TWI611682B - Cracking devices and methods thereof - Google Patents

Abstract

A cracking method for exposing a key of an encryption device includes: establishing a leakage model of the encryption device; performing mathematical operations on the leakage model according to input data of the complex array to generate a mathematical model; generating a hypothetical key of the complex array; using mathematics The model generates simulation data corresponding to the complex array of hypothetical keys; inputs the input data to the encryption device, and detects the leakage data of the complex array generated by the encryption device; performs mathematical operations on the leakage data to generate the operational data; and determines the analog data a correlation between each of the computing materials; and determining one of the hypothetical keys as a key based on the correlation.

Description

Cracking device and method

The invention relates to a device and a method for cracking a side channel attack, in particular to a device and a method for calculating a leakage model for correlation power consumption analysis to improve the efficiency of cracking.

Because IoT devices are unattended for most of the time and are easily targeted by hackers, the importance of physical security for IoT devices increases. Side-Channel Attack (SCA) exploits the physical characteristics of the device, such as power, electromagnetic waves, temperature, etc., to reveal the secret key and information about the target device. The study of side channel attacks can reveal potential weaknesses in the device, allowing designers to understand possible security gaps. To ensure security, designers must consider side channel attacks during the design process and test them with various side channel attack techniques.

In order to shorten the attack time of the side channel attack, it is necessary to reduce the noise and algorithm noise to reduce the amount of data to be processed and the complexity of the data, thereby increasing the attack efficiency.

In view of this, the present invention provides a cracking method for exposing a key of an encryption device. The cracking method includes: establishing a leakage model of the encryption device; and performing the leakage model according to the input data of the complex array. Generating a mathematical model; generating a hypothetical key of the complex array; generating the analog data corresponding to the complex array of the hypothetical keys by using the mathematical model; inputting the input data to the encryption device, and detecting the encryption device And generating the leakage data of the complex array; performing the above mathematical operation on the leakage data to generate an operation data; and determining, according to the correlation, one of the hypothetical keys as the key.

According to an embodiment of the present invention, the step of determining that one of the hypothetical keys is the key further comprises: calculating a correlation coefficient between each of the analog data and the operation data; and selecting according to the correlation coefficient One of the above simulation data is a target data, wherein the target data has the highest correlation coefficient; and the above-mentioned hypothesis key corresponding to the target data is the key.

According to an embodiment of the present invention, the leakage model is based on a first variable related to the input data, a second variable related to the hypothetical key, and one of the input data and the hypothetical key. Three variables, and outputting different leakage data, wherein the mathematical operation is used to eliminate the influence of the second variable of the leakage model.

According to an embodiment of the present invention, the encryption device encrypts the input data of the complex array according to the key to generate different leakage data, wherein the mathematical operation is further used to eliminate the second variable of the encryption device. influences.

According to an embodiment of the present invention, the step of generating the hypothesis key further includes: dividing the key into N parts; and performing hypothesis on each of the N parts of the key to generate N False of the above complex array A key is provided, wherein one of the complex array hypothesis keys corresponding to one of the N parts is determined to be one of the N parts before the assumption of the other of the N parts.

According to an embodiment of the present invention, the step of determining that one of the hypothesis keys is the key further comprises: determining that one of the complex array hypothesis keys corresponding to each of the N parts is the secret Each part of the key; and the above-mentioned key is obtained by combining N of the above-mentioned hypothetical keys.

The invention further provides a cracking device for exposing a key of an encryption device, comprising: a controller; and a time-invariant storage device. The non-time-varying storage device is configured to store a plurality of instructions, wherein the controller executes the corresponding step according to the instruction, including: establishing a leakage model of the encryption device; performing a mathematical operation on the leakage model according to the input data of the complex array Generating a mathematical model; generating a hypothetical key of the complex array; generating the analog data corresponding to the complex array of the hypothetical keys by using the mathematical model; inputting the input data to the encryption device, and detecting the complex number generated by the encryption device a leakage data of the group; performing the above mathematical operation on the leakage data to generate an operation data; and determining, according to the correlation between each of the simulation data and the operation data, that one of the hypothetical keys is the key.

According to an embodiment of the present invention, the step of determining that one of the hypothetical keys is the key further comprises: calculating a correlation coefficient between each of the analog data and the operation data; and selecting according to the correlation coefficient One of the above simulation data is a target data, wherein the target data has the highest correlation coefficient; and the above-mentioned hypothesis key corresponding to the target data is the key.

