# US 2014/0208104 A1 · Id-based encryption and signature method and terminal

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- Number: US 2014/0208104 A1
- Document ID: US20140208104A1
- Status: Published application
- Kind: A1
- Application number: 14/122,935
- Filed: 2012-05-31
- Published: 2014-07-24
- Earliest claimed: 2011-05-31
- Assignees: Snu R&Db Foundation; Samsung Sds Co., Ltd.
- Inventors: Hyo Jin Yoon; Seon Young Lee; Tae Kyoung Kwon; Soo Yeon Shin; Jung Hee Cheon
- Web page: https://patentgrep.com/patent/US20140208104A1

## CPC

- H04L 63/0428: {wherein the data content is protected, e.g. by encrypting or encapsulating the payload}
- H04L 9/3073: {involving pairings, e.g. identity based encryption [IBE], bilinear mappings or bilinear pairings, e.g. Weil or Tate pairing}
- H04L 9/3247: {involving digital signatures}
- H04L 63/0442: {wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption (cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30)}
- H04L 63/126: {the source of the received data}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Provided are an identity (ID)-based encryption and signature method and a terminal that use an ID of a transmitter or a receiver as a part of the filename or the extension of a file transmitted to the receiver by the transmitter. Accordingly, it is possible to enable a user to visually recognize that the file has been provided with security. Also, it is possible to designate an associated program for the extension, and the user can easily decrypt or verify the file through the designated associated program.

## Claims

### Claim 1

A terminal, comprising:
a processor;
a storage, accessible to the processor, configured to hold at least part of a file;
a transmitter configured to transmit the file to a receiver; and
an identity-based (ID-based) processing module, implemented by the processor, and configured to implement at least one pre-transmission file security measure with respect to the file using a component ID of one of the transmitter and the receiver to provide a processed file.

### Claim 2 (depends on 1)

The terminal of claim 1, wherein:
the ID-based processing module is further configured to use the component ID as at least a portion of a file identifier of the processed file; and
the portion of the file identifier is at least one of a part of a filename of the file and an extension of the file.

### Claim 3 (depends on 1)

The terminal of claim 1, wherein:
the at least one pre-transmission file security measure is encrypting the file;
the component ID is the receiver ID; and
the ID-based processing module is further configured to implement the encrypting of the file using the receiver ID as a public key.

### Claim 4 (depends on 1)

The terminal of claim 1, wherein:
the at least one pre-transmission file security measure is putting an electronic signature to the file;
the component ID is the transmitter ID; and
the ID-based processing module is further configured to implement the putting of the electronic signature to the file using a secret key corresponding to the transmitter ID.

### Claim 5 (depends on 2)

The terminal of claim 2, wherein:
the at least one pre-transmission file security measure is encrypting the file;
the component ID is the receiver ID; and
the ID-based processing module is further configured to use the receiver ID as the portion of the file identifier.

### Claim 6 (depends on 2)

The terminal of claim 2, wherein:
the at least one pre-transmission file security measure is putting an electronic signature to the file using a secret key corresponding to the component ID;
the component ID is the transmitter ID; and
the ID-based processing module is further configured to use the component ID as the portion of the file identifier.

### Claim 7 (depends on 1)

The terminal of claim 1, wherein, the ID-based processing module is further configured to insert information indicating the pre-transmission file security measure in a header of the processed file.

### Claim 8 (depends on 1)

The terminal of claim 1, wherein the ID-based processing module is further configured to use a first extension to indicate that the pre-transmission file security measure is encrypting the file and to use a second extension to indicate that the pre-transmission file security measure is putting an electronic signature to the file.

### Claim 9 (depends on 8)

The terminal of claim 8, wherein:
the component ID is the receiver ID;
the pre-transmission file security measure is encrypting the file; and
the ID-based processing module is further configured to set a respective name of the processed file using an original filename of the file, an original extension of the file, a distinguisher, and the component ID;
wherein the distinguisher distinguishes between the original filename of the file and the component ID.

