Note: Descriptions are shown in the official language in which they were submitted.
CA 02798617 2012-12-10
DISPLAY OF SECURE MESSAGES ON A MOBILE COMMUNICATION
DEVICE
This application is a divisional of Application No. 2,528,525, filed
November 30,2005.
This invention relates generally to the display of messages on mobile
communication devices, and particularly to the display of secure messages on
such
devices.
Mobile communication devices with display screens are used to receive and
display electronic messages in text or graphical format. It is desirable for
such
devices to display received messages, such as e-mail messages, to users
without
excessive delay in new information being displayed on the screens of the
devices.
However, it is common for electronic messages to include more information
than that which will typically be displayed by a mobile communication device.
For
example, an e-mail message as sent may repeat the body of the message several
times
in different formats. It is common for the same content to be included in
plaintext
format, in rich text format and in HTML (hypertext markup language) format. At
the
mobile communication device, it is typically only appropriate to display the
message
body in one of the possible formats. Often, for reasons of efficiency, only
the
plaintext version of the message body will be displayed.
Where a user employs a mobile communications environment in which
messages are forwarded to the device from a message server, the server may be
configured to send only a single version of the message body to the mobile
communications device. This provides efficiencies in the communication to the
mobile communication device. From the perspective of the user of the device,
such
an approach will reduce the time that would otherwise have been taken for the
mobile
communications device to receive, process and redraw the screen as required by
the
device operation when in receipt of the differently formatted information.
However, this approach may not be available when mobile communication
devices are configured to receive messages that are sent in accordance with a
secure
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message format such as the Secure Multipurpose Internet Mail Extension
(S/MIME)
format. For such messages to be verified by a mobile communication device, it
is
often required that the entire message (or a significant portion of the
message) be
received by the device. However, where differently formatted message body
information is repeated in the message, the secure message will include more
data
than will be displayed by the mobile communication device. As a result, the
user of
the device may experience undesirably slow performance while the device
carries out
processing steps relating to the data that is not displayed to the user but
which steps
are carried out as the device receives the information necessary to enable the
message
to be verified by the device.
Accordingly, it is desirable to provide a system and method for the display of
secure messages on a mobile communications device in which a secure message
may
be received and displayed by the device without causing undue delays in
message
display.
Brief Description of the Drawings
Figure 1 is an overview of an example communication system in which a
wireless communication device may be used.
Figure 2 is a block diagram of a further example communication system
including multiple networks and multiple mobile communication devices.
Figure 3 is a block diagram of a wireless mobile device usable in the example
communication system.
Figure 4 is a flowchart showing the steps taken by a wireless mobile device to
communicate with a message server to manage the forwarding of information to
the
device.
Figure 5 is a flowchart showing the steps taken by a message server to manage
the forwarding of information that may be encrypted to a wireless mobile
device.
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Detailed Description
Accordingly, a system on a mobile communications device is provided for the
display of an incrementally received secure message. The system includes a
message
viewer application for scanning the received portions of the message. On
determination that the received portion of the message includes a first
displayable
portion of the message content, the system signals to a message server to halt
the
message server from forwarding further portions of the message content. The
system
further provides a mechanism for the user of the mobile communications device
to
cause the mobile communications device to further signal the message server to
recommence the forwarding of further portions of the secure message content to
permit the verification of the e-mail based on the further portions of the
secure
message content.
Advantages include improved display performance for the user of a mobile
communications device due to the halt in information being received from the
message server where the mobile device will process, but not display, the
information
that would otherwise be initially received by the mobile communications
device.
However, the user remains able to carry out a security verification of the
received
message at the mobile communications device.
The invention in one aspect comprises a method for receiving a message on a
mobile communications device, the message comprising a displayable message
content portion capable of being viewed on the mobile communications device,
the
end of the displayable message content portion being identified by a
predefined
indicator, the method comprising the steps of: receiving a first segment of
the
message; scanning the first segment for the predefined indicator; if the
predefmed
indicator is not found within the first segment, automatically receiving a
further
segment of the message; and scanning the further segment of the message for
the
predefined indicator.
In another aspect, the invention comprises a method for receiving a message
on a mobile communications device, the message comprising a displayable
message
content portion capable of being viewed on the mobile communications device,
the
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end of the displayable message content portion being identified by a
predefined
indicator, the method comprising the steps of: receiving a first segment of
the
message; scanning the first segment for the predefined indicator; if the
predefined
indicator is not found within the first segment, automatically receiving a
further
segment of the message; and scanning the further segment of the message for
the
predefined indicator, wherein the first and any further segment is transmitted
to the
mobile communications device by a server, the method further comprising the
step of
automatically transmitting a command to the server to transmit a further
segment of
the message, said step of transmitting a command being executable at any time
during
the method.
In a further aspect, the invention comprises a computer program product
comprising code operative to carry out the steps of any of the aforesaid
methods.
In a further aspect, the invention comprises a system for the display of a
message receivable on a mobile communications device to a user, the message
being
automatically incrementally forwarded in segments to the mobile communications
device by a message server, the message comprising a message content portion
displayable on the mobile communications device, the system comprising:
means adapted to scan received segments of the message to determine if the
entirety of a first displayable portion of the message has been received by
the mobile
communications device; and means adapted to signal the message server to
prevent
the automatic incremental forwarding of segments of the message on the
determination that the entirety of a first displayable portion has been
received.
