Method performed by at least one server for processing a data packet from a first computing device to a second computing device to permit end-to-end encryption communication

A method (500) performed by at least one server for processing a data packet from a first computing device to be transmitted to a second computing device is disclosed, in which the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the second computing device encrypted using a second encryption key to form encrypted identification data, and encrypted first and second encryption keys. The method comprises decrypting (504) the encrypted second encryption key; decrypting (506) the encrypted identification data using the decrypted second encryption key; and transmitting (508) the data packet based on the decrypted identification data, wherein the encrypted message and first encryption key are arranged to be undecryptable by the server to permit end-to-end encryption communication between the first and second computing devices. A related system is also disclosed.

FIELD AND BACKGROUND

The present invention relates to a method performed by at least one server for processing a data packet from a first computing device to a second computing device to permit end-to-end encryption communication, and a corresponding system.

Presently, certain messaging solutions perform two different encryption-decryption methods, for example in a scenario where a server is arranged between two computing devices, a sender and a recipient, in a communication network. The sender encrypts a message using a symmetric key which is randomly generated. The sender then encrypts the symmetric key using the server's public key, and thereafter transmits a data package, comprising the encrypted message and symmetric key, to the server. The server decrypts the encrypted symmetric key using its own private key, after which the server then re-encrypts the symmetric key with the recipient's public key and the re-formatted data package is forwarded to the recipient. It will be appreciated that since the server has the symmetric key, the server is however then able to access the encrypted message. On receiving the data package, the recipient decrypts the encrypted symmetric key with its own private key to retrieve the symmetric key which is used to decrypt the encrypted message. For such a scenario, the server has a copy of the symmetric key and is able to decrypt the encrypted message for audit purposes or archival of the decrypted message. However, this is not considered true end-to-end encryption communication, since the server has access to the content of the message.

For other conventional implementations, the server may be configured to re-generate a new symmetric key and re-encrypt the message with the new symmetric key, and encrypt the new symmetric key with the recipient's public key. In this situation, the server nonetheless still has access to the encrypted message and thus also does not enable true end-to-end encryption communication.

One object of the present invention is therefore to address at least one of the problems of the prior art and/or to provide a choice that is useful in the art.

SUMMARY

According to a 1staspect of the invention, there is provided a method performed by at least one server for processing a data packet from a first computing device to be transmitted to a second computing device, wherein the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the second computing device encrypted using a second encryption key to form encrypted identification data, and encrypted first and second encryption keys. The method comprises decrypting the encrypted second encryption key; decrypting the encrypted identification data using the decrypted second encryption key; and transmitting the data packet based on the decrypted identification data. The encrypted message and first encryption key are arranged to be undecryptable by the server to permit end-to-end encryption communication between the first and second computing devices.

The method advantageously enables realisation of a multiple-key encryption scheme that allows a sender to send encrypted messages to a recipient(s) by forwarding the encrypted messages through an intermediate server to perform re-routing of the data packet, but the server is however not enabled with the ability to decrypt the encrypted messages. This beneficially ensures that a true end-to-end encryption is achieved between the sender and the recipient(s).

Preferably, decrypting the encrypted second encryption key may include using a private key of the server to perform the decryption. Also, transmitting the data packet may include transmitting via an SMS, an MMS, instant messaging, an email, an attachment or an electronic document delivery service. The message may include text, images, animation, video or audio. It is to be appreciated that the first encryption key may be encrypted using a public key of the second computing device, or alternatively, the first encryption key may be encrypted using a public key of the server. More preferably, the second encryption key may be encrypted using a public key of the server. Yet preferably, the data packet may further include an initialization vector, and a digital signature generated based on the encrypted message.

According to a 2ndaspect of the invention, there is provided a method performed by a first computing device for processing information to be transmitted to a second computing device via at least one server to permit end-to-end encryption communication between the first and second computing devices. The method comprises encrypting a message and identification data of the second computing device respectively using first and second encryption keys; encrypting the first and second encryption keys; and transmitting the encrypted message, identification data, first and second encryption keys collectively as a data packet.