According to an embodiment of the present invention, the leakage model is based on a first variable related to the input data, a second variable related to the hypothetical key, and one of the input data and the hypothetical key. Three variables, and outputting different leakage data, wherein the mathematical operation is used to eliminate the influence of the second variable of the leakage model.

According to an embodiment of the present invention, the encryption device encrypts the input data of the complex array according to the key to generate different leakage data, wherein the mathematical operation is further used to eliminate the influence of the second variable of the encryption device. .

According to an embodiment of the present invention, the step of generating the hypothesis key further includes: dividing the key into N parts; and performing hypothesis on each of the N parts of the key to generate N a hypothesis key of the above complex array; wherein, before making an assumption about the other of the N parts, determining one of the complex array hypothesis keys corresponding to one of the N parts is the N One of the parts.

According to an embodiment of the present invention, the step of determining that one of the hypothesis keys is the key further comprises: determining that one of the complex array hypothesis keys corresponding to each of the N parts is the secret Each part of the key; and the above-mentioned key is obtained by combining N of the above-mentioned hypothetical keys.

10‧‧‧Encryption device

100, 300‧‧‧ crack device

310‧‧‧ Controller

320‧‧‧Time-independent storage devices

DI‧‧‧ input data

DO‧‧‧Disclosure information

SK‧‧‧Key

S21~S28‧‧‧Step process

1 is a schematic diagram showing a cracking apparatus according to an embodiment of the present invention; and FIG. 2 is a flow showing a cracking method according to an embodiment of the present invention. And FIG. 3 is a block diagram showing a cracking apparatus according to an embodiment of the present invention.

The above described objects, features, and advantages of the present invention will become more apparent from the description of the appended claims appended claims A good example. It is to be understood that the invention is not limited to the scope of the invention.

1 is a schematic view showing a cracking apparatus according to an embodiment of the present invention. As shown in Fig. 1, the encryption device 10 is for encrypting the input material DI based on the key SK, and in the process of encryption, the leak data DO is generated. According to an embodiment of the invention, the leakage data DO may be timing information, warning tones, indicator lights, power loss, and leakage electromagnetic waves, and the like. The cracking device 100 cracks the key SK used by the encryption device 10 according to a cracking method, and the cracking method will be described in detail below.

2 is a flow chart showing a method of cracking according to an embodiment of the present invention. In order to explain the present invention in detail, the flowchart of Fig. 2 will be explained with reference to Fig. 1. As shown in Fig. 2, the cracking device 100 first establishes a leak model of the encryption device 10 (step S21).

According to an embodiment of the invention, the leakage model is a function of the leakage data DO generated by the encryption device 10 based on the input data DI and the key SK. That is, the leakage model changes the output leakage data with the first variable related to the input data DI, the second variable related to the key SK, and the third variable related to the input data DI and the key SK. DO.

In order to reduce the algorithm noise, the cracking device 100 performs a mathematical operation on the leak model based on the input data DI of the complex array to generate a mathematical model (step S22) for eliminating the second variable related only to the key SK. According to an embodiment of the present invention, the simplest mathematical operation is to generate a mathematical model by adding or subtracting the leakage model according to the input data DI of the complex array.

Subsequently, the cracking device 100 makes a hypothesis on the key SK used by the encryption device 10, and generates a hypothetical key of the complex array (step S23). According to an embodiment of the invention, the key SK may be a 128-bit key. According to an embodiment of the present invention, the cracking apparatus 100 divides the key SK into a plurality of parts, and makes a hypothesis for each part to generate a hypothetical key of a complex array. For example, each part of the key SK includes 8 bits, and the cracking apparatus 100 makes a hypothesis for performing 8-bit each time, and generates ²⁸ sets of hypothetical keys. Compared with the 128-bit key SK exhaustive method to generate 2 ¹²⁸ sets of hypothesis keys, the cracking apparatus 100 proposed by the present invention can greatly reduce the hypothesis key required to be generated, thereby greatly improving the efficiency of cracking. .

The cracking device 100 further inputs the hypothesis key of the complex array into the mathematical model to generate the analog data of the complex array (step S24). Since the mathematical model has eliminated the influence of the second variable related to the key SK via the mathematical operation, the complex array The simulation data is only related to the first variable and the third variable.

