diff --git a/security/keymint/support/Android.bp b/security/keymint/support/Android.bp
index c2dba04..9e218b6 100644
--- a/security/keymint/support/Android.bp
+++ b/security/keymint/support/Android.bp
@@ -57,9 +57,11 @@
         "include",
     ],
     shared_libs: [
+        "libbase",
         "libcppbor_external",
         "libcppcose_rkp",
         "libcrypto",
+        "libjsoncpp",
     ],
 }
 
@@ -71,9 +73,11 @@
         "libgtest_main",
     ],
     shared_libs: [
+        "libbase",
         "libcppbor_external",
         "libcppcose_rkp",
         "libcrypto",
+        "libjsoncpp",
         "libkeymaster_portable",
         "libkeymint_remote_prov_support",
     ],
diff --git a/security/keymint/support/include/remote_prov/remote_prov_utils.h b/security/keymint/support/include/remote_prov/remote_prov_utils.h
index b02d273..406b7a9 100644
--- a/security/keymint/support/include/remote_prov/remote_prov_utils.h
+++ b/security/keymint/support/include/remote_prov/remote_prov_utils.h
@@ -87,4 +87,26 @@
  */
 ErrMsgOr<std::vector<BccEntryData>> validateBcc(const cppbor::Array* bcc);
 
+struct JsonOutput {
+    static JsonOutput Ok(std::string json) { return {std::move(json), ""}; }
+    static JsonOutput Error(std::string error) { return {"", std::move(error)}; }
+
+    std::string output;
+    std::string error;  // if non-empty, this describes what went wrong
+};
+
+/**
+ * Take a given certificate request and output a JSON blob containing both the
+ * build fingerprint and certificate request. This data may be serialized, then
+ * later uploaded to the remote provisioning service. The input csr is not
+ * validated, only encoded.
+ *
+ * Output format:
+ *   {
+ *     "build_fingerprint": <string>
+ *     "csr": <base64 CBOR CSR>
+ *   }
+ */
+JsonOutput jsonEncodeCsrWithBuild(const cppbor::Array& csr);
+
 }  // namespace aidl::android::hardware::security::keymint::remote_prov
diff --git a/security/keymint/support/remote_prov_utils.cpp b/security/keymint/support/remote_prov_utils.cpp
index 982a1eb..0cbee51 100644
--- a/security/keymint/support/remote_prov_utils.cpp
+++ b/security/keymint/support/remote_prov_utils.cpp
@@ -14,13 +14,15 @@
  * limitations under the License.
  */
 
+#include <iterator>
 #include <tuple>
 
-#include <remote_prov/remote_prov_utils.h>
-
-#include <openssl/rand.h>
-
+#include <android-base/properties.h>
 #include <cppbor.h>
+#include <json/json.h>
+#include <openssl/base64.h>
+#include <openssl/rand.h>
+#include <remote_prov/remote_prov_utils.h>
 
 namespace aidl::android::hardware::security::keymint::remote_prov {
 
@@ -180,4 +182,36 @@
     return result;
 }
 
+JsonOutput jsonEncodeCsrWithBuild(const cppbor::Array& csr) {
+    const std::string kFingerprintProp = "ro.build.fingerprint";
+
+    if (!::android::base::WaitForPropertyCreation(kFingerprintProp)) {
+        return JsonOutput::Error("Unable to read build fingerprint");
+    }
+
+    bytevec csrCbor = csr.encode();
+    size_t base64Length;
+    int rc = EVP_EncodedLength(&base64Length, csrCbor.size());
+    if (!rc) {
+        return JsonOutput::Error("Error getting base64 length. Size overflow?");
+    }
+
+    std::vector<char> base64(base64Length);
+    rc = EVP_EncodeBlock(reinterpret_cast<uint8_t*>(base64.data()), csrCbor.data(), csrCbor.size());
+    ++rc;  // Account for NUL, which BoringSSL does not for some reason.
+    if (rc != base64Length) {
+        return JsonOutput::Error("Error writing base64. Expected " + std::to_string(base64Length) +
+                                 " bytes to be written, but " + std::to_string(rc) +
+                                 " bytes were actually written.");
+    }
+
+    Json::Value json(Json::objectValue);
+    json["build_fingerprint"] = ::android::base::GetProperty(kFingerprintProp, /*default=*/"");
+    json["csr"] = base64.data();  // Boring writes a NUL-terminated c-string
+
+    Json::StreamWriterBuilder factory;
+    factory["indentation"] = "";  // disable pretty formatting
+    return JsonOutput::Ok(Json::writeString(factory, json));
+}
+
 }  // namespace aidl::android::hardware::security::keymint::remote_prov
diff --git a/security/keymint/support/remote_prov_utils_test.cpp b/security/keymint/support/remote_prov_utils_test.cpp
index c360c06..8697c51 100644
--- a/security/keymint/support/remote_prov_utils_test.cpp
+++ b/security/keymint/support/remote_prov_utils_test.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <android-base/properties.h>
 #include <cppbor_parse.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -23,6 +24,7 @@
 #include <openssl/curve25519.h>
 #include <remote_prov/remote_prov_utils.h>
 #include <cstdint>
+#include "cppbor.h"
 #include "keymaster/cppcose/cppcose.h"
 
 namespace aidl::android::hardware::security::keymint::remote_prov {
@@ -80,5 +82,20 @@
     EXPECT_THAT(eekPub, ElementsAreArray(geek->getBstrValue(CoseKey::PUBKEY_X).value_or(empty)));
 }
 
+TEST(RemoteProvUtilsTest, JsonEncodeCsr) {
+    cppbor::Array array;
+    array.add(1);
+
+    auto [json, error] = jsonEncodeCsrWithBuild(array);
+
+    ASSERT_TRUE(error.empty()) << error;
+
+    std::string expected = R"({"build_fingerprint":")" +
+                           ::android::base::GetProperty("ro.build.fingerprint", /*default=*/"") +
+                           R"(","csr":"gQE="})";
+
+    ASSERT_EQ(json, expected);
+}
+
 }  // namespace
 }  // namespace aidl::android::hardware::security::keymint::remote_prov