Preferably, the message may include text, images, animation, video or audio. Further, transmitting the data packet may include transmitting via an SMS, an MMS, instant messaging, an email, an attachment or an electronic document delivery service. More preferably, encrypting the first encryption key may include encrypting using an encryption key of the second computing device, or an encryption key of the server. In addition, the encryption key of the second computing device may include a public key thereof, and the encryption key of the server may include a public key thereof. Encrypting the second encryption key may include encrypting using an encryption key of the server. The encryption key of the server may include a public key thereof.

Preferably, the method may further comprise displaying an interface to enable a user of the first computing device to select the message from a plurality of messages, and the second computing device from a plurality of computing devices able to receive the data packet. The data packet may further include an initialization vector, and a digital signature generated based on the encrypted message.

According to a 3rdaspect of the invention, there is provided a method performed by a first computing device for processing a data packet from a second computing device forwarded via at least one server to permit end-to-end encryption communication between the first and second computing devices, wherein the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the first computing device encrypted using a second encryption key to form encrypted identification data, and encrypted first and second encryption keys. The method comprises decrypting the encrypted first encryption key; and decrypting the encrypted message using the decrypted first encryption key to obtain the message.

Preferably, decrypting the encrypted first encryption key may include using a private key of the first computing device to perform the decryption.

According to a 4thaspect of the invention, there is provided a system for exchanging a data packet between first and second computing devices via at least one server to permit end-to-end encryption communication between the first and second computing devices. The system comprises the first and second computing devices, and the server. The first computing device includes an encryption module for: encrypting a message and identification data of the second computing device respectively using first and second encryption keys; and encrypting the first and second encryption keys; and a transmission module for transmitting the encrypted message, identification data, first and second encryption keys collectively as the data packet to the server. The server is configured to process the data packet received from the first computing device and includes a decryption module for: decrypting the encrypted second encryption key of the data packet; and decrypting the encrypted identification data of the data packet using the decrypted second encryption key; and a transmission module for transmitting the data packet to the second computing device based on the decrypted identification data, wherein the encrypted message and first encryption key are arranged to be undecryptable by the server. The second computing device is configured to process the data packet received from the server and includes a decryption module for: decrypting the encrypted first encryption key of the data packet; and decrypting the encrypted message of the data packet using the decrypted first encryption key to obtain the message.

Preferably, the decryption module of the server may include being configured to use a private key of the server to decrypt the encrypted second encryption key.

On the other hand, the transmission module of the server may include being configured to transmit the data packet using an SMS, an MMS, instant messaging, an email, an attachment or an electronic document delivery service. The message may include text, images, animation, video or audio. The encryption key of the second computing device used by the encryption module of the first computing device to encrypt the first encryption key may preferably include a public key of the second computing device.

Preferably, the encryption module, of the first computing device may further be configured to encrypt the first encryption key using an encryption key of the second computing device, or an encryption key of the server. In addition, the encryption module of the first computing device may yet further be configured to encrypt the second encryption key using an encryption key of the server.

Preferably, the encryption key of the server used by the encryption module of the first computing device to encrypt the second encryption key may include a public key of the server. The data packet may further include an initialization vector, and a digital signature generated based on the encrypted message.

According to a 5thaspect of the invention, there is provided an encryption device for processing information to be transmitted to a computing device via at least one server to permit end-to-end encryption communication between the encryption and computing devices. The encryption device comprises an encryption module for: encrypting a message and identification data of the computing device respectively using first and second encryption keys; and encrypting the first and second encryption keys; and a transmission module for transmitting the encrypted message, identification data, first and second encryption keys collectively as a data packet.

According to a 6thaspect of the invention, there is provided a decryption device for processing a data packet from a computing device forwarded via at least one server to permit end-to-end encryption communication between the decryption and computing devices, wherein the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the first computing device encrypted using a second encryption key to form encrypted identification data, and encrypted first and second encryption keys. The decryption device comprises a decryption module for: decrypting the encrypted first encryption key; and decrypting the encrypted message using the decrypted first encryption key to obtain the message.