Figure 1 is an overview of an example communication system in which a
wireless communication device may be used. One skilled in the art will
appreciate
that there may be other different topologies, but the system shown in Figure 1
helps
demonstrate the operation of the secure message processing systems and methods
described in the present application. There may also be many message senders
and
recipients. The simple system shown in Figure 1 is for illustrative purposes
only.
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Figure 1 shows an e-mail sender 10, the Internet 20, a message server system
40, a wireless gateway 85, wireless infrastructure 90, a wireless network 105
and a
mobile communication device 100.
An e-mail sender system 10 may, for example, be connected to an ISP
(Internet Service Provider) on which a user of the system 10 has an account,
located
within a company, possibly connected to a local area network (LAN), and
connected
to the Internet 20, or connected to the Internet 20 through a large ASP
(application
service provider) such as America Online (AOL). Those skilled in the art will
appreciate that the systems shown in Figure 1 may instead be connected to a
wide
area network (WAN) other than the Internet, although e-mail transfers are
commonly
accomplished through Internet-connected arrangements as shown in Figure 1.
The message server 40 may be implemented, for example, on a network
computer within the firewall of a corporation, a computer within an ISP or ASP
system or the like, and acts as the main interface for e-mail exchange over
the Internet
20. Although other messaging systems might not require a message server system
40,
a mobile device 100 configured for receiving and possibly sending e-mail will
normally be associated with an account on a message server. Perhaps the two
most
common message servers are Microsoft Exchange and and Lotus Domino. These
products are often used in conjunction with Internet mail routers that route
and deliver
mail. These intermediate components are not shown in Figure 1, as they do not
directly play a role in the secure message processing described below. Message
servers such as server 40 typically extend beyond just e-mail sending and
receiving;
they also include dynamic database storage engines that have predefined
database
formats for data like calendars, to-do lists, task lists, e-mail and
documentation.
The wireless gateway 85 and infrastructure 90 provide a link between the
Internet 20 and wireless network 105. The wireless infrastructure 90
determines the
most likely network for locating a given user and tracks the user as they roam
between countries or networks. A message is then delivered to the mobile
device 100
via wireless transmission, typically at a radio frequency (RE), from a base
station in
the wireless network 105 to the mobile device 100. The particular network 105
may
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be virtually any wireless network over which messages may be exchanged with a
mobile communication device.
As shown in Figure 1, a composed e-mail message 15 is sent by the e-mail
sender 10, located somewhere on the Internet 20. This message 15 is normally
fully
in the clear and uses traditional Simple Mail Transfer Protocol (SMTP), RFC822
headers and Multipurpose Internet Mail Extension (MIME) body parts to define
the
format of the mail message. These techniques are known to those skilled in the
art.
The message 15 arrives at the message server 40 and is normally stored in a
message
store. In a preferred embodiment described in further detail below, messages
addressed to a message server account associated with a host system such as a
home
computer or office computer which belongs to the user of a mobile device 100
are
redirected from the message server 40 to the mobile device 100 as they are
received.
Regardless of the specific mechanism controlling the forwarding of messages
to the mobile device 100, the message 15, or possibly a translated or
reformatted
version thereof, is sent to the wireless gateway 85. The wireless
infrastructure 90
includes a series of connections to wireless network 105. These connections
could be
Integrated Services Digital Network (ISDN), Frame Relay or Ti connections
using
the TCP/IP protocol used throughout the Internet. As used herein, the term
"wireless
network" is intended to include three different types of networks, those being
(1)
data-centric wireless networks, (2) voice-centric wireless networks and (3)
dual-mode
networks that can support both voice and data communications over the same
physical base stations. Combined dual-mode networks include, but are not
limited to,
(1) Code Division Multiple Access (CDMA) networks, (2) the Groupe Special
Mobile
or the Global System for Mobile Communications (GSM) and the General Packet
Radio Service (GPRS) networks, and (3) future third-generation (3G) networks
like
Enhanced Data-rates for Global Evolution (EDGE) and Universal Mobile
Telecommunications Systems (UMTS). Some older examples of data-centric network
include the MobitexTM Radio Network and the DataTACTm Radio Network.
Examples of older voice-centric data networks include Personal Communication
Systems (PCS) networks like GSM, and TDMA systems.
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Figure 2 is a block diagram of a further example communication system
including
multiple networks and multiple mobile communication devices. The system of
Figure 2 is
substantially similar to the Figure 1 system, but includes a host system 30, a
redirection program
45, a mobile device cradle 65, a wireless virtual private network (VPN) router
75, an additional
wireless network 110 and multiple mobile communication devices 100. As
described above in
conjunction with Figure 1, Figure 2 represents an overview of a sample network
topology.
Although the message processing systems and methods described herein may be
applied to
networks having many different topologies, the network of Figure 2 is useful
in understanding an
automatic e-mail redirection system mentioned briefly above.
The central host system 30 will typically be a corporate office or other LAN,
but may instead be
a home office computer or some other private system where mail messages are
being exchanged.
