decryption challenge

Hi folks,

I have some questions regarding decryption or finding what algorithm was used for decryption. If someone could give me some hints I would appreciate it much.

My ciphertext has a length of multiples of 128 hex numbers (49398) and consists of hex chars.
I also found that it consists of blocks of 16 hex numbers length and there are repetitions of strings with a length of multiples of 16.
The layout of the cipher comes with line length of 128.
As far as I can seethere is no string repetition within one line.

Where could I read to get more information about this? I wonder why there are repetitions with a length 16 hex numbers? I thought in good encrypted ciphers there are no repetitions.