Added ECDHE

Author: dgarske

stsafe/README.md

@@ -84,6 +84,8 @@ Tests wolfSSL crypto callbacks with STSAFE:
 - RNG with STSAFE-A120
 - ECC P-256/P-384 key generation via crypto callback
 - ECDSA P-256/P-384 sign/verify
+- ECDHE P-256 ephemeral key generation
+- ECDHE P-256 shared secret computation
 
 ```bash
 make wolfssl && ./wolfssl_stsafe_test
@@ -94,6 +96,7 @@ make wolfssl && ./wolfssl_stsafe_test
 Comprehensive tests with benchmarks:
 - RNG benchmark
 - ECDSA P-256 benchmark (keygen, sign, verify timing)
+- ECDH P-256 key exchange (uses ECDHE ephemeral keys)
 - Multiple sequential operations
 
 ```bash
@@ -148,6 +151,8 @@ Test Summary: 5 passed, 0 failed
 | ECC P-256 KeyGen | ~40 ms | 25 ops/sec |
 | ECDSA P-256 Sign | ~51 ms | 19.5 ops/sec |
 | ECDSA P-256 Verify | ~79 ms | 12.7 ops/sec |
+| ECDHE P-256 KeyGen | ~42 ms | ~24 ops/sec |
+| ECDHE P-256 Shared Secret | ~38 ms | ~26 ops/sec |
 
 ## Directory Structure
 

stsafe/wolfssl_stsafe_full_test.c

@@ -276,6 +276,26 @@ static int test_ecdh_p256(void)
     }
     printf("    SW Key generated in %.2f ms\n", (end - start) / 1000.0);
 
+    /* Set RNG on keys for shared secret computation */
+    ret = wc_ecc_set_rng(&keyHW, &rng);
+    if (ret != 0) {
+        printf("  Error: wc_ecc_set_rng (HW) failed: %d\n", ret);
+        wc_ecc_free(&keyHW);
+        wc_ecc_free(&keySW);
+        wc_FreeRng(&rng);
+        TEST_FAIL("ECDH P-256 set RNG HW");
+        return -1;
+    }
+    ret = wc_ecc_set_rng(&keySW, &rng);
+    if (ret != 0) {
+        printf("  Error: wc_ecc_set_rng (SW) failed: %d\n", ret);
+        wc_ecc_free(&keyHW);
+        wc_ecc_free(&keySW);
+        wc_FreeRng(&rng);
+        TEST_FAIL("ECDH P-256 set RNG SW");
+        return -1;
+    }
+
     /* Compute shared secret using STSAFE (HW priv * SW pub) */
     printf("  Computing shared secret (STSAFE: HW priv * SW pub)...\n");
     start = get_time_us();
@@ -460,10 +480,8 @@ int main(void)
     test_rng_benchmark();
     test_ecdsa_p256_benchmark();
 
-    /* Note: ECDH requires ephemeral keys via stse_generate_ECDHE_key_pair
-     * which is not yet implemented in the crypto callback.
-     * Skipping ECDH test for now. */
-    printf("\n[SKIP] ECDH P-256 - requires ECDHE key generation (not yet implemented)\n");
+    /* ECDH test - now uses ECDHE ephemeral keys */
+    test_ecdh_p256();
 
     test_multiple_operations();