Within the host system 30 is the message server 40, running on a computer
within the firewall of
the host system that acts as the main interface for the host system to
exchange e-mail with the
Internet 20. In the system of Figure 2, the redirection program 45 enables
redirection of data
items from the server 40 to a mobile communication device 100. Although the
redirection
program 45 is shown to reside on the same machine as the message server 40 for
ease of
presentation, there is no requirement that it must reside on the message
server. The redirection
program 45 and the message server 40 are designed to co-operate and interact
to allow the
pushing of information to mobile devices 100. In this installation, the
redirection program 45
takes confidential and non-confidential corporate information for a specific
user and redirects it
out through the corporate firewall to mobile devices 100. A more detailed
description of the
redirection software 45 may be found in the commonly assigned United States
Patent 6,219,694
("the '694 Patent"), entitled "System and Method for Pushing Information From
A Host System
To A Mobile Data Communication Device Having A Shared Electronic Address", and
issued to
the assignee of the instant application on April 17, 2001. This push technique
may use a wireless
friendly encoding, compression and encryption technique to deliver all
information to a mobile
device, thus effectively extending the
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CA 02798617 2012-12-10
security firewall to include each mobile device 100 associated with the host
system
30.
As shown in Figure 2, there may be many alternative paths for getting
information to the mobile device 100. One method for loading information onto
the
mobile device 100 is through a port designated 50, using a device cradle 65.
This
method tends to be useful for bulk information updates often performed at
initialization of a mobile device 100 with the host system 30 or a computer 35
within
the system 30. The other main method for data exchange is over-the-air using
wireless networks to deliver the information. As shown in Figure 2, this may
be
accomplished through a wireless VPN router 75 or through a traditional
Internet
connection 95 to a wireless gateway 85 and a wireless infrastructure 90, as
described
above. A VPN connection could be established directly through a specific
wireless
network 110 to a mobile device 100. The possibility of using a wireless VPN
router
75 is contemplated to be used with Internet Protocol (IP) Version 6 (IPV6) on
IP-
based wireless networks. This protocol will provide enough IP addresses to
dedicate
an IP address to every mobile device 100 and thus make it possible to push
information to a mobile device 100 at any time. A principal advantage of using
this
wireless VPN router 75 is that it could be an off-the-shelf VPN component,
thus it
would not require a separate wireless gateway 85 and wireless infrastructure
90 to be
used. A VPN connection would preferably be a Transmission Control Protocol
(TCP)/IP or User Datagram Protocol (UDP)/IP connection to deliver the messages
directly to the mobile device 100. If a wireless VPN 75 is not available then
a link 95
to the Internet 20 is the most common connection mechanism available and has
been
described above.
In the automatic redirection system of Figure 2, a composed e-mail message
15 leaving the e-mail sender 10 arrives at the message server 40 and is
redirected by
the redirection program 45 to the mobile device 100. As this redirection takes
place
the message 15 is re-enveloped, as indicated at 80, and a possibly proprietary
compression and encryption algorithm can then be applied to the original
message 15.
In this way, messages being read on the mobile device 100 are no less secure
than if
they were read on a desktop workstation such as 35 within the firewall. All
messages
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exchanged between the redirection program 45 and the mobile device 100
preferably
use this message repackaging technique. Another goal of this outer envelope is
to
maintain the addressing information of the original message except the
sender's and
the receiver's address. This allows reply messages to reach the appropriate
destination, and also allows the "from" field to reflect the mobile user's
desktop
address. Using the user's e-mail address from the mobile device 100 allows the
received message to appear as though the message originated from the user's
desktop
system 35 rather than the mobile device 100.
With reference back to the port 50 and cradle 65 connectivity to the mobile
device 100, this connection path offers many advantages for enabling one-time
data
exchange of large items. For those skilled in the art of personal digital
assistants
(PDAs) and synchronization, the most common data exchanged over this link is
Personal Information Management (PIM) data 55. When exchanged for the first
time
this data tends to be large in quantity, bulky in nature and requires a large
bandwidth
to get loaded onto the mobile device 100 where it can be used on the road.
This serial
link may also be used for other purposes, including setting up a private
security key
111 such as an S/MIME or PGP (Pretty Good Privacy data encryption) specific
private key, the Certificate (Cert) of the user and their Certificate
Revocation Lists
(CRLs) 60. The private key is preferably exchanged so that the desktop 35 and
mobile device 100 share one personality and one method for accessing all mail.
The
Cert and CRLs are normally exchanged over such a link because they represent a
large amount of the data that is required by the device for S/MIME, PGP and
other
public key security methods.
S/MIME is a message security protocol that enables end-to-end authorization
and protection of data integrity and privacy from the time that the originator
sends the
message until the message recipient decodes and reads the message. S/MIME
allows
message senders to digitally sign messages using their digital signature,
encrypt
messages with the recipient's public key, or both digitally sign and encrypt
the
message.
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In the preferred embodiment an S/MIME message may be verified both at
message server 40 and at mobile device 100, both shown in Figure 2. For a user
of
the mobile communications device, verification at mobile device 100 provides a
higher level of security than relying on the verification at message server
40. In some
cases, however, the verification at message server 40 may be sufficient for
the user.
In mobile device 100, a verification application is executable to determine if
some or
all of a received message meets message security protocol requirements. The
verification application executed on the mobile device 100 may decrypt the
message
received at the mobile device 100, or it may verify a digital signature
appended to the
message, or it may both decrypt and verify a digital signature, depending on
whether
the message received was encrypted, signed, or both signed and encrypted,
respectively. If the verification application is executed at the message
server 40, the
verification application may still decrypt, verify the digital signature of,
or both
decrypt and verify the digital signature of a message received at the server
40, but the
resultant decrypted message then delivered to the mobile device 100 could thus
be
subject to tampering undetected by the user of the mobile device 100 upon
receipt of
the resultant message.