According to a 7thaspect of the invention, there is provided a method performed by at least one server for processing a data packet from a first computing device to be transmitted to a second computing device, wherein the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the second computing device encrypted using a second encryption key to form encrypted identification data, an encrypted first encryption key formed by encrypting the first encryption key using a third encryption key associated with the second computing device, and an encrypted second encryption key formed by encrypting the second encryption key using an encryption key associated with the server. The method comprises decrypting the encrypted second encryption key; decrypting the encrypted identification data using the decrypted second encryption key; and transmitting the data packet based on the decrypted identification data. The encrypted first encryption key is arranged to be decryptable only using a fourth encryption key associated with the second computing device; and the third and fourth encryption keys of the second computing device are configured as a pair of asymmetric keys.

Preferably, the encryption key associated with the server may include a public key of the server. Following on, decrypting the encrypted second encryption key may include using a private key of the server to perform the decryption. Further, transmitting the data packet may include transmitting via an SMS, an MMS, instant messaging, an email, an attachment or an electronic document delivery service. The message may include text, images, animation, video or audio. Yet preferably, the third and fourth encryption keys respectively may include a public key and a private key of the second computing device. The data packet may further include an initialization vector, and a digital signature generated based on the encrypted message.

It should be apparent that features relating to one aspect of the invention may also be applicable to the other aspects of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A system100(i.e. seeFIG. 1) and corresponding method500(i.e. seeFIG. 5) for exchanging a data packet102between first and second computing devices104,106(i.e. two parties) via at least one server108to permit end-to-end encryption communication is disclosed, according to a first embodiment. The system100includes the first and second computing devices104,106, and the server108, which is configurationally arranged intermediate to the first and second computing devices104,106. It is to be appreciated that the server108is configured with associated public key and private key, as per the public-key infrastructure (i.e. asymmetric keys cryptography) terminology. Similarly, the second computing device106is also configured with associated public key and private key. In the context ofFIG. 1, the first computing device104is a sender of the data packet102, and the second computing device106is an eventual intended recipient of the data packet102. But it will also be appreciated that the opposite relationship is possible in other instances, i.e. the second computing device106becomes the sender, while the first computing device104becomes the recipient. In particular, the system100enables true end-to-end encryption communication between the sender and recipient, while still allowing the server108to route the data packet102in a secure manner, but without being able to decrypt a secure message embedded in the data packet102to access the contents of the message. Also for sake of simplicity in illustrating and describing, only one server102is shown inFIG. 1, although it will be understood that the data packet102may be forwarded through multiple servers108(i.e. a server cluster) before being received by the second computing device106. In the said scenario of multiple servers108, it is to be appreciated that each of the servers108is configured to have access to a common set of public key and private key (e.g. which may be stored locally on each server108, or be stored on a storage server equally accessible by all the multiple servers108). Specifically, the common set of public key and private key is to be used for the purpose of encrypting and decrypting identification data of the second computing device106, which will be elaborated below. It is further to be appreciated that the first and second computing devices104,106, and the server108resides in a communication network.

Examples of the first and second computing devices104,106include mobile computing devices (e.g. smartphones like iPhone™ or tablets like iPad™), wired computers (e.g. desktop personal computers) or the like. However, for the purpose of this embodiment, the first and second computing devices104,106are mobile computing devices running on a predetermined suitable mobile operating system (e.g. iOS™ from Apple Inc™). For ease of referencing hereinafter, the first and second computing devices104,106are respectively referred to as the encryption device104and the decryption device106(in the context of true end-to-end encryption communication relationship), unless otherwise explicitly stated. It will also be appreciated that there can be multiple encryption devices104and decryption devices106arranged within the system100in the communication network to exchange different data packets102with one another, but not however specifically shown inFIG. 1in this instance, for sake of brevity. As for the server108, examples include any types of server suitably configured for performing the task of routing the data packet102between the encryption device104and decryption device106.

