CN104901944A - Security protocol cipher-text information inference method based on main body interactive behavior - Google Patents

Abstract

The invention relates to a security protocol cipher-text information inference method based on main body interactive behavior, comprising the steps as follows: recognizing step information of a protocol related message in a network according to a specific message format, that is to recognize that some data message belongs to the No. N step in a protocol operation process, and adequately using a protocol specification format, a message which can be monitored in a network system, and data information such as user online interactive behavior, and so on to perform certain calculation and recover cipher text information in a protocol interaction process under the condition that cipher text information is not decoded. The security protocol cipher-text information inference method based on main body interactive behavior of the invention is suitable for security protocol using all kinds of cryptosystems and does not need to deploy and add a monitoring program on a monitor host. In a practical application, the security protocol cipher-text information inference method based on main body interactive behavior of the invention is wide in applied range, small in boundedness and fast in analysis speed, and is suitable for further strengthening monitor and management of the network and improving capacity of an information system to resist hostile attack.

Description

Based on the security protocol cipher-text information estimating method of main body interbehavior

Technical field

The present invention relates to network safety filed, particularly a kind of security protocol cipher-text information estimating method based on main body interbehavior.

Background technology

Protocol identification is the important step of a large amount of network security key application, as intrusion detection, network QoS, traffic monitoring, user behavior analysis etc., all significant for network manager, service provider, user.Message data Network Based, the protocol type that identifying information system adopts, and then analyze the key content that user interactions behavioural information is procotol identification, contribute to various network application implementing monitoring and management, effectively can reduce the security risk of systems face, promote the ability that information system resists malicious attack.Along with the extensive use of cryptographic technique, security protocol is widely applied in the various core in the Internet, crucial application, and various data in network traffics the proportion relevant to security protocol increases day by day.But network security protocol adopts cryptographic technique to be encrypted protection to key message in a large number, and the related data gathered in network comprises a lot of ciphertext item.Due to cryptographic algorithm to crack difficulty very large, can not resolve encrypt data when lacking correct key.Therefore only dependence message data can not complete the collection to some key messages, cannot obtain some key messages in message encrypt data.In network data, the protocol type that identifying information system adopts, and then the behavior of analysis user interactions contributes to strengthening various network application implementing monitoring and management, effectively can reduce the security risk of systems face, promotes the ability that information system resists malicious attack.But; along with the extensive use of cryptographic technique; security protocol adopts cryptographic technique to be encrypted protection to key message in a large number, result in the related data gathered in network and comprises the ciphertext item much cannot resolved, and this is that the management and control of the network information brings very large problem.

At present main existence two class methods are resolved to network message information: a class is the method for message flow information Network Based, and the method for analytic target, utilizes merely network traffics to resolve procotol with the network data flow collected; An other class is the method that based target mainframe program performs track, the method carries out binary dynamic trace analysis to the server program realizing procotol, by following the tracks of the handling process of binary file to message, message being resolved, the content recognition to a certain extent to cipher protocol can be realized at present.The analytical method of message flow information Network Based is mainly through catching network traffic data, based on flow port, clear data in load, the statistical natures of packet etc. are implemented to analyze, the method with the network data flow collected for analytic target, utilize merely network traffics to resolve procotol, but the method is only analyzed plaintext agreement at present, cannot process encrypt data, as depicted in figs. 1 and 2, based on famous network protocol analysis instrument Wireshark, ssl protocol encrypted handshake message message is resolved, it is ciphertext that Wireshark only can identify this message content, but encrypting messages all the other features any cannot be further analyzed and utilize, protocol-dependent application program running state feature on based target main frame, it is the another kind of thinking of network protocol analysis, these class methods by specific Binary analysis platform, by analyzing on main frame application program to the processing procedure of data and then infer the plaintext structure that ciphertext is corresponding and the cryptographic algorithm that ciphertext uses.Although these class methods can process encrypted message, but need on destination host, obtain the application information carried on an agreement, and dispose specific monitoring tool, and then the acquisition that could realize specific program running information, therefore, such method and technology realizes complicated, application limitation is larger, cannot really meet to data message monitoring requirements in network environment, and in actual applications, when obtaining target program, these class methods will lose efficacy.