In some cases, the verification application executable by mobile device 100
will be unable to complete the verification process without receipt of the
entire
message or a significant portion of the message. For example, where a portion
of a
message is digitally signed it is typical for the verification of the
signature to rely on
the content of that portion of the message. Thus where a portion of the
message,
perhaps as much as the entire message body itself, is encoded or signed in
this way,
this portion of the message subject to verification, as well as any digital
certificate
attached to the message, must be received by mobile device 100 before
verification at
mobile device 100 is able to be carried out. If the message to be verified
comprises
other file attachments, then typically all of the attachments must be received
by the
mobile device 100 before the verification application can verify the message.
The above operational characteristic may adversely affect the speed at which
information is displayed to a user of mobile device 100. This is particularly
the case
where the message being received by mobile device 100 has either repeated
message
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body contents (as where plaintext, rich text and/or HTML formatted message
body
versions are included) or attachments. In either case, information may be
received
which information is not displayable to the user or is not intended to be
displayed to
the user of the mobile device 100.
An approach to solving this potential adverse impact on perceived device
responsiveness is for the message server 40 to edit messages being forwarded
to the
mobile communication device 100. Such an editing step can remove certain
repeated
portions of the message body. For example, if the message received at the
message
server 40 contains the content of the message in plaintext and in HTML, then
the
server 40 could strip out the HTML portion of the message before forwarding it
to the
mobile device 100. However, where the mobile communication device 100 executes
a verification application, it will not be possible for the message server 40
itself to
automatically edit messages to remove such repeated portions, since this would
cause
the verification step to fail.
Accordingly, the execution of a verification application by the mobile device
100 may require the device 100 to receive non-displayable or repetitive
portions
before verification can be accomplished, and consequently the mobile device
100 may
exhibit slower than optimal display characteristics as the non-displayable or
repetitive
information is received and processed by mobile device 100.
According to the preferred embodiment, however, a message viewer
application for displaying messages to a user executable on the mobile
communication device 100 also operates to potentially reduce the number of
portions
of the message that will be forwarded by the message server 40. In the
preferred
embodiment, mobile communication device 100 is able to communicate with the
message server 40 to manage the forwarding of information to the device. As
shown
in Figure 4, the message data for a first message received by the message
server 40 is
forwarded to the mobile communication device 100 in segments or chunks of
predetermined size (for example, in segments of up to 1 kilobyte), initially
with a first
segment being forwarded at step 405. This first segment comprises only content
that
can be displayed to the user on the mobile device 100; so, for example, if the
message
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is encrypted, the segment may be empty if the message was not previously
decrypted
by the message server 40. In that case, the user would see only header
information
for the message (e.g., the sender information, the timestamp, or the subject
line) and
would be advised by the message viewer application that additional content is
available for downloading and verification by the verification application.
Otherwise,
if the message is not encrypted, the first segment sent at step 405 comprises
message
content.
After receipt of each segment at the mobile communication device 100, the
message viewer application scans the message data received in that segment at
step
410. There are two results of the segment scan at step 410 that are shown in
Figure 4.
At decision step 430 (described below), the renderable nature of the segment
determines future steps. At decision step 431, the presence of a delimiter
determines
whether a complete renderable portion of the message has been received at the
mobile
device 100. For example, if the message viewer application on the mobile
device 100
is capable of displaying plaintext content to the user, as opposed to other
formats such
as Rich Text Format (RTF) or HTML, the message viewer application scans for a
predetermined indicator, such as a defmed boundary delimiter, that is known to
define
the end of plaintext content. In the preferred embodiment, the message is
defined
using the S/MIME protocol and therefore different parts of the message body
are
delimited in defined ways. For example, a plaintext portion of the message
body is
preceded by a defined boundary delimiter such as "--Part_Boundary_Alternative"
with a content format specifier, for example, "Content-Type: text/plain".
Similar content format specifiers ("Content-Type: text/html" and "Content-
Type: text/RTF" for HTML and RTF format, respectively) may be found in
message content portions of messages received by the mobile communication
device
100. Thus, the message view application at step 410 may scan or search the
received
message segment for the presence of "--Part_Boundary_Alternative Content-
Type: text/plain". If such a delimiter, or other predefined indicator, is
found in
the message segment, then the message view application may determine that it
has
received a complete portion of plaintext content and instructs the server 40
to cease
sending further segments at step 415. If such a delimiter is not found in the
message
segment by the scan, then a further message segment is automatically delivered
to the
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mobile communication device 100 by the message server 40 at step 405. The
further
message segment is similarly scanned or searched at step 410, and yet a
further
message segment is automatically delivered at step 405 from the message server
40 if
the delimiter is not found. At any time during this process, the user of the
mobile
communication device 100 may view the segments of the message that have
already
been downloaded to the mobile device 100.
Thus, in the preferred embodiment, the scan carried out by the message viewer
application parses the incoming message segments to determine whether a first
set of
plaintext information has been received. In preferred embodiment given above,
the
delimiters are defined in accordance with Request for Comment 2046 (RFC 2046),
which describes MIME alternate encodings of message text. In particular,
section
5.1.4 of RFC 2046 describes the inclusion of alternative parts in "order of
increasing
faithfulness to the original content". In practice in accordance with this
order of
increasing faithfulness, the most simple encoding (typically plaintext) is
included in
the message prior to other encodings (HTML and Rich Text, for example). Thus,
by
following the method outlined above, a complete portion of plaintext content
may be
downloaded without user intervention, and without downloading message segments
comprising exclusively non-displayable or repetitive information to the mobile
device
100.
