diff --git a/lib/hpke/CMakeLists.txt b/lib/hpke/CMakeLists.txt
index 44806c4e..1d7fb1ae 100644
--- a/lib/hpke/CMakeLists.txt
+++ b/lib/hpke/CMakeLists.txt
@@ -14,7 +14,7 @@ file(GLOB_RECURSE LIB_SOURCES CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src
 
 add_library(${CURRENT_LIB_NAME} ${LIB_HEADERS} ${LIB_SOURCES})
 add_dependencies(${CURRENT_LIB_NAME} bytes tls_syntax)
-target_link_libraries(${CURRENT_LIB_NAME} PRIVATE bytes tls_syntax OpenSSL::Crypto)
+target_link_libraries(${CURRENT_LIB_NAME} PRIVATE bytes tls_syntax OpenSSL::Crypto nlohmann_json::nlohmann_json)
 target_include_directories(${CURRENT_LIB_NAME}
   PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
diff --git a/lib/hpke/src/signature.cpp b/lib/hpke/src/signature.cpp
index ec038447..9b0c99fa 100644
--- a/lib/hpke/src/signature.cpp
+++ b/lib/hpke/src/signature.cpp
@@ -14,6 +14,8 @@
 #include <openssl/evp.h>
 #include <openssl/rsa.h>
 
+using namespace nlohmann;
+
 namespace hpke {
 
 struct GroupSignature : public Signature
@@ -113,7 +115,7 @@ struct GroupSignature : public Signature
   {
     bytes x;
     bytes y;
-    nlohmann::json json_jwk;
+    json json_jwk;
     json_jwk["crv"] = group.jwt_curve_name;
     json_jwk["kty"] = group.jwt_key_type;
 
@@ -133,7 +135,7 @@ struct GroupSignature : public Signature
   {
     bytes x;
     bytes y;
-    nlohmann::json json_jwk;
+    json json_jwk;
     json_jwk["crv"] = group.jwt_curve_name;
     json_jwk["kty"] = group.jwt_key_type;