Patent Application
20200099508
The disclosed invention is in the field of cryptography.
Computer networks and systems often comprise sensitive information that must be protected at all times to ensure the reliability and confidentiality of the systems and networks. One common approach to securing sensitive information is cryptography. There are many types of cryptography available for a myriad of different applications. One such type of cryptography is RSA cryptography, which involves the use of randomly generated prime numbers that are kept private. These numbers are then used to calculate different private keys. RSA cryptography uses the private keys in conjunction with public keys, which are shared with entities that wish to communicate with the entity that generated the private keys. Messages are encrypted using the public keys of a device receiving the message, and decrypted using the private key(s) of the device receiving the message.
The problem with RSA cryptography is that it is computationally expensive due to the possibility of using division operations, which makes RSA cryptography impractical for a cost-effective solution for real-time data transmissions.
Another type of cryptography is Chaotic Neural Network (CNN) cryptography. CNN cryptography is a faster method of encrypting information than RSA cryptography, while still maintaining security comparable to that of more computationally expensive ciphers. This permits CNN cryptography to have applications in devices that do not have as much computational power as a desktop computer.
The problem with CNN cryptography is that the initial values shared between devices are not secured, thus there is some vulnerability.
Therefore, there is a need for systems and methods to perform secure real-time encryption and decryption using minimal processing power in a Defense-in Depth (DiD) approach to help secure systems from cyberattack, for example industrial control systems.
The DiD strategy is a driving philosophy behind combining multiply types of encryption, for example a RSA-CNN cipher. It has been proven time and time again that no cybersecurity cipher or system architecture is hack proof. The goal is to make cracking the cipher take longer than the time required to detect the intrusion and start either manual or automated countermeasures. The present application combines several layers of defenses, for example by combining RSA encryption with CNN encryption, to achieve secure encryption and decryption using minimal processing power.
A first layer is the RSA encryption of two values, α and xo, that are used to start a CNN encryption process. Without the correct public and private key, α and xo will not be correct. The second layer is the α and xo that is needed in the CNN process; if those two values are incorrect, then the CNN will not decrypt to the correct values. The third layer is the CNN itself, if the neural network is not structured and trained in exactly the same way as the encrypting CNN, then it will not properly decrypt the values. A hostile entity would have to break through all three layers of that encryption at a minimum in order to gain access to the data. In addition, if there is any change to the RSA keys or the CNN, then the hostile entity essentially has to restart the attempt to crack the cypher. There can be multiple levels of authentication as well that can help prevent an unwanted entity from accessing these devices, such as passwords, password length, or device ID. By further encrypting these extra authentications in separate instances of CNN encryption, the multiple instances of random α and xo further increase the security of the cypher.
The present invention provides hybrid encryption methods, comprising the steps of: at a first device, generating a first set of initial values corresponding to a password and generating a second set of initial values corresponding to data to be encrypted; encrypting the password by chaotic neural network (CNN) encryption using the first set of initial values; encrypting the data by CNN encryption using the second set of initial values; RSA-encrypting first set of initial values and the second set of initial values; and transmitting all encrypted data to a second device.
The present invention provides hybrid encryption methods, comprising the steps of: at a first device, generating a plurality of initial values; passing the plurality of initial values into a first function and generating a chaotic noise vector; RSA-encrypting the plurality of initial values; passing plaintext and the chaotic noise vector into a chaotic function logic block and generating ciphertext; and transmitting the ciphertext and the RSA-encrypted initial values to a second device.
The present invention provides hybrid encryption methods, comprising the steps of: at a first device, passing an initial value through a first non-linear function and obtaining an encrypted value; and transmitting the encrypted value over a public domain to a second device; at a second device, receiving the encrypted value decrypting the encrypted value by using an inverse or an approximation of the inverse of the first non-linear function, resulting in a decrypted value; passing the decrypted value through at least one operation in order to determine whether a consensus between the first device and the second device is reached; outputting an encrypted predicted value from the at least one operation; passing the encrypted predicted value through at least a second non-linear function to obtain a new value; and transmitting the new value to the first device; and at the first device: receiving the new value and decrypting the new value by using an inverse or an approximation of the inverse of the second non-linear function, resulting in a new decrypted value; and passing the new decrypted value through at least one operation in order to determine whether a consensus between the first device and the second device is reached.
