Add 'no padding' mode

include/polarssl/cipher.h

@@ -109,6 +109,7 @@ typedef enum {
     POLARSSL_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding         */
     POLARSSL_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding             */
     POLARSSL_PADDING_ZEROS,         /**< zero padding (not reversible!) */
+    POLARSSL_PADDING_NONE,          /**< never pad (full blocks only)   */
 } cipher_padding_t;
 
 typedef enum {

library/cipher.c

@@ -657,6 +657,23 @@ static int get_zeros_padding( unsigned char *input, size_t input_len,
     return 0;
 }
 
+/*
+ * No padding: don't pad :)
+ *
+ * There is no add_padding function (check for NULL in cipher_finish)
+ * but a trivial get_padding function
+ */
+static int get_no_padding( unsigned char *input, size_t input_len,
+                              size_t *data_len )
+{
+    if( NULL == input || NULL == data_len )
+        return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
+
+    *data_len = input_len;
+
+    return 0;
+}
+
 int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen)
 {
     int ret = 0;
@@ -677,12 +694,27 @@ int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen)
     {
         if( POLARSSL_ENCRYPT == ctx->operation )
         {
+            /* check for 'no padding' mode */
+            if( NULL == ctx->add_padding )
+            {
+                if( 0 != ctx->unprocessed_len )
+                    return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
+
+                return 0;
+            }
+
             ctx->add_padding( ctx->unprocessed_data, cipher_get_iv_size( ctx ),
                     ctx->unprocessed_len );
         }
         else if ( cipher_get_block_size( ctx ) != ctx->unprocessed_len )
         {
-            /* For decrypt operations, expect a full block */
+            /*
+             * For decrypt operations, expect a full block,
+             * or an empty block if no padding
+             */
+            if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len )
+                return 0;
+
             return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
         }
 
@@ -743,6 +775,13 @@ int cipher_set_padding_mode( cipher_context_t *ctx, cipher_padding_t mode )
         return 0;
     }
 
+    if( POLARSSL_PADDING_NONE == mode )
+    {
+        ctx->add_padding = NULL;
+        ctx->get_padding = get_no_padding;
+        return 0;
+    }
+
     return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
 }
 

tests/suites/test_suite_cipher.aes.data

@@ -245,6 +245,66 @@ AES Encrypt and decrypt 49 bytes with zeros padding
 depends_on:POLARSSL_AES_C
 enc_dec_buf:POLARSSL_CIPHER_AES_128_CBC:AES-128-CBC:128:49:POLARSSL_PADDING_ZEROS
 
+AES Encrypt and decrypt 0 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_dec_buf:POLARSSL_CIPHER_AES_128_CBC:AES-128-CBC:128:0:POLARSSL_PADDING_NONE
+
+AES Encrypt and decrypt 16 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_dec_buf:POLARSSL_CIPHER_AES_128_CBC:AES-128-CBC:128:16:POLARSSL_PADDING_NONE
+
+AES Encrypt and decrypt 32 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_dec_buf:POLARSSL_CIPHER_AES_128_CBC:AES-128-CBC:128:32:POLARSSL_PADDING_NONE
+
+AES Encrypt and decrypt 48 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_dec_buf:POLARSSL_CIPHER_AES_128_CBC:AES-128-CBC:128:48:POLARSSL_PADDING_NONE
+
+AES Try encrypting 1 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:1:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 2 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:2:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 7 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:7:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 8 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:8:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 9 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:9:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 15 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:15:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 17 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:17:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 31 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:31:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 33 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:33:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 47 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:47:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+AES Try encrypting 49 bytes with no padding
+depends_on:POLARSSL_AES_C
+enc_fail:POLARSSL_CIPHER_AES_128_CBC:POLARSSL_PADDING_NONE:128:49:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
 AES Encrypt and decrypt 0 bytes in multiple parts
 depends_on:POLARSSL_AES_C
 enc_dec_buf_multipart:POLARSSL_CIPHER_AES_128_CBC:128:0:0:

tests/suites/test_suite_cipher.blowfish.data

@@ -245,6 +245,66 @@ BLOWFISH Encrypt and decrypt 49 bytes with zeros padding
 depends_on:POLARSSL_BLOWFISH_C
 enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:49:POLARSSL_PADDING_ZEROS
 
+BLOWFISH Encrypt and decrypt 0 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:0:POLARSSL_PADDING_NONE
+
+BLOWFISH Encrypt and decrypt 8 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:8:POLARSSL_PADDING_NONE
+
+BLOWFISH Encrypt and decrypt 16 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:16:POLARSSL_PADDING_NONE
+
+BLOWFISH Encrypt and decrypt 32 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:32:POLARSSL_PADDING_NONE
+
+BLOWFISH Encrypt and decrypt 48 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_dec_buf:POLARSSL_CIPHER_BLOWFISH_CBC:BLOWFISH-CBC:128:48:POLARSSL_PADDING_NONE
+
+BLOWFISH Try encrypting 1 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:1:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 2 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:2:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 7 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:7:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 9 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:9:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 15 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:15:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 17 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:17:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 31 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:31:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 33 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:33:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 47 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:47:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+BLOWFISH Try encrypting 49 bytes with no padding
+depends_on:POLARSSL_BLOWFISH_C
+enc_fail:POLARSSL_CIPHER_BLOWFISH_CBC:POLARSSL_PADDING_NONE:128:49:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
 BLOWFISH Encrypt and decrypt 0 bytes in multiple parts
 depends_on:POLARSSL_BLOWFISH_C
 enc_dec_buf_multipart:POLARSSL_CIPHER_BLOWFISH_CBC:128:0:0:

tests/suites/test_suite_cipher.camellia.data

@@ -245,6 +245,66 @@ CAMELLIA Encrypt and decrypt 49 bytes with zeros padding
 depends_on:POLARSSL_CAMELLIA_C
 enc_dec_buf:POLARSSL_CIPHER_CAMELLIA_128_CBC:CAMELLIA-128-CBC:128:49:POLARSSL_PADDING_ZEROS
 
