diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index 3ee2ab7..c5a50c0 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -86,6 +86,7 @@
     MBEDTLS_CIPHER_ID_CAMELLIA,  /**< The Camellia cipher. */
     MBEDTLS_CIPHER_ID_BLOWFISH,  /**< The Blowfish cipher. */
     MBEDTLS_CIPHER_ID_ARC4,      /**< The RC4 cipher. */
+    MBEDTLS_CIPHER_ID_CHACHA20,  /**< The Chacha20 cipher. */
 } mbedtls_cipher_id_t;
 
 /**
@@ -145,6 +146,7 @@
     MBEDTLS_CIPHER_CAMELLIA_128_CCM,     /**< Camellia cipher with 128-bit CCM mode. */
     MBEDTLS_CIPHER_CAMELLIA_192_CCM,     /**< Camellia cipher with 192-bit CCM mode. */
     MBEDTLS_CIPHER_CAMELLIA_256_CCM,     /**< Camellia cipher with 256-bit CCM mode. */
+    MBEDTLS_CIPHER_CHACHA20,             /**< Chacha20 stream cipher. */
 } mbedtls_cipher_type_t;
 
 /** Supported cipher modes. */
@@ -190,7 +192,7 @@
 /** Maximum length of any IV, in Bytes. */
 #define MBEDTLS_MAX_IV_LENGTH      16
 /** Maximum block size of any cipher, in Bytes. */
-#define MBEDTLS_MAX_BLOCK_LENGTH   16
+#define MBEDTLS_MAX_BLOCK_LENGTH   64
 
 /**
  * Base cipher information (opaque struct).