Add HPKE interop test between signum and Bouncy Castle

Author: nodh

vck-openid/src/jvmTest/kotlin/at/asitplus/wallet/lib/openid/HpkeInteropTest.kt

@@ -0,0 +1,58 @@
+package at.asitplus.wallet.lib.openid
+
+import at.asitplus.signum.indispensable.ECCurve
+import at.asitplus.signum.indispensable.KeyAgreementPrivateValue
+import at.asitplus.signum.supreme.agree.Ephemeral
+import at.asitplus.signum.supreme.asymmetric.HPKE
+import at.asitplus.testballoon.matrix.matrixSuite
+import io.kotest.matchers.shouldBe
+import org.bouncycastle.crypto.hpke.HPKE as BcHpke
+import kotlin.random.Random
+
+/**
+ * Verifies that signum's HPKE (RFC 9180) implementation is interoperable with Bouncy Castle's,
+ * for the cipher suite required by ISO/IEC 18013-7 Annex C (as used in [DcApiVerifier]):
+ * DHKEM(P-256, HKDF-SHA256), HKDF-SHA256, AES-128-GCM.
+ */
+val HpkeInteropTest by matrixSuite {
+
+    val signumHpke = HPKE(HPKE.KEM.DHKEM_P256_HKDF_SHA256, HPKE.KDF.HKDF_SHA256, HPKE.AEAD.AES_128_GCM)
+    val bcHpke = BcHpke(BcHpke.mode_base, BcHpke.kem_P256_SHA256, BcHpke.kdf_HKDF_SHA256, BcHpke.aead_AES_GCM128)
+
+    val plaintext = Random.nextBytes(257)
+    val info = Random.nextBytes(64)
+    val aad = Random.nextBytes(32)
+
+    test("signum seals, Bouncy Castle opens") {
+        val recipientKeyPair = bcHpke.generatePrivateKey()
+        val recipientPublicKey = signumHpke.kem.DeserializePublicKey(
+            bcHpke.serializePublicKey(recipientKeyPair.public)
+        )
+
+        val sealed = signumHpke.SealBase(pkR = recipientPublicKey, info = info, aad = aad, pt = plaintext)
+
+        bcHpke.open(
+            sealed.encapsulatedSecret, recipientKeyPair, info, aad, sealed.ciphertext,
+            null, null, null,
+        ) shouldBe plaintext
+    }
+
+    test("Bouncy Castle seals, signum opens") {
+        val recipientKey = KeyAgreementPrivateValue.ECDH.Ephemeral(ECCurve.SECP_256_R_1).getOrThrow()
+        val recipientPublicKey = bcHpke.deserializePublicKey(
+            signumHpke.kem.SerializePublicKey(recipientKey.publicValue)
+        )
+
+        val sealed = bcHpke.seal(recipientPublicKey, info, aad, plaintext, null, null, null)
+        val ciphertext = sealed[0]
+        val encapsulatedSecret = sealed[1]
+
+        signumHpke.OpenBase(
+            enc = encapsulatedSecret,
+            skR = recipientKey,
+            info = info,
+            aad = aad,
+            ct = ciphertext,
+        ) shouldBe plaintext
+    }
+}