Summary of the invention

For deficiency of the prior art, the invention provides a kind of security protocol cipher-text information estimating method based on main body interbehavior, make full use of protocol specification form, the message that can monitor in network system, and the data message of user's online interaction behavior, do not needing under the condition that cipher-text information is decrypted, calculating to a certain extent and recovery are carried out to the cipher-text information in protocol interaction process, be applicable to the security protocol adopting various cryptographic system, do not need to add monitoring facilities in monitoring main frame deploy, there is applied range, limitation is little, the advantages such as analysis speed is fast, contribute to the monitor and managment strengthened further network, promote the ability that information system resists malicious attack.

According to design provided by the present invention, a kind of security protocol cipher-text information estimating method based on main body interbehavior, comprises following steps:

Step 1. agreement initiator A sends message 1 to protocol responses side B, and message 1 comprises cipher text part if protocol responses side B receives after message 1 send message 2 to agreement third party S, decision message 1 expection of respective party B can be met; Message 2 comprises ciphertext item if send to the message 3 of agreement initiator A after agreement third party S receives message 2, decision message 2 expection of S, that is: X can be met _{1_2}=X _{2_2}; Message 3 comprises wherein, X _irepresent unknown variable, K _as, K _bs, K _abbe respectively the wildcard of the wildcard of agreement initiator A and agreement third party S, protocol responses side B and agreement third party S, the session key of agreement initiator A and protocol responses side B;

If step 2. is after message 1, message 2 and message 3, collect the message 4 that agreement initiator A sends to protocol responses side B, decision message three can meet the expection of agreement initiator A, judge X _{3_3}=X _{2_1}=X _{1_1}; Message 4 comprises ciphertext item with

If step 3. is after message 1, message 2, message 3 and message 4, collect the decrypt communications messages between protocol responses side B and agreement initiator A, then message 4 meets the expection of protocol responses side B, judges X _{4_1}=X _{3_1}=X _{3_5_1}, X _{4_2}=X _{3_5_2}, X _{4_3}=X _{4_4}=X _{3_4}=X _{2_3}=X _{3_5_3}.

Above-mentioned, main body comprises agreement initiator A, protocol responses side B and agreement third party S, terminate to gather the interacting message behavior between main body to conversation procedure from protocol conversation, calculate by the interbehavior of agreement running and cleartext information the information that in protocol interaction message, ciphertext comprises.

Beneficial effect of the present invention:

The present invention is according to specific message format, the Step Information of the agreement association message in network is identified, namely identify certain data message and belong to N number of step in agreement running, and make full use of protocol specification form, the message that can monitor in network system, and the data message such as user's online interaction behavior, do not needing under the condition that cipher-text information is decrypted, calculating to a certain extent and recovery are carried out to the cipher-text information in protocol interaction process, be applicable to the security protocol adopting various cryptographic system, do not need to add monitoring facilities in monitoring main frame deploy.The advantages such as in actual applications, have applied range, limitation is little, and analysis speed is fast, contribute to the monitor and managment strengthened further network, promote the ability that information system resists malicious attack.

Accompanying drawing illustrates:

Fig. 1 is the ssl protocol encrypted handshake message message schematic diagram that in prior art, wireshark gathers;

The protocol format schematic diagram that Fig. 2 resolves for the wireshark shown in Fig. 1;

Fig. 3 is calculation process schematic diagram of the present invention.

Embodiment:

Below in conjunction with accompanying drawing and technical scheme, the present invention is further detailed explanation, and describe embodiments of the present invention in detail by preferred embodiment, but embodiments of the present invention are not limited to this.

Embodiment one, see Fig. 3, the present embodiment, in conjunction with classical protocols reciprocal process, further illustrates the embodiment of the security protocol cipher-text information estimating method that the present invention is based on main body interbehavior, as follows:

$1.A\→B:ID\_A,{\{X_{1\_1},X_{1\_2}\}}_{K_{as}}$

$2.B\→S:ID\_A,ID\_B,{\{X_{2\_1},X_{2\_2}\}}_{K_{as}},{\{X_{2\_3},X_{2\_4}\}}_{K_{bs}}$

$3.S\→A:{\{X_{3\_1},X_{3\_2}\}}_{K_{as}},{\{X_{3\_3},X_{3\_4},{\left\{X_{3\_5\_1},X_{3\_5\_2},X_{3\_5\_3}\right\}}_{K_{bs}}\}}_{K_{ab}}$

$4.A\→B:{\{X_{4\_1},X_{4\_2},X_{4\_3}\}}_{K_{bs}},{\left\{X_{4\_4}\right\}}_{K_{ab}}$

In conjunction with the interbehavior of protocol specification, protocol body and the sequential relationship of internet message, detailed technology protocol step of the present invention is described below:

