Tech Layer for the ZK Identity Stack

Decentralized identity on Solana integrates four key operations:

1. DID Mapping & Resolution

2. VC Issuance & Verification

3. ZK Proof Verification

4. Decentralized Storage Integration

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1. DID Integration with Solana

Solana acts as the programmable identity layer.

Bitcoin anchors → Solana resolves.

DID Mapping Example (Solana/Anchor Pseudocode)

#[account]
pub struct DidRecord {
    pub did: String,
    pub storage_ref: [u8; 32],
    pub active: bool,
}

pub fn register_did(ctx: Context<RegisterDid>, did: String, storage_ref: [u8; 32]) -> Result<()> {
    let record = &mut ctx.accounts.did_record;
    record.did = did;
    record.storage_ref = storage_ref;
    record.active = true;
    Ok(())
}

This stores the link between:

• DID identifier

• storage reference

• active state

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2. Verifiable Credential Workflow

VCs are issued by trusted entities (or DAOs). They remain off-chain, with references hashed and stored in Solana contracts.

VC Workflow Example

1. Issuer signs credential

2. Metadata stored on Arweave/IPFS

3. Hash recorded on Solana contract

4. Verification queries DID + VC reference

Example Contract Snippet (Anchor)

#[account]
pub struct VcRegistry {
    pub owner: Pubkey,
    pub vc_hash: [u8; 32],
    pub issued_at: i64,
}

pub fn issue_vc(ctx: Context<IssueVc>, vc_hash: [u8; 32]) -> Result<()> {
    let record = &mut ctx.accounts.vc_registry;
    record.owner = ctx.accounts.user.key();
    record.vc_hash = vc_hash;
    record.issued_at = Clock::get()?.unix_timestamp;
    Ok(())
}

---

3. Credential-Based Access Control

Smart contracts can enforce:

• gated access

• membership verification

• reputation-weighted voting

• compliance-level proof

Access Logic Example

pub fn has_credential(ctx: Context<CheckCred>, required_hash: [u8; 32]) -> Result<bool> {
    let vc = &ctx.accounts.vc_registry;
    Ok(vc.vc_hash == required_hash)
}

Application logic executes based on the result.

---

4. ZK Proof Verification

Solana can verify zkSNARK proofs using circuits compiled to the Solana runtime.

Pseudocode for verifying a zk-proof:

pub fn verify_proof(proof: ZkProof, public_input: &[u8]) -> bool {
    // call verifier program
    zk_program::verify(proof, public_input)
}

This may use:

• Groth16

• PlonK

• Circom

• Halo2

The actual implementation depends on chosen ZK backend.

ZK Identities established on Solana as the programmable engine for identity workflows:

• fast DID mapping

• efficient VC referencing

• ZK verification

• cross-chain data coordination