X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fsec%2Fcipher.h;h=22eb313bdd27e3f08db35394962d786e1971f63d;hb=HEAD;hp=f0f37a36e600fce33169ebdaec7075a11944c637;hpb=b3a62d6cd1d6f304304956ea87ab9d5c1ff87031;p=bertos.git

diff --git a/bertos/sec/cipher.h b/bertos/sec/cipher.h
index f0f37a36..22eb313b 100644
--- 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);
 }
 
 /*********************************************************************************/
@@ -149,13 +169,51 @@ INLINE void cipher_ctr_begin(BlockCipher *c, void *counter)
 }
 
 /**
- * Encrypt a block (in-place) using the current key in CBC mode.
+ * Encrypt a block (in-place) using the current key in CTR mode.
  */
 void cipher_ctr_encrypt(BlockCipher *c, void *block);
 
 /**
- * Decrypt a block (in-place) using the current key in CBC mode.
+ * Decrypt a block (in-place) using the current key in CTR mode.
  */
 void cipher_ctr_decrypt(BlockCipher *c, void *block);
 
+/**
+ * Generate the crypted stream block in CTR mode for the current
+ * counter, and then bump it.
+ *
+ * This function is basically the core CTR operation, without the final
+ * XOR pass with the plaintext or ciphertext. For normal CTR usage,
+ * you never need to call it.
+ */
+void cipher_ctr_step(BlockCipher *c, void *block);
+
+
+/*********************************************************************************/
+/* OFB mode                                                                      */
+/*********************************************************************************/
+
+/**
+ * Initialize OFB by setting the IV.
+ *
+ * \note the memory pointed by \a iv will be used and modified by the OFB
+ * functions. It is caller's responsibility to keep it available until there is
+ * no more OFB work to do.
+ */
+INLINE void cipher_ofb_begin(BlockCipher *c, void *iv)
+{
+	c->buf = iv;
+}
+
+/**
+ * Encrypt a block (in-place) using the current key in OFB mode.
+ */
+void cipher_ofb_encrypt(BlockCipher *c, void *block);
+
+/**
+ * Decrypt a block (in-place) using the current key in OFB mode.
+ */
+void cipher_ofb_decrypt(BlockCipher *c, void *block);
+
+
 #endif /* SEC_CIPHER_H */