The general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as defined in the appended claims. Other aspects of the present invention will be apparent to those skilled in the art in view of the detailed description of the invention as provided herein.
The summary, as well as the following detailed description, is further understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings exemplary embodiments of the invention; however, the invention is not limited to the specific methods and devices disclosed. In addition, the drawings are not necessarily drawn to scale. In the drawings:
The present invention may be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, applications, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. The term “plurality”, as used herein, means more than one. When a range of values is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.
It is to be appreciated that certain features of the invention which are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, references to values stated in ranges include each and every value within that range.
A key idea behind CNN cryptography is that without the correct initial values and conditions in the CNN, then the results cannot be decrypted into anything of value to a hostile actor. Even a small difference between initial conditions would result in a vastly different signal being sent due to the random and chaotic nature of CNN encryption. Thus, the initial conditions, variables corresponding to the password and actual data (alphas), and the length of the password must be protected.
The initial CNN conditions may be transmitted in a safe, reliable manner by pairing CNN cryptography with another type of encryption, for example with RSA encryption. While RSA encryption is computationally expensive and thus impractical for devices with low computing power, it can be used in a more limited capacity when paired with CNN cryptography. For example, RSA encryption may be used to transmit initial conditions for the CNN functions used in the encryption, the two alphas (one for the password and one for the actual data), and the length of the password. The CNN encryption is used for both the password itself, and the actual data that is being transmitted, which allows for real-time encrypted communication between smaller, less computationally powerful devices. When the parameters of the CNN functions or the password changes, then another RSA encrypted communication occurs.
Generally, at a first device, a password is first changed from a string of letters to a double vector of numbers. Then the length of the password, the initial conditions of the CNN, and the alphas used in the CNN functions are encrypted using the RSA keys. The second device that receives the encrypted password then decrypts the password length using the RSA keys and determines if the password length matches the one it considers valid from the authorized database. If the length is correct, then the password is decrypted to see if the password is a verified one. This double step to verification of the password increases the security of the transmissions. The passwords that are exchanged are authorized and registered in a database identifying each device for security and organizational reasons. In addition, a device's password and the passwords of the devices that it is authorized to communicate with, are stored on the hardware of the device itself. If the password is deemed correct, then the CNN encrypted data is downloaded and decrypted using the RSA decrypted initial values and alphas for the CNN functions that encrypted the desired data. If, during any step of the password decryption, it is determined to not be correct in any way, a request is sent back to the original sender, requesting the correct password. The CNN encrypted data is not accepted and decrypted.
Depending on the security standards for the use of the device, the time frame between CNN encryption changes or new RSA key calculations can be changed. This combination of encryption schemes makes for a secure system to transmit data. In order to decrypt the transmitted data, or perhaps insert falsified data, the attacker would need knowledge on both RSA and CNN cryptography and how they are implemented with each other.
Turning now to
The neural network used in the hybrid encryption method is known as a chaotic neural network. The initial values put into the network's input layer are randomized. This means that the path the input takes through the layers is different each time and without the correct initial value, the initial value cannot be decrypted. The input is randomized in the CNN through two values, α and xo. These values themselves are randomized every time an encrypted message is sent. The CNN used in herein may have several layers, for example three layers, that serve to scramble the binary values of the data being encrypted.
The following paragraph details some of the code and math behind the CNN. First, the values of α and xo are randomly generated using the following equations:
α=0.45*rand+0.04 (1)
a=α,b=1−α (2)
x
o=(b−a)*rand+a (3)
Next, the values of μ and λ are created from α.
After μ and λ are generated, then the remaining values of x are generated using the following equation:
x=μ*x(i−1)*(1−x(i−1))+λ (6)
From x, the matrix b is generated and contains the binary representation of the values in x. The matrix b is then the input into the neural network to be encrypted further. First, each byte is given a weight and a value of 0 in the first input layer.
