demo: add scrypt demonstration program

Using test vector from RTC 7914

Fixes #14108

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/16109)

diff --git a/demos/kdf/scrypt.c b/demos/kdf/scrypt.c
new file mode 100644 (file)
index 0000000..2be9908
--- /dev/null
+++ b/demos/kdf/scrypt.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2021 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
+ */
+
+#include <stdio.h>
+#include <openssl/core_names.h>
+#include <openssl/crypto.h>
+#include <openssl/kdf.h>
+#include <openssl/obj_mac.h>
+#include <openssl/params.h>
+
+/*
+ * test vector from
+ * https://datatracker.ietf.org/doc/html/rfc7914
+ */
+
+/*
+ * Hard coding a password into an application is very bad.
+ * It is done here solely for educational purposes.
+ */
+static unsigned char password[] = {
+    'p', 'a', 's', 's', 'w', 'o', 'r', 'd'
+};
+
+/*
+ * The salt is better not being hard coded too.  Each password should have a
+ * different salt if possible.  The salt is not considered secret information
+ * and is safe to store with an encrypted password.
+ */
+static unsigned char scrypt_salt[] = {
+    'N', 'a', 'C', 'l'
+};
+
+/*
+ * The SCRYPT parameters can be variable or hard coded.  The disadvantage with
+ * hard coding them is that they cannot easily be adjusted for future
+ * technological improvements appear.
+ */
+static unsigned int scrypt_n = 1024;
+static unsigned int scrypt_r = 8;
+static unsigned int scrypt_p = 16;
+
+static const unsigned char expected_output[] = {
+
+    0xfd, 0xba, 0xbe, 0x1c, 0x9d, 0x34, 0x72, 0x00,
+    0x78, 0x56, 0xe7, 0x19, 0x0d, 0x01, 0xe9, 0xfe,
+    0x7c, 0x6a, 0xd7, 0xcb, 0xc8, 0x23, 0x78, 0x30,
+    0xe7, 0x73, 0x76, 0x63, 0x4b, 0x37, 0x31, 0x62,
+    0x2e, 0xaf, 0x30, 0xd9, 0x2e, 0x22, 0xa3, 0x88,
+    0x6f, 0xf1, 0x09, 0x27, 0x9d, 0x98, 0x30, 0xda,
+    0xc7, 0x27, 0xaf, 0xb9, 0x4a, 0x83, 0xee, 0x6d,
+    0x83, 0x60, 0xcb, 0xdf, 0xa2, 0xcc, 0x06, 0x40
+};
+
+int main(int argc, char **argv)
+{
+    int rv = 1;
+    EVP_KDF *kdf = NULL;
+    EVP_KDF_CTX *kctx = NULL;
+    unsigned char out[64];
+    OSSL_PARAM params[6], *p = params;
+    OSSL_LIB_CTX *library_context = NULL;
+
+    library_context = OSSL_LIB_CTX_new();
+    if (library_context == NULL) {
+        fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
+        goto end;
+    }
+
+    /* Fetch the key derivation function implementation */
+    kdf = EVP_KDF_fetch(library_context, "SCRYPT", NULL);
+    if (kdf == NULL) {
+        fprintf(stderr, "EVP_KDF_fetch() returned NULL\n");
+        goto end;
+    }
+
+    /* Create a context for the key derivation operation */
+    kctx = EVP_KDF_CTX_new(kdf);
+    if (kctx == NULL) {
+        fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n");
+        goto end;
+    }
+
+    /* Set password */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD, password,
+                                             sizeof(password));
+    /* Set salt */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, scrypt_salt,
+                                             sizeof(scrypt_salt));
+    /* Set N (default 1048576) */
+    *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_N, &scrypt_n);
+    /* Set R (default 8) */
+    *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_R, &scrypt_r);
+    /* Set P (default 1) */
+    *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_SCRYPT_P, &scrypt_p);
+    *p = OSSL_PARAM_construct_end();
+
+    /* Derive the key */
+    if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) {
+        fprintf(stderr, "EVP_KDF_derive() failed\n");
+        goto end;
+    }
+
+    if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
+        fprintf(stderr, "Generated key does not match expected value\n");
+        goto end;
+    }
+
+    rv = 0;
+end:
+    EVP_KDF_CTX_free(kctx);
+    EVP_KDF_free(kdf);
+    OSSL_LIB_CTX_free(library_context);
+    return rv;
+}