Foundations of Cryptography in Blockchain: Types,  Applications & Everything You Need to Know

Blockchain technology has revolutionized the way we perceive and handle digital transactions. At the core of blockchain technology lies cryptography, a field that ensures the security, integrity, and confidentiality of data within the blockchain.

Although we defined cryptography in Essential Blockchain, Cryptocurrency and Web3 Terms You Should Know, we will now see in-depth what it entails.

In this comprehensive blog article, we will dive into the foundations of cryptography in blockchain, exploring its types, applications, and everything you need to know to understand the concept  of this vital aspect of decentralized systems.

What is Cryptography in Blockchain Technology

A question that often arises is how secure blockchain is and what contributes to its security?.

The security of blockchain is underpinned by two key concepts: Cryptography and Hashing.

Cryptography encrypts messages in the P2P network while hashing helps secure block information and link blocks in the blockchain.

Cryptography primarily focuses on ensuring the safety of participants, transactions, and security against double-spending.

This article specifically concentrates on thoroughly discussing these two fundamental concepts.

As we mentioned earlier, blockchain is structured through two main concepts the cryptography and hashing so lets discuss them.

1. Cryptography

Cryptography is a technique or a set of protocols that secure information from any third party during a process of communication.

Cryptography safeguards data from unauthorized access, and in blockchain, it ensures the security of transactions between two nodes ( Participants) within the blockchain network.

It comprises two Greek terms as well: “Kryptos,” signifying hidden,” and “Graphein,” denoting “to write.”

Cryptography serves as the backbone of blockchain technology, providing the necessary tools to secure transactions and maintain the trust less nature of the decentralized network.

Read also: What is Decentralization in Blockchain Technology?

Some Terminology Related to Cryptography:

  • Encryption: involves transforming plaintext into a random sequence of bits.
  • Key: contains specific information necessary to access the cryptographic algorithm.
  • Decryption: is the reverse of encryption, converting a random bit sequence back into plain text.
  • A cipher, or cryptographic algorithm, is a mathematical function that converts plaintext into cipher text—a random sequence of bits.

Types of Cryptography

The two primary cryptographic techniques employed in blockchain are symmetric key cryptography and public-key cryptography. Meaning,

The two types of cryptography are:

  • Symmetric-key cryptography.
  • Asymmetric-key cryptography.

Let’s discuss each of these topics in detail.

1. Symmetric Key Cryptography:

It is also referred to as secret-key cryptography.

In symmetric key cryptography, a single key is used for both encryption and decryption. It focuses on a similar key for encryption as well as decryption.

Each participant in the blockchain network shares the same secret key, ensuring secure communication between them.

The symmetric key encryption method is also applicable to secure website connections or encryption of data.

While efficient, symmetric key cryptography faces challenges in securely distributing and managing the secret key. The sender and receiver exchange keys in a secure manner.

A widely-used symmetric-key cryptography system is the Data Encryption Standard (DES). In this cryptographic algorithm, the key within a cipher is employed to encrypt the data, and only those with access to the secret key can decrypt the data. Examples of such cryptographic algorithms include AES, DES, and others.


  • Referred to as Secret Key Cryptography.
  • Involves both parties sharing the same key for maintaining secrecy.
  • Well-suited for bulk encryptions.
  • Demands less computational power, enabling faster transfers.

2. Public-Key Cryptography:

Public-key cryptography, or asymmetric cryptography, utilizes a pair of keys: a public key for encryption and a private key for decryption. Uses different keys for the encryption and decryption process.

Participants have a public key visible to everyone and a private key kept confidential.

This public key method help completely unknown parties to share information between them like email id while private key helps to decrypt the messages and it also helps in the verification of the digital signature.

Example: ECC,DSS  .

This method addresses the key distribution challenge but demands more computational resources.


  • Also identified as Public-key cryptography,
  • It is commonly employed for sharing secret keys in symmetric cryptography.
  • The execution involves a lengthy processing time.
  • Plays a crucial role in authenticating website servers.

2. Cryptography Hash Function in Blockchain

Cryptographic hashing is a notable application of cryptography, particularly in ensuring immutability within the blockchain.

Unlike encryption with keys, cryptographic hashing involves the creation of a unique hash for each transaction verification.

The hash is added to the block, forming a chain of linked blocks with a continuous hashing process, ultimately resulting in a root hash. This root hash is vital for linking blocks and maintaining data integrity. Any alteration in block data breaks the blockchain. Commonly used hash functions include MD5 and SHA-1.

In blockchain, a cryptographic hash function act’s as a mathematical algorithm that takes input data and produces a fixed-size string of characters, which is typically a hash.

This hash is unique to the input data, and even a small change in the input will result in a substantially different hash. Hash functions play a crucial role in ensuring the integrity of blockchain data.

Properties of Cryptographic Hash:

  • The hash function remains constant for a specific message.
  • Even minor data alterations causes a significant change in the hash value.
  • The input value cannot be guessed from the output hash function.
  • They are fast and efficient as they largely rely on bitwise operations.

Benefits of Hash function in Blockchain:

1. Bandwidth Efficiency:

Think of hash functions like a shorthand for data. Instead of sending the entire message, you can send a compact hash that represents it. It’s like sending a brief code instead of a lengthy letter, making transactions quicker and using less network bandwidth.

