verify.h

The verifier API executes a proof verification. when calling c4_verify_from_bytes, c4_verify needs to be called until the status is either C4_ERROR or C4_SUCCESS.

Example:

 verify_ctx_t ctx = {0};
 for (
     c4_status_t status = c4_verify_from_bytes(&ctx, request_bytes, method, json_parse(args), chain_id);
     status == C4_PENDING;
     status = c4_verify(&ctx))
     curl_fetch_all(&ctx.state);
 if (ctx.success) {
   ssz_dump_to_file_no_quotes(stdout, ctx.data);
   return EXIT_SUCCESS;
 }
 else if (ctx.state.error) {
   fprintf(stderr, "proof is invalid: %s\n", ctx.state.error);
   return EXIT_FAILURE;
 }

verify_flags_t

verifier/verify.h

a bitmask holding flags used during the verification context.

typedef uint32_t verify_flags_t;

verify_flag_t

verifier/verify.h

a enum as list of flags used during the verification context.

typedef enum {
  VERIFY_FLAG_FREE_DATA = 1 << 0, // if set, the data section will be freed after verification. This flag is set when the verifier generates the actual result data from the proof and needs cleanup afterwards.
} verify_flag_t;

flags

verifier/verify.h

a struct holding the verification context.

typedef struct {
  char*          method;       // the rpc-method
  json_t         args;         // the rpc-args as json array
  ssz_ob_t       proof;        // the proof as ssz object using the Proof-Type directly
  ssz_ob_t       data;         // the data as ssz object or Empty if not needed
  ssz_ob_t       sync_data;    // the sync-data as ssz object or Empty if not needed
  bool           success;      // true if the verification was successful
  c4_state_t     state;        // the state of the verification holding errors or data requests.
  chain_id_t     chain_id;     // the chain-id of the verification
  bytes_t        witness_keys; // the witness keys used to sign the checkpoints (multiple addresses are concatinated bytes with 20 bytes each)
  verify_flags_t flags;

method_type_t

verifier/verify.h

a enum as list of method types.

typedef enum {
  METHOD_UNDEFINED     = 0, // the method is not defined
  METHOD_PROOFABLE     = 1, // the method is proofable
  METHOD_UNPROOFABLE   = 2, // the method is unproofable
  METHOD_NOT_SUPPORTED = 3, // the method is not supported
  METHOD_LOCAL         = 4  // the method is executed locally
} method_type_t;

c4_get_request_type

verifier/verify.h

get the request type for a given chain-type. For each chain-type there is one request-type used, the request-type will be specified by the verifier-module.

const ssz_def_t* c4_get_request_type(chain_type_t chain_type);

c4_get_chain_type_from_req

verifier/verify.h

get the chain-type from a given request.

The chain-type is based on the first byte of the request, which corresponds to the chain_type_t enum value.

chain_type_t c4_get_chain_type_from_req(bytes_t request_bytes);

Parameters

• request_bytes : the request bytes to analyze

Returns

the chain type, defaults to C4_CHAIN_TYPE_ETHEREUM for invalid requests

c4_get_req_type_from_req

verifier/verify.h

get the request type from a given request.

The request-type is based on the chain type extracted from the request.

const ssz_def_t* c4_get_req_type_from_req(bytes_t request_bytes);

Parameters

• request_bytes : the request bytes to analyze

Returns

the SSZ definition for the request type

c4_verify

verifier/verify.h

the main verification function executing the verifier in the modules.

c4_status_t c4_verify(verify_ctx_t* ctx);

Parameters

• ctx : the verification context

Returns

C4_SUCCESS, C4_ERROR, or C4_PENDING

c4_verify_from_bytes

verifier/verify.h

shortcut to verify a request from bytes.

c4_status_t c4_verify_from_bytes(verify_ctx_t* ctx, bytes_t request_bytes, char* method, json_t args, chain_id_t chain_id);

Parameters

• ctx : the verification context.

• request_bytes : the request as bytes.

• method : the method to verify (required, cannot be NULL).

• args : the arguments for the method as json array.

• chain_id : the chain-id of the request.

Returns

C4_SUCCESS, C4_ERROR, or C4_PENDING

c4_verify_free_data

verifier/verify.h

free all allocated memory from the verification context. it does not free the verification context itself.

void c4_verify_free_data(verify_ctx_t* ctx);

c4_verify_init

verifier/verify.h

initialize the verification context.

c4_status_t c4_verify_init(verify_ctx_t* ctx, bytes_t request_bytes, char* method, json_t args, chain_id_t chain_id);

Parameters

• ctx : the verification context (required, cannot be NULL).

• request_bytes : the request as bytes.

• method : the method to verify (required, cannot be NULL).

• args : the arguments for the method as json array.

• chain_id : the chain-id of the request.

Returns

C4_SUCCESS or C4_ERROR

c4_get_method_type

verifier/verify.h

get the method type for a given chain-id and method.

method_type_t c4_get_method_type(chain_id_t chain_id, char* method);