CN100539555C - Electron post transmission method based on scalable message online protocol and credit mechanism - Google Patents

Abstract

Electron post transmission method based on scalable message online protocol and credit mechanism belongs to network safety filed.It is characterized in that: in method, utilized based on XMPP protocol of I M platform and ensured source identity authenticity effectively.On sending, Email message takes " pull-mode " transmission mode.In message transmitting procedure, utilize the IM platform to safeguard the feature of user online status, the transmission means of taking piecemeal transmission and transmit leg to combine with the direct-connected transmission of recipient.And, also invented unique credit mechanism is combined with the black and white lists strategy in the method, in real time the method that attack is taken precautions against to rubbish message.This method can be deployed at present widely used based on the XMPP protocol of I M platform.The server forwards that method adopts and the transmission plan of end-to-end direct-connected message transfer have alleviated original load of server, can not impact original IM service performance.

Description

Electron post transmission method based on scalable message online protocol and credit mechanism

Technical field

(Extensible Messaging and Presence Protocol, XMPP) electron post transmission method with credit mechanism belongs to Internet technical field, relates in particular to the technology of network security aspect based on the scalable message online protocol.

Background technology

Along with the development of Internet Internet with popularize, Email is convenient, fast with it, unique charm becomes one of indispensable means of communication in people's daily life cheaply.But Email brings greatly easily simultaneously to people, also demonstrates its defective that can not be ignored and hidden danger day by day, and especially spam is attacked.It has had a strong impact on people's normal interchange.At present, the source identity of a lot of spams is all forged, and this has brought very big influence just for Spam filtering, improvement work.And easy the having its source in of forging of source identity: the Email communications protocol lacks necessary ID authentication mechanism.Present most of Email host-host protocol adopts simple message transfer protocol (SMTP) (Simple Mail Transfer Protocol, SMTP) agreement.This agreement proposes when computer network is at the early-stage, is trusty between the user that the hypothesis that it proposes is to use Email to exchange.Based on this hypothesis, smtp protocol is not considered necessary authenticating user identification process at the beginning of design.Just because of the defective in this design, thereby caused present forgery source identity to carry out spreading unchecked of spam attack.

In order to solve source identity forgery problem in the Email service, proposed at present such as the order of expansion smtp protocol to support to send the Auth method of carrying out authentication before the Email; And expand SMTP heading information, and review Sender-ID, the DomainKey technology of Email service-domain identity authenticity in conjunction with the DNS technology.Yet because the Email service had been popularized already and be deep-rooted comprehensively, the improvement that such " legacy system " carried out is difficult to accomplish comprehensively promote and dispose.

In the face of so real situation, many researchers, even comprise that the maker of smtp protocol has proposed to redesign the idea that New Deal is supported the Email service, so that fundamentally solve the problem that existing Email service is run into.If we can find a kind of being widely used from existing communication tool based on the Internet, application mode and Email service class are seemingly, and the intercommunion platform that its communications protocol is safer, perfect, and make up one and the similar message mechanism of Email on this basis.So, this not only can effectively solve the problem in the existing Email service, and because such message mechanism is to be structured on the intercommunion platform of an extensive use already, and it has possessed certain user base, this is in that promote also can be relatively easy when disposing this message mechanism.The present invention be with at present same widely used and have authentication to ensure communication platform---(Instant Messaging, IM) platform be the basis to instant message, the electron post transmission method of a safety of structure.And on this basis, utilize credit mechanism to take precautions against those and utilize true identity to send the attack of rubbish message.

Summary of the invention

The objective of the invention is to by electron post transmission method that ensures source identity authenticity of IM platform construction.And on this basis, utilize credit mechanism to take precautions against those send rubbish message with true identity attack.

Here said IM platform is meant the IM service that makes up based on the XMPP communications protocol.The XMPP agreement is based on the Data Transport Protocol XML language, that take asynchronous system, and it is widely used in the IM service.Why select the platform based on this protocol of I M, its reason is: (1) this agreement designs based on the XML language.This makes its versatility and extensibility strong; (2) high safety.ID authentication mechanism that the XMPP agreement is built-in and security strategy have been contained the behavior of forged identity effectively, and then have guaranteed the true and reliable property of identity, and actual application also proved this authentication mechanism and security strategy implement in the deployment also relatively easy; (3) the customer group basis of certain scale is arranged.From 2000 so far, the whole world has nearly had more than 10000 mutual each other server of instant message be based on (comprising the Google Talk server) of XMPP protocol construction.This just formed one huge, based on the true and reliable XMPP network communication environment of identity, be convenient to our message mechanism deployment and popularization in the future.

