Brute-force resistant encryption method

Abstract

The present invention is a method for encrypting a dataset, comprising the design of an algorithm, called an alteration algorithm, which modifies or deletes one or more selected parts of the information in the dataset to obtain a new dataset, and the use of this algorithm to modify all or part of the original file. The originality of the method lies in the fact that the choice of information to be deleted or modified, such as replacing it with other, different data, results in several plausible datasets, among which it is impossible to determine which is correct. Therefore, a brute-force decryption attempt cannot recover the encrypted data. Abstract Figure: Fig. 1

Description

Title of invention: Brute force resistant encryption method Technical field

[0001] The invention is a means of encrypting a set of data which resists decryption attempts by brute force technique. Prior art

[0002] Widely used encryption algorithms such as RSA and elliptic curve cryptography (ECC) are known, which quantum computers could potentially break, making digital identities vulnerable to theft, fraud and exploitation, and more generally putting virtually all Internet security at risk. Technical problem

[0003] The advent of quantum computing and advances in artificial intelligence will make it possible to find all encryption keys in a very short time, using brute force attacks.

[0004] Various solutions are being studied, such as replacing cryptography algorithms with quantum-resistant algorithms, improving key lengths, or using post-quantum cryptography, but the transition to these methods may take time.

[0005] The objective of the present invention is to resist attempts to decrypt files by brute force. Brief description of the drawings

[0006] The invention will be well understood, and other aims, advantages and characteristics thereof will appear more clearly on reading the description which follows, which is illustrated by [Fig.l].

[0007] [Fig.l] is a diagram showing a procedure for encrypting and decrypting a data set called an original file comprising the following steps: 1. analysis of the original file to discover its nature and select the information called original information, which is characteristic of the original file, 2. creation of an algorithm called an alteration algorithm which modifies or deletes original information, 3. modification of all or part of said original file, by the alteration algorithm, to obtain the file called altered file, and calculation of an information element called meaningful message containing the inverse algorithm of the alteration algorithm or a means of obtaining it, 4. sending the altered file and the significant message via networks of different natures, 5. decryption of the corrupted file. Statement of the invention

[0008] The invention is a method for encrypting a set of data called an original file comprising the following steps: 1. design of an algorithm called an alteration algorithm which modifies or deletes one or more selected parts of the information of said original file, hereinafter called original information, to obtain a set of data called an altered file containing information called altered information, said alteration algorithm being reversible in the sense that there is an algorithm called an inverse algorithm making it possible to replace in said altered file said altered information with said original information, 2. modification of all or part of said original file, by said alteration algorithm, to obtain said altered file, 3. calculation of an information element called a meaningful message containing said inverse algorithm or a means of obtaining it, characterized in that the choice of said original information is such that their replacement by other data different from said original information results in a plausible data set different from said original file. Detailed description of the invention

[0009] Decrypting an encrypted file by the brute force method consists of imagining a very large number of decryption keys and trying to decrypt the file in question by numerous successive attempts made with each of these imagined decryption keys.

[0010] Decryption is considered successful when a plausible solution has been obtained, the word plausible meaning above and below something that can be held to be true, or acceptable, or admissible, or credible, or imaginable, or possible, or probable, or admissible, or valid, or likely. This can for example be an identity photograph if the encrypted file is an encrypted photo, or the text of a contract if it is a contract.

[0011] If the decryption results in an implausible solution, it is considered a failure.

[0012] If it results in a plurality of plausible solutions, the best quantum artificial intelligence cannot determine which is the correct solution.

[0013] The present invention is based on the principle of carrying out a prior modification of the encrypted information such that an attempt at decryption results in a solution incorrect or simply different, or that several decryption attempts result in plausible solutions between which the decryption method cannot choose which is the correct one.

[0014] The alteration algorithm modifies or deletes one or more selected parts of the information in said original file, to reduce its significant value. The person skilled in the art knows very well what the important information in an image or text, and in general in any file containing information, is and can select it. He can then either modify it or simply delete it.

[0015] In the case where a modification is a deletion of information, the decryption attempt consists of trying to replace the deleted parts with imagined information allowing plausible solutions to be reached, and we find ourselves in the same case as in that of a modification which is not a deletion of information, in the sense that brute force seeks numerous solutions allowing the original file to be found.

[0016] The alteration algorithm must be reversible, in the sense that there must exist an algorithm called an inverse algorithm allowing the altered information to be replaced in the altered file by the original information, but this is the case for all encryption algorithms which must allow decryption.

[0017] This inverse algorithm can be described in clear text in an information element called a meaningful message, but it can also be recorded on a computer or in a memory, and in this case the meaningful message can only include the reference or the address at which this algorithm can be obtained.

[0018] The altered file must not contain any information allowing it to be linked to a meaningful message, so that hacking the server containing the altered files does not allow the meaningful message to be found which makes the altered file intelligible.

[0019] A secure implementation consists of sending the altered file and the meaningful message separately to the person authorized to decrypt the altered file, by different means of communication, and without either of these two elements allowing it to be brought closer to the other.

