18. A method for tokenization of sensitive strings, the method comprising: receiving a sensitive string of characters; selecting a substring of the sensitive string of characters; forming an intermediate tokenized string of characters, by a processor, by replacing the selected substring of the sensitive string of characters with a first token; selecting a substring of the intermediate tokenized string of characters, the selected substring of the intermediate tokenized string of characters including at least one character replaced by the first token; and forming a final tokenized string of characters, by the processor, by replacing the selected substring of the intermediate tokenized string of characters with a second token, the second token being different from the first token.
32. The method of claim 18 , further comprising modifying the selected substring of the sensitive string of characters prior to replacing the selected substring with a token.