System and method for sending secure messages

Abstract

Electronic messages are sent from a sending system to an identified recipient and are encrypted using information contained in a certificate for that recipient. An electronic device and method are provided for detecting receipt of a command to initiate transmission of a composed message to a recipient, and after said detection but prior to transmitting the message, determining that no valid digital certificate for said recipient is available at the communication device; retrieving a valid digital certificate for said recipient from a source over a network; and encrypting said composed message using the valid digital certificate; then initiating transmission of the encrypted, composed message to the recipient. Retrieval of the valid digital certificate can include repeated retrieval and validation of certificates until a valid certificate is obtained.

1 . A method, comprising:
 detecting, at an communication device, a command to initiate transmission of a composed message to a recipient;   after detection of said command and prior to said transmission, the communication device:
 determining that no valid digital certificate for said recipient is available at the communication device; 
 retrieving a valid digital certificate for said recipient from a source over a network; and 
 encrypting said composed message using the valid digital certificate; and 
   initiating transmission of the encrypted composed message to the recipient.   
     
     
         2 . The method of  claim 1 , wherein said command comprises selection of a send option of a messaging application executing at the communication device. 
     
     
         3 . The method of  claim 2 , wherein said determining is carried out by said messaging application. 
     
     
         4 . The method of  claim 2 , wherein said determining, retrieving and encrypting are carried out by said messaging application. 
     
     
         5 . The method of  claim 1 , wherein said retrieving comprises:
 obtaining a digital certificate from a first source; and   if it is determined that said digital certificate is invalid, repeating said obtaining from a further source until a valid digital certificate is obtained.   
     
     
         6 . The method of  claim 1 , wherein said determining comprises querying a certificate status provider for a status of a digital certificate currently stored at the communication device. 
     
     
         7 . The method of  claim 5 , wherein said retrieving further comprises querying a certificate status provider for a status of the digital certificate obtained from the first source. 
     
     
         8 . The method of  claim 1 , further comprising determining, prior to said encrypting, that the composed message is to be sent in encrypted form to the recipient. 
     
     
         9 . The method of  claim 8 , wherein said determining that the composed message is to be sent in encrypted form is carried out after said detection and prior to determining that no valid digital certificate for said recipient is available. 
     
     
         10 . The method of  claim 1 , wherein said retrieving is carried out at least in part over a wireless network. 
     
     
         11 . An electronic device, comprising:
 a memory adapted to store one or more digital certificates;   a communication subsystem;   a processor in communication with the memory and the communication subsystem, the processor being configured to:
 detect a command to initiate transmission of a composed message to a recipient; 
 after detection of said command and prior to said transmission:
 determine that no valid digital certificate for said recipient is available in the memory; 
 retrieve, using the communication subsystem, a valid digital certificate for said recipient from a source over a network; and 
 encrypt said composed message using the valid digital certificate; and 
 
 initiate transmission of the encrypted composed message to the recipient. 
   
     
     
         12 . The electronic device of  claim 11 , wherein the processor is configured to execute a messaging application, and said command comprises selection of a send option of the messaging application. 
     
     
         13 . The electronic device of  claim 12 , wherein the processor is configured to carry out said determining through execution of the messaging application. 
     
     
         14 . The electronic device of  claim 12 , wherein the processor is configured to carry out said determining, retrieving and encrypting through execution of the messaging application. 
     
     
         15 . The electronic device of  claim 11 , wherein the processor is configured to retrieve the valid digital certificate by:
 obtaining a digital certificate from a first source; and   if it is determined that said digital certificate is invalid, repeating said obtaining from a further source until a valid digital certificate is obtained.   
     
     
         16 . The electronic device of  claim 11 , wherein the processor is configured to query a certificate status provider for a status of a digital certificate currently stored at the electronic device to determine that no valid digital certificate for said recipient is available. 
     
     
         17 . The electronic device of  claim 15 , wherein the processor is further configured to query a certificate status provider for a status of the digital certificate obtained from the first source. 
     
     
         18 . The electronic device of  claim 17 , wherein the processor is further configured to determine, prior to encrypting the composed message, that the composed message is to be sent in encrypted form to the recipient. 
     
     
         19 . The electronic device of  claim 18 , wherein the processor is configured to determine that the composed message is to be sent in encrypted form after said detection and prior to determining that no valid digital certificate for said recipient is available. 
     
     
         20 . The electronic device of  claim 11 , wherein the electronic device is a wireless electronic device.