diff --git a/index.js b/index.js
index 532caf3..3f33c7a 100644
--- a/index.js
+++ b/index.js
@@ -151,25 +151,55 @@ class MerkleTree {
       return []
     }
 
-    for (let i = 0; i < this.layers.length - 1; i++) {
-      const layer = this.layers[i]
-      const isRightNode = index % 2
-      const pairIndex = (isRightNode ? index - 1 : index)
+    if (this.isBitcoinTree) {
 
-      if (pairIndex < layer.length) {
-        proof.push({
-          position: isRightNode ? 'left': 'right',
-          data: layer[pairIndex]
-        })
+      // Proof Generation for Bitcoin Trees
+
+      for (let i = 0; i < this.layers.length - 1; i++) {
+        const layer = this.layers[i]
+        const isRightNode = index % 2
+        const pairIndex = (isRightNode ? index - 1 : index)
+
+        if (pairIndex < layer.length) {
+          proof.push({
+            position: isRightNode ? 'left': 'right',
+            data: layer[pairIndex]
+          })
+        }
+
+        // set index to parent index
+        index = (index / 2)|0
+
+        }
+
+        return proof
+
+      } else {
+
+        // Proof Generation for Non-Bitcoin Trees
+
+        for (let i = 0; i < this.layers.length; i++) {
+          const layer = this.layers[i]
+          const isRightNode = index % 2
+          const pairIndex = (isRightNode ? index - 1 : index + 1)
+
+          if (pairIndex < layer.length) {
+            proof.push({
+              position: isRightNode ? 'left': 'right',
+              data: layer[pairIndex]
+            })
+          }
+
+          // set index to parent index
+          index = (index / 2)|0
+
+          }
+
+          return proof
+
+        }
       }
 
-      // set index to parent index
-      index = (index / 2)|0
-    }
-
-    return proof
-  }
-
   /**
    * verify
    * @desc Returns true if the proof path (array of hashes) can connect the target node