In the preferred embodiment, the automatic delivery of the further segments
with each repeated execution of step 405 is controlled by a command referred
to here
as the AUTO MORE command. Preferably, the AUTO MORE command is specified
by the mobile communication device 100 by default, although it may be manually
specified by the user. When the default, or user-specified, AUTO MORE command
is
invoked, a predefined indicator, which may be a flag set in a communication
from the
device to the server, is sent by the mobile communication device 100 to the
message
server 40 at step 395. On receipt of the predefined indicator, the message
server 40
will carry out steps to send the further message segments to the mobile
communication device 100, without further requests being required from the
user of
the mobile device 100.
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Although in Figure 4 step 395 is shown as being executed prior to step 405,
persons skilled in the art will appreciate that the step may be executed at
other points
in the process; for example, the predefined indicator may have already been
received
by the message server 40 prior to receipt of the message at the server 40
(this may be
the case if the AUTO MORE command is invoked by default). Alternatively, step
395 may be executed by the mobile communication device 100 after receipt of a
message segment at step 405; for example, the indicator may be sent to the
message
server 40 together with other data acknowledging receipt of the message
segment.
Preferably, the predefined indicator is communicated to the message server 40
at
intervals, or during any other status communication between the mobile
communication device 100 and the message server 40. In the preferred
embodiment,
the message viewer application communicates the predefined indicator to the
message
server 40. In alternate embodiments, a software module on the mobile
communication device 100 may instead be configured to communicate the
predefmed
indicator to the message server 40 based on commands sent between the message
viewer application and the software module.
If the message viewer application on the mobile device 100 detects the
predetermined delimiter in a received message segment, the AUTO MORE command
for that particular message is disabled, and this is communicated to the
server 40 at
step 415. The message server 40 is thus instructed to cease sending segments
of that
message to the mobile device 100.
This heuristic is adopted in the preferred embodiment based on the assumption
that the viewable content to be received by mobile communications device 100
is
contained in the first plaintext portion of the message content. In fact,
other portions
of the message may contain plaintext portions, or the mobile device may
include
functionality to permit display of the message content having other encodings.
In the
preferred embodiment efficiencies are obtained by using the heuristic
described.
Preferably, the downloading of further message segments is executed by the
mobile
communication device 100 only when the user is viewing the content downloaded
so
far of that particular message, in order to reduce memory usage on the mobile
device
100. However, in an alternate embodiment, the message viewer application may
scan
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the initial message segments of other messages not currently being viewed by
the user
and download the remaining displayable portions of those other messages
according
to the method described above. This embodiment may be less desirable, as it
increases the volume of data transmission between the mobile device 100 and
the
message server 40.
In the preferred embodiment, the potential for perceived delays in the
operation of the mobile device is reduced due to the message server 40 halting
the
automatic forwarding of content to the mobile communication device 100, as
described above. Content that is not viewable in the preferred embodiment by
the
mobile communication device 100 is not automatically forwarded to the device
by the
message server 40. In the situation where the message comprises signed,
encrypted,
or signed and encrypted content which is not readily viewable by the message
viewer
application, some efficiencies may still be realized. The message viewer
application,
upon recognition of the message as an encrypted message at step 430, may
disable the
AUTO MORE command at step 415. The user may then optionally manually invoke
the AUTO MORE mode in order to download and verify the content of the entire
message. Preferably, if the message viewer application recognizes the
application as
being digitally signed but not encrypted, the message viewer application still
receives
a further segment 405 if the delimiter or other predefined indicator is not
found in the
first segment, since the message still contains displayable content besides
the digital
certificate attached to the message.
Thus, the ability to verify a signed and/or encrypted S/MIME message
remains available to the user of the device 100. In this scenario, the message
viewer
application may alternatively provide a VERIFY command to be manually invoked
by the user, which both invokes the AUTO MORE command, and then invokes the
verification application after all segments of the signed and/or encrypted
message
have been downloaded.
It will be appreciated that this approach to the display of secure e-mails
will
require the user to be familiar with the potential for the received message to
have a
tentative security status. A received S/MIME message may be accompanied by an
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indication that the message server 40 has verified the message, but the
message may
also be indicated to the user to have an indeterminate status as to
verification at the
mobile device. The user's command to receive further portions of the message
(by
use of AUTO MORE, for example), if selected, will result in other parts of the
message being forwarded to allow the verification process at the mobile device
to be
carried out. In the meantime, the user experience is enhanced as there is a
reduction
in response time at the mobile device 100 due to the reduction in non-viewable
information being forwarded to the device 100.
In a further preferred embodiment, further efficiencies are provided for
viewing the displayable portions of a message. Referring to Figure 5, after
the server
40 receives a message for forwarding at step 440, server 40 sends a first
segment at
step 445. As referred to above, preferably this first segment comprises
message
content, but in the circumstance where the message is encrypted, the first
segment
may not comprise any message content unless it is decrypted at the server 40.
If the user of mobile communications device 100 wishes to view the remainder
of the displayable portion of the message, the user may send a MORE ALL
command
to the message server 40. This MORE ALL command may be invoked manually, or
it may be set as a default on the mobile communication device 100. If the MORE
ALL command is not sent to the message server 40, the steps referred to below
will
not be carried out by the server of the preferred embodiment. In either case,
the
mobile device 100 transmits a predetermined indicator to the message server 40
requesting the remainder of the displayable portion of the message. Once the
server
40 receives this MORE ALL command (decision branch 450), the server 40 parses
the remainder of the message at step 455 in order to identify the end of the
portion of
the message content comprising content that is displayable to the user on the
mobile
device 100. This parsing step is generally similar to the step 410 described
in the
context of the mobile device 100 with respect to each individual segment
received at
the device 100. However, in this particular embodiment, it is the message
server 40
that scans the message for the delimiter or other predefined indicator
identifying the
end of the displayable (such as plaintext) portion of the message.
