demo: add pbkdf2 demonstration program

Using test vector from RTC 7914

Fixes #14107

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

1 files changed, 117 insertions, 0 deletions

diff --git a/demos/kdf/pbkdf2.c b/demos/kdf/pbkdf2.c
new file mode 100644
index 0000000000..3e0adaee79
--- /dev/null
+++ b/demos/kdf/pbkdf2.c
@@ -0,0 +1,117 @@
+/*
+ * 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 pbkdf2_salt[] = {
+    'N', 'a', 'C', 'l'
+};
+    
+/*
+ * The iteration parameter 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 pbkdf2_iterations = 80000;
+
+static const unsigned char expected_output[] = {
+
+    0x4d, 0xdc, 0xd8, 0xf6, 0x0b, 0x98, 0xbe, 0x21,
+    0x83, 0x0c, 0xee, 0x5e, 0xf2, 0x27, 0x01, 0xf9,
+    0x64, 0x1a, 0x44, 0x18, 0xd0, 0x4c, 0x04, 0x14,
+    0xae, 0xff, 0x08, 0x87, 0x6b, 0x34, 0xab, 0x56,
+    0xa1, 0xd4, 0x25, 0xa1, 0x22, 0x58, 0x33, 0x54,
+    0x9a, 0xdb, 0x84, 0x1b, 0x51, 0xc9, 0xb3, 0x17,
+    0x6a, 0x27, 0x2b, 0xde, 0xbb, 0xa1, 0xd0, 0x78,
+    0x47, 0x8f, 0x62, 0xb3, 0x97, 0xf3, 0x3c, 0x8d
+};
+
+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[5], *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, "PBKDF2", 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, pbkdf2_salt,
+                                             sizeof(pbkdf2_salt));
+    /* Set iteration count (default 2048) */
+    *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_ITER, &pbkdf2_iterations);
+    /* Set the underlying hash function used to derive the key */
+    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
+                                            "SHA256", 0);
+    *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;
+}