The Future of JSON in the Post-Quantum Computing Era

Introduction: JSON Meets the Quantum Challenge

JSON (JavaScript Object Notation) has become the de facto standard for data interchange on the web and beyond. Its simplicity, human-readability, and ease of parsing across various programming languages have cemented its position. Meanwhile, the world is rapidly approaching the era of quantum computing, which poses a significant threat to much of our current cryptographic infrastructure.

While JSON itself is merely a data format and not a cryptographic system, it is the carrier for vast amounts of sensitive data that are routinely secured using cryptographic methods. Digital signatures embedded within JSON objects (like in JWS), encrypted payloads carried in JSON structures (like in JWE), and authentication tokens represented as JSON (like in JWT) all rely on cryptographic algorithms currently vulnerable to sufficiently powerful quantum computers.

This article explores how the advent of post-quantum cryptography (PQC), designed to withstand quantum attacks, will intersect with JSON usage. We'll look at potential impacts on data size, performance, standards, and the practical considerations for developers.

JSON's Ubiquity in the Digital Landscape

Before delving into quantum threats, let's briefly recap JSON's role. It's fundamental in:

• Web APIs: The primary format for data exchange between clients and servers.
• Configuration Files: Human-readable configuration for applications and services.
• Data Storage: NoSQL databases often use JSON-like documents.
• Inter-service Communication: Message queues and microservices often serialize data as JSON.
• Security Tokens: Standards like JWT, JWS, JWE use JSON structures to carry authentication and authorization information, signed or encrypted.

Its widespread adoption means any significant shift in underlying security mechanisms will inevitably ripple through systems that rely on JSON.

The Post-Quantum Threat to Current Cryptography

Current public-key cryptography, including RSA and Elliptic Curve Cryptography (ECC), relies on the computational difficulty of certain mathematical problems (factoring large numbers or finding discrete logarithms on elliptic curves). Shor's algorithm, if run on a large enough quantum computer, can solve these problems efficiently, breaking the security of these algorithms.

This threat primarily affects:

• Asymmetric Encryption: Used for securing communication channels (like TLS handshakes) and encrypting data for specific recipients.
• Digital Signatures: Used for verifying identity and ensuring data integrity (e.g., code signing, document signing, securing JWTs).

Symmetric encryption (like AES) and hashing algorithms (like SHA-256) are less affected, requiring only a doubling of key size for equivalent security against Grover's algorithm, a less potent quantum threat.

Post-Quantum Cryptography (PQC)

Post-quantum cryptography refers to new cryptographic algorithms being developed to be resistant to attacks by both classical and quantum computers. The U.S. National Institute of Standards and Technology (NIST) has been running a multi-year process to standardize PQC algorithms. The main families include:

• Lattice-based cryptography (e.g., CRYSTALS-Kyber for KEMs, CRYSTALS-Dilithium for signatures)
• Hash-based cryptography (e.g., LMS, XMSS, SPHINCS+)
• Code-based cryptography (e.g., Classic McEliece)
• Multivariate polynomial cryptography
• Isogeny-based cryptography

These algorithms have different characteristics compared to current RSA/ECC, particularly regarding key sizes and signature sizes, as well as computational performance.

Impact on JSON Data Structures

JSON's core structure (objects, arrays, primitives) is fundamentally stable and will not change due to PQC. However, the *content* stored within JSON fields will be affected, specifically the parts representing cryptographic keys, signatures, or encrypted data.

1. Data Size

Many PQC algorithms have significantly larger key sizes and signature sizes compared to their pre-quantum counterparts. For instance:

• An RSA 2048-bit public key is ~256 bytes.
• An ECC P-256 public key is ~64 bytes.
• A CRYSTALS-Kyber public key is ~800-1200 bytes (depending on security level).
• An RSA 2048-bit signature is ~256 bytes.
• An ECC P-256 signature is ~64-72 bytes.
• A CRYSTALS-Dilithium signature is ~1300-2500 bytes (depending on security level).
• Hash-based signatures like SPHINCS+ can be even larger, though often stateful or with different trade-offs.