[0020] In the application to the identification of persons, it is for example recommended to send to the holder of a digital identity the altered file comprising data rendered unintelligible from his biometric characteristics either by an Internet link allowing it to be downloaded, or by an email, and to send the significant message by text message or by post or even by hand delivery.

[0021] For maximum efficiency, the modification of the original file made by the alteration algorithm concerns essential data 1- to make it more difficult to understand or more difficult to use for the use case for which it is intended, that is to say on data without which the altered file is no longer useful for the desired objective, 2- and so that the replacement of this selected information by other data produces a plausible file.

[0022] The alteration algorithm is therefore advantageously established after an analysis of the original file to discover its nature and select the original information to be deleted or modified.

[0023] Such an operation is accessible to those skilled in the art, but can advantageously be entrusted to an artificial intelligence specially trained for this.

[0024] The meaningful message may also contain information deleted or modified from said original file by the alteration algorithm. This deleted or modified information may also be integrated into a data set to which said meaningful message provides access.

[0025] This information may be the title of the protected information or some of its essential characteristics. For example, it may be all the variable information inserted in a form. This makes it possible, for example, to sign and communicate identities or certificates to third parties, who may, if necessary, obtain additional information, such as an identity photo or a certified copy of a contract, by submitting the meaningful message to the competent server.

[0026] All or part of the significant message and / or the altered file are advantageously provided with a means of controlling their own integrity, such as a hash, a checksum for example, and / or a digital signature making it possible to guarantee their non-repudiation and, where appropriate, to authenticate their author.

[0027] In the case where the original file is the description of a security marking characterized by a series of pixels characteristic of color, and / or brightness, and / or light reflection varying or not depending on the point of view and / or the lighting conditions, the alteration algorithm can be very simple since any modification or deletion of data is essential, and any solution can be plausible.

[0028] In the case where the original file is a descriptive file of an object or a person, the alteration algorithm advantageously comprises the modification or deletion of dimensional values ​​of the object or person considered;

[0029] In the case where the original file includes an image such as a drawing, a photograph or a video of an object or a person, the alteration algorithm advantageously includes one or more deformations of the image considered and / or a combination between said image and another image.

[0030] In the case where the original file contains words and / or digital data, for example a text such as the description of a method or a device, a contract, an order, a report, a press article, the alteration algorithm advantageously includes the replacement of certain of said words and / or said digital data by other different words and / or digital data, advantageously mentions essential to the interpretation or understanding of the text in question.

[0031] In the case where the original file is a key controlling access to a physical or digital domain, a solution can be considered plausible as long as it opens access, even if the domain is not the right one. It is advantageous if the physical or digital domains to which access can be given by brute force resemble the one to which the original file gives access so that the corresponding solutions are considered plausible.

[0032] Advantageously, the alteration algorithm successively comprises one or more alterations according to at least two of those described above in paragraphs 27 to 31.

[0033] Advantageously, more than a hundred decryption attempts should result in different plausible solutions, but an improved version of the present method can also be such that several thousand decryption attempts result in different plausible solutions.

[0034] A single altered file can be combined with several different meaningful messages. In combination with a single altered file, different so-called secondary meaningful messages can, for example, produce an identity card or passport, a visa, a driver's license, a social security card, a disability certificate, a work stoppage certificate, an insurance certificate, a power of attorney, a membership card, an invitation, a train ticket, a payment card, etc., or simply the certification that the original file exists and can be decrypted by an authorized person.

[0035] It is advantageous that a so-called primary meaningful message, for example issued by a public authority or a trusted third party, can be used by third parties such as banks, transport companies, event organizers, administrations and private companies and even individuals to generate such secondary meaningful messages.

[0036] To enable the transmission of secondary significant messages, it is advantageous for the so-called primary significant message that enabled their generation to include a part that is easily identified as having to be reproduced in a secondary significant message so that the latter can be combined with the altered file associated with the primary significant message, or that it includes a reference with which to associate the secondary significant message.

[0037] The decryption algorithm called inverse algorithm is advantageously provided with an algorithm reference and the significant message includes a means of obtaining it, for example its reference in a database.

[0038] It is desirable that the means of decrypting the corrupted file be provided to a person or computer responsible for decryption only after verification that the person or computer in question is authorized to decrypt the corrupted file.

[0039] Strong identification is therefore desirable. It makes it possible, on the one hand, to determine which part of the population or computers can decrypt the corrupted file, but also to limit the number of successive attempts to decrypt the corrupted file, which would not be possible without strong identification, since a fraudster could use several different identities, for example several IP addresses, to carry out a large number of successive attempts in a limited time.

[0040] The meaningful message can advantageously take the form of a character string, a barcode or an internet link.

[0041] It may advantageously include references or links to the altered file, and / or several links to distinct parts of this file which may be deposited at different addresses.

