# A Survey of Blockchain Applications for Management in Agriculture and Livestock Internet of Things
## 2 Preliminaries
### Blockchain Technology in Agriculture and Animal Husbandry: An Overview
#### 2.2.4 Cryptographic Security in Agricultural and Animal Husbandry Applications  
When mentioning blockchain, many people first think of cryptocurrencies, which fundamentally rely on cryptographic algorithms, while blockchain technology utilizes various cryptographic techniques for network security and functionality. In blockchain, cryptography is also used to achieve three main security objectives: confidentiality (hiding information through encryption techniques), integrity (using cryptographic hash functions to prevent illegal modifications), and availability (ensuring information is always accessible to intended users) [72]. The cryptographic technology foundational to blockchain is crucial for the privacy and integrity of data, particularly in the agricultural and pastoral IoT, where this encryption technology safeguards sensitive information collected by sensors on crop or animal health from unauthorized access [73].  
Cryptographic algorithms ensure the security and confidentiality of sensitive agricultural and livestock data. For instance, in agricultural e-commerce platforms, encryption can protect transaction details between farmers and buyers. In animal husbandry, cryptographic methods can secure data related to genetic records or health tracking of high-value livestock, preventing unauthorized access or tampering. This ensures the integrity of critical agricultural information in digital ecosystems.  
Below are some key cryptographic technologies in blockchain technology:  
Hash functions [74]: Hash functions in blockchain technology are crucial for ensuring data integrity and security by generating a unique identifier or hash value. This mechanism enables the blockchain to effectively ascertain if any data have been altered.  
Public key cryptography [75]: Within blockchain environments, the method uses a pair of keys for asymmetric encryption: a public key, often used as the recipient's address, and a private key for signing transactions, thus ensuring data security and maintaining user anonymity.  
Digital signatures [76]: By combining hash functions and public key cryptography, digital signatures authenticate transactions, enabling recipients to verify the sender's identity.  
Elliptic Curve Cryptography (ECC) [77]: Used mainly in blockchain, ECC generates smaller, more efficient digital signatures with its smaller key size and high security, making it the preferred technology for cryptocurrencies like Bitcoin and Ethereum.  
Zero-knowledge proofs [78]: Using this technology, one party can confirm the accuracy of a claim to another party without disclosing the details of the claim.  
Merkle Trees [79]: The Merkle Tree efficiently and securely validates large data volumes within the blockchain. Through hash functions, Merkle Trees connect blocks of data, forming a verifiable data structure.  
Collectively, these cryptographic technologies establish the foundation for blockchain security and functionality, extending its application beyond cryptocurrencies to encompass a variety of decentralized applications.