From b2e1c69b7922e2886e44345b2009dd36c986ad08 Mon Sep 17 00:00:00 2001
From: Lena Boeckmann <lena.boeckmann@haw-hamburg.de>
Date: Thu, 19 Oct 2023 14:12:49 +0200
Subject: [PATCH] examples/psa_crypto: Update example to work with SEs

---
 examples/psa_crypto/example_ecdsa_p256.c | 11 ++++++++++-
 examples/psa_crypto/main.c               |  5 +++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/examples/psa_crypto/example_ecdsa_p256.c b/examples/psa_crypto/example_ecdsa_p256.c
index 4f60a4916d..fe5fa8a170 100644
--- a/examples/psa_crypto/example_ecdsa_p256.c
+++ b/examples/psa_crypto/example_ecdsa_p256.c
@@ -81,10 +81,13 @@ psa_status_t example_ecdsa_p256(void)
     }
 
 #ifdef SECURE_ELEMENT
+    /* Currently there is no support for message signature and verification on secure elements */
     psa_set_key_lifetime(&pubkey_attr, lifetime);
+    psa_set_key_usage_flags(&pubkey_attr, PSA_KEY_USAGE_VERIFY_HASH);
+#else
+    psa_set_key_usage_flags(&pubkey_attr, PSA_KEY_USAGE_VERIFY_MESSAGE);
 #endif
     psa_set_key_algorithm(&pubkey_attr, ECC_ALG);
-    psa_set_key_usage_flags(&pubkey_attr, PSA_KEY_USAGE_VERIFY_MESSAGE);
     psa_set_key_bits(&pubkey_attr, PSA_BYTES_TO_BITS(pubkey_length));
     psa_set_key_type(&pubkey_attr, PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1));
 
@@ -99,6 +102,12 @@ psa_status_t example_ecdsa_p256(void)
         return status;
     }
 
+#ifdef SECURE_ELEMENT
+    /* Currently there is only support for hash signature and verification on secure elements,
+       so we can't verify the message, but only the hash */
+    return psa_verify_hash(pubkey_id, ECC_ALG, hash, sizeof(hash), signature, sig_length);
+#endif
+
     /* verify on original message with internal hashing operation */
     return psa_verify_message(pubkey_id, ECC_ALG, msg, sizeof(msg), signature, sig_length);
 }
diff --git a/examples/psa_crypto/main.c b/examples/psa_crypto/main.c
index b146d69335..a45e27220b 100644
--- a/examples/psa_crypto/main.c
+++ b/examples/psa_crypto/main.c
@@ -24,7 +24,10 @@
 extern psa_status_t example_cipher_aes_128(void);
 extern psa_status_t example_hmac_sha256(void);
 extern psa_status_t example_ecdsa_p256(void);
+
+#ifndef SECURE_ELEMENT
 extern psa_status_t example_eddsa(void);
+#endif
 
 #ifdef MULTIPLE_SE
 extern psa_status_t example_cipher_aes_128_sec_se(void);
@@ -61,12 +64,14 @@ int main(void)
         printf("ECDSA failed: %s\n", psa_status_to_humanly_readable(status));
     }
 
+#ifndef SECURE_ELEMENT
     start = ztimer_now(ZTIMER_USEC);
     status = example_eddsa();
     printf("EdDSA took %d us\n", (int)(ztimer_now(ZTIMER_USEC) - start));
     if (status != PSA_SUCCESS) {
         printf("EdDSA failed: %s\n", psa_status_to_humanly_readable(status));
     }
+#endif
 
 #ifdef MULTIPLE_SE
     puts("Running Examples with secondary SE:");