Consider a JSON object carrying a digital signature, like a JSON Web Signature (JWS). A detached JWS structure might look something like this (simplified):

{
  "protected": "eyJhbGciOiJFUzI1NiJ9", // Header (e.g., Algorithm=ES256)
  "signature": "AbCD...XYZ"          // Base64Url encoded signature
}

If the signature algorithm changes from ES256 (ECC) to a PQC signature like Dilithium, the Base64Url encoded signature string in the "signature" field will become substantially longer.

Similarly, for JSON Web Encryption (JWE), which carries encrypted data within a JSON structure, the keying material or the encrypted payload size might change.

{
  "protected":"eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0", // Encrypted header (e.g., A128CBC-HS256)
  "encrypted_key":"CEK_goes_here",            // Encrypted Content Encryption Key (CEK)
  "iv":"base64url_encoded_iv",                // Initialization Vector
  "ciphertext":"base64url_encoded_ciphertext",// Actual encrypted data
  "tag":"base64url_encoded_authentication_tag"// Authentication tag
}

In a PQC context, the "encrypted_key" field would likely contain a ciphertext generated by a PQC Key Encapsulation Mechanism (KEM) like Kyber, which would be larger than an RSA or ECDH encrypted key.

This increase in data size could impact network bandwidth, storage requirements, and potentially memory usage during processing, especially in constrained environments or for very large numbers of transactions.

2. Performance

PQC algorithms often have different performance characteristics than current ones. Some are faster for key generation or signing, while others are slower for verification or encryption/decapsulation. Many PQC algorithms are based on operations on large polynomials or matrices, which can be computationally intensive.

While JSON parsing/serialization speed itself is unlikely to be the bottleneck, the time spent performing the cryptographic operations on the data carried within JSON (e.g., verifying a large PQC signature string, decrypting a PQC-encrypted blob) will increase for some algorithms. Developers need to be mindful of this when designing systems that perform frequent cryptographic operations on JSON data.

3. Representation of PQC Artifacts in JSON

How will PQC public keys, private keys (less common in JSON but possible), signatures, and ciphertexts be represented?

• Keys: Public keys will need standardized formats. Existing standards like X.509 certificates and JSON Web Keys (JWK) will need updates to accommodate PQC algorithm types and key formats. A JWK for an ECC key might look like:

  {
    "kty": "EC",
    "crv": "P-256",
    "x": "f83_X...kP",
    "y": "...base64url..."
  }

  A JWK for a PQC key (e.g., Dilithium) will need new "kty" and algorithm identifiers, and fields to carry the potentially larger key components, likely still Base64Url encoded:

  {
    "kty": "OKP", // Example, standard not finalized
    "alg": "Dilithium2", // Example algorithm identifier
    "public_key": "longer_base64url_encoded_pk_component1...",
    "public_key_param2": "longer_base64url_encoded_pk_component2..." // Depending on algorithm structure
    // ... potentially other fields
  }

• Signatures and Ciphertexts: These will also be binary data represented as strings within JSON, typically using Base64 or Base64Url encoding to be compatible with JSON's string type. The increase in size will manifest as longer strings.

4. Schema Evolution

While the fundamental JSON grammar is unchanged, schemas that define the structure of JSON documents will need updates. Schemas (like JSON Schema) that currently specify a field should contain a Base64Url encoded ECC signature string of a certain maximum length might need to loosen length constraints or specify new algorithm types permitted in associated header fields.

Existing fields that carried RSA/ECC public keys will need to accept PQC public key formats. This means JSON structures and the code parsing them will need to become aware of new algorithm identifiers and be able to handle the new data formats and potentially larger sizes.

