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Using audio-visual data as content-key in Cryptography

IP.com Disclosure Number: IPCOM000250491D
Publication Date: 2017-Jul-25
Document File: 4 page(s) / 232K

Publishing Venue

The IP.com Prior Art Database


Technical contribution: Minor Length of time the claimed invention is expected to be used: < 5 years Evaluator questions from disclosure POU8-2016-0060 at time of final decision 21-Jun-2016

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Using Audio-Visual Data as Content-Key in Cryptography


Disclosed are a system and method to improve security and performance of cryptography systems using an audio-visual database as the content key.

The two primary types of symmetric cryptography systems for secure communication are stream cipher (e.g., eStream(Grain 128a)) and block cipher (e.g., AES-128 or 3DES). Each system has its limitations. With stream cipher, a key never be used twice. Another limitation is the periodicity of pseudo-random key generator. Block cipher is suitable only for the encryption of a single block under a fixed key and it needs more machinery. There is always a need to improve security and performance.

Figure 1: Existing Public Key Crypto System (PKCS)

The novel contribution is a system and method that uses an audio-visual database as the content key (different usage from steganography); it is a database model of AV content. The length of each piece of AV content is different. The process uses a session key as the concatenation of ‘r’ indexes of the database to retrieve AV content.

To accommodate cases in which the message stream is longer than the AV database content at index ‘k1’ to ‘kr’, multiple options are built into the database:

 Wrap the content to beginning  Move to the next index content  We can have pre-defined skip-index in AV database

The system provides a periodic refresh of AV database with new content. There is only one call to random number generation for each session.

The content is encrypted/decrypted faster due to a stream cipher. In addition, the content-key is reusable, with no security risk.

The main component of the novel approach is a shared audio visual (AV) database. Like a streaming movie video database, it contains n files. Each file should be of a different length to avoid periodicity detection.

Following the AV database, the components and process are:

1. Session key establishment that uses an RSA algorithm*

A. Set a large integer “n” such that n=p*q where “p” and “q” are prime numbers

B. Find “e” and “d” such that “e*d = 1 (mod phi)” where phi=(p-1)*(q-1)

C. Public key is (n,e). Private key is (n,d)

2. Compute a random number ‘k’ of “r * log2(N)” bits

A. It is session key

B. It gives “r” keys: each an index for AV database

3. Encrypt ‘k’ as “c = k^e mod n” and send to receiver.

4. Decrypt it...