requests to change the encryption parameter, the cryptographic parameter negotiation request is sent to the softswitch through the SIP protocol, and the softswitch then sends the cryptographic parameter negotiation request to the media gateway through the H.248 protocol. The media gateway selects the encryption parameter supported by the local end in the received encryption parameter, modifies the current encryption parameter, returns the modified encryption parameter to the softswitch, and finally sends it to the IP terminal, and the re-negotiation is completed.

If the renegotiation is unsuccessful, that is, the media gateway does not accept the encryption parameters provided by the IP terminal during the renegotiation process, the original encryption parameters are retained.

If the media gateway initiates renegotiation, the softswitch is notified by the H.248 Notify message, which is the same as the renegotiation process initiated by the IP terminal.

In summary, the present invention can flexibly negotiate whether to support encryption functions, encryption algorithms, encryption parameters such as encryption keys, encryption keys, etc., softswitch, etc., by supporting end-to-end negotiation functions of encryption parameters. The control device does not need to control this negotiation process, which increases the flexibility of the encrypted transmission and improves the service security of the IP network.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Rights request

An encryption method for an NGN service, which is characterized by comprising:

The method for encrypting an NGN service according to claim 1, wherein the encryption method specifically includes:

A. The calling party initiates encryption parameter negotiation;

C. The calling party confirms the encryption parameter selected by the called party, and the encryption negotiation succeeds, and the specific part of the media stream is encrypted and transmitted by using the negotiated encryption parameter.

The method for encrypting an NGN service according to claim 2, wherein the step A further includes: before initiating the encryption parameter negotiation:

The method for encrypting an NGN service according to claim 2, wherein the step A further comprises: the calling party allocates an IP resource for the call service, and reserves an encrypted resource at the same time.

The method for encrypting an NGN service according to claim 2, wherein the step A further comprises: receiving, by the softswitch, an encryption parameter negotiation message of the calling party, and transparently transmitting the message to the called party, the softswitch Do not participate in the negotiation process.

The encryption method of the NGN service according to claim 2, wherein the encryption parameter in the negotiation of the encryption parameter initiated by the calling party in the step A is a plurality of encryption parameter sequences selectable by the called party.

The method for encrypting an NGN service according to any one of claims 1 to 6, wherein the encryption parameter comprises: confirming encryption, confirming no encryption, encrypting algorithm, key, and/or encrypting object. .

The method for encrypting an NGN service according to claim 2, wherein the encryption method further comprises:

The encryption method for an NGN service according to claim 8, wherein the encryption method further comprises: if the renegotiation is unsuccessful, retaining the originally negotiated encryption parameter.