I’m trying to break an unknown code. I’m given:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 ` ~ ! @ # $ % ^ & * ( ) – _ = + [ { ] } | ; : ‘ ” , < . > / ?

mP3Mr38RsISc/civexG8hJD9xK93EbiElP3Ar3MRpISI/dyvbxGghIz92K9rEayEgP3UrwwRxYTr/b2vCBHBhO/9ua8EEc2Euf3wrx0RtIT6/aqvGRGqhP/9pK8UEd2E9P3RrwER34SC/fWvYRGJhIX98q8HEc6E/v2srxARyIT3/bCvExHLow==

and

ABCDEFGHIJKLMNOP

mJ/Ny3l3s+yQl8XDcX+79Nndjo88MfSk

My first thought was the encoded strings would be the base64 or some variation of it for the given strings. Given the format and characters in the coded strings I’m still not sure what else it could be. (all characters in the coded strings are base64 characters even with padding).

When I tried that, I got an interesting repeating pattern in the base64 decoding of the encoded strings but it can’t be the solution since there are overlapping patterns for different characters in the input.

Compared the lengths. Hash mappings. Can’t figure it out.

Any input would be really appreciated!