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As is described in more detail below, once the complete displayable portion of
the message is found by identifying the delimiter within the message, the
message
server 40 then transmits the displayable portion of the message to the mobile
device
100. The transmission of the remaining displayable portion of the message may
be
carried out in a plurality of segments, as described above, or the remainder
of the
displayable portion may be transmitted as a single, larger segment. However
the
remainder of the displayable portion of the message is received by the mobile
communication device 100, it is the message server 40 that scans the message
for the
appropriate delimiter, and not the mobile device 100. The transmission of any
further
segments of the displayable portion of the message by the server 40 is carried
out
without any further MORE ALL or AUTO MORE commands from the mobile device
100. The MORE ALL and AUTO MORE commands described above may be used
concurrently with respect to the same message being viewed on the mobile
device
100. While the AUTO MORE command may be invoked by default, and the mobile
device 100 may scan each received message segment for the predefined indicator
or
delimiter indicating the end of the displayable portion of the message, the
user may
manually intervene and hasten the downloading of the entire viewable content
of the
message to the mobile device by invoking the MORE ALL command. Preferably, the
MORE ALL command is available to be invoked by the user via a menu option or
other command keystroke or action in the message viewing application.
In the event that the message received by the message server 40 is digitally
signed, encrypted, or both digitally signed and encrypted, some efficiencies
may still
be realized using the MORE ALL command. If the message is digitally signed
(see
decision branch 460), then upon receiving the MORE ALL command from the mobile
communication device 100, the message server 40 will have parsed the message
to
identify the displayable content of the message at step 455, but also removes
any
digital certificates attached to the message (step 465) before transmitting
the
displayable message content to the mobile device 100 at step 470. If the
message is
encrypted (or signed and encrypted)(see decision branch 475), then the
displayable
content within the message may be transmitted to the mobile device 100
pursuant to a
MORE ALL command only if the message server 40 receives the session key
applicable to the encrypted message from the mobile device 100 first.
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Figure 5 shows steps 480,485 and 490 which carry out the decryption of the
message, if the session key is available. As will be appreciated the server 40
will
invoke a time out condition if the session key is not received.
As will be appreciated by those skilled in the art, this reduces the security
of
the message and is therefore less desirable. However, if the message server 40
is
provided with the key and can decrypt the message, the message may then be
parsed
at step 455 and then the displayable portions transmitted to the mobile device
100 at
step 470.
As another example, the systems and methods disclosed herein may be used
with many different computers and devices, such as a wireless mobile
communications device shown in Figure 3. With reference to Figure 3, the
mobile
device 100 is a dual-mode mobile device and includes a transceiver 311, a
microprocessor 338, a display 322, non-volatile memory 324, random access
memory
(RAM) 326, one or more auxiliary input/output (I/O) devices 328, a serial port
330,
an input device, such as a keyboard 332, a speaker 334, a microphone 336, a
short-
range wireless communications sub-system 340, and other device sub-systems
342.
The transceiver 311 includes a receiver 312, a transmitter 314, antennas 316
and 318, one or more local oscillators 313, and a digital signal processor
(DSP) 320.
The antennas 316 and 318 may be antenna elements of a multiple-element
antenna,
and are preferably embedded antennas. However, the systems and methods
described
herein are in no way restricted to a particular type of antenna, or even to
wireless
communication devices.
The mobile device 100 is preferably a two-way communication device having
voice and data communication capabilities. Thus, for example, the mobile
device 100
may communicate over a voice network, such as any of the analog or digital
cellular
networks, and may also communicate over a data network. The voice and data
networks are depicted in FIGURE 3 by the communication tower 319. These voice
and data networks may be separate communication networks using separate
infrastructure, such as base stations, network controllers, etc., or they may
be
integrated into a single wireless network.
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The transceiver 311 is used to communicate with the network 319, and
includes the receiver 312, the transmitter 314, the one or more local
oscillators 313
and the DSP 320. The DSP 320 is used to send and receive signals to and from
the
transceivers 316 and 318, and also provides control information to the
receiver 312
and the transmitter 314. If the voice and data communications occur at a
single
frequency, or closely-spaced sets of frequencies, then a single local
oscillator 313
may be used in conjunction with the receiver 312 and the transmitter 314.
Alternatively, if different frequencies are utilized for voice communications
versus
data communications for example, then a plurality of local oscillators 313 can
be used
to generate a plurality of frequencies corresponding to the voice and data
networks
319. Information, which includes both voice and data information, is
communicated
to and from the transceiver 311 via a link between the DSP 320 and the
microprocessor 338.
The detailed design of the transceiver 311, such as frequency band, component
selection, power level, etc., will be dependent upon the communication network
319
in which the mobile device 100 is intended to operate. For example, a mobile
device
100 intended to operate in a North American market may include a transceiver
311
designed to operate with any of a variety of voice communication networks,
such as
the Mobitex or DataTAC mobile data communication networks, AMPS, TDMA,
CDMA, PCS, etc., whereas a mobile device 100 intended for use in Europe may be
configured to operate with the GPRS data communication network and the GSM
voice communication network. Other types of data and voice networks, both
separate
and integrated, may also be utilized with a mobile device 100.
