System and method for printing postage

1. A method for conducting a web-based postage transaction, the method being implemented by a computer system, the method comprising:

providing, by the computer system, an applet embedded on a web page to a client computer, the embedded applet being provided in response to the client computer accessing the web page;

receiving, by the computer system, from the client computer, a request related to a postage transaction; and

causing, by the computer system, in response to the request, a validation check to be performed by providing a validation token to the embedded applet at the client computer to be validated by the embedded applet,

wherein, based on a determination by the embedded applet at the client computer that the validation token is valid, the embedded applet at the client computer is configured to execute at least a part of the request.

2. The method of claim 1 , wherein the request comprises a print request to print postage indicium, the method further comprising:

providing, by the computer system, postage indicium data representing the postage indicium to the embedded applet at the client computer such that the postage indicium data remains inaccessible by the client computer for rendering the postage indicium at a display device of the client computer; and

wherein, based on the determination by the embedded applet at the client computer that the validation token is valid, the embedded applet at the client computer executes at least part of the request by rendering the postage indicium to a printer in communication with the client computer without the postage indicium being rendered at the display device of the client computer.

3. The method of claim 1 , wherein receiving the request from the client computer comprises receiving, by the computer system, a print request from the embedded applet at the client computer.

4. The method of claim 1 , wherein the embedded applet at the client computer is configured such that, had the embedded applet determined that the validation token was not valid, the embedded applet would not have executed the request.

5. The method of claim 1 , wherein the validation token comprises a session identifying token that expires in response to a specified condition.

6. The method of claim 5 , wherein the specified condition is the expiration of a selected amount of time.

7. The method of claim 5 , wherein the specified condition is a disconnection between the computer system and the client computer.

8. The method of claim 1 , wherein the determination by the embedded applet at the client computer that the validation token is valid comprises the embedded applet (i) decrypting the validation token to produce a decrypted version and (ii) comparing the decrypted version against session information to determine that the validation token is valid.

9. The method of claim 1 , wherein the embedded applet is compiled from the embedded applet's source code that includes a plurality of reference host addresses,

wherein the validation check by the embedded applet at the client computer comprises using at least one of the plurality of reference host addresses to validate a host web server, of the computer system, to which the client computer is connected, and

wherein the embedded applet at the client computer executes at least part of the request further based on a determination by the embedded applet at the client computer that the host web server is a valid host web server.

10. A system for conducting a web-based postage transaction, the system comprising a computer system configured by computer program instructions that cause the computer system to:

provide an applet embedded on a web page to a client computer, the embedded applet being provided in response to the client computer accessing the web page;

receive, from the client computer, a request related to a postage transaction; and

cause, in response to the request, a validation check to be performed by providing a validation token to the embedded applet at the client computer to be validated by the embedded applet,

wherein, based on a determination by the embedded applet at the client computer that the validation token is valid, the embedded applet at the client computer is configured to execute at least a part of the request.

11. The system of claim 10 , wherein the request comprises a print request to print postage indicium, and wherein the computer system is caused to:

provide postage indicium data representing the postage indicium to the embedded applet at the client computer such that the postage indicium data remains inaccessible by the client computer for rendering the postage indicium at a display device of the client computer; and

wherein, based on the determination by the embedded applet at the client computer that the validation token is valid, the embedded applet at the client computer executes at least part of the request by rendering the postage indicium to a printer in communication with the client computer without the postage indicium being rendered at the display device of the client computer.

12. The system of claim 10 , wherein receiving the request from the client computer comprises receiving a print request from the embedded applet at the client computer.

13. The system of claim 10 , wherein the embedded applet at the client computer is configured such that, had the embedded applet determined that the validation token was not valid, the embedded applet would not have executed the request.

14. The system of claim 10 , wherein the validation token comprises a session identifying token that expires in response to a specified condition.

15. The system of claim 14 , wherein the specified condition is the expiration of a selected amount of time.

16. The system of claim 14 , wherein the specified condition is a disconnection between the computer system and the client computer.

17. The system of claim 14 , wherein the determination by the embedded applet at the client computer that the validation token is valid comprises the embedded applet (i) decrypting the validation token to produce a decrypted version and (ii) comparing the decrypted version against session information to determine that the validation token is valid.

18. The system of claim 14 , wherein the embedded applet is compiled from the embedded applet's source code that includes a plurality of reference host addresses,

wherein the validation check by the embedded applet at the client computer comprises using at least one of the plurality of reference host addresses to validate a host web server, of the computer system, to which the client computer is connected, and

wherein the embedded applet at the client computer executes at least part of the request further based on a determination by the embedded applet at the client computer that the host web server is a valid host web server.

19. One or more non-transitory computer-readable storage media comprising computer instructions that, when executed by one or more processors of a computer system, cause the computer system to perform operations comprising:

providing an applet embedded on a web page to a client computer, the embedded applet being provided in response to the client computer accessing the web page;

receiving, from the client computer, a request related to a postage transaction; and

causing, in response to the request, a validation check to be performed by providing a validation token to the embedded applet at the client computer to be validated by the embedded applet,

wherein, based on the embedded applet at the client computer (i) decrypting the validation token to produce a decrypted version and (ii) determining from the decrypted version that the validation token is valid, the embedded applet at the client computer is configured to execute at least part of the request.

20. The one or more non-transitory computer-readable storage media of claim 19 , wherein the embedded applet at the client computer is configured to compare the decrypted version against session information to determine whether the validation token is valid.