Secure Elements in Blockchain Networks
In the C4IIoT project, we use Hyperledger Fabric (HLF)ANDROULAKI, Elli, et al. Hyperledger fabric: a distributed operating system for permissioned blockchains. En Proceedings of the Thirteenth EuroSys Conference. 2018. p. 1-15., which is an open source project of a permissioned blockchain infrastructure with modular architecture, allowing managing consensus and trust among different entities. HLF is part of the Hyperledger open source community started by the Linux Foundation.
HLF is used enable auditability of various events, such as when generating data items (e.g. sensor readings by IoT devices), when storing data at a persistent cloud storage service, and when issuing alerts or insights by the analytics. In addition, HLF protects the integrity of data stored on the cloud storage, by having the data generators document the hash of the data in the tamper-proof ledger upon data creation.
HLF works with cryptographic material for tasks like signing transactions, enrolment of new nodes in the network and safeguard data access policies. Typically, this cryptographic material, like ECC private keys and certificates, is stored in a software wallet. This way of storing the keys generates vulnerabilities within the system, for instance, the recovery of keys by a third party in a malicious way, and this implies the loss of credential of the owner, unauthorized access control or the data leakage. To endorse this, CipherTrace Cryptocurrency Anti-Money Laundering Report Q4 2018 CipherTrace Cryptocurrency Anti-Money Laundering Report Q4 2018 Online https://ciphertrace.com/cryptocurrency-anti-money-laundering-report-q4-2018/ shows the rapid rise in crypto concurrency theft from currency exchanges due to the hacking of the private key or software-only security systems.
C4IIoT proposes using hardware security modules (HSMs) in the blockchain elements that require handling sensitive private keys to solve the issues mentioned above. In this way, the HSMs will further offer security to other layers of the architecture, including the facilitation of strong authentication and authorization schemes that are based on security tokens, like PKCS #11 https://tools.ietf.org/html/rfc7512. These security tokens, implemented in hardware-enforced secure enclaves are responsible for identity and access management, as well as for ensuring accountability; as a result, they will prevent false identities to commit fraud, acquire sensitive data, commit data theft, or manipulate the system by any means.
This advantages lies mainly in three aspects: Frist one, a True Random Number Generator (TRNG), the keys are generated by a secure way; this makes high entropy values in the key generation. Therefore, it makes increase the level of security. Second one, tamper-proof protection which consists in the secure storage of private keys or sensitive information, preventing an attacker from retrieving or modifying the information, the module are designed in a way that the information is not accessible from an external means, avoiding physicals attacks, for example probing and side-channel attacks. Third one, key backup and restoration, especially in blockchain technologies like HLF, where the certification authority exits, attacks on this entity can lead to the loss of cryptographic data since it is the most centralizing element in the network.
Infineon Technologies AG provides suitable HSMs. Infineon offers a wide range of security and smart card solutions https://www.infineon.com/cms/en/product/security-smart-card-solutions/. In C4IIoT project, some of them are used. Figure 1. They will be explained below:
- Blockchain Security 2Go https://www.infineon.com/cms/en/product/security-smart-card-solutions/blockchain-security-2go/ https://github.com/Infineon/Blockchain: The storage of the blockchain user credentials in unencrypted memory either from computer or cellphone is extremely risky as an attacker may retrieve confidential information. Security can be enhanced by integrating a dedicated Hardware Security Module (HSM) into the device microcontroller. This separates critical operations and credential storage from other software operations, therefore provides robust protection against software attacks.
In C4IIoT project, this module has been used in order to authenticate operators in the blockchain inside of a smart factory. The user blockchain credentials are stored in the cards which make possible, in addition to being able to identify oneself when handling a device through NFC interface, to sign transactions to the blockchain network. These transactions can trigger events using smart contracts, which are installed in the blockchain network. These events are triggered following the business logic established by the partners, which belong to the consortium.
- OPTIGA™ TPM 2.0 https://www.infineon.com/cms/en/product/security-smart-card-solutions/optiga-embedded-security-solutions/optiga-tpm/: OPTIGA™ TPM (Trusted Platform Module) security chips provide robust protection for critical data and processes in order to protect the integrity and authenticity of embedded devices and systems. OPTIGA™ TPM security chips offers an easy integration into all platform architectures and operating system, it is based on Trusted Computing Group (TCG) standards which define a range of open, vendor-neutral, global industry standards to support interoperability between trusted computing platforms.
In C4IIoT project, the secure element has been used in order to authenticate devices into the blockchain network. In this use case, the secure element works as a PKCS #11 hardware wallet to generate and store the cryptographic material using in the communication with the blockchain. By this way, the device is protected to physical attacks avoiding the tampering of the keys and therefore the impersonation of the device.
In the integration of these secure elements with the blockchain networks, they must use the same standards; and in particular the same cryptographic curve.
Blockchain security 2go, for instance, shares the same elliptic cryptographic curve (ECC) with Ethereum and Bitcoin: ECC secp256k1. In the case of the OPTIGA™ TPM 2.0, it shares the ECC curve with Hyperledger Fabric: ECC secp256r1 (NIST curve).
This makes it possible the integration of the two components within the framework of C4IIoT: Hyperledger Fabric and OPTIGA™ TPM 2.0. In addition, the communication between both components is possible due to both share the Public-Key Cryptography Standards (PKCS). For instance, the certificate signing request defined in PKCS#10, which is a mechanism between an entity and the certificate authority in order to apply for a digital identity certificate. In addition, they share the PKCS#11, which enables a generic API to create and manipulate cryptographic tokens.
The union of these two components creates a complete robustness within a system; it adds hardware-enable security (thanks to the secure element) to the security by horizontal device-to-device communication (provide by the blockchain).
In industrial processes, this can greatly reduce costs and increase efficiency; particularly where information must be shared between companies or the fulfilment of arrangements must be assured, making the security the most relevant element adding security. Advanced hardware-enabled security features, allowing secure-by-design IoT devices, and decentralized access help to build a secure and trusty ecosystem of large industries and small-medium entities.
|↑1||ANDROULAKI, Elli, et al. Hyperledger fabric: a distributed operating system for permissioned blockchains. En Proceedings of the Thirteenth EuroSys Conference. 2018. p. 1-15.|
|↑2||CipherTrace Cryptocurrency Anti-Money Laundering Report Q4 2018 Online https://ciphertrace.com/cryptocurrency-anti-money-laundering-report-q4-2018/|