In today’s digital age, where data breaches and cyber threats have become increasingly prevalent, ensuring robust cybersecurity has become a critical concern for individuals, businesses, and governments.
In this landscape, a Hardware Security Module (HSM) plays a significant role in enhancing cybersecurity by providing a secure environment for key management and cryptographic operations while safeguarding sensitive data.
HSM is a dedicated hardware device inside or outside the Central Processing Unit (CPU) containing one or more secure crypto processor chips. Some everyday use cases for HSMs include financial services, Government and Defense, Healthcare, Cloud services, Internet of Things (IoT) & Automotive.
HSMs are designed to perform various cryptographic operations, including key generation, encryption, decryption, digital signatures, and hashing while ensuring the trusted execution and data integrity over communications.
Cryptographic Key Management by HSM:
The major role of HSM in Cyber security is cryptographic key management. HSMs generate, store, and manage cryptographic keys used for encryption, decryption, authentication, and digital signatures. The key generation is based on random numbers with high entropy levels. The key storage is on the secure repository inside the HSM which can’t be extracted even if the physical device is compromised. The complete key management system includes key generation, key distribution, access control, Key storage, key rotation, Key backup and recovery, key expiration, and key destruction as shown below.
Encryption and decryption by HSM:
Encryption is the process of converting readable text (referred to as plaintext) into a scrambled, unreadable format (referred to as ciphertext) using an encryption algorithm and a secret key. The primary goal of encryption is to ensure that even if an unauthorized entity gains access to the encrypted data, it cannot understand it without the corresponding decryption key. Decryption is the reverse process of encryption. It involves converting ciphertext back into its original plaintext form using a decryption algorithm and the correct decryption key. Only those with the proper decryption key can successfully reverse the encryption process and obtain the original plaintext.
Commonly used encryption techniques:
Symmetric Encryption: Symmetric encryption uses a single secret key to both encrypt and decrypt data. It is fast and efficient, making it suitable for resource-constrained devices. Common symmetric encryption algorithms include Advanced Encryption Standard (AES), Data Encryption Standard (DES), and Triple DES (3DES), International Data Encryption Algorithm (IDEA).
Asymmetric Encryption (Public Key Encryption): Asymmetric encryption uses a pair of keys – a public key for encryption and a private key for decryption. The public key is widely distributed, while the private key is kept secret. It is commonly used for secure key exchange, digital signatures, and secure communications. Common asymmetric encryption algorithms include RSA (Rivest-Shamir-Adleman), Digital Signature Standard (DSS), Diffie-Hellman (DH), and Elliptic Curve Cryptography (ECC).
Data integrity and authentication algorithms by HSM
Hash Functions: Hash functions are one-way mathematical algorithms used to generate a fixed-size output (hash value) from variable-size input data. Hash functions are commonly used in combination with other encryption techniques to ensure data integrity and authentication.
Majorly used Hash functions: Secure Hash Algorithm 256-bit (SHA-256), Secure Hash Algorithm 3 (SHA-3), Message Digest Algorithm 5 (MD5), Secure Hash Algorithm 1 (SHA-1).
Secure Communication Protocols: Protocols like Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) provide secure communication over networks, ensuring confidentiality, integrity, and authenticity of data during transmission between two devices. The data transmitted between different systems remains encrypted and protected from interception or manipulation.
HSMs are designed to create a secure boundary for cryptographic operations and communications. So, this feature is very useful in Secure On-board communication where communication between different components within an embedded system takes place (e.g., communication between sensors/actuators and Microprocessor).
Majorly used Secure Communication Protocols: Secure Sockets Layer/Transport Layer Security (SSL/TLS), Internet Protocol Security (IPsec), Secure Shell (SSH), Secure/Multipurpose Internet Mail Extensions (S/MIME), Wi-Fi Protected Access 3 (WAP3).
Message Authentication Codes (MAC): MACs are cryptographic techniques used to verify the integrity and authenticity of a message. A MAC is generated using a secret key and added to the message. Upon receipt, the recipient recalculates the MAC to verify if the message has been tampered with.
Majorly used MAC algorithms: (Hash-based Message Authentication Code (HMAC), Cipher Block Chaining Message Authentication Code (CBC-MAC), Cipher-based Message Authentication Code (CMAC), Poly305.
Trusted Execution through HSM:
Trusted Execution in HSM refers to the secure and isolated environment in which critical cryptographic operations and sensitive data processing take place within the HSM. Trusted execution ensures that these operations are performed within a protected boundary thus reducing the risk of unauthorized access, tampering, or exposure of sensitive information to the host system or external attackers. This also contains Secure Boot and Firmware Validation where HSMs are utilized during the boot process to verify the authenticity and integrity of the firmware and software running on the device. This prevents unauthorized or malicious code from being executed in the system.
Protection of Sensitive data in devices and cloud:
HSMs provide a secure boundary for sensitive data, preventing unauthorized access or tampering. They are designed to resist various physical and logical attacks, including tampering, side-channel attacks, and brute-force attacks. In cloud environments, HSMs protect cryptographic keys and sensitive data, ensuring that cloud providers cannot access these critical assets without authorization.
HSMs are used for strong authentication and multi-factor authentication (MFA) mechanisms. They securely store authentication credentials and perform authentication operations, making it more difficult for attackers to compromise user accounts. HSMs are designed to be physically tamper-resistant, which is very important in mobile application frameworks where MFA is significantly used.
Secure OTA Updates:
Secure OTA (Over-The-Air) is the process of updating and maintaining the software or firmware of a device remotely and securely. It’s commonly used in Internet of Things (IoT) devices, automotive systems, smartphones, and other connected devices. The main objective of Security in OTA is to ensure software updates are delivered and installed without security risks, user data is not compromised and maintained the integrity and functionality of the device. HSMs can serve as a root of trust for the OTA process, providing a secure foundation for establishing trust in the update process and ensuring that the updates come from a trusted source.
In scenarios where cryptographic operations are computationally intensive, HSMs can provide hardware acceleration at significantly higher speeds than general-purpose computing systems thereby improving the performance of cryptographic tasks without compromising security.
Overall, HSMs are a critical component of a cybersecurity strategy, particularly in industries that handle sensitive data or require strong cryptographic measures to protect their assets, comply with regulations, and maintain the trust of their users. Siri AB can provide you with consultation support for handling HSM in various applications.
About the Author
Ishwaraprasada is a product owner with several years of experience in the Automotive domain. His area of expertise includes Autosar, Cyber security, Functional safety, Base Software, Battery management system, Vehicle Charging standards, Inverters & Engine management software for PC and Trucks.
Siri AB is Gothenburg, Sweden based organisation with expertise in Automotive, Telecom and IoT engineering. Siri AB can provide you with consultative and implementation support for HSM in various applications.