Updated readme

Author: ihaveroot

README.md

@@ -5,6 +5,7 @@ I had made this a while back while tinkering with python, forgotten about it and
 
 I've always disliked having to open another term to verify hashsums when downloading important files. Generally speaking, any organization that creates Paas, Saas or any of the types, usually have hash checksums beside the download of their binaries. I found it a bit tedious to copy the hashsum, open a term in the directory and then run 'hashutil', 'md5sum', 'sha256sum', etc. to verify the two hashes, I'm sure there's other tools that do this, though this was fun lil project to make.
 
+Since this is more of an archival thing, I most likely will not be modifying or updating this program in the future.
 
 ## Examples
 If a match is found:
@@ -81,7 +82,7 @@ Windows: Hashcheck.exe "C:\Users\ihr rules\Desktop\domain_admin.txt"
 
 
 ## Linux
-I initally wrote this for windows, it will execute, though, if you're running it from the command line, omit line 280 else it will yield the error of:
+I initally wrote this for windows, it will execute, though, if you're running it from the command line, [omit line 280](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L280) else it will yield the error of:
 ```
 sh: 1: pause: Permission denied
 ```
@@ -97,4 +98,69 @@ You may do the same by:
 - Typing in: `shell:sendto`
 - Adding the most recent release to the folder location
 
-![Sendto](/img/run.png)
+![Sendto](/img/run.png)
+
+
+## Adding your own
+I've planned for the ability to add your own libraries if the default hashing algorithms aren't enough. Shown is what you need to modify for the capability.
+
+In [`compute_file_hash`](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L57) add your hash type and the library for the hashing algorithm:
+```python
+    ...
+    #elif hash_type == 'foobar':
+    #    hash_func = library.hashing_algorithm()
+    elif hash_type == 'BLAKE2b':
+        hash_func = hashlib.blake2b()
+    ...
+```
+
+Since `foobar` is computing the file hash before `blake2b` you need to modify the [`hash_types`](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L199) list in [`assign`](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L198) so that the `foobar` identifier comes before `blake2b`
+```python
+    hash_types = ['MD5', 
+                  'SHA-1', 
+                  'SHA256', 
+                  'SHA512', 
+                  'BLAKE2s', 
+                  #'FOOBAR',
+                  'BLAKE2b']
+```
+
+If the length of the `foobar` hash algorithm is of a different length then you must add it to the map variable [`hash_length_map`](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L137) in [`display_confidence_hashes`](https://github.com/ihaveroot/Hashcheck/blob/907a846dbdacd990b038fd6d2bdc7524c99145aa/Hashcheck.py#L135). 
+
+```python
+    hash_length_map = {
+        128: [list[3][1], list[5][1]],
+         64: [list[2][1], list[4][1]],
+         40: [list[1][1], list[1][1]],
+         32: [list[0][1], list[0][1]],
+        # foobar hash length of 16
+        # foobar hash is in the 5th
+        #  position, and the hash is
+        #  in the first array.
+        #16: [list[5][1], list[5][1]]
+    }
+```
+
+The map has the hashing lengths of `128, 64, 40, 32` since `BLAKE2b/SHA512` and `BLAKE2s/SHA256` have the same hash lengths they're mapped to the corresponding numerical length values:
+```python
+       SHA512      BLAKE2b
+128: [list[3][1], list[5][1]],
+
+       SHA256      BLAKE2s
+ 64: [list[2][1], list[4][1]],
+    ...
+```
+
+We only have one hash length of 32, it is mapped twice to the same hash, being MD5:
+```python
+        MD5         MD5
+ 32: [list[0][1], list[0][1]],
+```
+
+As such, if `foobar` doesn't have one of these hash lengths you must add it and the position of `foobar` in the `hash_length_map`:
+```python
+        FOOBAR      FOOBAR
+ 16: [list[5][1], list[5][1]]
+```
+
+Pretty straight forward, see source for additional comments. I'm sure you'll figure it out.