need help with markov chain, or possibly another solution for decrypt of AES-256

[philsmd]

Code:

echo teststring | openssl enc -e -aes-256-ecb -K 0000123400001234000012340000123400001234000012340000123400001234 | xxd -g 1

and

Code:

echo teststring | openssl enc -e -aes-256-ecb -K 7c6801007c6801007c6801007c6801007c6801007c6801007c6801007c680100 | xxd -g 1

this will actually encrypt "teststring\n", but this was part of my testing, since I also wanted to match substrings not just identical strings (i.e. the test was: does the output *contain* "teststring" ?)