Fix missing casts on return

closes #236
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index cccc5d8..a4e7731 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -368,7 +368,7 @@
     if( ctx->iv_size != 0 )
         return (int) ctx->iv_size;
 
-    return ctx->cipher_info->iv_size;
+    return (int) ctx->cipher_info->iv_size;
 }
 
 /**
@@ -416,7 +416,7 @@
     if( NULL == ctx || NULL == ctx->cipher_info )
         return MBEDTLS_KEY_LENGTH_NONE;
 
-    return ctx->cipher_info->key_bitlen;
+    return (int) ctx->cipher_info->key_bitlen;
 }
 
 /**