Passcode Walkthrough for Niantic Project Post 2014-01-22 passcode#1
Difficulty Rating (out of 8. 1-5 are regular difficulty levels, 6-8 are very challenging):
How/where to find the source of the passcode
FILE ID: xDZt4Ovws5urijtwcDKn
Examining the FILE ID given, there are a few clues that will help us know how it’s ciphered.
Clue #1: The number of characters in the string is divisible by 4, in this case it’s 5 (20 4). Base64 encoding takes 3 ASCII bytes (3 x 8 = 24 bits) and converts them to 4 characters in the Base64 alphabet, which is composed of 6-bit values (4 x 6 =24 bits). The Base64 alphabet is composed of uppercase characters, lowercase characters, numbers, a plus sign, and a forward slash.
Clue #2: Blend of uppercase, lowercase, and numbers. Good chance it’s Base64.
Clue #3: One of the ends of the string be converted to start with M, N, or O. M, N, and O are the Base64 characters that will match the beginning of decimal numbers when converted into ASCII.
With the clues in hand, we can safely assume this will be Base64. First, change the uppercase characters to lowercase characters and vice versa.
Now we need to get the N to the beginning, so reverse the string:
Run it through a Base64 decoder:
Passcode items gained:
L8 Resonator (3)
L3 Xmp Burster (2)
Portal Shield (2) (Very Rare)