+CAMELLIA Encrypt and decrypt 0 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_dec_buf:POLARSSL_CIPHER_CAMELLIA_128_CBC:CAMELLIA-128-CBC:128:0:POLARSSL_PADDING_NONE
+
+CAMELLIA Encrypt and decrypt 16 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_dec_buf:POLARSSL_CIPHER_CAMELLIA_128_CBC:CAMELLIA-128-CBC:128:16:POLARSSL_PADDING_NONE
+
+CAMELLIA Encrypt and decrypt 32 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_dec_buf:POLARSSL_CIPHER_CAMELLIA_128_CBC:CAMELLIA-128-CBC:128:32:POLARSSL_PADDING_NONE
+
+CAMELLIA Encrypt and decrypt 48 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_dec_buf:POLARSSL_CIPHER_CAMELLIA_128_CBC:CAMELLIA-128-CBC:128:48:POLARSSL_PADDING_NONE
+
+CAMELLIA Try encrypting 1 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:1:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 2 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:2:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 7 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:7:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 8 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:8:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 9 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:9:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 15 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:15:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 17 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:17:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 31 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:31:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 33 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:33:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 47 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:47:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+CAMELLIA Try encrypting 49 bytes with no padding
+depends_on:POLARSSL_CAMELLIA_C
+enc_fail:POLARSSL_CIPHER_CAMELLIA_128_CBC:POLARSSL_PADDING_NONE:128:49:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
 CAMELLIA Encrypt and decrypt 0 bytes in multiple parts
 depends_on:POLARSSL_CAMELLIA_C
 enc_dec_buf_multipart:POLARSSL_CIPHER_CAMELLIA_128_CBC:128:0:0:

tests/suites/test_suite_cipher.des.data

@@ -245,6 +245,66 @@ DES Encrypt and decrypt 49 bytes with zeros padding
 depends_on:POLARSSL_DES_C
 enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:49:POLARSSL_PADDING_ZEROS
 
+DES Encrypt and decrypt 0 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:0:POLARSSL_PADDING_NONE
+
+DES Encrypt and decrypt 8 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:8:POLARSSL_PADDING_NONE
+
+DES Encrypt and decrypt 16 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:16:POLARSSL_PADDING_NONE
+
+DES Encrypt and decrypt 32 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:32:POLARSSL_PADDING_NONE
+
+DES Encrypt and decrypt 48 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_dec_buf:POLARSSL_CIPHER_DES_CBC:DES-CBC:56:48:POLARSSL_PADDING_NONE
+
+DES Try encrypting 1 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:1:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 2 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:2:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 7 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:7:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 9 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:9:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 15 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:15:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 17 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:17:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 31 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:31:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 33 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:33:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 47 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:47:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
+DES Try encrypting 49 bytes with no padding
+depends_on:POLARSSL_DES_C
+enc_fail:POLARSSL_CIPHER_DES_CBC:POLARSSL_PADDING_NONE:56:49:POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED
+
 DES Encrypt and decrypt 0 bytes in multiple parts
 depends_on:POLARSSL_DES_C
 enc_dec_buf_multipart:POLARSSL_CIPHER_DES_CBC:56:0:0:

tests/suites/test_suite_cipher.function

@@ -91,6 +91,46 @@ enc_dec_buf:cipher_id:cipher_string:key_len:length:pad_mode:
     TEST_ASSERT( 0 == cipher_free_ctx( &ctx_enc ) );
 END_CASE
 
+BEGIN_CASE
+enc_fail:cipher_id:pad_mode:key_len:length:ret:
+    size_t length = {length};
+    unsigned char key[32];
+    unsigned char iv[16];
+
+    const cipher_info_t *cipher_info;
+    cipher_context_t ctx;
+
+    unsigned char inbuf[64];
+    unsigned char encbuf[64];
+
+    size_t outlen = 0;
+
+    memset( key, 0, 32 );
+    memset( iv , 0, 16 );
+
+    memset( &ctx, 0, sizeof( ctx ) );
+
+    memset( inbuf, 5, 64 );
+    memset( encbuf, 0, 64 );
+
+    /* Check and get info structures */
+    cipher_info = cipher_info_from_type( {cipher_id} );
+    TEST_ASSERT( NULL != cipher_info );
+
+    /* Initialise context */
+    TEST_ASSERT( 0 == cipher_init_ctx( &ctx, cipher_info ) );
+    TEST_ASSERT( 0 == cipher_setkey( &ctx, key, {key_len}, POLARSSL_ENCRYPT ) );
+    TEST_ASSERT( 0 == cipher_set_padding_mode( &ctx, {pad_mode} ) );
+    TEST_ASSERT( 0 == cipher_reset( &ctx, iv ) );
+
+    /* encode length number of bytes from inbuf */
+    TEST_ASSERT( 0 == cipher_update( &ctx, inbuf, length, encbuf, &outlen ) );
+    TEST_ASSERT( {ret} == cipher_finish( &ctx, encbuf + outlen, &outlen ) );
+
+    /* done */
+    TEST_ASSERT( 0 == cipher_free_ctx( &ctx ) );
+END_CASE
+
 BEGIN_CASE
 dec_empty_buf:
     unsigned char key[32];