Method thinking provided by the present invention is: our the e-mail system structure of design can be as shown in Figure 1.This transfer approach is based on the transmission of messages pattern of " pull-mode ": promptly for mail to be sent, the originator client does not directly send mail, but at first submit the request of posting a letter to server, server filters request according to our the rubbish message strobe utility based on credit mechanism of design.For the request of posting a letter that strobe utility stops, server is not accepted the mail that it this time will be sent; And for the addresser who checks by filtration, server receives it and transmits the email message of coming.If this moment, the recipient was also simultaneously online, then message directly is transmitted to the recipient.In addition, in order to improve the forward efficiency of server, will carry out passing through server forwards again after piecemeal is handled at transmit leg for the message that capacity is bigger; Simultaneously, if the recipient is also simultaneously online when sending mail, receiving-transmitting sides can be held consultation by server and be set up direct-connected end to end channel, and (mainly being under the situation of transmission block form message) cooperatively interacts with the server forwards channel and finish the transmission of mail in case of necessity.Then transfer to the transmitting-receiving client as for the maintenance of minute block state information and bring in maintenance.So both alleviated the forwarding and the state-maintenance burden of server, the original service performance of IM server is not affected; Simultaneously the recipient is got the mail immediately.

Simultaneously, this method has also designed unique method and has filtered rubbish message.Although the black and white lists strategy is the most simple and effective Spam filtering mechanism, in traditional Email environment, because shortage makes this strategy be difficult to play a role to effective guarantee of source identity authenticity.Equally, in classical inverse spam scheme, also proposed filtering policy, but source identity authenticity also is the precondition that at first must satisfy, otherwise is difficult to guarantee the accuracy of credit mechanism based on credit mechanism.By comparison, our invention based on XMPP protocol of I M platform on the Email service that makes up because its agreement makes the rubbish message assailant to attack by forged identity to the guarantee of authentication.This makes strobe utility and the credit mechanism of using black and white lists all obtain guarantee.This method has adopted the method that credit mechanism is combined with the black and white lists strategy to prevent and treat rubbish message and has attacked, and utilizes the real-time servicing of IM platform to user state information, can accomplish in real time attack to be taken precautions against.

The invention is characterized in: in method, utilized based on XMPP protocol of I M platform and ensured source identity authenticity effectively.On sending, Email message takes " pull-mode " transmission mode.In message transmitting procedure, utilize the IM platform to safeguard the feature of user online status, the transmission means of taking piecemeal transmission and transmit leg to combine with the direct-connected transmission of recipient.And, also invented unique credit mechanism is combined with the black and white lists strategy, in real time the method that attack is taken precautions against to rubbish message.

This method contains following steps successively:

Step (1) is at first carried out authentication with instant message IM server as user's transmit leg, so that set up maintenance state and transmission data communication channel;

Step (2), the user finishes writing of Email message by after the authentication of step (1), and transfers to the Client Agent transmission message of described IM;

Step (3), described IM client are submitted the forwards request to the IM server after receiving message, and this IM server checks that at first current existing how many requests of transmitting of transmit leg are rejected, and specifies the upper limit, then execution in step (5) if surpass, otherwise, execution in step (4) then;

Step (4), this IM server according in the described forwarding request of step (3) as user's transmit leg and recipient's information, use rubbish message filter method to filter rubbish message according to the following steps based on credit mechanism and black and white lists mechanism:

Step (4.1), the contacts list that user's white list information of collecting with the IM server constitutes is constructed a prestige network in the IM server;

Step (4.2), this IM server is the directed graph of source point based on one of the prestige net structure in the step (4.1) with the described user of step (4), oriented line between the node among the figure represents that existence is ready that the contact that exchanges concerns that the recipient in the step (4) is also contained in described contacts list of step (4.1) and the described directed graph of step (4.2) between the user;

Step (4.3), user's overall credit worthiness described in the calculation procedure (4.1) according to the following steps:

Step (4.3.1), the IM server is collected the prestige network that constitutes with described contacts list, determines the matrix T of a N * N, and wherein, N is illustrated in user's number of registering in this IM server, and the element in the matrix T satisfies following relational expression:

T _Ij=1/NumOfVote (i), when node i in the contacts list of node j,

Described node j is the transmit leg in the step (4.1), and node i is the recipient,

NumOfVote (i) represents node i is listed in the node number of the contacts list of controlling oneself,

T _Ij=0, other;

Step (4.3.2), by following formula calculate matrix T ':

T '=cT+ (1-c) E, wherein T is the matrix T described in the step (4.3.1), and c is the probable value of value between [0,1], and E represents the Boolean matrix of N * N and has only the element on the diagonal is 1,

Step (4.3.3), the characteristic value characteristic of correspondence vector of the absolute value maximum of compute matrix T ', each corresponding element is the overall credit worthiness of each node in this characteristic vector;

Step (4.4), computing node A is with respect to the local credit worthiness of node C as follows, and herein, node A is a transmit leg, and node C is the recipient:

Step (4.4.1) by the prestige network, is found out and is not more than the 3 reachable path S set et that jump between transmit leg node A and the recipient's node C _Path

Step (44.2) is for described S set et _Path, be calculated as follows the local credit worthiness of node A on every paths ${\mathrm{Local\; Value}}_{A\→C}^{\mathrm{path}}:$

${\mathrm{Local\; Value}}_{A\→C}^{\mathrm{path}}=\frac{\underset{i\∈T}{\mathrm{\Σ}}\mathrm{GlobalValue}\left(i\right)}{\left|\right|T\left|\right|},$ Wherein gather T and represent the node A set that other nodes except node A are formed to the reachable path of node C, the overall credit worthiness of GlobalValue (i) expression node i, ‖ T ‖ represents to gather the number of node among the T;

Step (4.4.3), according to the local credit worthiness of described node A to every reachable path of node C, the local credit worthiness LocalValue after the gathering of the relative node C of computing node A _{A → C}:

$\mathrm{Local}{\mathrm{Value}}_{A\→C}=\frac{\underset{i\∈{\mathrm{Set}}_{\mathrm{path}}}{\mathrm{\Σ}}{\mathrm{LocalValue}}_{A\→C}^i}{\left|\right|{\mathrm{Set}}_{\mathrm{path}}\left|\right|},$ ‖ Set wherein _Path‖ represents S set et _PathIn comprise the number of reachable path;

Step (4.5), judge the prestige type of user A according to following steps:

Step (4.5.1) is obtained the blacklist grade of user A, and the blacklist grade point is directly provided by other numbers of users that user A is piped off;

Step (4.5.2), if: the blacklist grade point is zero, and then user A is a domestic consumer; Otherwise, execution in step (4.5.3);

Step (4.5.3) is obtained the local credit worthiness of user A with respect to recipient user C, if less than the local credit worthiness threshold value of setting, then user A is the assailant; If: there is not local credit worthiness, then obtains overall credit worthiness, change step (4.5.4) over to;

Step (4.5.4), if: the blacklist grade point is less than the threshold value of the blacklist grade of setting, and then user A is a domestic consumer; Otherwise, execution in step (4.5.5);

Step (4.5.5) if the current letter number of refusing of user A is refused the letter threshold value less than what set, then is judged to be domestic consumer; Otherwise user A is the assailant;

Step (5) is if judge in the step (4) that user A is a domestic consumer, then receives the request of posting a letter of user A;

Step (6), if judge in the step (4) that user A is the assailant, the then refusal request of posting a letter, the refuse letter number current user A adds 1; If user A is current refuse that the letter number surpass to set refuse the letter threshold value, judge that then user A is a malicious attacker, find all users that user A listed in white list simultaneously, their letter number of refusing is added 1.

The IM server also judges that according to the blacklist of recipient's customization the transmit leg user is whether in this blacklist in described step (3), if the transmit leg user is in this blacklist, then transmit leg user's the current letter number of refusing is added 1, and refuse its forwards request.

Electron post transmission method based on XMPP and credit mechanism proposed by the invention, can widespread deployment to based on the XMPP protocol of I M platform, so that the service function of similar Email to be provided to the user, and avoid the attack of spam effectively, improve fail safe.Since this method be deployed at present widely used based on the XMPP protocol of I M platform, so on disposing and promoting, be out of question.In addition, the realization of this scheme just to the expansion of original communications protocol, can not impact original IM communication yet.And the transmission plan of server forwards that is adopted and end-to-end direct-connected transmission Email message has also alleviated original load of server, can the performance of original IM service not impacted.So this method is fully feasible.