On the other hand, the cracking device 100 also inputs the input data DI of the complex array to the encryption device 10 to detect the leaked data DO of the complex array generated by the encryption device 10 based on the respective input data DI and the key SK (step S25). In order to The simulation data of the group is compared with the leak data DO of the complex array, and the cracking device 100 performs the mathematical operation performed on the leak model by the measured leak data DO of the complex array to generate the operation data (step S26). According to an embodiment of the present invention, performing the same mathematical operation on the leak data DO of the complex array eliminates the influence of the second variable associated only with the key SK and reduces the measurement noise.

Subsequently, the cracking device 100 judges the correlation between each of the complex data of the complex array and the arithmetic data (step S27). According to an embodiment of the present invention, the cracking apparatus 100 calculates a correlation coefficient between each of the complex array of analog data and the operation data, and is used to determine the correlation between each of the complex array of analog data and the operational data. .

Then, the cracking device 100 acquires the key SK used by the encryption device 10 based on the correlation between the analog data of the complex array and the arithmetic data (step S28). According to an embodiment of the present invention, when one of the analog data of the complex array has the highest correlation coefficient, the analog data representing the group is the closest to the operational data, and therefore the hypothesis of the group corresponding to the simulated data of the group is assumed. The key should be closest to the key SK used by the encryption device 10.

According to another embodiment of the present invention, the cracking apparatus 100 may divide the key SK into a plurality of parts to make a hypothesis, and generate a plurality of hypothesis keys for each part. When the cracking device 100 determines that each of the hypothetical keys matches the portion corresponding to the key SK used by the encryption device 10, the cracking device 100 combines the matching hypothesis keys to obtain the key SK.

For example, the cracking device 100 divides the key SK into a first part and a second part, and makes a hypothesis of the first part to generate a first hypothesis key of the complex array. When judging that the first part is one of the first hypothetical keys, the second Part of the assumption is made to generate a second hypothesis key of the complex array. When it is determined that the second part is one of the second hypothesis keys, the cracking apparatus 100 combines the first part and the second part to obtain the key SK.

Figure 3 is a block diagram showing a cracking device according to an embodiment of the present invention. The cracking device 300 of Fig. 3 corresponds to the cracking device 100 of Fig. 1. As shown in FIG. 3, the cracking device 300 includes a controller 310 and a time-invariant storage device 320 for storing a plurality of instructions. After the controller 310 executes the complex instructions stored by the time-invariant storage device 320, the corresponding steps of the cracking method 200 shown in FIG. 2 are executed.

Since the cracking device and the cracking method proposed by the present invention perform mathematical operations on the leak model and the complex arithmetic data, not only the complexity of the data is reduced, but also the algorithm noise and the measurement noise can be effectively reduced. According to an embodiment of the present invention, the mathematical operation performed on the leakage model and the complex operation data may be a difference between two sets of different input data, and if necessary, the cracking device and the cracking method proposed by the present invention may include other The operation, for example, requires additional input data to eliminate the effects of the second variable associated with the key.

組的運算資料，因此透過數學運算可以大幅度地增加所需的運算資料量。再者，假定密鑰SK係為128位元，因此窮舉法需要確認運算資料以及模擬資料之相關性達2¹²⁸次，然而本發明所提出之破解裝置以及方法可將密鑰128分段確認其相關性，也就是，當破解裝置100將密鑰SK分為128段進行確認，破解裝置100僅需確認運算資料以及模擬資料之間的相關性降低至128次，此舉將大幅度降低資料處理 量，並且節省資料處理時間。 In addition, when inputting the input data DI of the N groups and performing mathematical operations using the two sets of input data,

The computational data of the group, so the amount of computational data required can be greatly increased by mathematical operations. Furthermore, it is assumed that the key SK is 128 bits, so the exhaustive method needs to confirm the correlation between the arithmetic data and the analog data up to 2 ¹²⁸ times. However, the cracking apparatus and method proposed by the present invention can confirm the key 128 in stages. Correlation, that is, when the cracking device 100 divides the key SK into 128 segments for confirmation, the cracking device 100 only needs to confirm that the correlation between the computing data and the analog data is reduced to 128 times, which will greatly reduce the data. Processing volume and saving data processing time.

