wolfSSL · aidangarske · Jun 5, 2026
diff --git a/.github/workflows/interop.yml b/.github/workflows/interop.yml
@@ -0,0 +1,101 @@
+name: Interop
+
+on:
+  push:
+    branches: [ 'main', 'release/**' ]
+  pull_request:
+    branches: [ '**' ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  TCOSE_SHA: ff4c5f7c6fbbe27bb582214ff1878bf58ebc6c43
+  QCBOR_SHA: 930708bb86481e88879eb1d87fd4d664f1d69503
+
+jobs:
+  discover:
+    uses: ./.github/workflows/_resolve-wolfssl.yml
+
+  interop:
+    name: wolfCOSE <-> t_cose (OpenSSL, wolfSSL ${{ matrix.wolfssl-version }})
+    needs: discover
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.discover.outputs.matrix) }}
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y autoconf automake libtool libssl-dev
+
+    - name: Cache wolfSSL (${{ matrix.wolfssl-version }})
+      if: matrix.wolfssl-version != 'master'
+      id: cache-wolfssl
+      uses: actions/cache@v4
+      with:
+        path: ~/wolfssl-install
+        key: wolfssl-interop-${{ matrix.wolfssl-version }}-v1
+
+    - name: Build wolfSSL (${{ matrix.wolfssl-version }})
+      if: matrix.wolfssl-version == 'master' || steps.cache-wolfssl.outputs.cache-hit != 'true'
+      run: |
+        cd ~
+        git clone --depth 1 --branch ${{ matrix.wolfssl-ref }} \
+            https://github.com/wolfSSL/wolfssl.git
+        cd wolfssl
+        ./autogen.sh
+        ./configure --enable-ecc --enable-ed25519 --enable-ed448 \
+                    --enable-curve25519 --enable-aesgcm --enable-aesccm \
+                    --enable-sha384 --enable-sha512 --enable-keygen \
+                    --enable-rsapss --enable-hkdf --enable-aeskeywrap \
+                    --prefix=$HOME/wolfssl-install
+        make -j$(nproc)
+        make install
+
+    # QCBOR and t_cose are BSD-3-Clause; fetched at pinned SHAs, not vendored.
+    - name: Build QCBOR @ pinned SHA
+      run: |
+        cd ~
+        mkdir -p interop-deps/QCBOR && cd interop-deps/QCBOR
+        git init -q
+        git fetch --depth 1 -q https://github.com/laurencelundblade/QCBOR.git $QCBOR_SHA
+        git checkout -q FETCH_HEAD
+        make libqcbor.a
+
+    - name: Build t_cose @ pinned SHA (OpenSSL adapter)
+      run: |
+        cd ~/interop-deps
+        mkdir -p t_cose && cd t_cose
+        git init -q
+        git fetch --depth 1 -q https://github.com/laurencelundblade/t_cose.git $TCOSE_SHA
+        git checkout -q FETCH_HEAD
+        make -f Makefile.ossl libt_cose.a \
+             QCBOR_INC="-I $HOME/interop-deps/QCBOR/inc" \
+             QCBOR_LIB="$HOME/interop-deps/QCBOR/libqcbor.a"
+
+    - name: Build wolfCOSE
+      run: |
+        export WOLFSSL_DIR=$HOME/wolfssl-install
+        make CFLAGS="-std=c99 -DHAVE_ANONYMOUS_INLINE_AGGREGATES=1 -Os -Wall -Wextra -I./include -isystem $WOLFSSL_DIR/include" \
+             LDFLAGS="-L$WOLFSSL_DIR/lib -lwolfssl"
+
+    - name: Run t_cose interop
+      run: |
+        export WOLFSSL_DIR=$HOME/wolfssl-install
+        export LD_LIBRARY_PATH=$WOLFSSL_DIR/lib
+        make interop-tcose \
+             TCOSE_DIR=$HOME/interop-deps/t_cose \
+             QCBOR_DIR=$HOME/interop-deps/QCBOR \
+             TCOSE_CRYPTO_LIB="-lcrypto" \
+             CFLAGS="-std=c99 -DHAVE_ANONYMOUS_INLINE_AGGREGATES=1 -Os -Wall -Wextra -I./include -isystem $WOLFSSL_DIR/include" \
+             LDFLAGS="-L$WOLFSSL_DIR/lib -lwolfssl"
diff --git a/.gitignore b/.gitignore
@@ -8,6 +8,9 @@
 tests/test_wolfcose
 tools/wolfcose_tool
 examples/lifecycle_demo
+tests/interop/t_cose/interop_tcose
+tests/interop/t_cose/QCBOR/
+tests/interop/t_cose/t_cose/
 
