Description:Field of the Invention
The present invention is Piccolo (a lightweight block cipher) that provides multiple security levels in resource-constrained applications such as Internet of Things (IoTs). Piccolo encrypts 64-bits plaintext with three key sizes of 80-bits, and 128-bits producing 64-bits ciphertext.

Objectives of this invention

For secure communication between resource-constrained devices, lightweight cryptographic algorithms are immensely important. The hardware architectures of these algorithms were implemented on FPGA and/or ASIC platforms. However, design modification and resource optimization for these lightweight algorithms are still an open issue. Piccolo is a lightweight block cipher, performs two operations datapath processing and key scheduling. This block cipher serves inputs of 64-bits plaintext &80-/128-bits master keys and produces output of 64-bits ciphertext. As all other lightweight block ciphers are implemented only encryption algorithm for one key variant, area footprint is less. However, flexible architecture results are for all key variants of Piccolo cipher such as 80-bits, and 128-bits. Hence, flexible architecture provided the flexibility to use a variant of any key sizes according to the required multiple security levels. Due to this, hardware requirement is large but invented architecture achieved high throughput compared to other lightweight block ciphers as well as previous method of Piccolo cipher. Hence, the invented architecture was found suitable for high throughput IoT applications to transform secure information through the internet by enabling devices for communication and computing process.

Background of the invention
Cryptography plays a significant role in making secure communication. It is used to send information or message in a secure way to protect it from unauthorized access. Cryptography is the study of statistical procedures inter-related to information security characteristics such as confidentiality, non-repudiation, data integrity, and authentication. It involves two processes namely, encryption and decryption to secure the data while transmission through the channels. Ciphers are data encrypting technique that involves several processes to protect the hidden information during data transmission. Using these methodologies, data can be barred from meticulous attacks. Lightweight cipher techniques are more preferable for low-resource devices because of their limited computing power. Moreover, block cipher techniques play a very important role in security of such devices.
Conclusively, various lightweight block ciphers have been developed in recent past. The hardware of these ciphers was implemented on FPGA and/or ASIC platforms. However, design modification and resource optimization for these lightweight ciphers are still an open issue. Some of the current ciphers such as HIGHT, PRESENT, m-Crypton, KATAN/ KTANTAN, LBlock, MIBS, Rectangle, PRINCE, SFN, Twine, and MISTY1 are lightweight algorithms specially designed for resource-constrained applications. The hardware implementation is mainly motivated by bringing optimization of lightweight primitives such as area, power, and speed. Different design techniques are developed to rework the designs for different applications. With the implementation of many techniques, the speed of cryptographic algorithms can be increased. One approach is to implement parallel modular exponentiation computations for large pieces of data. Other strategy is to add pipeline registers in the architecture of the hardware. Several works have proposed pipeline techniques in self-controller architecture. Moreover, parallel data transmission processing lines have also been introduced to increase the speed of the m-Crypton algorithm whereas pipelined design can also increase the speed/ throughput of cryptographic algorithm (H. E. Michail, G. S. Athanasiou, V. I. Kelefouras, G. Theodoridis, T. Stouraitis, and C. E. Goutis, “Area-throughput trade-offs for SHA-1 and SHA-256 hash functions’ pipelined designs,” Journal of Circuits, Systems and Computers, vol. 25, no. 4, pp. 1–26, 2016). A brief description presented about cryptographic architecture that incorporates different efficient models (H. D. Azari and D. P. V Joshi, “An efficient implementation of present cipher model with 80 bit and 128 bit key over FPGA based hardware architecture,” International Journal of Pure and Applied Mathematics, vol. 119, no. 14, pp. 1825–1832, 2018). Azari et al proposed architecture for PRESENT cipher that includes encryption process as well as decryption process by means of 64-bits input data security using 80-bits and 128-bits keys at different hardware levels.
The number of previous hardware implementations of lightweight block ciphers have been presented on FPGA platform.The Piccolo encryption algorithm allows 64-bit of plaintextand variable key lengths of 80 and 128-bit of key inputto ensure the security of the algorithm as per applicationconcern. The difference in key size and number of round(R)are 25 for 80-bit key and 31 for 128-bit key size referredto the algorithm as Piccolo-80 and Piccolo-128. Most of thesymmetric block ciphers are divided into two parts, the keyscheduling part, which generates a different number of uniquekeys and the data encryption part, which undergoes severalrounds of transformation by making use of keys (K. Shibutaniet al. “Piccolo: an ultra-lightweight blockcipher," Cryptographic Hardware and Embedded Systems–CHES 2011, pp. 342-357, 2011).In (B. Rashidi, “Flexible structures of lightweight block ciphers PRESENT, SIMON and LED,” IET Circuits, Devices & Systems, vol. 14, no. 3, pp. 369-380), Rashidiet al have developed a flexible architecturefor lightweight block ciphers PRESENT, SIMON and LED suitable for constrained devices. From these implementations one can see that there was slight decrease in area but throughput was reduced tremendously when design moved from low-bit key implementation to high-bit key implementation. It was caused by an increase in the amount of control signals. As a result, these adaptable designs will be beneficial in applications such as the Internet of Things (IoT). The Internet of Things (IoT) is a network that connects embedded objects like sensors that can generate, interact with, and share data with one another. There are numerous applications for the Internet of Things, including e-health, e-commerce, smart homes, smart cities, smart hospitals, and so on. These devices transmit massive amounts of data. These applications are optimized and advanced by building new IoT-based devices and solutions.