[0042] One or more so-called complementary files may be recorded and be accessible by the alteration algorithm and / or by the altered file and / or by the significant message or a combination of several of these three elements, and may contain data and / or links to data recorded with trusted third parties (for example a medical file, a diploma, etc.).

[0043] In a more secure version, decryption of the corrupted file can only be performed by a secure computer. The algorithms can then remain secret.

[0044] In this more secure mode of implementation, the meaningful message and / or the alteration algorithm and / or the inverse algorithm are advantageously kept confidential by a secure computer, which uses this or these elements to combine them together.

[0045] In an even more secure version, the method involves the reception by a server of a set of data called the attempt file and the comparison between this attempt file with data obtained by combining the altered file and the significant message, and the sending to a designated third party of the result of this comparison without sending them either the original file or the attempt file.

[0046] This prevents the original file from being distributed. The user simply has to send what he thinks is the original file, or what this set of data represents, so that the secure computer can respond yes or no as to whether what he has sent is authentic or not.

[0047] Except when it is only a matter of issuing original data sets to reconstruct a not very secret file such as an identity photo, the main aim of which is to prevent it from being used to create databases allowing While it is important to prevent unauthorized persons from manufacturing counterfeit documents or identifying individuals without their consent, this more secure implementation is especially recommended for the protection of other biometric characteristics such as fingerprints or DNA signatures, or for highly confidential documents.

[0048] The means for decrypting said altered file advantageously comprises carrying out a prior operation which takes more than 10 seconds or at least 1 second.

[0049] This prior operation is advantageously unpredictable so that a fraudster cannot produce a recording of a prior operation carried out previously, and for example captured on a communications network.

[0050] In communications between a sender and a receiver of a protected data set according to the present invention, whether these communications are direct or pass through an intermediate server, the altered file and the significant message are advantageously transmitted by networks of different natures. One can for example be transmitted by the web and the other by text message.

[0051] This has the advantage of preventing a third party from bringing together the altered file and the meaningful message to obtain the original file.

[0052] The present invention is also a set of data protected by an encryption method according to one of the methods described above.

[0053] It is also an algorithm for altering an original file consisting of modifying all or part of this original file, according to any one of the methods described above, and a decryption method such as those described above. Applications

[0054] The methods described above apply to the storage or transmission of all data requiring confidentiality. They can be applied to all forms of files representing images, music, videos, software, graphics, engineering plans, texts such as medical prescriptions, medical examination reports, expert reports, contracts, payment orders, etc.

[0055] The main applications are - digital identity, the holder of which may only keep a signed meaningful message, in printed or electronic form, to identify himself, - medical prescriptions, certificates and attestations of all kinds, contracts, purchase orders, invoices, etc. which can be easily authenticated by their recipients, - software, music or video on demand services, newspapers and magazines, video games, means of controlling connected objects, - and generally the securing of all types of large or sensitive data.

Claims

Claims

1. Method for encrypting a set of data called an original file comprising the following steps:

1. designing an algorithm called an alteration algorithm which modifies or deletes one or more selected parts of the information of said original file, hereinafter called original information, to obtain a set of data called an altered file containing information called altered information, said alteration algorithm being reversible in the sense that there is an algorithm called an inverse algorithm making it possible to replace in said altered file said altered information with said original information, 2. modification of all or part of said original file, by said alteration algorithm, to obtain said altered file, 3.calculation of an information element called a meaningful message containing said inverse algorithm or a means of obtaining it, characterized in that the choice of said original information is such that their replacement by other data different from said original information results in a plausible data set different from said original file.

2. Encryption method according to claim 1 characterized in that said alteration algorithm is established after an analysis of said original file to discover its nature and select said original information.

3. Encryption method according to any one of the preceding claims, characterized in that information deleted or modified from said original file by said alteration algorithm is integrated into said significant message or into a set of data to which said significant message allows access.

4. Encryption method according to any one of the preceding claims, said original file comprising an image, characterized in that said alteration algorithm comprises one or more deformations of said image.

5. Encryption method according to any one of the preceding claims, said original file comprising an image, characterized in that said alteration algorithm comprises a combination between said image and another image.

6. An encryption method according to any one of the preceding claims- characterized in that the means for decrypting said altered file is only provided to a person or computer responsible for decryption after verification that said person or computer is authorized to decrypt said altered file.

7. Encryption method according to any one of the preceding claims, characterized in that one or more so-called complementary files can be recorded and be accessible by the alteration algorithm and / or by the altered file and / or by the significant message or a combination of several of these three elements.

8. Encryption method according to any one of the preceding claims, characterized in that the decryption of the file can only be carried out by a secure computer which confidentially keeps said altered file and / or said alteration algorithm and / or said reverse algorithm.

9. Encryption method according to any one of the preceding claims, characterized in that it comprises the reception by a server of a set of data called the tentative file and the comparison between said tentative file with data obtained by combining said altered file and said significant message, and the sending to a designated third party of the result of this comparison without sending them either said original file or said tentative file.

10. A data set protected by an encryption method according to any one of the preceding claims.

Images