Referring toFIG. 2, the encryption device104is configured to execute an encryption program code (not shown) for processing information into the data packet102to be provided to the decryption device106, whereas the decryption device106is configured to execute a decryption program code (not shown) for processing the received data packet102. On the other hand, the server108is configured to execute a data-packet processing code (not shown), which is based on the method500ofFIG. 5, for processing the data packet102sent by the encryption device104to the decryption device106. It will be appreciated that, in this embodiment, the encryption and decryption program codes are locally installed on the encryption device and decryption device104,106, and further, the encryption and decryption program codes are realised as native mobile applications (e.g. as a software usable by users). Specifically, the encryption device104includes the following modules: an encryption module1042, a display module1046, a transmission module1048and a processor module10410, while the decryption device106includes the following modules: a receiver module1062, and a decryption module1064. Similarly, the data-packet processing code is implemented as an application specific program (which may be configured to run as a background process) and locally installed on the server108. For the server108, the following modules are arranged therewithin: a receiver module1082, a decryption module1084, and a transmission module1086. In this instance, it is to be understood that the respective said modules of the encryption device204and decryption device206are implemented in software, and thus are incorporated respectively into the encryption program code and decryption program code. This applies mutatis mutandis to the said modules of the server108.

Reference is now made toFIGS. 3 and 4to describe a method300performed by the encryption device104(i.e. the sender) for processing information to be transmitted to the decryption device106(i.e. the recipient) via the server108to permit end-to-end encryption communication. At step302of the method300, the display module1046is arranged to display a software interface (not shown) to enable a user (not shown) of the encryption device104to select a desired message (i.e. input data) from a plurality of messages to be sent to the decryption device106. It will be appreciated that the message includes text, images, animation, video, audio or the like. In addition, at the step302, the user also uses the software interface to select a recipient (from a plurality of devices) of the selected message, which in this context is the decryption device106. Further, the interface also displays an option on whether end-to-end encryption is desired by the user. If the user selects the end-to-end encryption option, the encryption device104proceeds to prepare the data packet102, to embed the selected message, based on a secure packet format400as shown inFIG. 4. Also, to proceed with the end-to-end encryption communication, the encryption device104is configured to then randomly generate a symmetric message encryption key (not shown) and a recipient info encryption key (not shown), the purposes of which are elaborated below. In addition, a new unique set of message encryption key and recipient info encryption key is generated for each data packet102to be transmitted by the encryption device104. It is further to be appreciated that the data packet102may be embedded as a payload of a standard IP packet.

Referring toFIG. 4, the packet format400includes seven data fields401-407in total, although additional necessary data fields may be added if required. Specifically, the seven data fields401-407include (based on an arranged order of data sequence in the packet format400): a version-number field401, an encrypted-message-key field402, an encrypted-recipient-information-key field403, an initialization-vector field404, an encrypted-recipient-information field405, an encrypted-message field406, and a digital-signature407field. To briefly explain, the version-number field401defines a present version of the packet format400in use, the encrypted-message-key field402stores the message encryption key encrypted using the public key of the decryption device106, while the encrypted-recipient-information-key field403stores the recipient info encryption key encrypted using the public key of the server108. For a scenario comprising multiple servers108, the encrypted-recipient-information-key field403stores the recipient info encryption key which is encrypted instead using the common public key accessible by all the servers108, as afore explained. The initialization-vector field404defines a starting variable used for encryption (as will be appreciated by skilled persons), the encrypted-recipient-information field405stores identification data of the decryption device106encrypted using the recipient info encryption key, whereas the encrypted-message field406stores the selected message encrypted using the message encryption key, and the digital-signature field407stores an authentication checksum generated based on the encrypted message (as stored in the encrypted-message field406). It is to be appreciated that the identification data of the decryption device106refers to associated location information, such as an IP address, of the decryption device106, which would enable the server108to identify, forward and route the data packet102from the encryption device104to the decryption device106. Thus, the identification data is location information associated with the recipient, since the decryption device106is the recipient of the data packet102in this instance. It is to be appreciated that the encryption device104obtains the identification data of the decryption device106, as distributed by the server108through a separate communication channel/means, which is not the focus of the discussion of the present invention.

It is to be appreciated that the software interface, displayed by the display module1046of the encryption device104, automatically separates the identification data from the message (without requiring any user intervention), for the purpose of enabling the identification data to be encrypted separately from the message (which will also be encrypted). This is now elaborated below.