 # Editor / OS
 *.swp

diff --git a/Makefile b/Makefile
@@ -59,7 +59,7 @@ SCEN_IOTFLEET    = examples/scenarios/iot_fleet_config
 SCEN_SENSOR      = examples/scenarios/sensor_attestation
 SCEN_BROADCAST   = examples/scenarios/group_broadcast_mac
 
-.PHONY: all shared test coverage tool tool-test cmdline-test demo demos comprehensive scenarios c99-check clean
+.PHONY: all shared test coverage tool tool-test cmdline-test demo demos comprehensive scenarios interop-tcose c99-check clean
 
 # --- Core library ---
 all: $(LIB_A)
@@ -164,6 +164,27 @@ scenarios: $(LIB_A)
 	./$(SCEN_BROADCAST) || exit 1
 	@echo "=== All scenario examples passed ==="
 
+# --- t_cose wire-interop (t_cose on OpenSSL; t_cose + QCBOR fetched at pinned SHAs) ---
+# The harness TU never includes OpenSSL headers (they collide with wolfSSL on
+# SHA256 etc.); the t_cose-side key loader is a separate TU. CI overrides
+# TCOSE_CRYPTO_INC / TCOSE_CRYPTO_LIB per platform (system libssl on Linux).
+TCOSE_DIR        ?= $(HOME)/interop-deps/t_cose
+QCBOR_DIR        ?= $(HOME)/interop-deps/QCBOR
+TCOSE_CRYPTO_INC ?=
+TCOSE_CRYPTO_LIB ?= -lcrypto
+INTEROP_DIR       = tests/interop/t_cose
+INTEROP_BIN       = $(INTEROP_DIR)/interop_tcose
+INTEROP_CFLAGS    = $(CFLAGS) -std=c99 -I$(TCOSE_DIR)/inc -I$(QCBOR_DIR)/inc
+
+interop-tcose: $(LIB_A)
+	$(CC) $(INTEROP_CFLAGS) -DT_COSE_USE_OPENSSL_CRYPTO -c $(INTEROP_DIR)/interop_tcose.c -o $(INTEROP_DIR)/interop_tcose.o
+	$(CC) -std=c99 -Wall -Wextra -I$(TCOSE_DIR)/inc -I$(QCBOR_DIR)/inc $(TCOSE_CRYPTO_INC) \
+	      -c $(INTEROP_DIR)/interop_key_ossl.c -o $(INTEROP_DIR)/interop_key.o
+	$(CC) -o $(INTEROP_BIN) $(INTEROP_DIR)/interop_tcose.o $(INTEROP_DIR)/interop_key.o \
+	      $(LIB_A) $(TCOSE_DIR)/libt_cose.a $(QCBOR_DIR)/libqcbor.a \
+	      $(TCOSE_CRYPTO_LIB) $(LDFLAGS) -lm
+	./$(INTEROP_BIN)
+
 # --- C99 conformance gate ---
 # Compiles every translation unit (core, tests, tool, examples) under strict
 # ISO C99 with -pedantic-errors -Werror so any non-C99 construct fails the
@@ -195,5 +216,6 @@ clean:
 	rm -f $(OBJ) $(TEST_BIN) $(TOOL_BIN) $(DEMO_BIN) $(ENC_DEMO) $(MAC_DEMO) \
 	    $(SIGN1_DEMO) $(COMP_SIGN) $(COMP_ENCRYPT) $(COMP_MAC) $(COMP_ERRORS) \
 	    $(SCEN_FIRMWARE) $(SCEN_MULTIPARTY) $(SCEN_IOTFLEET) $(SCEN_SENSOR) $(SCEN_BROADCAST) \
+	    $(INTEROP_DIR)/*.o $(INTEROP_DIR)/*.su $(INTEROP_BIN) \
 	    $(LIB_A) $(LIB_SO) src/*.su tests/*.su examples/comprehensive/*.su examples/scenarios/*.su \
 	    src/*.gcno src/*.gcda tests/*.gcno tests/*.gcda *.gcov
diff --git a/docs/Testing.md b/docs/Testing.md
@@ -50,6 +50,26 @@ Runs real-world scenario examples:
 - Sensor attestation
 - Group broadcast MAC
 
