diff --git a/aes.c b/aes.c
index 4c7645f..2561951 100644
--- a/aes.c
+++ b/aes.c
@@ -73,7 +73,7 @@ static const uint8_t* Key;
 
 #if defined(CBC) && CBC
   // Initial Vector used only for CBC mode
-  static uint8_t* Iv;
+  static const uint8_t* Iv;
 #endif
 
 // The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
@@ -434,7 +434,7 @@ static void InvCipher(void)
   AddRoundKey(0);
 }
 
-static void BlockCopy(uint8_t* output, uint8_t* input)
+static void BlockCopy(uint8_t* output, const uint8_t* input)
 {
   uint8_t i;
   for (i=0;i<KEYLEN;++i)
@@ -577,6 +577,47 @@ void AES128_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length,
   }
 }
 
+void AES128_CBC_encrypt_buffer16_ip(uint8_t* data, uint32_t length, const uint8_t* key, const uint8_t* iv)
+{
+  int i;
+
+  state = (state_t*)data;
+
+  Key = key;
+  KeyExpansion();
+
+  Iv = (uint8_t*)iv;
+
+  for(i = 0; i < length; i += 16)
+  {
+    XorWithIv(data);
+    state = (state_t*)data;
+    Cipher();
+    Iv = data;
+    data += 16;
+  }
+}
+
+void AES128_CBC_decrypt_buffer16_ip(uint8_t* data, uint32_t length, const uint8_t* key, const uint8_t* iv)
+{
+  int i;
+  uint8_t iv_copy[32];
+  
+  Key = key;
+  KeyExpansion();
+
+  BlockCopy(iv_copy, iv);
+
+  for(i = 0; i < length; i += 16)
+  {
+	BlockCopy(&iv_copy[(i + 16) % 32], data);
+    state = (state_t*)data;
+    InvCipher();
+	Iv = &iv_copy[i % 32];
+    XorWithIv(data);
+    data += 16;
+  }
+}
 
 #endif // #if defined(CBC) && CBC
 
diff --git a/aes.h b/aes.h
index 708a09c..27b6f18 100644
--- a/aes.h
+++ b/aes.h
@@ -33,6 +33,13 @@ void AES128_ECB_decrypt(uint8_t* input, const uint8_t* key, uint8_t *output);
 void AES128_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv);
 void AES128_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv);
 
+/*
+ * In-place encrypt/decrypt functions (whole blocks only)
+ * data[] and length must be a multiple of 16 bytes
+ */
+void AES128_CBC_encrypt_buffer16_ip(uint8_t* data, uint32_t length, const uint8_t* key, const uint8_t* iv);
+void AES128_CBC_decrypt_buffer16_ip(uint8_t* data, uint32_t length, const uint8_t* key, const uint8_t* iv);
+
 #endif // #if defined(CBC) && CBC