Cryptanalysis

Monday 24 June 2019, 05:26  #1
question about number sequence
Paul Welsh
  • 1 posts

How would one go about identifying the type of encoding used or to decode the next numbers in a sequence such as this? Eg what method is being used to get the second 14 digit number from the first 14 digit number?

Recognizable patterns in the first 2 digits of the second set of numbers are that every next number in the sequence gets -8, but that every 14th number is -11. Also when the first number ends in 0 (every ten numbers), the second set gets a +4 in the first 2 digits.

What type of sequence or encryption is this where changing +1 on the input (first number set) gives an output with that type of pattern on the first 2 digits of the output (second number set) with the rest of the digits ’appearing’ random?

Here is the sequence:

14100009411042 90353196201897
14100009411043 82597638949765
14100009411044 74692001001792
14100009411045 66465647592460
14100009411046 58725547789554
14100009411047 50235246702673
14100009411048 42430671999717
14100009411049 34030063576811
14100009411050 38365988774167
14100009411051 30653542860732
14100009411052 22522864938343
14100009411053 14118074795317
14100009411054 06498403331943
14100009411055 95501055719254
14100009411056 87281570471824
14100009411057 79739303193960
14100009411058 71629849443848
14100009411059 63821904050834
14100009411060 67672043789705
14100009411061 59388713299460
14100009411062 51299808172042
14100009411063 43478768712729
14100009411064 35081772025377
14100009411065 27828870833132
14100009411066 19892452026861
14100009411067 11538971260790
14100009411068 03974564288514
14100009411069 92677621847634
14100009411070 96992174523590
14100009411071 88364231019898
14100009411072 80772721354239
14100009411073 72665311649126
14100009411074 64477520296046