Controlling data transmission

1. A method of controlling transmission of data over a data network, the method comprising:

authenticating a first user of a client system with a server system;

sending to the server system, a request message comprising data corresponding to a first group of user identifiers corresponding to a plurality of proposed recipients;

determining one or more updates to the group of user identifiers based at least in part on:

a group score based on a similarity measure indicative of a degree of overlap between the first group of user identifiers and a second group of user identifiers associated with an historical data package, the second group of user identifiers comprising a user identifier corresponding to the first user; and

a user score for a second user identifier in the second group based on the group score and access data indicative of a time at which the second user accessed a payload associated with the historical data package;

transmitting a control message to the client system, the control message comprising data indicative of the one or more updates to the group of user identifiers;

generating an updated group of user identifiers based on the data of the control message;

constructing a data package comprising a set of recipients based on the updated group of user identifiers; and

transmitting the data package to the set of recipients.

2. The method of controlling transmission of data according to claim 1 , wherein the one or more updates indicate that the second user identifier should be removed from the first group of user identifiers when the user score satisfies a removal condition and the first group of user identifiers includes the second user identifier.

3. The method of controlling transmission of data according to claim 1 , wherein the one or more updates indicate that the second user identifier should be added to the first group of user identifiers when the user score satisfies an addition condition and the first group of user identifiers does not include the second user identifier.

4. The method of controlling transmission of data according to claim 1 , wherein the historical data package is associated with a graph data structure which defines a relationship between the second group of user identifiers, the historical data package, the access data, and transmission data associated with a time at which the second historical data package was transmitted.

5. The method of controlling transmission of data according to claim 1 , wherein the second group of user identifiers is associated with a second historical data package, the method further comprising updating the group score for the second group of user identifiers based on the similarity measure and transmission data indicating a time at which the second historical data package was transmitted.

6. The method of controlling transmission of data according to claim 5 , further comprising updating the user score for the second user identifier in the second group of user identifiers based on access data indicating a time at which the second user accessed the second historical data package.

7. The method of controlling transmission of data according to claim 1 , wherein the similarity measure is calculated according to:

J

=



r

⋂

u

r

⋃

u



wherein r is the first group user identifiers and u is the second group of user identifiers.

8. The method of controlling transmission of data according to claim 1 , wherein the group score for the second group of user identifiers is updated based on a transmission decay function which is a function of the time that has elapsed since the time at which the historical data package was transmitted.

9. The method of controlling transmission of data according to claim 8 , wherein the transmission decay function is calculated according to:

1

+

tanh

⁡

(

-

Δ

⁢

⁢

D

t

+

α

1

β

1

)

wherein ΔD t is the number of days since the time at which the second data package was transmitted and α 1 and β 1 are tuneable parameters.

10. The method of controlling transmission of data according to claim 1 , wherein the user score for the second user identifier in the second group of user identifiers is updated based on an access decay function which is a function of the time that has elapsed since the time at which the second user accessed the payload associated with the historical data package.

11. The method of controlling transmission of data according to claim 10 , wherein the access decay function is calculated according to:

Θ

⁡

[

1

+

tanh

⁡

(

-

Δ

⁢

⁢

D

a

+

α

2

β

2

)

]

wherein ΔD a is the number of days since the time at which the second user accessed the payload associated with the historical data package and Θ, α 2 , and β 2 , are tuneable parameters.

12. The method of controlling transmission of data according to claim 1 , wherein the historical data package is an email message and the payload associated with the historical data package is content contained in a body of the email message.

13. The method of controlling transmission of data according to claim 1 , wherein the payload associated with the historical data package is an encrypted payload and the time indicated by the time at which the second user accessed the payload associated with the second data package corresponds to the time of receipt of a request from the second user to access the encrypted payload.

14. A non-transitory computer-readable storage medium comprising computer-executable instructions which, when executed by a processor, cause a computing device to perform a method of controlling transmission of data according to claim 1 .

15. A system for controlling transmission of data, the system comprising one or more processors; and a memory configured to store computer-executable instructions which, when executed by the one or more processors, cause the system to perform a method of controlling transmission of data according to claim 1 .