Description of the prior art
The study of securing communications and data is known as cryptography. The fast advancement and application of telecommunications technology in recent years has increased the significance of cryptographic systems. More and more private data is being transmitted through telecommunications networks and kept on file servers. This data includes everything from financial data to computerized voting. A data encryption method can be used to encrypt an n-bit block of input across a number of rounds; n is preferably 128 bits or greater. In contrast to the linear combination function, which combines two different one-to-one rounds, each of which is determined by a predefined number of bits in a memory for storing and loading sections, the bit-moving function can rotate, shift, or bit-permute round sections by predetermined numbers of bits, preferably to achieve active and effective fixed rotation. Nonlinear functions include S-boxes and variable rotation functions. Typically, each round uses a subkey combining function to create new round sections by joining a round Segment and a subkey section. (US6182216B1).The system and method for verifying a lightweight security protocol for a specific type of radio frequency identification equipment were disclosed in the past invention, this system included server end, read write line end andthe electronic tag being sequentially connected with, wherein: server end, for creating and store readwrite line information table and tag resolution information table, and for setting up communicationconnection so that read write line to be certified to be authenticated with read write line end;readwrite line end, in the read write line information table stored by server end in the Original Equipment Manufacturer (OEM) configurationdata of the radio-frequency module of corresponding information write valid reader, and for settingup communication connection to be authenticated read write line to be certified with server end; Electronic tag, was used for being arranged on corresponding product, to be identified correspondingproduct.The prior invention was a compact security protocol verification system and method for radio frequency identification equipment that could overcome the limitations of the prior art, such as its limited applicability and high energy consumption, and achieve the benefits of good safety and low energy consumption. (CN103281189B).
For a general-purpose CPU, an adaptable AES instruction set is offered. The instruction set contains instructions for key generation as well as a "one round" pass for AES encryption or decryption. When generating keys for 128/192/256-bit keys, an immediate can be used to specify the key size and a round number. Because tracking of implicit registers is not necessary, the flexible AES instruction set permits full use of pipelining capabilities. (US9641320B2).In the invention, the work was generally focused on a lightweight cryptographic engine (LCE). Data confidentiality and/or integrity were assured at a device and/or during transmission from or to the device using an LCE configured to implement one or more cryptographic primitives, also known as crypto primitives. The LCE's primary function is to offload cryptographic operations from a host system and implement the cryptographic primitive (s) within a confined size (for example, die area) and power budget. The restrictions were applicable to, say, a system that utilized the LCE. The system can, for instance, be a device from the Internet of Things (IoT). (US9773432B2).By utilizing an error coefficient and a chain block hash, the security service equipment and method described in the invention offered lightweight security. To create an encryption key, it was utilized to synchronize time with the terminal. This made it more challenging to secure security for a blockchain-based encryption key as well as security for communication with terminals. The encryption key of the terminal was generated as a hash through the hash algorithm in accordance with the invention to ensure the security of the communication session between the service-providing apparatus and the terminal. To create a symmetrical encryption, the hash was created using data from the other terminal's encryption key that was kept in the blockchain. (US20200213106A1).