Step 1: if after message 1,2, collect the message 3 that S sends to A, description messages 2 meets the expection of trusted third party S, can judge X _{1_2}=X _{2_2}=ID_A, X _{2_4}=ID_B;

Step 2: if after message 1,2,3, collect the message 4 that A sends to B, description messages 3 meets the expection of main body A, can judge X _{3_2}=ID_B, X _{3_3}=X _{2_1}=X _{1_1}=N1, N1 are can not computational item, are only mark herein;

Step 3: if after message 1,2,3,4 completes, collect the decrypt communications messages between main body B and A, description messages 4 meets the expection of main body B, can judge X _{4_1}=X _{3_1}=X _{3_5_1}=Ks, X _{4_2}=X _{3_5_2}=ID_A, X _{4_3}=X _{4_4}=X _{3_4}=X _{2_3}=X _{3_5_3}=N2, wherein, N2, Ks are can not computational item, are only mark.

Based on above-mentioned computational process, can be following situation by whole protocol interaction Procedure recovery:

$1.A\→B:ID\_A,{\{N_1,ID\_A\}}_{K_{as}}$

$2.B\→S:ID\_A,ID\_B,{\{N_1,ID\_A\}}_{K_{as}},{\{N_2,ID\_B\}}_{K_{bs}}$

$3.S\→A:{\{Ks,ID\_B\}}_{K_{as}},{\{N_1,N_2,{\left\{Ks,ID\_A,N_2\right\}}_{K_{bs}}\}}_{K_{ab}}$

$4.A\→B:{\{Ks,ID\_A,N_2\}}_{K_{bs}},{\left\{N_2\right\}}_{K_{\mathrm{ab}}}$

The present invention is based on protocol interaction specification and main body interbehavior, cipher-text information can be recovered to a certain extent; For subject identity mark etc., can refer to cleartext information and obtain the item of occurrence, being referred to as can computational item; For pure cipher-text information such as random number N 1, N2, Ks, can judge whether to comprise in ciphertext identical item, being referred to as can not computational item.

The present invention is applicable to the security protocol adopting various password physique, does not need to add monitoring facilities, applied range in detection main frame deploy, limitation is little, analysis speed is fast, contributes to the monitor and managment strengthened further network, promotes the ability that information system resists malicious attack.

The present invention is not limited to above-mentioned embodiment, and those skilled in the art also can make multiple change accordingly, but to be anyly equal to the present invention or similar change all should be encompassed in the scope of the claims in the present invention.

Claims (2)

1., based on a security protocol cipher-text information estimating method for main body interbehavior, it is characterized in that: comprise following steps:

Step 1. agreement initiator A sends message 1 to protocol responses side B, and message 1 comprises cipher text part if protocol responses side B receives after message 1 send message 2 to agreement third party S, decision message 1 expection of respective party B can be met; Message 2 comprises ciphertext item if send to the message 3 of agreement initiator A after agreement third party S receives message 2, decision message 2 expection of agreement third party S, that is: X can be met _{1_2}=X _{2_2}, message 3 comprises wherein, X _{1_1}, X _{1_2}, X _{2_1}, X _{2_2}, X _{1_3}, X _{3_4}, X _{3_1}, X _{3_2}, X _{3_3}, X _{3_4}, X _{3_5_1}, X _{3_5_2}, X _{3_5_3}all represent unknown variable, K _as, K _bs, K _abbe respectively the wildcard of the wildcard of agreement initiator A and agreement third party S, protocol responses side B and agreement third party S, the session key of agreement initiator A and protocol responses side B;

If step 2. is after message 1, message 2 and message 3, collect the message 4 that agreement initiator A sends to protocol responses side B, decision message three can meet the expection of agreement initiator A, judge X _{3_3}=X _{2_1}=X _{1_1}; Message 4 comprises ciphertext item with

If step 3. is after message 1, message 2, message 3 and message 4, collect the decrypt communications messages between protocol responses side B and agreement initiator A, then message 4 meets the expection of protocol responses side B, judges X _{4_1}=X _{3_1}=X _{3_5_1}, X _{4_2}=X _{3_5_2}, X _{4_3}=X _{4_4}=X _{3_4}=X _{2_3}=X _{3_5_3}.

2. the security protocol cipher-text information estimating method based on main body interbehavior according to claim 1, it is characterized in that: main body comprises agreement initiator A, protocol responses side B and agreement third party S, from protocol conversation, gather the interacting message behavior between main body to conversation end, calculate by the interbehavior of agreement running and cleartext information the information that in protocol interaction message, ciphertext comprises.