Added decrypt_names.py to help decoding encrypted logs

bin/decrypt_names.py

@@ -0,0 +1,59 @@
+#!/usr/bin/python
+"""
+This is a tool to decrypt file names in rclone logs.
+
+Pass two files in, the first should be a crypt mapping generated by
+
+rclone ls --crypt-show-mapping remote:path
+
+The second should be a log file that you want the paths decrypted in.
+
+Note that if the crypt mappings file is large it can take some time to
+run.
+"""
+
+import re
+import sys
+
+# Crypt line
+match_crypt = re.compile(r'NOTICE: (.*?): Encrypts to "(.*?)"$')
+
+def read_crypt_map(mapping_file):
+    """
+    Read the crypt mapping file in, creating a dictionary of substitutions
+    """
+    mapping = {}
+    with open(mapping_file) as fd:
+        for line in fd:
+            match = match_crypt.search(line)
+            if match:
+                plaintext, ciphertext = match.groups()
+                plaintexts = plaintext.split("/")
+                ciphertexts = ciphertext.split("/")
+                for plain, cipher in zip(plaintexts, ciphertexts):
+                    mapping[cipher] = plain
+    return mapping
+
+def map_log_file(crypt_map, log_file):
+    """
+    Substitute the crypt_map in the log file.
+
+    This uses a straight forward O(N**2) algorithm.  I tried using
+    regexps to speed it up but it made it slower!
+    """
+    with open(log_file) as fd:
+        for line in fd:
+            for cipher, plain in crypt_map.iteritems():
+                line = line.replace(cipher, plain)
+            sys.stdout.write(line)
+
+def main():
+    if len(sys.argv) < 3:
+        print "Syntax: %s <crypt-mapping-file> <log-file>" % sys.argv[0]
+        raise SystemExit(1)
+    mapping_file, log_file = sys.argv[1:]
+    crypt_map = read_crypt_map(mapping_file)
+    map_log_file(crypt_map, log_file)
+
+if __name__ == "__main__":
+    main()