Description of drawings

Fig. 1. based on the trusted Email service system structural representation of IM platform;

Fig. 2. based on the prestige network diagram of white list information structure;

Fig. 3. calculate the conditional equality that matrix T satisfies in the overall credit worthiness;

Fig. 4. calculate the matrix T that defines in the overall credit worthiness ' satisfied equation relation;

Fig. 5. calculate LocalValue in the local trust degree ^Path _{A → C}The computational methods schematic diagram;

Fig. 6. calculate LocalValue in the local trust degree _{A → C}The computational methods schematic diagram;

Embodiment

We mainly introduce a core mechanism of the present invention: based on the rubbish message filter method of credit mechanism and black and white lists strategy.For black and white lists information, we can extract white list information from the contact list information that each IM user submits to; And blacklist information we can obtain the interchange which user the user refuses by the Privacy Lists mechanism that the XMPP agreement provides.For credit mechanism, we need make up prestige network, prestige computation model, so that obtain user's credit worthiness.

For the foundation of prestige network, we are by user's white list information that server is collected, and promptly contact list information makes up the prestige network.By contacts list, we can obtain directed graph G as Fig. 2 ₁: (A → B) existence is ready that the contact that exchanges concerns (B is in the contacts list of A) to the oriented line between the node among the figure between the expression user.

For the prestige computation model, we have selected to calculate overall credit worthiness and local trust degree respectively based on overall credit worthiness and the prestige computation model of recommending based on the part.We adopt the rudimentary algorithm that calculates Google PageRank value to calculate overall credit worthiness.

The following description of computational algorithm of overall situation credit worthiness:

(1) server is collected the prestige network of contact list information such as Fig. 2, and the matrix T of definite N*N: wherein N represents the number of registered user in the IM service, and T _IjSatisfy the equation relation of Fig. 3, the node sum of the contacts list of controlling oneself is listed node i in NumOfVote among Fig. 3 (i) expression.

(2) establish matrix T ', it satisfies the equation relation of Fig. 4.

(3) the characteristic value characteristic of correspondence vector of the absolute value maximum of calculating T '.This characteristic vector is the overall credit worthiness of each node.

Calculate the computational methods following description of transmit leg node A with respect to the local credit worthiness of recipient's node C:

(1), finds out node C to being not more than the 3 reachable path S set et that jump between the node A by prestige network as Fig. 2 _Path

(2) for Set _PathIn every paths path, calculate the local credit worthiness LocalValue of A on this path ^Path _{A → C}, it satisfies the equation relation as Fig. 5.

(3) try to achieve local trust degree on every paths after, gather the local trust degree LocalValue that calculates the final relative C of A _{A → C}, it satisfies the equation relation as Fig. 6.

Claims (2)

1. based on the electron post transmission method of XMPP and credit mechanism, it is characterized in that: utilized based on XMPP protocol of I M platform and ensured that Email sends the authenticity of source identity, on sending, Email takes " pull-mode " transmission mode, in message transmitting procedure, utilize the IM platform to safeguard the feature of user online status, the transmission means of taking piecemeal transmission and transmit leg to combine with the direct-connected transmission of recipient, and, credit mechanism is combined with the black and white lists strategy, attack is taken precautions against to rubbish message in real time, and this method contains following steps successively:

Step (1) is at first carried out authentication with instant message IM server as user's transmit leg, so that set up maintenance state and transmission data communication channel;

Step (2), the user finishes writing of Email message by after the authentication of step (1), and transfers to IM Client Agent transmission message;

Step (3), described IM client are submitted the forwards request to the IM server after receiving message, and this IM server checks that at first current existing how many requests of transmitting of transmit leg are rejected, and specifies the upper limit, then execution in step (5) if surpass, otherwise, execution in step (4) then;

Step (4), this IM server according in the described forwarding request of step (3) as user's transmit leg and recipient's information, use rubbish message filter method to filter rubbish message according to the following steps based on credit mechanism and black and white lists mechanism:

Step (4.1), the contacts list that user's white list information of collecting with the IM server constitutes is constructed a prestige network in the IM server;

Step (4.2), this IM server is the directed graph of source point based on one of the prestige net structure in the step (4.1) with the described user of step (4), oriented line between the node among the figure represents that existence is ready that the contact that exchanges concerns that the recipient in the step (4) is also contained in described contacts list of step (4.1) and the described directed graph of step (4.2) between the user;

