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/examples/get_pck_crl.rs

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (c) 2025 Matter Labs
+
+use intel_dcap_api::{ApiClient, CaType, CrlEncoding, IntelApiError, PckCrlResponse};
+use x509_cert::{
+    der::{oid::AssociatedOid, Decode, SliceReader},
+    ext::pkix::{
+        crl::dp::DistributionPoint,
+        name::{DistributionPointName, GeneralName},
+        CrlDistributionPoints,
+    },
+};
+
+#[tokio::main]
+async fn main() -> Result<(), IntelApiError> {
+    let client = ApiClient::new()?;
+
+    let PckCrlResponse {
+        crl_data,
+        issuer_chain,
+    } = client
+        .get_pck_crl(CaType::Platform, Some(CrlEncoding::Der))
+        .await?;
+
+    let certs = x509_cert::certificate::CertificateInner::<
+        x509_cert::certificate::Rfc5280
+    >::load_pem_chain(issuer_chain.as_bytes()).map_err(
+        |_| IntelApiError::InvalidParameter("Could not load a PEM chain")
+    )?;
+
+    for cert in certs {
+        println!("Issuer: {}", cert.tbs_certificate.issuer);
+        println!("Subject: {}", cert.tbs_certificate.subject);
+        println!("Serial Number: {}", cert.tbs_certificate.serial_number);
+        println!("Not Before: {}", cert.tbs_certificate.validity.not_before);
+        println!("Not After: {}", cert.tbs_certificate.validity.not_after);
+
+        // Extract and print CRL distribution points
+        if let Some(extensions) = &cert.tbs_certificate.extensions {
+            for ext in extensions.iter() {
+                if ext.extn_id == CrlDistributionPoints::OID {
+                    // Create a SliceReader from the byte slice
+                    let mut reader = SliceReader::new(ext.extn_value.as_bytes()).map_err(|_| {
+                        IntelApiError::InvalidParameter(
+                            "Could not create reader from extension value",
+                        )
+                    })?;
+
+                    // Now pass the reader to decode_value
+                    if let Ok(dist_points) = Vec::<DistributionPoint>::decode(&mut reader) {
+                        for point in dist_points {
+                            if let Some(DistributionPointName::FullName(names)) =
+                                point.distribution_point
+                            {
+                                for name in names {
+                                    if let GeneralName::UniformResourceIdentifier(uri) = name {
+                                        let uri = uri.as_str();
+                                        let crl_bytes = reqwest::get(uri).await?.bytes().await?;
+                                        println!("CRL bytes (hex): {}", hex::encode(&crl_bytes));
+                                    }
+                                }
+                            }
+                        }
+                    } else {
+                        println!("Could not decode CRL distribution points");
+                    }
+                }
+            }
+        }
+    }
+
+    println!("CRL bytes (hex): {}", hex::encode(&crl_data));
+
+    Ok(())
+}