Binary data destruction after decode

[Sybil-E]

The binary data after decode is different from original data.

$ hexdump message.txt.gpg 
0000000 8c 0d 04 07 03 02 a5 25 df b2 ac 9f 26 ca d9 d2
0000010 51 01 f4 53 68 4e 50 24 3c 58 30 90 b0 81 d9 b7
0000020 54 40 9f 24 2a 8e 2a d4 2f 40 f7 42 68 8f b3 17
0000030 ff d1 8f aa b4 1b 73 34 64 b2 eb a5 f7 c8 7c 8b
0000040 e4 22 7a 0b 09 ca d9 71 21 b3 f6 2d f7 7c 6a b2
0000050 52 aa 30 ed 84 0c 28 b8 1b eb 2c c5 c7 11 5c 5b
0000060 d6 20                                          
0000062

$ ./LSBSteg.py encode -i before_hidden.png -o after_hidden.png -f message.txt.gpg

$ ./LSBSteg.py decode -i after_hidden.png -o result.txt.gpg

$ hexdump result.txt.gpg 
0000000 c2 8c 0d 04 07 03 02 c2 a5 25 c3 9f c2 b2 c2 ac
0000010 c2 9f 26 c3 8a c3 99 c3 92 51 01 c3 b4 53 68 4e
0000020 50 24 3c 58 30 c2 90 c2 b0 c2 81 c3 99 c2 b7 54
0000030 40 c2 9f 24 2a c2 8e 2a c3 94 2f 40 c3 b7 42 68
0000040 c2 8f c2 b3 17 c3 bf c3 91 c2 8f c2 aa c2 b4 1b
0000050 73 34 64 c2 b2 c3 ab c2 a5 c3 b7 c3 88 7c c2 8b
0000060 c3 a4 22 7a 0b 09 c3 8a c3 99 71 21 c2 b3 c3 b6
0000070 2d c3 b7 7c 6a c2 b2 52 c2 aa 30 c3 ad c2 84 0c
0000080 28 c2 b8 1b c3 ab 2c c3 85 c3 87 11 5c 5b c3 96
0000090 20                                             
0000091

My environment: Python 3.6.4