2. Data Block Security:

Hash functions act like a unique seal on data blocks. If someone tries to tamper with the information inside a block, the seal (hash) breaks. This ensures that data remains secure and unchanged, creating a digital lock on each block in the blockchain.

3. Simplified Transaction Verification:

Imagine each transaction having a unique fingerprint (hash). Verifying transactions is as easy as matching fingerprints. This unique identifier makes it quick to confirm the authenticity of transactions without going through the entire transaction details, streamlining the verification process in the blockchain. For example in bank apps etc.

Use of Cryptographic Hash Functions

As the blockchain is also public and accessible to everyone, it is important to secure data in the blockchain and keeps the data of the user safe from malicious hands. So, this can be achieved easily by cryptography in the following ways.

  1. When a transaction is checked and verified using the hash algorithm, its added to the blockchain, creating a connected chain of blocks as more confirmations happen in the network.
  2. Cryptography, which involves using math codes, ensures that only the right users can read and understand the transaction data safely.
  3. Many tools that use cryptography in blockchain have appeared over time, bringing different features to make the system more secure and functional.

Types of Cryptographic Algorithms:

Cryptographic algorithms are mathematical rules used for secure operations like encryption and decryption. Examples include AES (Advanced Encryption Standard), RSA (Rivest-Shamir-Adleman) and SHA-256 (Secure Hash Algorithm 256-bit), crucial for ensuring data security in computer systems.

  • Blockchain Wallets

A blockchain wallet, whether in the form of software or hardware, serves to store user transaction and personal data without holding the actual currency. Its primary function is to manage private keys and transaction balances, acting solely as a communication tool for executing transactions with other users, while the actual data or currency resides in blocks within the blockchain.

  • Digital Signatures

Digital signatures serve as evidence provided by the user to both the recipient and other nodes within the network, confirming its legitimacy as a participant authorized to conduct transactions. When commencing a transaction in the blockchain network, the user must initially generate a distinctive digital signature. This involves using a specialized algorithm to combine the transaction data with the user’s private key, ensuring both the node’s authenticity and the data’s integrity.

Benefits of Cryptography in Blockchain

There are a huge number of benefits of cryptography in blockchain some of them are stated below:

1. Security: Cryptography ensures data integrity and confidentiality on the blockchain, preventing unauthorized access and tampering.

2. Immutability: Cryptographic hashing guarantees that once data is on the blockchain, altering it would require changing all subsequent blocks, ensuring data permanence.

3. Authentication: Digital signatures verify participants’ identities, validating transactions and ensuring they come from legitimate sources.

4. Privacy: Cryptography, including zero-knowledge proofs, enables private and secure transactions without revealing sensitive information.

5. Consensus Mechanisms: Cryptographic algorithms, like PoW and PoS, maintain decentralized blockchain networks by ensuring agreement on the system’s state.

6. Key Management: Cryptography handles the secure generation, distribution, and storage of cryptographic keys, controlling access to private keys for secure transactions.

7. Smart Contract Security: Cryptography safeguards smart contract execution and data, preventing unauthorized access and manipulation.

8. Interoperability: Cryptography establishes secure communication between different blockchain networks, fostering integration and collaboration in the blockchain ecosystem.

Limitations of Cryptography in Blockchain

While cryptography forms the backbone of blockchain security, it is not without its limitations. Understanding these constraints is crucial for addressing potential vulnerabilities in decentralized systems. Here are key limitations of cryptography in blockchain:

1. Quantum Threats: The rise of quantum computers poses a risk to traditional cryptographic methods, demanding the adoption of quantum-resistant solutions for blockchain security.

2. Key Management: Securely managing cryptographic keys, especially in decentralized networks, remains challenging. Poor key management can lead to unauthorized access and compromise transaction integrity.

3. Human Factors: Human error, susceptibility to phishing attacks, and the challenge of key management for non-technical users pose vulnerabilities in blockchain security.

4. Algorithmic Vulnerabilities: The robustness of cryptographic algorithms is crucial. The discovery of vulnerabilities could be exploited to compromise the security of blockchain systems.

5. Centralization Risks: Certain consensus mechanisms, like PoS or DPoS, may introduce centralization risks, especially when a significant portion of tokens is concentrated in few hands.

6. Limited Privacy: While blockchain transactions are pseudonymous, privacy remains a concern. Techniques like zero-knowledge proofs aim to enhance privacy but may not be foolproof against advanced analysis.

7. Scalability Challenges: Cryptographic operations, especially in computationally intensive PoW, can hinder scalability as transaction volumes increase.

8. Regulatory Compliance: Cryptography’s strong encryption capabilities may conflict with regulatory transparency requirements. Striking a balance between privacy and compliance is challenging in regulated sectors.

In conclusion, cryptography is the cornerstone of blockchain’s security and decentralization. From encryption basics to diverse applications, its role is vital. Navigating challenges like quantum threats, cryptography remains dynamic, shaping a secure and transparent digital future. Understanding this foundation is key to unlocking the full potential of blockchain technology.

NEXT READING: What are Smart Contracts in Blockchain Technology: A Simple Explanation for Beginners

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