Step (4.3), user's overall credit worthiness described in the calculation procedure (4.1) according to the following steps:

Step (4.3.1), the IM server is collected the prestige network that constitutes with described contacts list, determines the matrix T of a N * N, and wherein, N is illustrated in user's number of registering in this IM server, and the element in the matrix T satisfies following relational expression:

T _Ij=1/NumOfVote (i), when node i in the contacts list of node j,

Described node j is the transmit leg in the step (4.1), and node i is the recipient,

NumOfVote (i) represents node i is listed in the node number of own contacts list,

T _Ij=0, other;

Step (4.3.2), by following formula calculate matrix T ':

T '=cT+ (1-c) E, wherein T is the matrix T described in the step (4.3.1), and c is the probable value of value between [0,1], and E represents the Boolean matrix of N * N and has only the element on the diagonal is 1,

Step (4.3.3), the characteristic value characteristic of correspondence vector of the absolute value maximum of compute matrix T ', each corresponding element is the overall credit worthiness of each node in this characteristic vector;

Step (4.4), computing node A is with respect to the local credit worthiness of node C as follows, and herein, node A is a transmit leg, and node C is the recipient:

Step (4.4.1) by the prestige network, is found out and is not more than the 3 reachable path S set et that jump between transmit leg node A and the recipient's node C _Path

Step (4.4.2) is for described S set et _Path, be calculated as follows the local credit worthiness of node A on every paths $\mathrm{LocalValu}{e}_{A\→C}^{\mathrm{path}}:$

$\mathrm{LocalValu}{e}_{A\→C}^{\mathrm{path}}=\frac{\underset{i\∈T}{\mathrm{\Σ}}\mathrm{GlobalValue}\left(i\right)}{\left|\right|T\left|\right|},$ Wherein gather T and represent the node A set that other nodes except node A are formed to the reachable path of node C, the overall credit worthiness of GlobalValue (i) expression node i, ‖ T ‖ represents to gather the number of node among the T;

Step (4.4.3), according to the local credit worthiness of described node A to every reachable path of node C, the local credit worthiness LocalValue after the gathering of the relative node C of computing node A _{A → C}:

$\mathrm{LocalValu}{e}_{A\→C}^{\mathrm{path}}=\frac{\underset{i\∈{\mathrm{Set}}_{\mathrm{path}}}{\mathrm{\Σ}}L{\mathrm{ocal\; Value}}_{A\→C}^i}{\left|\right|{\mathrm{Set}}_{\mathrm{path}}\left|\right|},$ ‖ Set wherein _Path‖ represents S set et _PathIn comprise the number of reachable path;

Step (4.5), judge the prestige type of user A according to following steps:

Step (4.5.1) is obtained the blacklist grade of user A, and the blacklist grade point is directly provided by other numbers of users that user A is piped off;

Step (4.5.2), if: the blacklist grade point is zero, and then user A is a domestic consumer; Otherwise, execution in step (4.5.3);

Step (4.5.3) is obtained the local credit worthiness of user A with respect to recipient user C, if less than the local credit worthiness threshold value of setting, then user A is the assailant; If: there is not local credit worthiness, then obtains overall credit worthiness, change step (4.5.4) over to;

Step (4.5.4), if: the blacklist grade point is less than the threshold value of the blacklist grade of setting, and then user A is a domestic consumer; Otherwise, execution in step (4.5.5);

Step (4.5.5) if the current letter number of refusing of user A is refused the letter threshold value less than what set, then is judged to be domestic consumer; Otherwise user A is the assailant;

Step (5) is if judge in the step (4) that user A is a domestic consumer, then receives the forwarding request of user A;

Step (6), if judge in the step (4) that user A is the assailant, then refusal is transmitted request, the refuse letter number current user A adds 1; If user A is current refuse that the letter number surpass to set refuse the letter threshold value, judge that then user A is a malicious attacker, find all users that user A listed in white list simultaneously, their letter number of refusing is added 1.

2. the electron post transmission method based on XMPP and credit mechanism according to claim 1, it is characterized in that, the IM server also judges that according to the blacklist of recipient's customization the transmit leg user is whether in this blacklist in described step (3), if the transmit leg user is in this blacklist, then transmit leg user's the current letter number of refusing is added 1, and refuse its forwards request.

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