1. The ciphertext area data is not displayed in the invoice details interface
It has been a while since TravelSky VAT invoicing software 3.0 has been launched. Careful users may find that the invoice query interface in 3.0 seems a bit different. Indeed, the data in the ciphertext area of the invoice is empty in the display interface of the invoice details of the TravelSky value-added tax invoicing software 3.0. Why is this happening? The author analyzed that TravelSky did so for data security considerations (as for whether this is the reason, the author is just guessing, and there is no way to verify it). Because the data in the cipher text area is the seven elements of the invoice (invoice code, invoice number, invoice date, buyer’s tax number, seller’s tax number, amount, and tax), the information is encrypted and calculated with a secure encryption algorithm to verify the authenticity of the invoice. Fake important data.
Figure-1 Invoice details query
According to the author's own speculation, at least the complete invoice data cannot be obtained through technical means in the UI interface, and the security of the invoice data is guaranteed in this link. But when the invoice is printed, the data in the ciphertext area of the invoice must be printed out, otherwise the printed invoice will be incomplete, and the printed out will not be an invoice.
2. Data processing in ciphertext area of invoice printing
Follow up according to the author, and then process the data in the ciphertext area of the invoice when printing the invoice, and then print it. It turns out that the data in the ciphertext area of the invoice is encrypted and stored in the database, and only the security measures are taken. Even if the database is compromised, there is at least an optical card to protect the data. Therefore, the data security mechanism of TravelSky is still considered Very thoughtful and in place.
Figure-2 Invoice print preview
Figure-3 Encrypted storage of invoice ciphertext data in the database
4. Invoice ciphertext encryption algorithm
The encrypted area of the invoice uses an extended algorithm similar to AES and uses a 256-bit key. For the specific algorithm, please refer to the author's previous blog post, which will not be repeated here.
https://blog.csdn.net/kongguoqing791025/article/details/111412475
5. Data decryption tool for invoice ciphertext area
The author of this article developed a data ciphertext decryption tool based on reverse analysis.
The download address of this tool csdn is as follows: https://download.csdn.net/download/delinkong/16185009
Figure-5 Data decryption tool for ciphertext area of TravelSky VAT invoicing software 3.0 database