1 files changed, 152 insertions, 0 deletions
diff --git a/srtp/crypto/cipher/null_cipher.c b/srtp/crypto/cipher/null_cipher.c
new file mode 100644
index 0000000..721f50c
--- /dev/null
+++ b/srtp/crypto/cipher/null_cipher.c
@@ -0,0 +1,152 @@
+/*
+ * null_cipher.c
+ *
+ * A null cipher implementation.  This cipher leaves the plaintext
+ * unchanged.
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *	
+ * Copyright (c) 2001-2006, Cisco Systems, Inc.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ *   Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ *   Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ * 
+ *   Neither the name of the Cisco Systems, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "datatypes.h"
+#include "null_cipher.h"
+#include "alloc.h"
+
+/* the null_cipher uses the cipher debug module  */
+
+extern debug_module_t mod_cipher;
+
+err_status_t
+null_cipher_alloc(cipher_t **c, int key_len) {
+  extern cipher_type_t null_cipher;
+  uint8_t *pointer;
+  
+  debug_print(mod_cipher, 
+	      "allocating cipher with key length %d", key_len);
+
+  /* allocate memory a cipher of type null_cipher */
+  pointer = (uint8_t*)crypto_alloc(sizeof(null_cipher_ctx_t) + sizeof(cipher_t));
+  if (pointer == NULL)
+    return err_status_alloc_fail;
+
+  /* set pointers */
+  *c = (cipher_t *)pointer;
+  (*c)->type = &null_cipher;
+  (*c)->state = pointer + sizeof(cipher_t);
+
+  /* set key size */
+  (*c)->key_len = key_len;
+
+  /* increment ref_count */
+  null_cipher.ref_count++;
+  
+  return err_status_ok;
+  
+}
+
+err_status_t
+null_cipher_dealloc(cipher_t *c) {
+  extern cipher_type_t null_cipher;
+
+  /* zeroize entire state*/
+  octet_string_set_to_zero((uint8_t *)c, 
+			   sizeof(null_cipher_ctx_t) + sizeof(cipher_t));
+
+  /* free memory of type null_cipher */
+  crypto_free(c);
+
+  /* decrement reference count */
+  null_cipher.ref_count--;
+  
+  return err_status_ok;
+  
+}
+
+err_status_t
+null_cipher_init(null_cipher_ctx_t *ctx, const uint8_t *key) {
+
+  debug_print(mod_cipher, "initializing null cipher", NULL);
+
+  return err_status_ok;
+}
+
+err_status_t
+null_cipher_set_iv(null_cipher_ctx_t *c, void *iv) { 
+  return err_status_ok;
+}
+
+err_status_t
+null_cipher_encrypt(null_cipher_ctx_t *c,
+		    unsigned char *buf, unsigned int *bytes_to_encr) {
+  return err_status_ok;
+}
+
+char 
+null_cipher_description[] = "null cipher";
+
+cipher_test_case_t  
+null_cipher_test_0 = {
+  0,                 /* octets in key            */
+  NULL,              /* key                      */
+  0,                 /* packet index             */
+  0,                 /* octets in plaintext      */
+  NULL,              /* plaintext                */
+  0,                 /* octets in plaintext      */
+  NULL,              /* ciphertext               */
+  NULL               /* pointer to next testcase */
+};
+
+
+/*
+ * note: the decrypt function is idential to the encrypt function
+ */
+
+cipher_type_t null_cipher = {
+  (cipher_alloc_func_t)         null_cipher_alloc,
+  (cipher_dealloc_func_t)       null_cipher_dealloc,
+  (cipher_init_func_t)          null_cipher_init,
+  (cipher_encrypt_func_t)       null_cipher_encrypt,
+  (cipher_decrypt_func_t)       null_cipher_encrypt,
+  (cipher_set_iv_func_t)        null_cipher_set_iv,
+  (char *)                      null_cipher_description,
+  (int)                         0,
+  (cipher_test_case_t *)       &null_cipher_test_0,
+  (debug_module_t *)            NULL
+};
+