The features of many embodiments are described above to enable those of ordinary skill in the art to clearly understand the form of the specification. Those having ordinary skill in the art will appreciate that the objectives of the above-described embodiments and/or advantages consistent with the above-described embodiments can be accomplished by designing or modifying other processes and structures based on the present disclosure. It is also to be understood by those skilled in the art that <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt;

S21~S28‧‧‧Step process

Claims (12)

A cracking method for exposing a key of an encryption device, the cracking method comprising: establishing a leakage model of the encryption device; performing a mathematical operation on the leakage model according to the input data of the complex array to generate a mathematical model; Generating a hypothetical key of the complex array; generating the analog data corresponding to the complex array of the hypothetical key by using the above mathematical model; inputting the input data to the encryption device, and detecting the leakage data of the complex array generated by the encryption device; The leakage data is subjected to the above mathematical operation to generate an operation data; determining a correlation between each of the simulation data and the operation data; and determining, according to the correlation, one of the hypothetical keys as the key . The method of claim 1, wherein the step of determining that one of the hypothetical keys is the key further comprises: calculating a correlation coefficient between each of the simulated data and the operational data. And selecting one of the simulation data according to the correlation coefficient as a target data, wherein the target data has the highest correlation coefficient; and determining that the hypothesis key corresponding to the target data is the key. The method of claim 1, wherein the leakage model is based on a first variable related to the input data, and the assumption a second variable related to the key and a third variable related to the input data and the hypothetical key, and outputting the different leakage data, wherein the mathematical operation is used to eliminate the second variable of the leakage model influences. The method of claim 3, wherein the encryption device encrypts the input data of the complex array according to the key to generate different leakage data, wherein the mathematical operation is used to eliminate the encryption device. The effect of the above second variable. The method of claim 1, wherein the step of generating the hypothesis key further comprises: dividing the key into N parts; and each of the N parts of the key A hypothesis is generated to generate N hypothetical keys of the complex array; wherein, before making an assumption to the other of the N parts, determining the complex array hypothesis key corresponding to one of the N parts One is one of the above N parts. The method of claim 5, wherein the step of determining that one of the hypothetical keys is the key further comprises: determining the complex array hypothesis key corresponding to each of the N parts One of the keys is a part of the above-mentioned key; and the above-mentioned key is obtained by combining N the above-mentioned hypothetical keys. A cracking device for exposing a key of an encryption device, comprising: a controller; and a time-invariant storage device for storing a plurality of instructions, wherein the controller Performing the corresponding steps according to the foregoing instructions, comprising: establishing a leakage model of the encryption device; performing a mathematical operation on the leakage model according to the input data of the complex array to generate a mathematical model; generating a hypothetical key of the complex array; The mathematical model generates analog data corresponding to the complex array of the hypothetical keys; inputs the input data to the encryption device, and detects leakage data of the complex array generated by the encryption device; performing the mathematical operation on the leakage data to generate a And calculating the data; and determining, according to the correlation between each of the simulation data and the operation data, that one of the hypothetical keys is the key. The cracking device of claim 7, wherein the step of determining that one of the hypothesis keys is the key further comprises: calculating a correlation coefficient between each of the simulation data and the operation data. And selecting one of the simulation data according to the correlation coefficient as a target data, wherein the target data has the highest correlation coefficient; and determining that the hypothesis key corresponding to the target data is the key. The cracking device of claim 7, wherein the leakage model is based on a first variable related to the input data, a second variable related to the hypothetical key, and the input data and the hypothesis The key is related to one of the third variables, and outputs different leakage data. The above mathematical operation is used to eliminate the influence of the second variable of the leakage model described above. The cracking device of claim 9, wherein the encryption device encrypts the input data of the complex array according to the key to generate different leakage data, wherein the mathematical operation is further used to eliminate the encryption device. The effect of the above second variable. The cracking device of claim 7, wherein the step of generating the hypothesis key further comprises: dividing the key into N parts; and each of the N parts of the key A hypothesis is generated to generate N hypothetical keys of the complex array; wherein, before making an assumption to the other of the N parts, determining the complex array hypothesis key corresponding to one of the N parts One is one of the above N parts. The cracking device of claim 11, wherein the step of determining that one of the hypothesis keys is the key further comprises: determining the complex array hypothesis key corresponding to each of the N parts One of the keys is a part of the above-mentioned key; and the above-mentioned key is obtained by combining N the above-mentioned hypothetical keys.