Resuming our description of the method300inFIG. 3, at step304, the encryption module1042(of the encryption device104) encrypts the selected message and identification data of the decryption device106respectively using the message encryption key and the recipient info encryption key, and stores the encrypted message and identification data respectively in the encrypted-message field406and encrypted-recipient-information field405(of the data packet102). A corresponding authentication checksum is also generated by the processor module10410(of the encryption device104) based on the encrypted message (using any suitable existing checksum algorithms), and stored in the digital-signature field407. Thereafter at step306, the encryption module1042(of the encryption device104) encrypts the message encryption key and the recipient info encryption key using respectively the public key of the decryption device106, and the public key of the server108. It is to be appreciated that for a scenario which comprises multiple servers108, the recipient info encryption key is instead encrypted using the common public key accessible by all the servers108, as above explained. The encrypted message encryption key, and recipient info encryption key are then respectively stored in the encrypted-message-key field402and encrypted-recipient-information-key field403(of the data packet102). The data packet102is then assembled into a complete form by the encryption device104. At step308, the transmission module1048(of the encryption device104) transmits the (assembled) data packet102to the server108. It is to be appreciated that the data packet may be transmitted via suitable digital messaging schemes such as using an SMS, an MMS, instant messaging (IM), an email, an attachment, an electronic document delivery service or the like.

The server108then performs a method500(as depicted inFIG. 5) for processing the data packet102that is received from the encryption device104, which permits true end-to-end encryption communication between the encryption device104and decryption device106. In particular, the server108first receives the data packet102via the receiver module1082(of the server108) at step502. The server108performs an authentication check using data retrieved from the digital-signature field407of the received data packet102to ensure that the encrypted message in the encrypted-message field406has not been tampered with at any point during transit from the encryption device104to the server108. Then, at step504, the decryption module1084of the server108is configured to decrypt the encrypted recipient info encryption key, as stored in the encrypted-recipient-information-key field403of the received data packet102, using the private key of the server108. This allows retrieval of the recipient info encryption key “in the clear” (i.e. unencrypted). It is to be appreciated that for a scenario which comprises multiple servers108, the encrypted recipient info encryption key is instead decrypted using the common private key which is accessible by all the servers108, as already above explained. Thereafter, the decryption module1084of the server108proceeds to decrypt the encrypted identification data, as stored in the encrypted-recipient-information field405of the data packet102, using the recipient info encryption key obtained in step504. This allows retrieval of the identification data “in the clear”. Once the server108determines where the data packet102needs to be routed to next, based on the identification data obtained in afore said step506, the transmission module1086of the server108then transmits and forwards the data packet102to the destination specified in the identification data. Of course, in the context of the current discussion, the identification data is associated with the decryption device106, and thus the data packet is to be forwarded to the decryption device106. Importantly, it is to be appreciated that the data packet102is forwarded by the server108verbatim to the decryption device106; that is, the server108does not (in anyway) alter, re-encrypt or re-format the data packet102which it receives from the encryption device104.

It is to be understood that during the performance of the method500ofFIG. 5, the server108will not be able to decrypt the encrypted-message field406and the encrypted-message-key field402of the data packet102. This is because the server108is not configured to have a copy of the private key of the decryption device106, which is required in order to decrypt the encrypted-message-key field402. Only with retrieval of the message encryption key “in the clear” would enable the encrypted-message field406to be decrypted to obtain the message “in the clear”. That is, the server108is unable to decrypt and access the message intended for the decryption device106, which beneficially permits secure end-to-end encryption communication between the sender and intended recipient.

FIG. 6then depicts a method600performed by the decryption device106for processing the data packet102received from the server108. At step602, the receiver module1062(of the decryption device106) receives the data packet102forwarded by the server108, and at step604, the decryption module1064(of the decryption device106) is configured to decrypt the encrypted-message-key field402of the data packet102to obtain the message encryption key “in the clear”. With successful retrieval of the decrypted message encryption key, the decryption module1064(of the decryption device106) is then arranged to use the message encryption key (obtained at step604) to decrypt the encrypted-message field406of the data packet102to obtain the decrypted message at step606. The decryption device106may then access and read the message that was transmitted by the encryption device104.

Further embodiments of the invention will be described hereinafter. For the sake of brevity, description of like elements, functionalities and operations that are common between the embodiments are not repeated; reference will instead be made to similar parts of the relevant embodiment(s).

