diff --git a/service_vm/comm/Android.bp b/service_vm/comm/Android.bp
index 3a18052..6e05587 100644
--- a/service_vm/comm/Android.bp
+++ b/service_vm/comm/Android.bp
@@ -43,3 +43,31 @@
         "std",
     ],
 }
+
+rust_defaults {
+    name: "libservice_vm_comm_test_defaults",
+    crate_name: "diced_open_dice_test",
+    srcs: ["tests/*.rs"],
+    test_suites: ["general-tests"],
+    prefer_rlib: true,
+    rustlibs: [
+        "libdiced_sample_inputs",
+        "libdiced_open_dice",
+    ],
+}
+
+rust_test {
+    name: "libservice_vm_comm.test",
+    defaults: ["libservice_vm_comm_test_defaults"],
+    rustlibs: [
+        "libservice_vm_comm",
+    ],
+}
+
+rust_test {
+    name: "libservice_vm_comm_nostd.test",
+    defaults: ["libservice_vm_comm_test_defaults"],
+    rustlibs: [
+        "libservice_vm_comm_nostd",
+    ],
+}
diff --git a/service_vm/comm/TEST_MAPPING b/service_vm/comm/TEST_MAPPING
new file mode 100644
index 0000000..e677ba2
--- /dev/null
+++ b/service_vm/comm/TEST_MAPPING
@@ -0,0 +1,12 @@
+// When adding or removing tests here, don't forget to amend _all_modules list in
+// wireless/android/busytown/ath_config/configs/prod/avf/tests.gcl
+{
+  "avf-presubmit" : [
+    {
+      "name" : "libservice_vm_comm.test"
+    },
+    {
+      "name" : "libservice_vm_comm_nostd.test"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/service_vm/comm/src/csr.rs b/service_vm/comm/src/csr.rs
new file mode 100644
index 0000000..5e1cbad
--- /dev/null
+++ b/service_vm/comm/src/csr.rs
@@ -0,0 +1,121 @@
+// Copyright 2023, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! This module contains the structs related to the CSR (Certificate Signing Request)
+//! sent from the client VM to the service VM for attestation.
+
+use alloc::vec;
+use alloc::vec::Vec;
+use ciborium::Value;
+use coset::{self, CborSerializable, CoseError};
+
+/// Represents a CSR sent from the client VM to the service VM for attestation.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct Csr {
+    /// The DICE certificate chain of the client VM.
+    pub dice_cert_chain: Vec<u8>,
+
+    /// The signed CSR payload in COSE_Sign structure, which includes two signatures:
+    /// - one by CDI_Leaf_Priv of the client VM's DICE chain,
+    /// - another by the private key corresponding to the public key.
+    pub signed_csr_payload: Vec<u8>,
+}
+
+impl Csr {
+    /// Serializes this object to a CBOR-encoded vector.
+    pub fn into_cbor_vec(self) -> coset::Result<Vec<u8>> {
+        let value = Value::Array(vec![
+            Value::Bytes(self.dice_cert_chain),
+            Value::Bytes(self.signed_csr_payload),
+        ]);
+        value.to_vec()
+    }
+
+    /// Creates an object instance from the provided CBOR-encoded slice.
+    pub fn from_cbor_slice(data: &[u8]) -> coset::Result<Self> {
+        let value = Value::from_slice(data)?;
+        let Value::Array(mut arr) = value else {
+            return Err(CoseError::UnexpectedItem(cbor_value_type(&value), "array"));
+        };
+        if arr.len() != 2 {
+            return Err(CoseError::UnexpectedItem("array", "array with 2 items"));
+        }
+        Ok(Self {
+            signed_csr_payload: try_as_bytes(arr.remove(1))?,
+            dice_cert_chain: try_as_bytes(arr.remove(0))?,
+        })
+    }
+}
+
+/// Represents the data to be signed and sent from the client VM to the service VM
+/// for attestation.
+///
+/// It will be signed by both CDI_Leaf_Priv of the client VM's DICE chain and
+/// the private key corresponding to the public key to be attested.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct CsrPayload {
+    /// COSE_Key encoded EC P-256 public key to be attested.
+    pub public_key: Vec<u8>,
+
+    /// A random array with a length between 0 and 64.
+    /// It will be included in the certificate chain in the attestation result,
+    /// serving as proof of the freshness of the result.
+    pub challenge: Vec<u8>,
+}
+
+impl CsrPayload {
+    /// Serializes this object to a CBOR-encoded vector.
+    pub fn into_cbor_vec(self) -> coset::Result<Vec<u8>> {
+        let value = Value::Array(vec![Value::Bytes(self.public_key), Value::Bytes(self.challenge)]);
+        value.to_vec()
+    }
+
+    /// Creates an object instance from the provided CBOR-encoded slice.
+    pub fn from_cbor_slice(data: &[u8]) -> coset::Result<Self> {
+        let value = Value::from_slice(data)?;
+        let Value::Array(mut arr) = value else {
+            return Err(CoseError::UnexpectedItem(cbor_value_type(&value), "array"));
+        };
+        if arr.len() != 2 {
+            return Err(CoseError::UnexpectedItem("array", "array with 2 items"));
+        }
+        Ok(Self {
+            challenge: try_as_bytes(arr.remove(1))?,
+            public_key: try_as_bytes(arr.remove(0))?,
+        })
+    }
+}
+
+fn try_as_bytes(v: Value) -> coset::Result<Vec<u8>> {
+    if let Value::Bytes(data) = v {
+        Ok(data)
+    } else {
+        Err(CoseError::UnexpectedItem(cbor_value_type(&v), "bytes"))
+    }
+}
+
+fn cbor_value_type(v: &Value) -> &'static str {
+    match v {
+        Value::Integer(_) => "int",
+        Value::Bytes(_) => "bstr",
+        Value::Float(_) => "float",
+        Value::Text(_) => "tstr",
+        Value::Bool(_) => "bool",
+        Value::Null => "nul",
+        Value::Tag(_, _) => "tag",
+        Value::Array(_) => "array",
+        Value::Map(_) => "map",
+        _ => "other",
+    }
+}
diff --git a/service_vm/comm/src/lib.rs b/service_vm/comm/src/lib.rs
index d8f7bd7..0818f24 100644
--- a/service_vm/comm/src/lib.rs
+++ b/service_vm/comm/src/lib.rs
@@ -19,9 +19,11 @@
 
