The accepted answer from Maarten Bodewes (https://crypto.stackexchange.com/a/38045) is applicable to the common case, assuming that proper secure encryption has been applied.
I.e. it is true that knowing some plaintexts is not useful in breaking encryption except to validated the probable key(s) found.
Repeating ciphertext substrings
However, additional information from comments states that some ciphertext substrings repeat. Taking this into account, I provide additional detail regarding improper ways to do encryption. Repeat of ciphertext substrings means that some parts of inputs map to same output. This likely means non-proper mode of operation has been applied or mode of operation has been misused, as secure encryption instead produce ciphertexts which appear entirely unrelated.
To analyze the changed segments, it is first needed to decode them.
0000000: da2a 1bde 044b bda6 ccd1 09cc b60b 4c1b .*...K........L.
0000010: 9cb8 9029 80db 198b 91ab 0151 ab0b 9109 ...).......Q....
0000020: 23c9 0b50 dcd1 6153 950d 910f 7953 59 #..P..aS....ySY
0000000: da2a 1bde 044b bda6 ccd1 010c b604 ccd1 .*...K..........
0000010: a93c d8d9 80db 198b 91ab 0151 ab0b 3b11 .<.........Q..;.
0000020: 15cb 5de6 9239 f551 0ba3 cb11 59ca 00 ..]..9.Q....Y..
If the length of changed segments is exactly 8 or 16 bytes at some 8 or 16 byte multiple location, changes are that the encryption is using ECB mode and cipher with 64-bit or 128-bit block, such as DES or AES. It could be something similar to Adobe ECB password database.
However, the segments in decoded ciphertext that have been changed are few bits here and there, instead of full 8 or 16 bytes. This could be result of e.g. misusing counter mode of operation, where plaintext is XORed with blocks from AES.
- Repeating parts in output mean that the parts have been improperly encrypted or those parts have not been encrypted at all.
- The further investigation of this issue would be specific to this system where the problem has been detected. It is likely very laborious to investigate the security of the system and to fix it.