diff --git a/lib/crypto/aes.js b/lib/crypto/aes.js
index c74e5716..dd579bc3 100644
--- a/lib/crypto/aes.js
+++ b/lib/crypto/aes.js
@@ -35,7 +35,7 @@ exports.encipher = function encipher(data, key, iv) {
  * @returns {Buffer}
  */
 
-exports.decipher = function decipher(data, key, iv) {
+exports.decipher = function _decipher(data, key, iv) {
   let decipher = crypto.createDecipheriv('aes-256-cbc', key, iv);
   try {
     return util.concat(decipher.update(data), decipher.final());
diff --git a/lib/crypto/digest.js b/lib/crypto/digest.js
index a9ed5967..ef0d8dd2 100644
--- a/lib/crypto/digest.js
+++ b/lib/crypto/digest.js
@@ -82,7 +82,7 @@ exports.hash256 = function hash256(data) {
  * @returns {Buffer} HMAC
  */
 
-exports.hmac = function hmac(alg, data, key) {
+exports.hmac = function _hmac(alg, data, key) {
   let hmac = crypto.createHmac(alg, key);
   return hmac.update(data).digest();
 };