Then the values of weight, the original data in binary form, XX, and θ are used to generate a matrix, dx, in the second layer of the network.
The final layer of the network takes the binary values generated in the second layer and reconstitutes them as an 8-bit integer:
The decryption code is structured similarly, but does not use the equations to generate the values of α and xo. Instead, the correct α and xo are sent over in the data to ensure that the neural network goes along the same path. In an embodiment, only the α and xo values are encrypted using RSA encryption, while the rest of the data that is being sent is being encrypted using the CNN. It is to be understood that the above-example is one embodiment for implementing the CNN. However, a person of ordinary skill in the art would understand that other suitable implementations of CNN may also be used and remain within the scope of the invention.
The second device 204 receives the encrypted data 220. Next, the second device 204 RSA-decrypts 222 the α and xo corresponding to the password, and CNN decrypts the password itself. If the password matches, then the second device 204 RSA decrypts the α and xo associated with the data, and CNN decrypts the data itself 224, resulting in the decrypted data 226.
Two initial values, a 302 and xo 304 are randomly generated by a first device to start a chaotic sequence. The initial values α 302 and xo 304 are passed through a first function 306 to generate a chaotic noise vector 308. The chaotic noise vector 308 and segments of a plaintext vector 310 are passed through parallel chaotic functions 312 in order to encrypt the plaintext 310 into ciphertext 314. The plaintext 310 may be broken up into small pieces, for example, 8 bits of the message may be sent to each parallel chaotic function 312 block at a time. Other lengths of the plaintext 310 may also be used. Furthermore, while
The initial values α 302 and xo 304 are encrypted using RSA encryption 316. Alternatively, other forms of encryption may be used to encrypt a 302 and xo 304, for example Blowfish, Twofish, AES, PGP (Pretty Good Privacy), etc. The segments of encrypted ciphertext are reassembled, and then the reassembled ciphertext 314 and the encrypted initial values α 302 and xo 304 are transmitted to a second device.
Two initial values, α 402 and xo 404 are randomly generated by a first device to start a chaotic sequence. The initial values α 402 and xo 404 are passed through a first function 406 to generate a chaotic noise vector 408. The chaotic noise vector 408 and segments of the XOR-ed plaintext 424 are passed through parallel chaotic function logic blocks 412 in order to encrypt the XOR-ed plaintext 424 into ciphertext 414. The XOR-ed plaintext 424 may be broken up into small pieces, for example, 8 bits of the message may be sent to each parallel chaotic function logic block 412 at a time. Other lengths of the XOR-ed plaintext 424 may also be used. Furthermore, while
The initial values α 402 and xo 404 are encrypted using RSA encryption 416. Alternatively, other forms of encryption may be used to encrypt initial values α 402 and xo 404. The segments of encrypted ciphertext are reassembled, and then the reassembled ciphertext 414 and the encrypted initial values α 402 and xo 404 are transmitted to a second device.
A first device 602 starts with an initial value 608 that is passed through a set of functions 610 and converted to encrypted value 612. The set of functions 610 may be any non-linear function that adds noise to the initial value 608 or modifies it in some manner. For example, the set of functions may comprise a neural network or other non-linear functions generally known to persons of ordinary skill in the art. Next, the encrypted value 612 is transmitted over the public domain 606 to a second device 604. The second device 604 receives encrypted value 612 and decrypts the encrypted value 612 by using an inverse or an approximation of the inverse 614 of the set of functions 610, resulting in a decrypted value 616. The second device 604 then runs operations 618 to see if the value received from the first device 602 reaches a consensus. For example, the operations may utilize the following formula:
a(k+1)=A(k)x(k)=αkξ(k), (7)
where k is the number of communication cycles that has occurred, A is a matrix defined as A(k)=(1−αk)I+αkW(k), and W is a matrix of weights that are changed as each communication cycle occurs in order to gain consensus.