### Claim 10 (depends on 2)

The terminal of claim 2, wherein:
the component ID comprises a plurality of respective receiver IDs; and
the ID-based processing module is further configured uses the plurality of respective receiver IDs as the portion of the file identifier.

### Claim 11 (depends on 10)

The terminal of claim 10, wherein the ID-based processing module is further configured to:
implement the pre-transmission file security measure in a hierarchical manner using the plurality of respective receiver IDs in sequence; and
insert information indicating the pre-transmission file security measure in a header of the processed.

### Claim 12 (depends on 10)

The terminal of claim 10, wherein the ID-based processing module is further configured to use a first extension of the file identifier to indicate that the pre-transmission file security measure is encrypting the file and to use a second extension of the file identifier to indicate that the pre-transmission file security measure is putting an electronic signature to the file.

### Claim 13 (depends on 1)

The terminal of claim 1, wherein the storage is further configured to store at least one receiver ID, at least one transmitter ID, and at least one secret key respectively corresponding to the at least one transmitter ID.

### Claim 14 (depends on 13)

The terminal of claim 13, wherein:
when the pre-transmission file security measure is encrypting the file, the ID-based processing module is further configured to encrypt the file using the at least one receiver ID as a public key; and
when the pre-transmission file security measure is putting an electronic signature to the file, the ID-based processing module is further configured to use a secret key corresponding to the at least one transmitter ID.

### Claim 15 (depends on 1)

The terminal of claim 1, wherein the ID-based processing module is further configured to implement two different pre-transmission file security measures, in sequence, with respect to the file, including, in any order:
encrypting using the receiver ID as a public key, and
putting an electronic signature using a secret key corresponding to the transmitter ID.

### Claim 16 (depends on 1)

The terminal of claim 1, further comprising a Multipurpose Internet Message Extensions (MIME) header generator configured to generate a MIME header including information indicating the pre-transmission file security measure taken with respect to the file, wherein the MIME header is transmitted by the transmitter together with the processed file.

### Claim 17

A terminal, comprising:
a processor;
a storage, accessible to the processor, configured to hold at least part of a received file;
a receiver configured to receive the received file from a transmitter; and
an identity-based (ID-based) processing module, implemented by the processor, and configured to implement at least one post-reception file security measure with respect to the received file to generate a finished file using a component ID, of one of the transmitter and the receiver, provided in at least a portion of a file identifier of the received file.

### Claim 18 (depends on 17)

The terminal of claim 17, wherein:
the post-reception file security measure is decrypting the received file;
the component ID is the receiver ID; and
the ID-based processing module is further configured to decrypt the received file using a secret key corresponding to the receiver ID.

### Claim 19 (depends on 17)

The terminal of claim 17, wherein:
the post-reception file security measure is verifying an electronic signature of the received file;
the component ID is the transmitter ID; and
the ID-based processing module is further configured to verify the electronic signature using the transmitter ID.

### Claim 20 (depends on 17)

The terminal of claim 17, wherein the ID-based processing module is further configured to make a determination as to whether the received file has been previously processed with a pre-transmission file security measure by checking a header pertaining to the received file.

### Claim 21 (depends on 17)

The terminal of claim 17, wherein:
the ID-based processing module is further configured to respond to detecting a first file extension in the file identifier of the received file by decrypting the received file, using a secret key corresponding to the receiver ID, as the post-reception file security measure; and
the ID-based processing module is further configured to respond to detecting a second file extension in the file identifier of the received file by verifying an electronic signature of the received file, using the transmitter ID, as the post-reception file security measure.

### Claim 22 (depends on 17)

The terminal of claim 17, wherein the ID-based processing module is further configured to respond, to detecting in the file identifier a plurality of receiver IDs, by decrypting the received file in a hierarchical manner using secret keys respectively corresponding to the plurality of receiver IDs, in sequence.

### Claim 23 (depends on 17)

The terminal of claim 17, wherein the ID-based processing module is further configured to respond, to detecting in the file identifier a plurality of transmitter IDS, by verifying an electronic signature of the file using the plurality of transmitter IDs in sequence.

