Audio Encryption via Time Block Permutation
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Solution Overview
Problem
Existing encryption methods for voice information fail to prevent unauthorized playback and interception while maintaining compatibility with standard audio formats like MPEG2 Layer 3 and MPEG2/4 AAC, and do not ensure error-free processing or unintelligibility of voice content.
Innovation Solution
The method involves subdividing discrete signal samples into time blocks, coding them, and altering their order using a permutation vector to introduce temporal discontinuity, ensuring high security and compatibility with standard codings by creating encrypted data blocks that are permutable without causing errors in decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If frequency range line permutation is used to encrypt audio data, then music signals become largely unrecognizable, but voice information remains intelligible because the spectral composition is not critical for voice intelligibility
Solution Approach 1:
The encryption method segments the audio signal into successive time blocks and processes them independently through a lookup table-based permutation system. This segmentation allows the encryption to operate on discrete units while maintaining the ability to reconstruct the original signal sequence during decryption, thereby preventing voice intelligibility in unauthorized playback while ensuring reliable decryption for authorized users
Solution Approach 2:
The patent introduces a temporal dimension to the encryption by permuting time blocks rather than just frequency components. The lookup table stores permutation patterns that reorder time blocks in a pseudo-random sequence, adding temporal discontinuity that destroys voice intelligibility while allowing complete reconstruction when the same permutation is applied during decryption
2Reliability
If strong encryption is applied to discrete signals, then security is improved, but errors may occur in unauthorized processing and compatibility with standard codings may be compromised
Solution Approach 1:
The encryption system performs preliminary actions by pre-computing and storing permutation patterns in a lookup table before the actual encryption process. The lookup table contains pre-calculated time block permutations that are applied during encryption, ensuring consistent and error-free operation while maintaining compatibility with standard coding formats through deterministic reconstruction
Solution Approach 2:
The patent changes the temporal parameter of the audio signal by permuting time blocks according to lookup table entries. This parameter transformation (reordering time blocks) provides strong encryption while maintaining compatibility with standard codings because the permutation is reversible and does not alter the fundamental structure or format of the encoded data blocks
3Loss of information
If temporal discontinuity is introduced by permuting time blocks, then voice intelligibility is prevented, but the signal may cause crackling or rustling artifacts when played back without decryption
Solution Approach 1:
The lookup table acts as an intermediary that mediates between the original time block sequence and the permuted encrypted sequence. During unauthorized playback, the permutation disrupts temporal continuity and prevents voice intelligibility. During authorized decryption, the same lookup table provides the inverse permutation, restoring temporal continuity and eliminating audio artifacts like crackling or rustling
Data Source
AI summary
In an inventive method for encrypting a discrete signal consisting of successive samples the successive samples are subdivided into successive time blocks, and the successive time blocks are then encoded into encoded data blocks having a predetermined order. Subsequently, the predetermined order of the encoded data blocks is altered in accordance with a predetermined interchange specification. The underlying findings are that a very high level of security of the encryption may be achieved by introducing temporal discontinuity, and that the occurrence of errors in unauthorized processing of signals encoded in such a manner maybe prevented, and the compatibility with standard codings may be ensured by performing the alteration of the chronological order in accordance with a coding of the discrete signal, i.e. with regard to encoded data blocks into which an encoder encodes the discrete signal.