Depending upon the type of network or networks 319, the access requirements
for the mobile device 100 may also vary. For example, in the Mobitex and
DataTAC
data networks, mobile devices are registered on the network using a unique
identification number associated with each mobile device. In GPRS data
networks,
however, network access is associated with a subscriber or user of a mobile
device. A
GPRS device typically requires a subscriber identity module ("SIM"), which is
required in order to operate a mobile device on a GPRS network. Local or non-
network communication functions (if any) may be operable, without the SIM
device,
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CA 02798617 2012-12-10
but a mobile device will be unable to carry out any functions involving
communications over the data network 319, other than any legally required
operations, such as '911' emergency calling.
After any required network registration or activation procedures have been
completed, the mobile device 100 may the send and receive communication
signals,
including both voice and data signals, over the networks 319. Signals received
by the
antenna 316 from the communication network 319 are routed to the receiver 312,
which provides for signal amplification, frequency down conversion, filtering,
channel selection, etc., and may also provide analog to digital conversion.
Analog to
digital conversion of the received signal allows more complex communication
functions, such as digital demodulation and decoding to be performed using the
DSP
320. In a similar manner, signals to be transmitted to the network 319 are
processed,
including modulation and encoding, for example, by the DSP 320 and are then
provided to the transmitter 314 for digital to analog conversion, frequency up
conversion, filtering, amplification and transmission to the communication
network
319 via the antenna 318.
In addition to processing the communication signals, the DSP 320 also
provides for transceiver control. For example, the gain levels applied to
communication signals in the receiver 312 and the transmitter 314 may be
adaptively
controlled through automatic gain control algorithms implemented in the DSP
320.
Other transceiver control algorithms could also be implemented in the DSP 320
in
order to provide more sophisticated control of the transceiver 311.
The microprocessor 338 preferably manages and controls the overall operation
of the mobile device 100. Many types of microprocessors or microcontrollers
could
be used here, or, alternatively, a single DSP 320 could be used to carry out
the
functions of the microprocessor 338. Low-level communication functions,
including
at least data and voice communications, are performed through the DSP 320 in
the
transceiver 311. Other, high-level communication applications, such as a voice
communication application 324A, and a data communication application 324B may
be stored in the non-volatile memory 324 for execution by the microprocessor
338.
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For example, the voice communication module 324A may provide a high-level user
interface operable to transmit and receive voice calls between the mobile
device 100
and a plurality of other voice or dual-mode devices via the network 319.
Similarly,
the data communication module 324B may provide a high-level user interface
operable for sending and receiving data, such as e-mail messages, files,
organizer
information, short text messages, etc., between the mobile device 100 and a
plurality
of other data devices via the networks 319.
The microprocessor 338 also interacts with other device subsystems, such as
the display 322, the RAM 326, the auxiliary input/output (I/O) subsystems 328,
the
serial port 330, the keyboard 332, the speaker 334, the microphone 336, the
short-
range communications subsystem 340 and any other device subsystems generally
designated as 342.
Some of the subsystems shown in FIGURE 3 perform communication-related
functions, whereas other subsystems may provide "resident" or on-device
functions.
Notably, some subsystems, such as the keyboard 332 and the display 322 may be
used
for both communication-related functions, such as entering a text message for
transmission over a data communication network, and device-resident functions
such
as a calculator or task list or other PDA type functions.
Operating system software used by the microprocessor 338 is preferably
stored in a persistent store such as non-volatile memory 324. The non-volatile
memory 324 may be implemented, for example, as a Flash memory component, or as
battery backed-up RAM. In addition to the operating system, which controls low-
level functions of the mobile device 310, the non-volatile memory 324 includes
a
plurality of software modules 324A-324N that can be executed by the
microprocessor
338 (and/or the DSP 320), including a voice communication module 324A, a data
communication module 324B, and a plurality of other operational modules 324N
for
carrying out a plurality of other functions. These modules are executed by the
microprocessor 338 and provide a high-level interface between a user and the
mobile
device 100. This interface typically includes a graphical component provided
through
the display 322, and an input/output component provided through the auxiliary
I/O
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CA 02798617 2012-12-10
328, keyboard 332, speaker 334, and microphone 336. The operating system,
specific
device applications or modules, or parts thereof, may be temporarily loaded
into a
volatile store, such as RAM 326 for faster operation. Moreover, received
communication signals may also be temporarily stored to RAM 326, before
permanently writing them to a file system located in a persistent store such
as the
Flash memory 324.
An exemplary application module 324N that may be loaded onto the mobile
device 100 is a personal information manager (PIM) application providing PDA
functionality, such as calendar events, appointments, and task items. This
module
324N may also interact with the voice communication module 324A for managing
phone calls, voice mails, etc., and may also interact with the data
communication
module for managing e-mail communications and other data transmissions.
Alternatively, all of the functionality of the voice communication module 324A
and
the data communication module 324B may be integrated into the PIM module.
The non-volatile memory 324 preferably also provides a file system to
facilitate storage of PIM data items on the device. The PIM application
preferably
includes the ability to send and receive data items, either by itself, or in
conjunction
with the voice and data communication modules 324A, 324B, via the wireless
networks 319. The PIM data items are preferably seamlessly integrated,
synchronized
and updated, via the wireless networks 319, with a corresponding set of data
items
stored or associated with a host computer system, thereby creating a mirrored
system
for data items associated with a particular user.