According to a second embodiment, in a scenario where there are multiple decryption devices106(i.e. more than one recipients for group communications), the encryption module1042(of the encryption device104) encrypts the identification data of each decryption device106using the recipient info encryption key associated with the corresponding decryption device106, thereafter stores all of the encrypted identification data into the encrypted-recipient-information field405of a new data packet102to be transmitted. In particular, all of the encrypted identification data are concatenated into a data string which is stored into the encrypted-recipient-information field405of the new data packet102. All the recipient info encryption keys of the multiple decryption devices106are then arranged to be encrypted (by the encryption module1042of the encryption device104) using the public key of the server108, and collectively stored in the encrypted-recipient-information-key field403of the data packet102. Furthermore, the encryption module1042(of the encryption device104) also uses the public key of each decryption device106to encrypt the message encryption key, which is then stored into the encrypted-message-key field402of the data packet102. More specifically, the message encryption key is independently and singly encrypted using the corresponding public key of each decryption device106to form an associated encrypted message encryption key. As will be appreciated, this process is performed for the public keys of all the decryption devices106, and the resulting encrypted message encryption keys generated are then subsequently concatenated into a data string, that is stored into the encrypted-message-key field402of the data packet102. It is to be appreciated that in this embodiment, the steps302-308in the method300ofFIG. 3are still performed similarly by the encryption device104; only the type and amount of data stored in the data packet102varies in respect of the first embodiment.

When the server108receives the data packet102transmitted by the encryption device104, the decryption module1084of the server108then decrypts the encrypted recipient info encryption key, as stored in the encrypted-recipient-information-key field403of the received data packet102, using the private key of the server108. This enables the server108to retrieve all the decrypted recipient info encryption keys of the multiple decryption devices106, which are then further respectively used to decrypt the corresponding segment of the data string as stored in the encrypted-recipient-information field405of the data packet102to obtain the decrypted identification data of all the multiple decryption devices106. With the decrypted identification data, the server108is then able to re-route the data packet102to each of the intended decryption devices106. When the data packet102is delivered to each of the decryption devices106, the respective decryption devices106then decrypts the corresponding encrypted message encryption keys (stored in the data string in the encrypted-message-key field402of the received data packet102) using the associated private keys of the respective decryption devices106to obtain a copy of the message encryption key. With the message encryption key, each decryption device106is able to decrypt the encrypted-message field406of the data packet102to obtain the decrypted message. It is to be appreciated that in this embodiment, the steps502-508in the method500ofFIG. 5are still performed similarly by the server108. It is also further to be appreciated that the server108does not need to re-encrypt the message, and neither is the server108able to re-encrypt the message, for reasons already stated in the first embodiment and thus not repeated for brevity.

According to a third embodiment, in a slight variation to the first embodiment, instead of the public key of the decryption device106, the public key of the server108is now used to encrypt the message encryption key at step306in the method300ofFIG. 3(as selected by the user of the encryption device104). This means that the server108is then able to access the encrypted message, because the server108can subsequently decrypt the encrypted message encryption key using the private key of the server108. Indeed, with retrieval of the message encryption key, the server108can thus decrypt the encrypted message to access it. That is, this means that the user of the encryption device104may also want the server108to be granted access to the contents of the encrypted message (e.g. for security verification purposes). Other than the above said variation, it will be appreciated that the remaining of the described details of the first embodiment apply to the third embodiment, with no other changes.

In summary, the proposed system100(and corresponding method) enables realisation and implementation of a multiple-key encryption scheme that allows a sender to send encrypted messages to one or multiple recipients by forwarding the encrypted messages through at least one (intermediate) server to perform the re-routing, but however does not permit the server to have the ability to decrypt the encrypted messages. This advantageously ensures that a true end-to-end encryption is maintained and achieved between the sender and the recipient(s), without allowing the server to actually decrypt the encrypted messages.

Also, the proposed system100is configured to allow the sender to make a determination on whether the sender wants the server to be able to access an encrypted message. If the sender wants the server to access the said encrypted message, the sender can select an option whereby the public key of the server may instead be used to encrypt the message encryption key (i.e. the third embodiment). But, if the sender instead wants a true end-to-end encryption, in which the server is unable to decrypt the encrypted message, then the first and second embodiments apply.