### Claim 24 (depends on 17)

The terminal of claim 17, wherein the ID-based processing module is further configured to implement two post-reception file security measures in sequence with respect to the received file, including, in any order:
decrypting using a secret key corresponding to the receiver ID; and
verifying the electronic signature using the transmitter ID.

### Claim 25 (depends on 17)

The terminal of claim 17, further comprising a Multipurpose Internet Message Extensions (MIME) header checker configured to check a MIME header, pertaining to the received file, for information indicating a pre-transmission file security measure used with respect to the received file;
wherein:
when the MIME header checker detects information indicating that the pre-transmission file security measure was encryption, the ID-based processing module responds by decrypting the received file using a secret key corresponding to the receiver ID; and
when the MIME header checker detects information indicating that the pre-transmission file security measure was putting an electronic signature, the ID-based processing module responds by verifying the electronic signature using the transmitter ID.

### Claim 26

An identity (ID)-based encryption and signature method, comprising:
implementing at least one pre-transmission file security measure with respect to a file, using a component ID, to provide a processed file;
wherein the at least one pre-transmission file security measure is one of encrypting the file, and putting an electronic signature to the file;
wherein the component ID is one of a transmitter ID and a receiver ID; and
wherein the implementing of the at least one pre-transmission file security measure is performed using a hardware processor.

### Claim 27 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising using the component ID as at least a portion of a file identifier of the file.

### Claim 28 (depends on 26)

The ID-based encryption and signature method of claim 26, wherein the at least one pre-transmission file security measure is the encrypting of the file, and the component ID is the receiver ID used as a public key

### Claim 29 (depends on 26)

The ID-based encryption and signature method of claim 26, wherein:
component ID is the transmitter ID; and
the at least one pre-transmission file security measure is the putting of the electronic signature to the file using a secret key corresponding to the transmitter ID.

### Claim 30 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising:
generating a header for the processed file; and
inserting information in the header indicating the pre-transmission file security measure taken with respect to the file.

### Claim 31 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising generating a file identifier of the processed file including a first extension when the pre-transmission file security measure is the encrypting of the file, and including a second extension when the pre-transmission file security measure is the putting of the electronic signature to the file.

### Claim 32 (depends on 31)

The ID-based encryption and signature method of claim 31, wherein:
the generating of the file identifier for the processed file further comprises setting an original filename of the processed file, an original extension of the processed file, a distinguisher, and the receiver ID as a filename of the encrypted file; and
the distinguisher distinguishes between the original filename and the receiver ID.

### Claim 33 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising, when the receiver ID is plural in number, using the plurality of IDs as the at least a portion of the file identifier.

### Claim 34 (depends on 33)

The ID-based encryption and signature method of claim 33, further comprising:
implementing the measure hierarchically using the plurality of IDs in sequence; and
inserting information in a header of the processed file indicating the implemented pre-transmission file security measure.

### Claim 35 (depends on 33)

The ID-based encryption and signature method of claim 33, further comprising:
implementing the pre-transmission file security measure hierarchically using the plurality of IDs in sequence; and
generating a file identifier of the processed file including a first extension when the pre-transmission file security measure is the encrypting of the file, and including a second extension when the pre-transmission file security measure is the putting of the electronic signature to the file.

### Claim 36 (depends on 26)

The ID-based encryption and signature method of claim 26, wherein the implementing of the pre-transmission file security measure is performed so that two sequential pre-transmission file security measures are performed with respect to the file, including, in any order:
encrypting the file using the receiver ID as a public key; and
putting the electronic signature to the encrypted file using a secret key corresponding to the transmitter ID.

### Claim 37 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising:
generating a Multipurpose Internet Message Extensions (MIME) header including information indicating the pre-transmission file security measure; and
transmitting the MIME header together with the processed file.

