Ultimately, it depends on what you mean by strong. For example, in terms of encryption, that is, assuming the ability of an attacker to decrypt your encrypted text without access to the key, it should be as strong as any other use of AES256 (there is some difference in the differential analysis between the individual encryption blocks with the known plain text , but this will be a weakness of the encryption algorithm, not the CTR mode itself).
, CTR, , . :
- nonce/counter , , . ).
- XORed , , 1- , , , HMAC, .