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.
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. 28. The method of claim 18 , wherein forming the intermediate tokenized string of characters and the final tokenized string of characters occurs at a second server in communication with a first server, and wherein the method further comprises: transferring to the first server at least one of the sensitive string of characters, the intermediate tokenized string of characters, and the final tokenized string of characters; canceling the received sensitive string of characters from the second server within a limited time from the transferring; and maintaining at least one of the intermediate tokenized string of characters and the final tokenized string of characters in a database connected to the second server.