# US 7,613,304 B2 · System and method for sending encrypted messages to a distribution list > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,304 B2 - Document ID: US7613304B2 - Status: Granted - Kind: B2 - Application number: 11/073,677 - Filed: 2005-03-08 - Published: 2006-09-14 - Granted: 2009-11-03 - Earliest claimed: 2005-03-08 - Assignees: Research In Motion Limited - Inventors: Neil P. Adams; Michael S. Brown; Michael K. Brown - Web page: https://patentgrep.com/patent/US7613304B2 ## CPC - H04L 51/48: Message addressing, e.g. address format or anonymous messages, aliases - H04L 9/3263: {involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements (network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823)} - H04L 51/214: using selective forwarding - H04L 63/0442: {wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30)} - H04L 51/066: Format adaptation, e.g. format conversion or compression - H04L 2209/80: Wireless - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A system and method for sending encrypted messages to a distribution list that facilitates the sending of such messages only to individuals or other entities associated with the distribution list that will be able to read the message. In one embodiment, the method comprises the steps of: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the respective member address is available on the computing device; encrypting the message to each member identified by the one or more member addresses for which a public key for the respective member is available on the computing device; sending the encrypted message to the distribution list address if each of the one or more member addresses associated with the distribution list identifies a member for which a public key is available on the computing device; and sending the message to each of the one or more member addresses that identifies a member for which a public key is available on the computing device otherwise. ## Claims ### Claim 1 A method of sending encrypted messages from a mobile communication device utilizing a distribution list, the method comprising: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the member address is available on the mobile communication device; for each member whose public key is available on the mobile communication device, encrypting the message to the member by employing asymmetric encryption at the mobile communication device using the public key for the member; sending the encrypted message to the distribution list address without replacing the distribution list address with member addresses if each of the one or more member addresses associated with the distribution list identifies at least one member whose public key is available on the mobile communication device; at the mobile communication device, determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device; at the mobile communication device, expanding the distribution list address within a header of the message only after determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, by replacing the distribution list address with one or more member addresses that identify one or more members whose public key is available on the mobile communication device; and sending the message to each of the one or more member addresses that identify one or more members whose public key is available on the mobile communication device if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device. ### Claim 2 (depends on 1) The method of claim 1, further comprising querying a server for the one or more member addresses associated with the distribution list address. ### Claim 3 (depends on 1) The method of claim 1, further comprising, for each of one or more members identified by the one or more member addresses associated with the distribution list address, searching for at least one certificate comprising the public key for the member. ### Claim 4 (depends on 3) The method of claim 3, further comprising, for each of one or more members identified by the one or more member addresses associated with the distribution list address, retrieving at least one certificate comprising the public key for the member. ### Claim 5 (depends on 4) The method of claim 4, further comprising verifying one or more properties of the retrieved at least one certificate comprising the public key for the member. ### Claim 6 (depends on 1) The method of claim 1, further comprising, for each of one or more members identified by the one or more member addresses associated with the distribution list address, verifying one or more properties of at least one certificate comprising the public key for the member. ### Claim 7 A computer-readable medium comprising a plurality of instructions executable on a mobile communication device, wherein the instructions, when executed, cause acts to be performed on the mobile communication device, the acts comprising: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the member address is available on the mobile communication device; for each member whose public key is available on the mobile communication device, encrypting the message to the member by employing asymmetric encryption at the mobile communication device using the public key for the member; sending the encrypted message to the distribution list address without replacing the distribution list address with member addresses if each of the one or more member addresses associated with the distribution list identifies at least one member whose public key is available on the mobile communication device; at the mobile communication device, determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device; at the mobile communication device, expanding the distribution list address within a header of the message only after determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, by replacing the distribution list address with one or more member addresses that identify one or more members whose public key is available on the mobile communication device; and sending the message to each of the one or more member addresses that identify one or more members whose public key is available on the mobile communication device if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device. ### Claim 8 A system for sending encrypted messages utilizing a distribution list comprising a mobile communication device, the mobile communication device comprising a processor and a memory, wherein the processor is configured to perform acts comprising: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the member address is available on the mobile communication device; for each member whose public key is available on the mobile communication device, encrypting the message to the member by employing asymmetric encryption at the mobile communication device using the public key for the member; sending the encrypted message to the distribution list address without replacing the distribution list address with member addresses if each of the one or more member addresses associated with the distribution list identifies at least one member whose public key is available on the mobile communication device; at the mobile communication device, determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device; at the mobile communication device, expanding the distribution list address within a header of the message only after determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, by replacing the distribution list address with one or more member addresses that identify one or more members whose public key is available on the mobile communication device; and sending the message to each of the one or more member addresses that identify one or more members whose public key is available on the mobile communication device if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device. ### Claim 9 (depends on 8) The system of claim 8, wherein said acts further comprise querying a server for the one or more member addresses associated with the distribution list address. ### Claim 10 (depends on 8) The system of claim 8, wherein the processor is further configured to: for each of one or more members identified by the one or more member addresses associated with the distribution list address, search for at least one certificate comprising the public key for the member. ### Claim 11 (depends on 10) The system of claim 10, wherein the processor is further configured to: for each of one or more members identified by the one or more member addresses associated with the distribution list address, retrieve at least one certificate comprising the public key for the member. ### Claim 12 (depends on 11) The system of claim 11, wherein the processor is further configured to verify one or more properties of the retrieved at least one certificate comprising the public key for the member. ### Claim 13 (depends on 8) The system of claim 8, wherein the processor is further configured to: for each of one or more members identified by the one or more member addresses associated with the distribution list address, verify one or more properties of at least one certificate comprising the public key for the member. ### Claim 14 A method of sending encrypted messages from a mobile communication device utilizing a distribution list, the method comprising: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the member address is available on the mobile communication device; for each member whose public key is available on the mobile communication device, encrypting the message to the member by employing asymmetric encryption at the mobile communication device using the public key for the member; at the mobile communication device, determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device; if each of the one or more member addresses associated with the distribution list identifies at least one member whose public key is available on the mobile communication device, sending the encrypted message to the distribution list address without replacing the distribution list address with member addresses; and if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device, providing an option of sending the encrypted message to the distribution list address if at least one of the one or more member addresses associated with the distribution list does not identify at least one member whose public key is available on the mobile communication device, determining if the option is exercised, sending the encrypted message to the distribution list address if the option is exercised, at the mobile communication device, expanding the distribution list address within a header of the message only after determining that not all members identified by the one or more member addresses associated with the distribution list are able to decrypt the message, by replacing the distribution list address with one or more member addresses that identify one or more members whose public key is available on the mobile communication device if the option is not exercised, and sending the message to each of the one or more member addresses that identify one or more members whose public key is available on the mobile communication device if the option is not exercised. ### Claim 15 (depends on 14) The method of claim 14, wherein said method further comprises querying a server for the one or more member addresses associated with the distribution list address. ### Claim 16 (depends on 14) The method of claim 14, further comprising: for each of one or more members identified by the one or more member addresses associated with the distribution list address, searching for at least one certificate comprising the public key for the member. ### Claim 17 (depends on 16) The method of claim 16, further comprising: for each of one or more members identified by the one or more member addresses associated with the distribution list address, retrieving at least one certificate comprising the public key for the member. ### Claim 18 (depends on 17) The method of claim 17, further comprising verifying one or more properties of the retrieved at least one certificate comprising the public key for the member. ### Claim 19 (depends on 14) The method of claim 14, further comprising: for each of one or more members identified by the one or more member addresses associated with the distribution list address, verifying one or more properties of at least one certificate comprising the public key for the member.