To reiterate, the proposed system100and method enable true end-to-end encryption communication between the sender and multiple recipients through the (at least one) server, in which the server is configured to route (and archive) data packets arranged with customized secure packet format having, multiple encryption fields. One of the encryption fields stores an encrypted message intended for the recipient by the sender, and the server is not able to decrypt and access the encrypted message (which is encrypted using a public key of the recipient). Specifically, the secure packet format defines information required by different parties, either for the purpose of archival, re-routing or the actual intended recipient(s). The identification data of the recipient is encrypted to prevent unauthorized access to the recipient's identification information. Particularly, the data packet is encrypted using a proposed multiple-key encryption scheme using a customized encryption software application, and is transmitted to the recipient(s) via a digital messaging platform and is received by the recipient(s) on the same type of digital messaging platform. To access the message, the recipient then decrypts the encrypted message (using the recipient's own private key) to view the message. It will be appreciated that the server receives the same data packet in the process of forwarding the data packet to the recipient, and is able to decrypt specific encryption fields of the data packet, i.e. the encrypted-recipient-information field405of the data packet to determine whether to re-route the data packet or to archive the data packet. However, the server is not configured with an encryption key (i.e. private key of the recipient) for decrypting the encrypted message stored in the data packet. This ensures that in a digital messaging system, where the (intermediate forwarding) server performs a critical role for routing messages between senders and recipients, the server is not able to decrypt the encrypted message and access the associated content. Hence, the proposed system enables a true end-to-end encryption system and scheme for the sender and recipients, but yet allows the server to participate in the forwarding/routing communications without compromising the security and authenticity of the content of the encrypted message transmitted by the sender to the recipient.

To also broadly summarise the proposed method, there is disclosed a method performed by at least one server for processing a data packet from a first computing device to be transmitted to a second computing device, wherein the data packet includes a message encrypted using a first encryption key to form an encrypted message, identification data of the second computing device encrypted using a second encryption key to form encrypted identification data, an encrypted first encryption key formed by encrypting the first encryption key using a third encryption key associated with the second computing device, and an encrypted second encryption key formed by encrypting the second encryption key using an encryption key associated with the server. The method comprises decrypting the encrypted second encryption key; decrypting the encrypted identification data using the decrypted second encryption key; and transmitting the data packet based on the decrypted identification data. Specifically, the encrypted first encryption key is arranged to be decryptable only using a fourth encryption key associated with the second computing device, wherein the third and fourth encryption keys of the second computing device are configured as a pair of asymmetric keys. That is, the pair of asymmetric keys comprises a public key (i.e. the third encryption key) and a private key (i.e. the fourth encryption key) as per the established concept of public-key cryptography.

The described embodiments should not however be construed as limitative. For example, it is to be appreciated that the encryption and decryption devices104,106may be any other types of suitable devices besides mobile computing devices. Also, the respective modules of the encryption device104and decryption device106(if implemented in software) may be programmatically integrated and provided as respective single, complete software applications that are installable on and executable by similar computing devices that may be envisaged for processing the data packet102. Optionally, the single complete software applications may be implemented in entirety in hardware, and a copy of such an implemented hardware is incorporated on each of the encryption device104and the decryption device106. The alternative configurations described in the immediate preceding two statements may also apply mutatis mutandis to the said modules of the server108. Moreover, alternatively, the encryption and decryption program codes may be stored on external storage devices, and are downloadable “on-demand” to be executed on the encryption device and decryption device104,106respectively when required. Further, in the software interface, as displayed by the display module1046of the encryption device104, an option to allow the user to select the server108as the recipient, instead of the decryption device106, may also be displayed. It is also to be appreciated that for a scenario of multiple servers108, the servers18may be collectively configured with a set of load balancing rules which determine where the data packet102is to be forwarded to. Further, the packet format400as shown inFIG. 4may be modified as necessary to include new data fields, or remove existing data fields, based on requirements of an intended application.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary, and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practising the claimed invention.