Summary of the Invention
According to requirement, this architecture is capable to handle multiple levels of security. By changing the control input, key scheduling algorithm can work any one of three key variants into a single design. Hence, unified architecture provides the flexibility to use a variant of key sizes according to the required security level.

Detailed description of the invention
Smart devices are increasingly using the Internet. The internet has connected the entire world, and even homes are starting to have smart locks, smart TVs, smart phones, PCs, and other devices. At the moment, these appliances are being watched online. The internet also allows for remote operation of refrigerators and air conditioners. Many customers are eager to adopt these IoT applications in order to support improved transportation, healthcare, and lifestyle options. In order to encourage the adaptation process for all smart applications, IoT must offer suitable protection and numerous levels of security.
The invented design is a unified architecture, which utilized one design for all available key variants. It means that claimed architecture is performing encryption process for all key sizes of 80-bits, and 128-bits. For this, it required an extra hardware for introduction of flexible concept but it worked for multiple security levels. The difference in the implementation of invented architecture of Piccolo cipher mainly occurs in the key updating part and round key generation part in the key scheduling block. However, the remaining blocks such as non-linear substitution block, bit permutation block, transpose block remains same irrespective of the key sizes. The unified structure for the key updating and round key generation can be used for all key sizes which can be selected by the user among all key lengths.
The unified architecture supports both key sizes ofencryption in a single architecture using extra hardware, whichincludes mostly of 2x1 multiplexers. The unified architectureof Piccolo encryption algorithm is mentioned in FIG. 1. It isevident that the resultant architecture of encryption functionis exactly the same as the previous architecture, but changesoccur in the key scheduling part. The whitening keys areassigned by using four multiplexers as it enables by input Sel.When Sel is 1, it chooses whitening values for 80-bit keyotherwise it chooses whitening values for 128-bit key length of Piccolo in key schedulingpart. The constant value generating section produces valuebased on concatenated value of counter (Count). The mostimportant thing is number of rounds are different for both 80- and 128-bits key scheduling. This can be done by adding oneextra multiplexer at the counter, if Sel is 1 it stops the counterat count equals to 25 for the 80-bit key, or else it stops thecounter at count equals to 31 for 128-bit key operation. Twomore multiplexers in similar way are employed in the designto take care of hexadecimal value XORing with concatenatedCount values. The key state registers are to store permutationkey values for 128-bit key operation and for 80-bit simplygiven feedback by using a series of multiplexers as mentionedin the architecture. The upper three 16-bit key values are notgoing to involve in round key (RK) generation in case of 80-bit key operation. There is no change in the round functionof encryption as it is similar for both 80- and 128-bits keys.The architecture takes 25 latency clock cycles to complete theentire encryption operation of 80-bit key Piccolo algorithmwhen input Sel is 1. When Sel is 0, the design takes 31 latencyclock cycles to complete the 128-bit key encryption operation.
FIG. 2 depicts a typical IoT architecture in which access control over "things" is obtained by innovative design. With the help of smart sensor RFID tags, actuators, and network connectivity, these devices are equipped with the ability to exchange, collect, and send data to a server. Examples of such applications include dependable and secure access to mobile devices, cloud databases, ATMs, and smart buildings. A senior citizen can also update the IoT healthcare system about their health status by logging in. In IoT applications, security levels differ in accordance with the availability of hardware resources and strength of security. Some appliances like smart buildings, smart phones, computers, ATMs etc., require high level of security. Here, security provided by 96-bits key is sufficient and appropriate. On the other hand, some systems like healthcare system, logistic and tracking applications etc., need low level of security. Therefore, 64-bits key security is enough and doesn't have large number of hardware resources. Hence, different applications in IoT can be connected with multiple security levels with limited hardware resources.The capacity to change system settings, such as key size, is referred to as flexibility. It is particularly important for applications with a variety of requirements. An excellent illustration of this is in IoT applications. Depending on the tasks they carry out, different levels of security will be needed by IoT devices and the systems that enable them. Depending on the degree of confidence in the sensors, the key size in a flexible construction can vary within a reasonable range. High-speed computations are made possible in a less essential application by employing a less secure encryption technique (a shorter key). Encrypting sensitive network data, such as healthcare IoT applications, necessitates a greater level of security (a longer key). As a result, these adaptable architectures will be useful for Internet of Things (IoT) applications. The Internet of Things (IoT) is a network that connects embedded objects like sensors that can generate, interact with, and share data. Many applications exist for the Internet of Things, including e-health, e-commerce, smart homes, smart cities, smart hospitals, and so on. These devices transmit large amounts of information. Building new gadgets and solutions based on IoT systems optimizes and advances these applications.

