feat(api): add Intel DCAP API client module

Introduced a new `intel-dcap-api` crate for interacting with Intel's DCAP APIs.
- Implemented various API client functionalities for SGX/TDX attestation services.
- Added support for registration, certification, enclave identity, and FMSPC retrieval.

Signed-off-by: Harald Hoyer <harald@matterlabs.dev>

crates/intel-dcap-api/src/responses.rs

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (c) 2025 Matter Labs
+
+/// JSON structure as defined in Appendix A of the API spec.
+/// Content may vary slightly between API v3 and v4.
+pub type TcbInfoJson = String;
+
+/// JSON structure as defined in Appendix B of the API spec.
+/// Content may vary slightly between API v3 and v4.
+pub type EnclaveIdentityJson = String;
+
+/// JSON Array of {tcb, tcbm, cert}.
+/// Content structure expected to be consistent between v3 and v4.
+pub type PckCertsJsonResponse = String;
+
+/// JSON Array of {fmspc, platform}.
+/// Content structure expected to be consistent between v3 and v4.
+pub type FmspcJsonResponse = String;
+
+/// JSON structure as defined in Appendix C of the API spec (V4 ONLY).
+pub type TcbEvaluationDataNumbersJson = String;
+
+/// Response structure for a PCK (Platform Configuration Key) Certificate.
+///
+/// Contains the PCK certificate, its issuer chain, TCB measurement, and FMSPC value.
+#[derive(Debug, Clone)]
+pub struct PckCertificateResponse {
+    /// PEM-encoded PCK certificate.
+    pub pck_cert_pem: String,
+    /// PEM-encoded certificate chain for the PCK certificate issuer.
+    /// Header name differs between v3 ("PCS-Certificate-Issuer-Chain") and v4 ("SGX-PCK-Certificate-Issuer-Chain").
+    pub issuer_chain: String,
+    /// TCBm value associated with the certificate (Hex-encoded).
+    pub tcbm: String,
+    /// FMSPC value associated with the certificate (Hex-encoded).
+    pub fmspc: String,
+}
+
+/// Response structure for multiple PCK (Platform Configuration Key) Certificates.
+///
+/// Contains a JSON array of PCK certificates, their issuer chain, and the associated FMSPC value.
+/// This struct represents the response for retrieving multiple PCK certificates from the Intel SGX API.
+#[derive(Debug, Clone)]
+pub struct PckCertificatesResponse {
+    /// JSON array containing PCK certificates and their associated TCB levels.
+    pub pck_certs_json: PckCertsJsonResponse, // String alias for now
+    /// PEM-encoded certificate chain for the PCK certificate issuer.
+    /// Header name differs between v3 ("PCS-Certificate-Issuer-Chain") and v4 ("SGX-PCK-Certificate-Issuer-Chain").
+    pub issuer_chain: String,
+    /// FMSPC value associated with the certificates (Hex-encoded).
+    pub fmspc: String,
+}
+
+/// Response structure for TCB (Trusted Computing Base) Information.
+///
+/// Contains the JSON representation of TCB information for a specific platform,
+/// along with the certificate chain of the TCB Info signer.
+#[derive(Debug, Clone)]
+pub struct TcbInfoResponse {
+    /// JSON containing TCB information for a specific platform (FMSPC).
+    pub tcb_info_json: TcbInfoJson, // String alias for now
+    /// PEM-encoded certificate chain for the TCB Info signer.
+    /// Header name differs slightly between v3 ("SGX-TCB-Info-Issuer-Chain") and v4 ("TCB-Info-Issuer-Chain" - check spec).
+    pub issuer_chain: String,
+}
+
+/// Response structure for Enclave Identity Information.
+///
+/// Contains the JSON representation of enclave identity details for QE, QvE, or QAE,
+/// along with its issuer chain.
+#[derive(Debug, Clone)]
+pub struct EnclaveIdentityResponse {
+    /// JSON containing information about the QE, QvE, or QAE.
+    pub enclave_identity_json: EnclaveIdentityJson, // String alias for now
+    /// PEM-encoded certificate chain for the Enclave Identity signer.
+    /// Header name seems consistent ("SGX-Enclave-Identity-Issuer-Chain").
+    pub issuer_chain: String,
+}
+
+/// Response structure for TCB Evaluation Data Numbers (V4 ONLY).
+///
+/// Contains the JSON representation of supported TCB Evaluation Data Numbers
+/// and its corresponding issuer chain.
+#[derive(Debug, Clone)]
+pub struct TcbEvaluationDataNumbersResponse {
+    /// JSON containing the list of supported TCB Evaluation Data Numbers (V4 ONLY).
+    pub tcb_evaluation_data_numbers_json: TcbEvaluationDataNumbersJson, // String alias for now
+    /// PEM-encoded certificate chain for the TCB Evaluation Data Numbers signer (V4 ONLY).
+    /// Header: "TCB-Evaluation-Data-Numbers-Issuer-Chain".
+    pub issuer_chain: String,
+}
+
+/// Response structure for Platform Configuration Key Certificate Revocation List (PCK CRL).
+///
+/// Contains the CRL data and its issuer chain for validating platform configuration keys.
+#[derive(Debug, Clone)]
+pub struct PckCrlResponse {
+    /// CRL data (PEM or DER encoded).
+    pub crl_data: Vec<u8>,
+    /// PEM-encoded certificate chain for the CRL issuer.
+    /// Header name differs between v3 ("PCS-CRL-Issuer-Chain") and v4 ("SGX-PCK-CRL-Issuer-Chain").
+    pub issuer_chain: String,
+}
+
+/// Response structure for the request to add a package.
+pub struct AddPackageResponse {
+    /// Platform Membership Certificates
+    pub pck_certs: Vec<u8>,
+    /// The certificate count extracted from the response header.
+    pub pck_cert_count: usize,
+}