While talking about blockchain one question that comes to everybody’s mind is what is the security of blockchain or how cryptography plays a role in blockchain security? Let’s understand these terms and the workings of cryptography and its various methods for encryption.
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Cryptography in blockchain technology
Cryptography is a technique to secure data from unauthorized access. In blockchain technology cryptography is used in secured communication or transactions between two nodes in a network. Blockchain technology mainly focuses on two terms: cryptography and hash function.
Cryptography is used for encryption of data, and hashing is used to secure the information between two blocks so that no other nodes or entities can alter the data. The main focus of cryptography in the blockchain is the safety of peer-to-peer nodes, that is participants, and transactions between them, and to secure chains against fraud transactions and double-spending. It ensures that the transaction can only be accessible to the participant node for whom it is intended.
Role of cryptography in blockchain technology
Cryptography is a method which is used to secure the information from a third party during the communication process. The word is composed of two Greek terms, the term Kryptos meaning “hidden,” and Graphein, meaning “to write. In blockchain technology cryptography is used in the protection of privacy and security of data. The methods included in cryptography are symmetric and asymmetric encryption.
There are 4 terms in cryptography that need to be understood, so let’s discuss them.
Encryption: It is the technique that is used to convert normal text into some coded form to protect messages from intercepting.
Key: The element that is used by the sender to decode the message at the receiver’s side sends its public key to verify the integrity of the message. These are two types of public and private keys.
Decryption: It is a technique to decrypt the coded message in plain text format with the help of keys.
Cipher: It’s a function that is used in converting plain text into some random sequence of bits called ciphertext.
Types of cryptography
Symmetric key: Symmetric key is used to encrypt the data in cryptography. In this method, one common key is used in encryption and decryption.
It is called secret-key cryptography. The problem is that the sender and receiver exchange keys in a secure manner in order to keep their security.
The famous algorithm in symmetric key cryptography is the Data Encryption System (DES). It uses a stream cipher and block cipher. In stream cipher, it changes the key as it works bit by bit. Block cipher encrypts the block at the time.
Asymmetric Key Cryptography: This technique or encryption method uses two key pairs, one for encryption and one decryption key also called public key and private key respectively. The asymmetric key algorithm generates a key pair which includes a private key and a unique public key. It is also known as public-key encryption. Asymmetric key cryptography is highly scalable. In Asymmetric key cryptography, the key exchange process is quite simple, here one member produces a secret key and encrypts it with the public key of the receiver then the receiver easily decrypts it with their private key for the establishment of a secure connection.
What is the hash function in cryptography? How it can be used in blockchain security
Cryptography hashing is also a technique for secure communication and it ensures that when data is transferred from the sender the receivers exactly receive the same data without any modification; it’s called the immutability property of cryptography. Hashing does not involve the use of keys. When a transaction is verified the hashing algorithm adds blocks to the blockchain with the previous block connected to the hash. The hashing structure is also called a link list in data structure. The first hash is called the root hash. The hash function helps maintain the integrity of blocks in the blockchain and it uses MD5 and SHA.
Property of hash functions
- If a change is made in the hash function all the hash followed by that block will change respectively.
- The input value of the block can not determined by the hash function of the output value or result.
- The output value is called a hash digest.
- It uses SHA 256, MD5.
- Fast and scalable.
- Tamper Proof.
Benefit of cryptography in blockchain
Encryption is employed in cryptography to safeguard information and communication on a network from unauthorized access and disclosure.
The immutability aspect of cryptography is instrumental in blockchain technology, ensuring secure linking of blocks and maintaining the integrity of stored data. It also prevents attackers from generating valid signatures for unauthorized queries based on previous queries and their signatures.
Cryptography enhances transaction record keeping by encrypting data and enabling data access through public and private keys. The tampering of data through cryptographic hashing is not feasible, thereby bolstering blockchain security.
With cryptography, transactions become irreversible, instilling confidence in the accuracy of the digital ledger and enabling secure recording of limitless transactions.
Digital signatures provide non-repudiation services, guarding against denial of messages by the sender. This is attributed to collision resistance, as each input value has a unique hash function, preventing any conflict between sent messages.
Cryptography plays a crucial role in computer security, particularly in the creation and storage of passwords. When users log in, their passwords are hashed and compared to the previously saved hash, ensuring encryption and preventing unauthorized access to the password database.
Digital currencies like Bitcoin utilize encryption to secure transactions and prevent fraud. Complex algorithms and cryptographic keys safeguard these transactions, making it highly challenging to tamper with or counterfeit them.
Cryptography is utilized to provide web browsing security, safeguarding users against eavesdropping and man-in-the-middle attacks. The Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols employ public key cryptography to encrypt data exchanged between the web server and the client, establishing a secure communication channel.
Authentication protocols make extensive use of cryptographic techniques to verify a user’s identity and ensure they have the necessary access privileges for resources. Additionally, the storage and verification of electronic signatures are reliant on cryptography for security.
Cryptography also plays a vital role in securing two-way communications such as video chats, instant messages, and email. Even with basic encryption, messages are guaranteed to be viewed only by the intended recipients. End-to-end encryption offers a high level of protection and privacy for consumers and is frequently employed in messaging apps such as WhatsApp and Signal.
Conclusion
Blockchain technology relies on cryptography for its internal operations. Blockchain wallets and transactions are based on public key encryption, cryptographic hashing functions ensure immutability and Merkle trees help organize transactions and improve blockchain efficiency. The fundamental concepts of cryptography align seamlessly with the core features of blockchain technology. Digital signatures are widely trusted for encrypting communication within the blockchain network, while cryptographic hash holds significant promise for cryptographic applications.