compact-engine/com.midnight.kuira.core.compact.proving/ProvingKeyManager

ProvingKeyManager

class ProvingKeyManager(context: Context, apkStampOverride: () -> String?? = null)

Manages proving key download, caching, and version tracking for local ZK proving.

Proving keys are downloaded from Midnight's S3 once (~24MB total) and cached in app internal storage. The phone can then prove transactions offline.

Key locations match the SDK's WasmProver.makeDefaultKeyMaterialProvider():

  • zswap/{ver}/spend.prover (10.5 MB)

  • zswap/{ver}/output.prover (5.5 MB)

  • zswap/{ver}/sign.prover (2.7 MB)

  • dust/{ver}/spend.prover (2.1 MB)

  • bls_midnight_2p13 (1.5 MB)

  • Corresponding .verifier and .bzkir files

Constructors

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constructor(context: Context, apkStampOverride: () -> String?? = null)

Types

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object Companion

Properties

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val keysDir: File

Directory where proving keys are cached on device.

Functions

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fun cachedSizeBytes(): Long

Total size of cached keys in bytes.

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fun clearCache()

Delete all cached proving keys.

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fun contractKeysDir(contractName: String): File

Directory for a specific contract's proving keys. Keys are stored at: proving_keys/contracts/{contractName}/{circuit}.{prover,verifier,bzkir}

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suspend fun downloadContractKeys(contractName: String, circuitNames: List<String>, baseUrl: String, onProgress: (Float) -> Unit = {}): Int

Download contract proving keys from a remote URL.

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suspend fun downloadWalletKeys(onProgress: (Float) -> Unit = {})

Download all wallet proving keys from S3.

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suspend fun ensureWalletKeysAvailable(onDownloadProgress: (Float) -> Unit = {}, logger: (String) -> Unit = {})

One-call wallet-key provisioning. Tries the dev shortcut first (installFromLocalTmp — adb-pushed files in /data/local/tmp/), then falls back to the S3 download (downloadWalletKeys) when the local-tmp pass didn't populate the BLS params + zswap/dust keys. After this returns, hasWalletKeys is true unless the download itself failed (in which case the underlying IOException propagates).

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fun hasBLSParams(): Boolean

Whether BLS parameters are available (needed for all proving).

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fun hasContractKeys(contractName: String, circuitNames: List<String>): Boolean

Whether all required circuit keys are cached for a contract.

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fun hasProvableCircuitKeys(circuitNames: List<String>): Boolean

Whether the prover can find circuit keys at the root keys directory.

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fun hasWalletKeys(): Boolean

Whether all wallet-required proving keys are cached and current version.

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fun installCircuitKeysForProving(circuitNames: List<String>, keysSourceDir: File, zkirSourceDir: File, overwrite: Boolean = false)

Install circuit keys to the root keys directory for the prover.

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fun installCircuitKeysFromAssets(assetDir: String = "keys", overwrite: Boolean = false)

Install a dApp's own contract circuit keys from the APK's bundled assets into the prover's keysDir, where the local prover resolves them.

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fun installContractKeys(contractName: String, circuitNames: List<String>, keysSourceDir: File, zkirSourceDir: File, overwrite: Boolean = false)

Copy contract proving keys from a source directory into the cache.

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fun installFromLocalTmp(localTmp: File = File("/data/local/tmp")): Boolean

Dev-only convenience: install proving keys from a local-tmp staging area pushed via adb push (the convention used by Kicks's build script, the SDK e2e test, and BBoard's canary). Looks at two well-known directories on the device:

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fun removeContractKeys(contractName: String)

Remove all cached keys for a contract.