diff --git a/lib/stream-hash.js b/lib/stream-hash.js
index 3f9b44133766c04866ab2ab178c061f35dbf8f42..368ed6d94da4401909b7eddc87d18354947daf33 100644
--- a/lib/stream-hash.js
+++ b/lib/stream-hash.js
@@ -7,19 +7,15 @@ class StreamHash extends Transform {
     constructor(attachment, algo) {
         super();
         this.attachment = attachment;
-        this.algo = (algo || 'md5').toLowerCase();
-        this.hash = crypto.createHash(algo);
         this.byteCount = 0;
     }
 
     _transform(chunk, encoding, done) {
-        this.hash.update(chunk);
         this.byteCount += chunk.length;
         done(null, chunk);
     }
 
     _flush(done) {
-        this.attachment.checksum = this.hash.digest('hex');
         this.attachment.size = this.byteCount;
         done();
     }