 extern crate alloc;
 
+mod csr;
 mod message;
 mod vsock;
 
+pub use csr::{Csr, CsrPayload};
 pub use message::{
     EcdsaP256KeyPair, GenerateCertificateRequestParams, Request, RequestProcessingError, Response,
     ServiceVmRequest,
diff --git a/service_vm/comm/tests/api_test.rs b/service_vm/comm/tests/api_test.rs
new file mode 100644
index 0000000..44a3ef9
--- /dev/null
+++ b/service_vm/comm/tests/api_test.rs
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use diced_open_dice::DiceArtifacts;
+use service_vm_comm::{Csr, CsrPayload};
+
+/// The following test data are generated with urandom
+const DATA1: [u8; 32] = [
+    0x8b, 0x09, 0xc0, 0x7e, 0x20, 0x3c, 0xa2, 0x11, 0x7e, 0x7f, 0x0b, 0xdd, 0x2b, 0x68, 0x98, 0xb0,
+    0x2b, 0x34, 0xb5, 0x63, 0x39, 0x01, 0x90, 0x06, 0xaf, 0x5f, 0xdd, 0xb7, 0x81, 0xca, 0xc7, 0x46,
+];
+const DATA2: [u8; 16] = [
+    0x6c, 0xb9, 0x39, 0x86, 0x9b, 0x2f, 0x12, 0xd8, 0x45, 0x92, 0x57, 0x44, 0x65, 0xce, 0x94, 0x63,
+];
+
+#[test]
+fn csr_payload_cbor_serialization() {
+    let csr_payload = CsrPayload { public_key: DATA1.to_vec(), challenge: DATA2.to_vec() };
+    let expected_csr_payload = csr_payload.clone();
+    let cbor_vec = csr_payload.into_cbor_vec().unwrap();
+    let deserialized_csr_payload = CsrPayload::from_cbor_slice(&cbor_vec).unwrap();
+
+    assert_eq!(expected_csr_payload, deserialized_csr_payload);
+}
+
+#[test]
+fn csr_cbor_serialization() {
+    let dice_artifacts = diced_sample_inputs::make_sample_bcc_and_cdis().unwrap();
+    let dice_cert_chain = dice_artifacts.bcc().unwrap().to_vec();
+    let csr = Csr { signed_csr_payload: DATA1.to_vec(), dice_cert_chain };
+    let expected_csr = csr.clone();
+    let cbor_vec = csr.into_cbor_vec().unwrap();
+    let deserialized_csr = Csr::from_cbor_slice(&cbor_vec).unwrap();
+
+    assert_eq!(expected_csr, deserialized_csr);
+}