# US 2010/0166181 A1 · Bandwidth efficient method and system for obscuring the existence of encryption in a communications channel

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- Number: US 2010/0166181 A1
- Document ID: US20100166181A1
- Status: Published application
- Kind: A1
- Application number: 12/345,186
- Filed: 2008-12-29
- Published: 2010-07-01
- Earliest claimed: 2008-12-29
- Assignees: Nortel Networks Limited
- Inventors: Marcus D. LEECH
- Web page: https://patentgrep.com/patent/US20100166181A1

## CPC

- H04L 63/0428: {wherein the data content is protected, e.g. by encrypting or encapsulating the payload}
- G09C 1/00: Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system (cryptographic typewriters G09C3/00)
- H04L 9/00: {Cryptographic mechanisms or cryptographic} arrangements for secret or secure communications; Network security protocols
- H04L 2209/30: Compression, e.g. Merkle-Damgard construction
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G09C: CIPHERING OR DECIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY

## Abstract

A system, method, and network interface obscures the existence of data encryption in a communication network is provided. A set of characters is generated by using a set of encryption keys as an input to a pseudo-random function. Each character corresponds to an index value. The encrypted data is divided into a plurality of parts. Each part is sectioned into a plurality of groups. Each group of the plurality of groups is encoded by mapping the group to a character in the set of characters according to its corresponding index value. The mapped characters are transmitted through the communication network.

## Claims

### Claim 1

A method of obscuring the existence of data encryption in a communication network, the method comprising:
generating a set of characters by using a set of encryption keys as an input to a pseudo-random function, each character corresponding to an index value;
dividing encrypted data into a plurality of parts;
sectioning each part into a plurality of groups;
encoding each part by mapping each group to a character in the set of characters according to its corresponding index value; and
transmitting the mapped characters through the communication network.

### Claim 2 (depends on 1)

The method of claim 1, wherein the set of characters includes sixty-four characters.

### Claim 3 (depends on 2)

The method of claim 2, wherein the sixty-four characters are pseudo-randomly selected from a full set of 256 ASCII characters.

### Claim 4 (depends on 1)

The method of claim 1, further comprising biasing generation of the set of characters such that a probability of selecting ASCII control characters as members of the set is decreased.

### Claim 5 (depends on 1)

The method of claim 1, further comprising biasing generation of the set of characters such that a probability of selecting a group of characters as members of the set is increased.

### Claim 6 (depends on 1)

The method of claim 1, wherein a part is an octet triplet and each group has six bits.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
generating a plurality of character sets; and
using a different character set to encode consecutive parts.

### Claim 8 (depends on 7)

The method of claim 7, wherein an assignment of character sets to parts is pseudo-randomly chosen.

### Claim 9 (depends on 8)

The method of claim 8, wherein the assignment of character sets to parts is chosen using the pseudo-random function used to generate the character sets.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
receiving an encoded data message, the encoded data message including characters in the set of characters;
dividing the encoded data message into groups of characters;
mapping each character to its corresponding index value to recreate the plurality of parts; and
decrypting each part of the plurality of parts.

### Claim 11

A network interface for obscuring the existence of data encryption, the network interface comprising:
a controller operating to:
generate a set of characters by using a set of encryption keys as an input to a pseudo-random function, each character corresponding to an index value;
divide encrypted data into a plurality of parts;
section each part of the plurality of parts into a plurality of groups; and
encode each part by mapping each group of the plurality of groups to a character in the set of characters according to its corresponding index value; and
a communication interface communicatively coupled to the controller, the communication interface operating to transmit the mapped characters through the communication network.

### Claim 12 (depends on 11)

The network interface of claim 11, wherein a part is an octet triplet and each group has six bits.

### Claim 13 (depends on 12)

The network interface of claim 12, wherein the sixty-four characters are pseudo-randomly selected from a full set of 256 ASCII characters.

### Claim 14 (depends on 11)

The network interface of claim 11, wherein the controller further operates to bias generation of the set of characters such that a probability of selecting ASCII control characters as members of the set is decreased.

### Claim 15 (depends on 11)

The network interface of claim 11, wherein the controller further operates to bias generation of the set of characters such that a probability of selecting a group of characters as members of the set of characters is increased.

### Claim 16 (depends on 11)

The network interface of claim 11, wherein the controller further operates to:
generate a plurality of character sets; and
use a different character set to encode consecutive parts.

### Claim 17 (depends on 16)

The network interface of claim 16, wherein an assignment of character sets to parts is fixed.

### Claim 18 (depends on 16)

The network interface of claim 16, wherein an assignment of character sets to parts is pseudo-randomly chosen.

### Claim 19 (depends on 11)

The network interface of claim 11, wherein the communication interface further operates to receive an encoded data message, the encoded data message including characters in the set of characters; and
wherein the controller further operates to:
divide the encoded data message into a plurality of groups of characters;
map each character to its corresponding index value to recreate the plurality of parts; and
decrypt each part of the plurality of parts.

### Claim 20

A system for obscuring the existence of data encryption in a communication network, the system comprising:
a first network interface operating to:
generate a set of alphabet characters by using a set of encryption keys as an input to a pseudo-random function, each alphabet character corresponding to an index value;
divide encrypted data into a plurality of parts;
section each part into a plurality of groups;
encode each part by mapping each of the plurality of groups to a character in the set of characters according to its corresponding index value; and
transmit the mapped characters through the communication network; and
a second network interface operating to:
receive an encoded data message, the encoded data message including the mapped characters;
divide the encoded data message into a plurality of groups of characters;
map each character to its corresponding index value to recreate the plurality of parts; and
decrypt each part of the plurality of parts.