Brief Description of Drawing
The List ofFigures, which are illustrated exemplary embodiments of the invention.
Figure 1 is an example of an embodiment of a hardware architecture that includes the invention;
Figure 2 is an example of used of invented architecture in IoT applications.
Figure 3 Performance of invention in terms of speed.

Detailed description of the drawing
As described above present invention relates to implement a single architecture for all available key sizes of Piccolo lightweight block cipher.
FIG. 1 is evident that the resultant architecture of encryption function is exactly the same as the previous architecture, but changes occur in the key scheduling part. The whitening keys are assigned by using four multiplexers as it enables by input Sel. When Sel is 1, it chooses whitening values for 80-bit key otherwise it chooses whitening values for 128-bit key length of Piccolo in key scheduling part. The constant value generating section produces value based on concatenated value of counter (Count). The most important thing is number of rounds are different for both 80- and 128-bits key scheduling. This can be done by adding one extra multiplexer at the counter, if Sel is 1 it stops the counter at count equals to 25 for the 80-bit key, or else it stops the counter at count equals to 31 for 128-bit key operation. Two more multiplexers in similar way are employed in the design to take care of hexadecimal value XORing with concatenated Count values.
FIG. 2 depicts a typical Internet of Things architecture that has employed innovative design to gain access control over the "things." These devices can exchange, collect, and send data to a server since they have actuators, smart sensor RFID tags, and network connectivity. These apps, as examples, provide dependable and secure access to smart buildings, mobile devices, cloud databases, ATMs, and other devices. Additionally, by logging into the IoT healthcare system, an elderly person can report their health status. In IoT applications, security levels differ in accordance with the availability of hardware resources and strength of security. Some appliances like smart buildings, smart phones, computers, ATMs etc., require high level of security. Here, security provided by 96-bits key is sufficient and appropriate. On the other hand, some systems like healthcare system, logistic and tracking applications etc., need low level of security. Therefore, 64-bits key security is enough and doesn't have large number of hardware resources. Hence, different applications in IoT can be connected with multiple security levels with limited hardware resources.
FIG. 3 shows the present invention ofunified architecture of Piccolo lightweight block cipher achieved high efficiency in terms of throughput per area (Mbps/slice) than other lightweight block ciphers in respective of FPGA devices.The invented flexible architecture of Piccolo cipher is implemented on different FPGA platforms such as Spartan-3, Virtex-4, and Virtex-5 devices. The architecture is implemented in such a way that it provides a hardware solution to introduce secure implementation for resource-constrained applications.Moreover, the invented implementation has high hardware efficiency in terms of throughput per area (Mbps/slice) compared to other state-of-the-art implementations of lightweight block ciphers such as mCrypton, LBlock, PRESENT, Clefia, PRINTCIPHER, XTEA, KLEIN, Humming bird, QTL, LEA etc., on same FPGA devices. Hence, inventedunified implementation of Piccolo lightweight block cipher showed higher speed in terms of throughput (Mbps). , Claims:The following claims define the scope of the invention:

Claims:
1. The invention is to implement an architecture of Piccolo (a lightweight block cipher) that provides multiple security levels in resource-constrained applications such as Internet of Things (IoTs).
a) The unified architecture worked for all key variants of Piccolo cipher such as 80-bitsand 128-bits.
b) The unified architecture provided the flexibility to use a variant of any key sizes according to the required multiple security levels.
c) The invented architecture was found suitable for high throughput IoT applications to transform secure information through the internet by enabling devices for communication and computing process.
2. As per Claim 1, the single architecture has been designed for all available key sizes.
3. As per Claim 1, the multiple security levels can be achieved by varying key sizes and available longer key size (128-bits).
4. As per Claim 1, the invented flexible architecture showed high throughput for high-speed IoT applications.