Unlike traditional cryptography that's built on mammoth mathematical complexity to reverse engineer the encryption; Quantum Cryptography depends on Physics Laws.
It relies on unique principles of quantum mechanics:
- Particles can exist in more than one place or in more than one state; to predict there is no means.
- Photons' spins can be measured randomly in binary positions.
- Quantum state can't be measured without being altered; as basic act of measuring impacts the state of system.
- Particles can be partially, but not completely cloned.
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QKD ain't used to encrypt data; but secure key exchange between 2 parties by collaboratively building a shared private key similar to one used by symmetric key encryption.
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QKD sends individual photons across an optic cable; each representing a bit (or Qubit). The photon spin series becomes the key. Polarized filters on sender's side change the physical orientation of each photon to a specific spin.
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A cryptographic primitive allowing two untrusted parties to agree on set of trust parameters.
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Leverages principles of superposition and entanglement, to ensure a fair and secure coin flip.
Goal is to have Quantum-resistant cryptography; 6 primary areas:
- Lattice-based Cryptography
- Multivariate Cryptography
- Hash-based Cryptography
- Code-based Cryptography
- Isogeny-based Cryptography
- Symmetric key quantum resistance
General Encryption
- Crytals Kyber is an IND-CCA2-secure KEM (key encapsulation mechanism), one of the finalists for NIST's Post-Quantum Cryptography Project. Whose security is based on the hardness of solving the LWE (learning with errors) problem over module lattices.
Digital Signature Scheme
sources:
2022: NIST's 4 Quantum Resistant Cryptography Algorithm