Module 2: Cryptographic Foundations
Essential cryptographic principles for blockchain security
Cryptography in Blockchain Video
The Role of Cryptography in Blockchain Security
Cryptography is the foundation of blockchain security, providing the mathematical tools and techniques that enable the core security properties of blockchain systems. Without cryptography, blockchain technology as we know it would not be possible.
Key Cryptographic Functions in Blockchain
Cryptography serves several critical functions in blockchain systems:
- Authentication: Verifying the identity of transaction initiators through digital signatures
- Data Integrity: Ensuring that data hasn't been tampered with using cryptographic hash functions
- Consensus: Enabling agreement on the state of the blockchain through cryptographic proofs
- Privacy: Providing varying levels of transaction privacy through encryption techniques
- Access Control: Restricting access to assets through cryptographic key pairs
Types of Cryptography in Blockchain
Blockchain systems utilize several types of cryptography, each serving specific security functions:
Symmetric Cryptography
Uses a single key for both encryption and decryption. While efficient, it requires a secure channel to share the key. In blockchain, symmetric cryptography is often used for encrypting data stored on the blockchain, but is less common than asymmetric cryptography for core functions.
Examples: AES, ChaCha20
Asymmetric Cryptography
Uses key pairs (public and private keys) where the public key can be freely shared while the private key remains secret. This is fundamental to blockchain, enabling digital signatures and address generation without requiring pre-shared secrets.
Examples: ECDSA, EdDSA, RSA
Cryptographic Hash Functions
One-way functions that convert input data of any size into a fixed-size output (hash). They are essential for creating block headers, transaction IDs, Merkle trees, and proof-of-work consensus.
Examples: SHA-256, Keccak-256, Blake2
Zero-Knowledge Proofs
Allows one party to prove to another that a statement is true without revealing any additional information. Used in privacy-focused blockchains and layer-2 scaling solutions.
Examples: zk-SNARKs, zk-STARKs, Bulletproofs
Cryptography as a Security Foundation
The security of blockchain systems ultimately depends on the strength of their cryptographic primitives. If these cryptographic foundations were to be compromised (e.g., through advances in quantum computing or the discovery of vulnerabilities), the security of the entire blockchain would be at risk. This is why blockchain systems typically use well-established, thoroughly vetted cryptographic algorithms rather than novel or proprietary ones.
Duration
5 hours
Resources
6 learning resources
Type
Theory