SEC: improve cipher API to allow variable-key ciphers.

[bertos.git] / bertos / sec / cipher.h

diff --git a/bertos/sec/cipher.h b/bertos/sec/cipher.h
index f67cb809d00d8a0530acb7b8069403aeee563418..24c24b0da656f1ae6d32f5f666db5155a7811eff 100644 (file)
--- a/bertos/sec/cipher.h
+++ b/bertos/sec/cipher.h
@@ -43,7 +43,7 @@
 
 typedef struct BlockCipher
 {
-       void (*set_key)(struct BlockCipher *c, const void *key);
+       void (*set_key)(struct BlockCipher *c, const void *key, size_t len);
        void (*enc_block)(struct BlockCipher *c, void *block);
        void (*dec_block)(struct BlockCipher *c, void *block);
 
@@ -54,7 +54,10 @@ typedef struct BlockCipher
 
 
 /**
- * Return the key length (in bytes)
+ * Return the key length (in bytes).
+ *
+ * In case of ciphers that allow a variabile key size with a fixed state
+ * (eg: Blowfish), this returns the preferred key length.
  */
 INLINE size_t cipher_key_len(BlockCipher *c)
 {
@@ -73,12 +76,29 @@ INLINE size_t cipher_block_len(BlockCipher *c)
  * Set the current key used by the cipher.
  *
  * \note the buffer pointed by \a key is not modified and it is
- * not needed anymore after this call returns.
+ * not needed anymore after this call returns. Its lenght must match
+ * the value returned by \a cipher_key_len().
  */
 INLINE void cipher_set_key(BlockCipher *c, const void *key)
 {
        ASSERT(c->set_key);
-       c->set_key(c, key);
+       c->set_key(c, key, c->key_len);
+}
+
+/**
+ * Set the current key (of variable size) used by the cipher.
+ *
+ * This function is useful for ciphers that allow a variable size for the key
+ * (even with a fixed state). For all the other ciphers, the length must
+ * match the value returned by \a cipher_key_len().
+ *
+ * \note the buffer pointed by \a key is not modified and it is
+ * not needed anymore after this call returns.
+ */
+INLINE void cipher_set_vkey(BlockCipher *c, const void *key, size_t len)
+{
+       ASSERT(c->set_key);
+       c->set_key(c, key, len);
 }
 
 /*********************************************************************************/