+### Interoperability (t_cose)
+
+```bash
+make interop-tcose \
+  TCOSE_DIR=/path/to/t_cose QCBOR_DIR=/path/to/QCBOR \
+  TCOSE_CRYPTO_LIB="-lcrypto"
+```
+
+Proves RFC 9052 wire interoperability between wolfCOSE (on wolfCrypt) and
+[t_cose](https://github.com/laurencelundblade/t_cose) (on OpenSSL): each library
+produces COSE messages the other consumes, both directions, across every
+algorithm both implement — ES256/384/512, PS256/384/512, EdDSA (Ed25519, Ed448),
+HMAC 256/384/512, and AES-GCM 128/192/256. The bytes on the wire are the only
+interface; the two APIs are never reconciled. Each primitive class also exercises
+a tamper case that wolfCOSE must reject.
+
+t_cose and QCBOR are BSD-3-Clause and are not vendored; the
+[Interop CI job](../.github/workflows/interop.yml) fetches them at pinned
+SHAs. See `tests/interop/t_cose/README.md` for the fixed test-key provenance.
+
 ---
 
 ## Code Coverage

diff --git a/tests/interop/t_cose/README.md b/tests/interop/t_cose/README.md
@@ -0,0 +1,91 @@
+# wolfCOSE ⇄ t_cose Interop
+
+A wire-interoperability conformance suite: wolfCOSE (on wolfCrypt) and
+[t_cose](https://github.com/laurencelundblade/t_cose) (on OpenSSL) each produce
+COSE messages the other consumes, in both directions, for every algorithm both
+implement. The COSE bytes on the wire are the only interface — the two libraries'
+APIs are never reconciled. This demonstrates RFC 9052/9053 conformance, not a
+performance or feature comparison.
+
+## What is covered
+
+| Message     | Algorithms (both directions)                         |
+|-------------|------------------------------------------------------|
+| COSE_Sign1  | ES256/384/512, PS256/384/512, EdDSA (Ed25519, Ed448) |
+| COSE_Mac0   | HMAC 256/384/512                                      |
+| COSE_Encrypt0 | AES-GCM 128/192/256                                |
+
+Each primitive class also runs a negative case — a tampered signature, MAC tag,
+or AEAD tag — that wolfCOSE must reject.
+
+CBOR byte-for-byte equality is an explicit non-goal: CBOR permits multiple valid
+encodings, so the suite verifies that each side *reconstructs and validates* the
+other's output, never that the two producers emit identical bytes.
+
+## Dependencies (not vendored)
+
+t_cose and QCBOR are BSD-3-Clause. They are **not** redistributed here; CI fetches
+them at pinned SHAs and links them:
+
+- t_cose `dev` @ `ff4c5f7c6fbbe27bb582214ff1878bf58ebc6c43`
+- QCBOR @ `930708bb86481e88879eb1d87fd4d664f1d69503`
+
+wolfCOSE itself stays zero-allocation; this harness is test-only.
+
+## Building locally
+
+Fetch the pinned SHAs (same sequence CI uses) and build, from this directory:
+
+```bash
+# QCBOR @ pinned SHA
+mkdir -p QCBOR && cd QCBOR && git init -q && \
+  git fetch --depth 1 -q https://github.com/laurencelundblade/QCBOR.git \
+    930708bb86481e88879eb1d87fd4d664f1d69503 && \
+  git checkout -q FETCH_HEAD && make libqcbor.a && cd ..
+
+# t_cose @ pinned SHA (OpenSSL adapter)
+mkdir -p t_cose && cd t_cose && git init -q && \
+  git fetch --depth 1 -q https://github.com/laurencelundblade/t_cose.git \
+    ff4c5f7c6fbbe27bb582214ff1878bf58ebc6c43 && \
+  git checkout -q FETCH_HEAD && \
+  make -f Makefile.ossl libt_cose.a \
+    QCBOR_INC="-I ../QCBOR/inc" QCBOR_LIB="../QCBOR/libqcbor.a" && cd ..
+
+# the suite (from the repo root)
+make interop-tcose \
+  TCOSE_DIR=$PWD/tests/interop/t_cose/t_cose \
+  QCBOR_DIR=$PWD/tests/interop/t_cose/QCBOR \
+  TCOSE_CRYPTO_LIB="-lcrypto"
+```
+
+## Files
+
+| File                  | Role                                                          |
+|-----------------------|---------------------------------------------------------------|
+| `interop_tcose.c`     | Table-driven harness; wolfCrypt side; both directions per case |
+| `interop_key_ossl.c`  | t_cose-side OpenSSL key loader (isolated TU — wolfSSL and OpenSSL headers collide on `SHA256`) |
