Asymmetric Encryption

A cryptographic system using mathematically related public-private key pairs where the public key encrypts data that only the corresponding private key can decrypt, enabling secure communication, digital signatures, and trustless verification without pre-shared secrets.

Semantic Classification

Content

Definition

• Cryptographic system using mathematically related public and private key pairs

• Public key encrypts data that only corresponding private key can decrypt

• Foundational primitive for blockchain identity, signatures, and secure communication

  Core Components

• Public Key: Openly shared identifier for encryption and signature verification

• Private Key: Secret value for decryption and signature generation

• Key Generation: Algorithm producing mathematically related key pair

• Trapdoor Function: Easy to compute forward, hard to reverse without private key

  Technical Characteristics

• Computational Asymmetry: Encryption easy, decryption requires secret key

• Non-Repudiation: Private key holder cannot deny signed message

• Key Distribution: Public keys shared openly without secure channel

• Mathematical Foundation: Number theory, elliptic curves, lattices

  Common Algorithms

• RSA: Integer factorization-based, 2048-4096 bit keys

• ECDSA: Elliptic Curve Digital Signature Algorithm

• EdDSA: Twisted Edwards curve signatures (Ed25519)

• BLS: Boneh-Lynn-Shacham signature aggregation

• Post-Quantum: Lattice-based, hash-based for quantum resistance

  Blockchain Applications

• Wallet address derivation from public keys

• Transaction signing and verification

• Multi-signature schemes

• Threshold cryptography

• Zero-knowledge proof generation

  Key Curves in Blockchain

• secp256k1: Bitcoin, Ethereum signature curve

• Ed25519: High-performance Edwards curve

• BLS12-381: Pairing-friendly curve for advanced protocols

• Curve25519: Key agreement protocol

  Relationships

  Security Properties

• Confidentiality: Only recipient decrypts

• Authentication: Verify sender identity

• Integrity: Detect message tampering

• Non-Repudiation: Cryptographic proof of authorship

  Performance Characteristics

• Slower than symmetric encryption (10-1000x)

• Key operations: signing, verification, key exchange

• Hardware acceleration (e.g., specialized elliptic curve processors)

• Trade-off: security vs computational cost

  Blockchain-Specific Considerations

• Deterministic key derivation (BIP32/BIP44)

• Address format and checksum schemes

• Signature malleability prevention

• Multi-signature coordination

• Threshold signature schemes

  Key Management

• Hierarchical deterministic (HD) wallets

• Mnemonic seed phrase backup (BIP39)

• Hardware wallet private key isolation

• Secure enclave storage on mobile devices

  Advantages

• No pre-shared secret required

• Enables digital signatures

• Scalable key distribution

• Foundation for trustless systems

  Limitations

• Computationally expensive

• Larger key sizes than symmetric

• Vulnerable to quantum attacks (RSA, ECDSA)

• Complex key management requirements

  Quantum Resistance

• Current blockchain algorithms vulnerable

• Migration path to post-quantum cryptography

• Lattice-based alternatives (CRYSTALS-Dilithium)

• Hash-based signatures (SPHINCS+)

  Related Concepts

• Digital Signature

• Elliptic Curve Cryptography

• Hash Function

• Key Derivation Function

  cryptography asymmetric-encryption public-key blockchain-security

  Relationships

Provenance