1 files changed, 75 insertions, 0 deletions
diff --git a/demos/pkey/EVP_PKEY_DSA_paramfromdata.c b/demos/pkey/EVP_PKEY_DSA_paramfromdata.c
new file mode 100644
index 000000000000..4c9e55820e94
--- /dev/null
+++ b/demos/pkey/EVP_PKEY_DSA_paramfromdata.c
@@ -0,0 +1,75 @@
+/*-
+ * Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+/*
+ * Example showing how to load DSA params from raw data
+ * using EVP_PKEY_fromdata()
+ */
+
+#include <openssl/param_build.h>
+#include <openssl/evp.h>
+#include <openssl/core_names.h>
+#include "dsa.inc"
+
+int main(int argc, char **argv)
+{
+    int rv = EXIT_FAILURE;
+    OSSL_LIB_CTX *libctx = NULL;
+    const char *propq = NULL;
+    EVP_PKEY_CTX *ctx = NULL;
+    EVP_PKEY *dsaparamkey = NULL;
+    OSSL_PARAM_BLD *bld = NULL;
+    OSSL_PARAM *params = NULL;
+    BIGNUM *p = NULL, *q = NULL, *g = NULL;
+
+    p = BN_bin2bn(dsa_p, sizeof(dsa_p), NULL);
+    q = BN_bin2bn(dsa_q, sizeof(dsa_q), NULL);
+    g = BN_bin2bn(dsa_g, sizeof(dsa_g), NULL);
+    if (p == NULL || q == NULL || g == NULL)
+        goto cleanup;
+
+    /* Use OSSL_PARAM_BLD if you need to handle BIGNUM Parameters */
+    bld = OSSL_PARAM_BLD_new();
+    if (bld == NULL)
+        goto cleanup;
+    if (!OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_FFC_P, p)
+            || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_FFC_Q, q)
+            || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_FFC_G, g))
+        goto cleanup;
+    params = OSSL_PARAM_BLD_to_param(bld);
+    if (params == NULL)
+        goto cleanup;
+
+    ctx = EVP_PKEY_CTX_new_from_name(libctx, "DSA", propq);
+    if (ctx == NULL) {
+        fprintf(stderr, "EVP_PKEY_CTX_new_from_name() failed\n");
+        goto cleanup;
+    }
+
+    if (EVP_PKEY_fromdata_init(ctx) <= 0
+            || EVP_PKEY_fromdata(ctx, &dsaparamkey, EVP_PKEY_KEY_PARAMETERS, params) <= 0) {
+        fprintf(stderr, "EVP_PKEY_fromdata() failed\n");
+        goto cleanup;
+    }
+
+    if (!dsa_print_key(dsaparamkey, 0, libctx, propq))
+        goto cleanup;
+
+    rv = EXIT_SUCCESS;
+cleanup:
+    EVP_PKEY_free(dsaparamkey);
+    EVP_PKEY_CTX_free(ctx);
+    OSSL_PARAM_free(params);
+    OSSL_PARAM_BLD_free(bld);
+    BN_free(g);
+    BN_free(q);
+    BN_free(p);
+
+    return rv;
+}