The operations 618 output an encrypted predicted value 620, which is passed through a set of functions 622, resulting in a value 624. As described above, the set of functions 622 may be any non-linear set of functions. The value 624 is transmitted to the first device 602, where the first device 602 decrypts the value 624 by using an inverse or an approximation of the inverse 626 of the set of functions 622, resulting in a decrypted value 628. The first device 602 then runs operations 630 to check if the value received from the second device 604 reaches a consensus. The operations 630 may be the same or similar to the operations performed on the second device 604.
The communication cycle in
The operations 718 output an encrypted predicted value 720, which is passed through a set of functions 722, resulting in a value 724. As described above, the set of functions 722 may be any non-linear set of functions. The value 724 is transmitted to the first device 702, where the first device 702 decrypts the value 724 by using an inverse or an approximation of the inverse 726 of the set of functions 722, resulting in a decrypted value 728. The first device 702 then runs operations 730 to check if the value received from the second device 704 reaches a consensus. The operations 730 may be the same or similar to the operations performed on the second device 704.
The communication cycle in
The operations 826 outputs an encrypted predicted value 828, which is passed through a set of functions 830, resulting in a value 832. As described above, the set of functions 830 may be any non-linear set of functions. The second device 804 then RSA-encrypts 834 the value 832, and transmits an RSA-encrypted value 836 to the first device 802 over the public domain 806. The first device 802 then RSA-decrypts 838 the RSA-encrypted value 836, and further decrypts the resulting RSA-decrypted value 840 by using an inverse or an approximation of the inverse 842 of the set of functions 830, resulting in a decrypted value 844. The first device 802 then runs operations 846 to check if the value received from the second device 804 reaches a consensus. The operations 846 may be the same or similar to the operations performed on the second device 804.
The communication cycle in
Each respective device 902, 904, 906 receives the other devices' values and decrypts them using an inverse or an approximation of the inverse 924 of the set of functions 914. This step converts the encrypted values 916, 918, 920 into decrypted values 926, 928, 930. Each respective device then runs operations to see if the decrypted values 926, 928, 930 received from other devices reach consensus. For example, the operations may utilize Formula (7), discussed above, where k is the number of communication cycles that has occurred, and A is a matrix defined as A(k)=(1−αk)I+αkW(k), and W is a matrix of weights that are changed as each communication cycle occurs in order to gain consensus.
The communication cycle in
Method 900 utilizes a chaotic neural network to learn key register information by adding noise into the public domain 922 until a consensus is reached. This method may be utilized by any number of connected devices, and may also be layered such that a first consensus may be reached by all devices (for example, between the first, second, and third devices 902, 904, 906) and a second consensus may be reached between a subset of those devices (for example, between the first and third devices 902 and 906) if a private connection between the first and third devices 902, 906 is desired.
The methods described above avoid the need to use large keys for RSA encryption. The computational speed required for RSA encryption is a function of key length. The longer the key length, the longer the computational time and processing power needed. The methods described above combine advantages of multiple types of encryption, for example RSA and CNN, to allow for real-time encryption applications when an incorrect real-time decision may hurt or destabilize the system. In these applications, a fast encryption/decryption method is needed.
While hybrid encryption methods and systems have been described in connection with the various embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments of hybrid encryption methods and systems without deviating therefrom. For example, one skilled in the art will recognize that the hybrid encryption methods and systems as described in the instant application may apply to any suitable cryptography method for encrypting the initial values of the CNN cryptography, such as Blowfish, Twofish, AES, PGP (Pretty Good Privacy), etc. Furthermore, it is understood that the hybrid encryption methods and systems described herein may be used in both real-time and off-line communication. Applications for the hybrid encryption methods and systems may be in control systems, automation, manufacturing, and the service industry. The encrypted data may be a wide range of sensor data, actuator command data, image data, or text data, among others. Therefore, the hybrid encryption methods and systems described herein should not be limited to any single embodiment, but rather should be constructed in breadth and scope in accordance with the appended claims.
This application claims benefit of U.S. Provisional Application No. 62/437,611, filed Dec. 21, 2016, the contents of which are hereby incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2017/068028 | 12/21/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62437611 | Dec 2016 | US |