Context objects representing at least partially decoded data items, as well as
fully decoded data items, are preferably stored on the mobile device 100 in a
volatile
and non-persistent store such as the RAM 326. Such information may instead be
stored in the non-volatile memory 324, for example, when storage intervals are
relatively short, such that the information is removed from memory soon after
it is
stored. However, storage of this information in the RAM 326 or another
volatile and
non-persistent store is preferred, in order to ensure that the information is
erased from
memory when the mobile device 100 loses power. This prevents an unauthorized
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CA 02798617 2012-12-10
party from obtaining any stored decoded or partially decoded information by
removing a memory chip from the mobile device 100, for example.
The mobile device 100 may be manually synchronized with a host system by
placing the device 100 in an interface cradle, which couples the serial port
330 of the
mobile device 100 to the serial port of a computer system or device. The
serial port
330 may also be used to enable a user to set preferences through an external
device or
software application, or to download other application modules 324N for
installation.
This wired download path may be used to load an encryption key onto the
device,
which is a more secure method than exchanging encryption information via the
wireless network 319. Interfaces for other wired download paths may be
provided in
the mobile device 100, in addition to or instead of the serial port 330. For
example, a
USB port would provide an interface to a similarly equipped personal computer.
Additional application modules 324N may be loaded onto the mobile device
100 through the networks 319, through an auxiliary I/O subsystem 328, through
the
serial port 330, through the short-range communications subsystem 340, or
through
any other suitable subsystem 342, and installed by a user in the non-volatile
memory
324 or RAM 326. Such flexibility in application installation increases the
functionality of the mobile device 100 and may provide enhanced on-device
functions, communication-related functions, or both. For example, secure
communication applications may enable electronic commerce functions and other
such fmancial transactions to be performed using the mobile device 100.
When the mobile device 100 is operating in a data communication mode, a
received signal, such as a text message or a web page download, is processed
by the
transceiver module 311 and provided to the microprocessor 338, which
preferably
further processes the received signal in multiple stages as described above,
for
eventual output to the display 322, or, alternatively, to an auxiliary I/O
device 328. A
user of mobile device 100 may also compose data items, such as e-mail
messages,
using the keyboard 332, which is preferably a complete alphanumeric keyboard
laid
out in the QWERTY style, although other styles of complete alphanumeric
keyboards
such as the known DVORAK style may also be used. User input to the mobile
device
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100 is further enhanced with a plurality of auxiliary I/O devices 328, which
may
include a thumbwheel input device, a touchpad, a variety of switches, a rocker
input
switch, etc. The composed data items input by the user may then be transmitted
over
the communication networks 319 via the transceiver module 311.
When the mobile device 100 is operating in a voice communication mode, the
overall operation of the mobile device is substantially similar to the data
mode, except
that received signals are preferably be output to the speaker 334 and voice
signals for
transmission are generated by a microphone 336. Alternative voice or audio I/O
subsystems, such as a voice message recording subsystem, may also be
implemented
on the mobile device 100. Although voice or audio signal output is preferably
accomplished primarily through the speaker 334, the display 322 may also be
used to
provide an indication of the identity of a calling party, the duration of a
voice call, or
other voice call related information. For example, the microprocessor 338, in
conjunction with the voice communication module and the operating system
software,
may detect the caller identification information of an incoming voice call and
display
it on the display 322.
A short-range communications subsystem 340 is also included in the mobile
device 100. The subsystem 340 may include an infrared device and associated
circuits and components, or a short-range RF communication module such as a
BluetoothTM module or an 802.11 module, for example, to provide for
communication with similarly-enabled systems and devices. Those skilled in the
art
will appreciate that "Bluetooth" and "802.11" refer to sets of specifications,
available
from the Institute of Electrical and Electronics Engineers, relating to
wireless personal
area networks and wireless local area networks, respectively.
The systems' and methods' data may be stored in one or more data stores.
The data stores can be of many different types of storage devices and
programming
constructs, such as RAM, ROM, Flash memory, programming data structures,
programming variables, etc. It is noted that data structures describe formats
for use in
organizing and storing data in databases, programs, memory, or other computer-
readable media for use by a computer program.
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The systems and methods may be provided on many different types of
computer-readable media including computer storage mechanisms (e.g., CD-ROM,
diskette, RAM, flash memory, computer's hard drive, etc.) that contain
instructions
for use in execution by a processor to perform the methods' operations and
implement
the systems described herein.
The computer components, software modules, functions and data structures
described herein may be connected directly or indirectly to each other in
order to
allow the flow of data needed for their operations. It is also noted that a
module or
processor includes but is not limited to a unit of code that performs a
software
operation, and can be implemented for example as a subroutine unit of code, or
as a
software function unit of code, or as an object (as in an object-oriented
paradigm), or
as an applet, or in a computer script language, or as another type of computer
code.
Various embodiments of the present invention having been thus described in
detail by way of example, it will be apparent to those skilled in the art that
variations
and modifications may be made without departing from the invention. The
invention
includes all such variations and modifications as fall within the scope of the
appended
claims.
A portion of the disclosure of this patent document contains material which is
subject to copyright protection. The copyright owner has no objection to the
facsimile reproduction by any one of the patent document or patent disclosure,
as it
appears in the Patent and Trademark Office patent file or records, but
otherwise
reserves all copyrights whatsoever.
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