Encryption algorithm which produces comparable results for substrings I am wondering is there any encryption algorithm available which produces comparable string.

I am expecting the output as shown below.

Data        |       output
---------------------------------------------
testData    |  uTrildHcKpM
testData_1  |  uTrildHcKpMiopu


Please let me know if you happen to know such algorithms.
It is somewhat unclear what you mean by comparable strings. But from the example you give, one might construe that you want the same substrings in different plaintext messages to be encrypted in the same way. This property is obviously very bad for an encryption scheme (given a number of plaintext/ciphertext pairs it would be easy to derive a lot of information about the encryption scheme).

There are however early instances of encryption with such a bad property like the monoalphabetic substitutions (Caesar's cipher for example).