+| `interop_cases.h`     | Shared key-id enum so a key means the same on both sides       |
+| `interop_keys.h`      | Fixed DER/symmetric test-key fixtures (provenance below)       |
+
+## Test-key provenance (fixtures, not production keys)
+
+Committed for determinism. Generated once with OpenSSL:
+
+```bash
+# EC private keys (SEC1/RFC 5915 DER)
+openssl genpkey -algorithm EC -pkeyopt ec_paramgen_curve:P-256 -outform DER
+openssl genpkey -algorithm EC -pkeyopt ec_paramgen_curve:P-384 -outform DER
+openssl genpkey -algorithm EC -pkeyopt ec_paramgen_curve:P-521 -outform DER
+
+# EdDSA private keys (PKCS#8 DER)
+openssl genpkey -algorithm ED25519 -outform DER
+openssl genpkey -algorithm ED448   -outform DER
+
+# RSA-2048 private key (PKCS#1 DER)
+openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 | \
+  openssl rsa -outform DER -traditional
+```
+
+OpenSSL loads all of these via `d2i_AutoPrivateKey`; wolfCrypt via the matching
+`wc_{Ecc,Ed25519,Ed448,Rsa}PrivateKeyDecode`. Symmetric keys are fixed bytes,
+loaded backend-agnostically through `t_cose_key_init_symmetric`.
diff --git a/tests/interop/t_cose/interop_cases.h b/tests/interop/t_cose/interop_cases.h
@@ -0,0 +1,23 @@
+/* interop_cases.h — shared identifiers for the wolfCOSE<->t_cose interop matrix.
+ * Both the wolfCrypt-side harness and the t_cose-side key loader include this so
+ * a key id means the same thing on both sides. Test-only.
+ */
+#ifndef WOLFCOSE_INTEROP_CASES_H
+#define WOLFCOSE_INTEROP_CASES_H
+
+/* Which fixed key fixture a case uses (see interop_keys.h). */
+enum it_key {
+    IT_KEY_P256 = 0,
+    IT_KEY_P384,
+    IT_KEY_P521,
+    IT_KEY_ED25519,
+    IT_KEY_ED448,
+    IT_KEY_RSA2048,
+    IT_KEY_SYM16,
+    IT_KEY_SYM24,
+    IT_KEY_SYM32,
+    IT_KEY_SYM48,
+    IT_KEY_SYM64
+};
+
+#endif /* WOLFCOSE_INTEROP_CASES_H */
diff --git a/tests/interop/t_cose/interop_key_ossl.c b/tests/interop/t_cose/interop_key_ossl.c
@@ -0,0 +1,53 @@
+/* interop_key_ossl.c — t_cose-side asymmetric key loader, OpenSSL backend (test-only).
+ *
+ * Isolated from the wolfCrypt side: this TU includes OpenSSL + t_cose's
+ * backend-agnostic key header ONLY (no wolfSSL), so the two crypto stacks never
+ * collide in one translation unit (they both define SHA256 etc.). Loads the same
+ * shared DER bytes the wolfCrypt side uses, via d2i_AutoPrivateKey (SEC1, PKCS#1
+ * and PKCS#8 are all auto-detected). Symmetric keys are handled in the harness
+ * via the backend-agnostic t_cose_key_init_symmetric().
+ *
+ * Copyright (C) 2026 wolfSSL Inc.  GPL-3.0-or-later (see wolfCOSE LICENSE).
+ */
+
+#include "t_cose/t_cose_key.h"
+#include <openssl/evp.h>
+#include <openssl/x509.h>
+
+#include "interop_cases.h"
+#include "interop_keys.h"
+
+struct t_cose_key interop_tcose_load(int key_id);
+void              interop_tcose_free(struct t_cose_key key);
+
+static const unsigned char* der_for(int key_id, long* len)
+{
+    switch (key_id) {
+        case IT_KEY_P256:    *len = (long)p256_der_len;    return p256_der;
+        case IT_KEY_P384:    *len = (long)p384_der_len;    return p384_der;
+        case IT_KEY_P521:    *len = (long)p521_der_len;    return p521_der;
+        case IT_KEY_ED25519: *len = (long)ed25519_der_len; return ed25519_der;
+        case IT_KEY_ED448:   *len = (long)ed448_der_len;   return ed448_der;
+        case IT_KEY_RSA2048: *len = (long)rsa2048_der_len; return rsa2048_der;
+        default:             *len = 0;                     return NULL;
+    }
+}
+
+struct t_cose_key interop_tcose_load(int key_id)
+{
+    struct t_cose_key k;
+    long len = 0;
+    const unsigned char* der = der_for(key_id, &len);
+    const unsigned char* p = der;
+
+    k.key.ptr = NULL;
+    if (der != NULL) {
+        k.key.ptr = d2i_AutoPrivateKey(NULL, &p, len);
+    }
+    return k;
+}
+
+void interop_tcose_free(struct t_cose_key key)
+{
+    EVP_PKEY_free((EVP_PKEY*)key.key.ptr);
+}