Developer Considerations

The transition to PQC will require significant effort from developers, touching various layers where JSON is used:

• Cryptographic Libraries: Developers will need to adopt new versions of cryptographic libraries that implement the standardized PQC algorithms (e.g., OpenSSL, BoringSSL, libsodium, or language-specific libraries like those in Go, Java, Python, Node.js). These libraries will handle the complex mathematical operations, but developers need to know how to use the new functions for key generation, signing, verification, encapsulation, and decapsulation.
• Protocol Updates: Protocols that use cryptography, and often carry related data in or as JSON (like TLS, SSH, VPNs, secure messaging protocols), will be updated to support PQC. Developers using these protocols via standard libraries will benefit automatically, but might need configuration changes (e.g., specifying allowed PQC cipher suites).
• Standards Compliance: Standards like JWS, JWE, JWK, JWT, and potentially newer ones like COSE (CBOR Object Signing and Encryption) which can also sign/encrypt JSON (though designed for CBOR), will be revised. Developers implementing or using libraries for these standards will need to upgrade and understand the new PQC-specific parameters (e.g., "alg" values for Dilithium, Kyber).
• Backward Compatibility and Migration: A "flag day" where everyone switches to PQC simultaneously is unrealistic. Systems will need to support a transition period, likely using hybrid approaches (signing data with both a traditional and a PQC signature, or encrypting session keys with both RSA/ECC and PQC KEMs). This adds complexity to JSON structures (e.g., a JWS might have multiple signatures).
• Performance Tuning: Profiling and optimizing code that performs PQC operations will be necessary. Hardware acceleration for specific PQC algorithms might become available, impacting deployment decisions.
• Data Management: Larger keys and signatures mean larger data records or network packets. While often manageable, in high-throughput or low-bandwidth scenarios, developers might need to reconsider data structures, employ compression techniques, or optimize data serialization/deserialization.

Examples in JSON Context

Let's visualize the change with a simplified example of a signed configuration object.

Current (ECC Signature)

{
  "config_data": {
    "param1": "value1",
    "param2": 123,
    "enabled": true
  },
  "signature": "MEUCIGH...long_base64url_ecc_sig...oBv756s",
  "algorithm": "ES256"
}

Here, the signature is relatively short.

Post-Quantum (Dilithium Signature)

{
  "config_data": {
    "param1": "value1",
    "param2": 123,
    "enabled": true
  },
  "signature": "longer_base64url_dilithium_signature_much_much_longer_than_ecc_or_rsa_...",
  "algorithm": "Dilithium3" // Example PQC alg identifier
}

The primary visual and practical difference is the length of the signature string. This longer string needs to be stored, transmitted, parsed, and processed.

Hybrid Signature Example

{
  "config_data": {
    "param1": "value1",
    "param2": 123,
    "enabled": true
  },
  "signatures": [
    {
      "signature": "MEUCIGH...base64url_ecc_sig...oBv756s",
      "algorithm": "ES256"
    },
    {
      "signature": "longer_base64url_dilithium_signature_...",
      "algorithm": "Dilithium3"
    }
  ]
}

During the transition, a structure might carry multiple signatures for the same data, allowing systems that haven't migrated to PQC to still verify the traditional signature, while migrated systems can verify the PQC one. This further increases JSON payload size.

Conclusion: Evolution, Not Revolution, for JSON

The core JSON format is resilient. It's a simple, flexible container for data. The post-quantum transition will not break JSON itself or require a fundamental change in how we structure objects and arrays.

However, developers working with security-sensitive data carried in JSON need to prepare for significant changes in the size and processing requirements of cryptographic elements. This includes:

• Understanding the new PQC algorithms and their trade-offs.
• Adopting updated cryptographic libraries and standards.
• Planning for increased data sizes, particularly for signatures and public keys.
• Considering the performance implications of PQC operations.
• Managing backward compatibility and implementing hybrid solutions during the migration phase.

The future of JSON in the post-quantum era is not about changing JSON, but about adapting the ecosystem and practices around it to accommodate the next generation of cryptography. Developers who understand these implications will be better positioned to build secure and efficient systems for the quantum age.