### Claim 38 (depends on 26)

The ID-based encryption and signature method of claim 26, further comprising:
receiving a processed file as a received file; and
implementing a post-reception file security measure with respect to the received file to provide a finished file;
wherein:
the at least one post-reception file security measure includes one of decrypting the received file, and verifying an electronic signature of the received file; and
when at least a portion of the file identifier of the received file includes the component ID, the post-reception file security measure is implemented using the component ID.

### Claim 39 (depends on 38)

The ID-based encryption and signature method of claim 38, wherein, when the post-reception file security measure is the decrypting of the received file and the component ID is the receiver ID, a secret key corresponding to the receiver ID is used in the decrypting.

### Claim 40 (depends on 38)

The ID-based encryption and signature method of claim 38, wherein, when the post-reception file security measure is the verifying of the electronic signature of the received file and the component ID is the transmitter ID, the transmitter ID is used in the verifying.

### Claim 41 (depends on 38)

The ID-based encryption and signature method of claim 38, further comprising:
receiving a header pertaining to the received file;
determining, based on the header, one or more pre-transmission file security measures previously implemented with respect to the received file.

### Claim 42 (depends on 38)

The ID-based encryption and signature method of claim 38, further comprising:
checking an extension of the received file;
when the extension is a first extension, decrypting the received file using a secret key corresponding to the receiver ID;
when the extension is a second extension, verifying an electronic signature of the received file using the transmitter ID.

### Claim 43 (depends on 38)

The ID-based encryption and signature method of claim 38, further comprising:
the portion of the file identifier of the received file including the receiver ID, in plural, as the component ID;
responding to the presence of the receiver ID in plural by hierarchically decrypting the received file using secret keys, respectively corresponding to the plurality of receiver IDs, in sequence.

### Claim 44 (depends on 38)

The ID-based encryption and signature method of claim 38, further comprising:
the portion of the file identifier of the received file including the transmitter ID, in plural, as the component ID;
responding to the presence of the transmitter ID in plural by verifying an electronic signature of the received file using the plurality of transmitter IDs in sequence.

### Claim 45 (depends on 38)

The ID-based encryption and signature method of claim 38, wherein:
when the pre-transmission file security measure implemented with respect to the received file includes the encrypting and then the putting of an electronic signature to the encrypted file, the post-reception file security measure includes:
verifying the electronic signature using the transmitter ID, and then
decrypting using a secret key corresponding to the receiver ID; and
when the pre-transmission file security measure implemented with respect to the received file includes the putting of the electronic signature to the file and then the encrypting the file with the electronic signature, the post-reception file security measure includes:
decrypting using the secret key corresponding to the receiver ID, and then
verifying the electronic signature using the transmitter ID.

### Claim 46 (depends on 38)

The ID-based encryption and signature method of claim 38, further comprising:
receiving a MIME header pertaining to the received file; and
implementing the post-reception file security measure based on an indication included the MIME header.

### Claim 47

A terminal, comprising:
a processor;
a storage, accessible to the processor, configured to hold at least part of a file;
a transmitter configured to transmit the file to a receiver; and
an identity-based (ID-based) processing module, implemented by the processor, and configured to implement a pre-transmission file security measure with respect to the file to provide a processed file;
wherein the pre-transmission file security measure is implemented using at least a portion of a file identifier of the processed file.

### Claim 48 (depends on 47)

The terminal of claim 47, wherein the ID-based processing module is further configured to generate the file identifier of the processed file using a component ID of at least one of the transmitter and the receiver.

### Claim 49

A terminal, comprising:
a processor;
a storage, accessible to the processor, configured to hold at least part of a received file;
a receiver configured to receive the received file from a transmitter; and
an identity-based (ID-based) processing module, implemented by the processor, and configured to implement at least one post-reception file security measure with respect to the received file to provide a finished file;
wherein the post-reception file security measure is implemented using at least a portion of a file identifier of the received file.

### Claim 50 (depends on 49)

The terminal of claim 49, wherein the portion of the file identifier of the received file is a component ID of one of the transmitter and the receiver.