In the answers in this question I found a reply: TurboPower LockBox 3: AES128 and padding ISO 10126
(2) For most chaining modes, TPLB3 will automatically add salt. This is normally a good thing, but if you need it without, you can remove the option for it.
How can I do that? Namely I need encryption which has the same cipher text length as the plain text length.
Assuming that you are not using ECB, the simplest way would be to remove the first 8 bytes of the ciphertext. The first 8 bytes (64 bits) is the salt nonce. It is also the low 64 bits of the IV. The high 64 bits of the IV are zero.
Please note: Not salting your messages is very bad practice and a security weakness. (Refer to wikipedia for more information). You say you need encryption which has the same ciphertext length as the plaintext length. This is basically saying, you want weak encryption. It's up to you, but my advice is the think about your requirements very carefully before proceeding.
An alternative technique would be to create your own chaining mode and register it in the cryptographic library. For example, if you wanted CBC without salt, create a class descendant from TCBC (unit TPLB3.CBC) and just override the ChainingFeatures() function to add the cfNoNounce feature. Refer to in-line comments in unit TPLB3.BlockCipher. However, my recommendation is the first method.
You might also like to read answers to related questions:
Also note that if you are using ECB chaining mode, there is no salt, was this mode has the cfNoNounce feature automatically. (ECB is bad. Don't use it, except for testing purposes).
I am the main author of TPLockBox 3, and I maintain the version of the library at:
I assume that you are using that version, and not the SourceForge one. I am expecting to release version 3.6.0 on 7-Nov-2014.