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True Random Number Generator (TRNG) provides the different keys for device authentication and cryptography. Typically, the TRNG is implemented in a standalone module into the systems, increasing the complexity and area of the implementation. In addition, the system needs to store the key generated by the TRNG in non-volatile memory for the different applications. However, implementing a Non-Volatile Random Access Memory (NVRAM) requires additional technology features, usually unavailable or expensive. This paper presents a unified NVRAM-TRNG in a $0.18\mu m$ standard CMOS technology without an additional mask or fabrication steps. The unified implementation does not need additional circuits for the random number generation mode. The differential NVRAM bit cell is implemented using a high voltage transistor to resist the non-volatile memory application. The NVRAM presents times of 15-ms of programming and erasing and 20-ns of reading functions. The bit cell needs a voltage of 8.5-V for the programming and erasing functions. The TRNG implemented passes the NIST SP800-22 statistical test and NIST SP800-90B entropy test with a 0.9859 minimum entropy. The entropy and statistical test are applied with Process, Voltage, and Temperature (PVT) variations. The implementation occupies a 476- $\mu m^{2}$ with 14.69- $10^{3} F^{2}$ of area normalized. Besides, the NVRAM bit cell in TRNG mode shows a bit rate of 50-Mbps. Finally, the implementation as TRNG reports a 49.5- $\mu W$ power consumption with 0.99-pJ/bit energy efficiency, respectively.

True Random Number Generator (TRNG) is used in many applications, generally for generating random cryptography keys. In this way, the trust of the cryptography system depends on the quality of the random numbers generated. However, the entropy fluctuations produced by external perturbations generate some false positives in the random sequence. These false positives can generate a disastrous scenario, depending on the application. This work presents the results of different tests to demonstrate the robustness and health of the TRNG based on frequency collapse. The TRNG passed all entropy tests provided for NIST SP800-90B and AIS31. The entropy test denotes a 0.9789 minimum normalized entropy and 7.998 Shannon entropy. In addition, the TRNG passes the health tests provided for NIST SP800-90B. The health test shows a number of identical values $I_{v}=0\%$ , $I_{v-1} < 0.004\%$ and a maximum cutoff value $MC_{v}=10$ with $LMC_{v}=13$ in the repetition count and adaptive proportion tests, respectively. The implementation passed all the statistical tests provided for NIST SP800-22 and AIS20. Besides, the implementation passes the different tests with Process, Voltage, and Temperature (PVT) variations. The TRNG is implemented in a $0.18~\mu m$ General Purpose (GP) CMOS technology, occupying $25600~\mu m^{2}$ with four entropy sources. Finally, the implementation presents a 7.3 until 9.2-Mb/s of bit rate, 0.56 until 1.88-mW of power consumption, and 77.2 until 204.3-pJ/bit of energy per bit using an entropy source with 16 and 2 delay stages, respectively.

A Trusted Execution Environment (TEE) sets a platform to secure applications based on the Chain-of-Trust (CoT). The starting point of the CoT is called the Root-of-Trust (RoT). However, the RoT implementation often relies on obscurity and provides little flexibility when generating keys to the system. In this paper, a TEE System-on-a-Chip (SoC) architecture is proposed based on a heterogeneous design by combining 64-bit Linux-capable processors with a 32-bit Micro-Controller Unit (MCU). The TEE is built on the 64-bit cores, while the 32-bit MCU takes care of sensitive data and activities. The MCU is isolated from the TEE side by an Isolated Bus (IBus) that sits above the conventional System Bus (SBus). Besides the 32-bit processor, the isolated sub-system contains a Random Access Memory (RAM), a Read-Only Memory (ROM) for storing the boot program, and another ROM for storing root keys. For cryptography accelerators, we have 512-bit Secure Hashing Algorithm 3 (SHA3-512), 128/256-bit Advanced Encryption Standard (AES-128/256), Ed25519, and True Random Number Generator (TRNG) attached to the Peripheral Bus (PBus). Additionally, besides the public channel, the TRNG module also has a private channel that goes directly to the IBus. With RoT implemented inside the isolated sub-system, the RoT is inaccessible from the TEE side after boot. Furthermore, the hidden MCU’s secure boot program makes the key generation flexible and could be updated for many security schemes. To summarize, the proposed design features a flexible and secure boot procedure with complete isolation from the TEE domain. Moreover, exclusive secure storage for the root key and cryptographic accelerators are available for the boot process. The implementation was tested on a Virtex-7 XC7VX485T Field-Programmable-Gate-Array (FPGA). It was also synthesized in a Very Large-Scale Integrated (VLSI) circuit with the ROHM-180nm process library.

All cryptography systems have a True Random Number Generator (TRNG). In the process of validating, these systems are necessary for prototyping in Field Programmable Gate Array (FPGA). However, TRNG uses an entropy source based on non-deterministic effects challenging to replicate in FPGA. This work shows the problems and solutions to implement an entropy source based on frequency collapse in multimodal Ring Oscillators (RO). The entropy source implemented in FPGA pass all SP800-90B tests from the National Institute of Standards and Technology (NIST) with a good entropy compared to related works. The TRNG passes all NIST SP800-22 with and without the post-processing stage. Besides, the TRNG and the post-processing stage pass all tests of Application notes and Interpretation of the Scheme (AIS31). The TRNG implementation on a Xilinx Artix-7 XC7A100TCSG324 FPGA occupies less than 1% of the resources. This work presents $0.62~\mu \text{s}$ up to $9.92~\mu \text{s}$ of sampling latency and 1.1 Mbps up to 9.1 Mbps of bit rate throughput.

Hardware acceleration of cryptography algorithms represents an emerging approach to obtain benefits in terms of speed and side-channel resistance compared to software implementations. In addition, a hardware implementation can provide the possibility of unifying the functionality with some secure primitive, for example, a true random number generator (TRNG) or a physical unclonable function (PUF). This paper presents a unified PUF-ChaCha20 in a field-programmable gate-array (FPGA) implementation. The problems and solutions of the PUF implementation are described, exploiting the metastability in latches. The Xilinx Artix-7 XC7A100TCSG324-1 FPGA implementation occupies 2416 look-up tables (LUTs) and 1026 flips-flops (FFs), reporting a 3.11% area overhead. The PUF exhibits values of 49.15%, 47.52%, and 99.25% for the average uniformity, uniqueness, and reliability, respectively. Finally, ChaCha20 reports a speed of 0.343 cycles per bit with the unified implementation.

Transport Layer Security (TLS) provides a secure channel for end-to-end communications in computer networks. The ChaCha20–Poly1305 cipher suite is introduced in TLS 1.3, mitigating the sidechannel attacks in the cipher suites based on the Advanced Encryption Standard (AES). However, the few implementations cannot provide sufficient speed compared to other encryption standards with Authenticated Encryption with Associated Data (AEAD). This paper shows ChaCha20 and Poly1305 primitives. In addition, a compatible ChaCha20–Poly1305 AEAD with TLS 1.3 is implemented with a fault detector to reduce the problems in fragmented blocks. The AEAD implementation reaches 1.4-cycles-per-byte in a standalone core. Additionally, the system implementation presents 11.56-cycles-per-byte in an RISC-V environment using a TileLink bus. The implementation in Xilinx Virtex-7 XC7VX485T Field-Programmable Gate-Array (FPGA) denotes 10,808 Look-Up Tables (LUT) and 3731 Flip-Flops (FFs), represented in 23% and 48% of ChaCha20 and Poly1305, respectively. Finally, the hardware implementation of ChaCha20–Poly1305 AEAD demonstrates the viability of using a different option from the conventional cipher suite based on AES for TLS 1.3.