Database encryption to provide write protection
An online computer system including a database uses an encrypted table that allows for write protection its contents. Middleware logic operating on the system acts as an interface for access to the database, so that any business logic on the system accesses the database through simple procedural calls to the middleware rather than directly to the database itself. The middleware logic abstracts logic that helps implement write protection with the encrypted table. Data to be encrypted that has been traditionally written to other tables is migrated to the encrypted table, where the data encrypted using an authenticated encryption with additional data (AEAD) algorithm. To implement AEAD, the original table, column, and primary key indicating where the data would have otherwise been stored are together used as additional authenticated data (AAD). This tuple of information is also stored in the encrypted table.
1. A computer implemented method comprising:
receiving a read request to a database, the read request specifying an original table (OT) name of one of a plurality of tables in the database and a column name of one of a plurality of columns in the OT;
determining an OT row identifier identifying a row of the OT where a data entry was to be read from;
determining, based on the OT name, column name, and row identifier, that an encrypted data entry corresponding to the read request does not exist in an encrypted table (ET) which is different than the OT;
responsive to determining that an encrypted data entry, corresponding to the read request, does not exist in the ET:
retrieving the data entry from a first location in the OT corresponding to the column name and the OT row identifier; and
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT row identifier;
obtaining a cipher text based on the data entry and the AAD, wherein the cipher text encodes the data entry and the AAD together;
writing the cipher text to an ET location in a cipher text column of the ET, the ET location in a row of the ET also storing the OT name, the column name, and the OT row identifier; and
returning the data entry in response to the read request.
2. The computer implemented method of claim 1 , wherein the OT row identifier is an OT primary key identifying a row of the OT.
3. The computer implemented method of claim 1 , further comprising:
deleting the data entry from the OT.
4. The computer implemented method of claim 1 , wherein determining that an encrypted data entry corresponding to the read request does not exist in the ET comprises checking if a row of the ET matches a tuple of the OT name, column name, and OT row identifier.
5. The computer implemented method of claim 1 , wherein obtaining the cipher text comprises:
communicating the data entry, the AAD, and an identification of a cryptographic key to a cryptography service; and
responsive to the communication, receiving a cipher text from the cryptography service.
6. The computer implemented method of claim 1 , further comprising:
accessing the row of the ET corresponding to the OT row identifier;
creating a second AAD based on at least some of the contents of the row other than the cipher text;
communicating the cipher text and the second AAD to a cryptography service;
responsive to the cryptography service returning the data entry, validating the encryption as successful; and
responsive to the cryptography service returning a decryption error, reporting that the encryption was unsuccessful or that a write attack has occurred.
7. The computer implemented method of claim 1 , wherein writing the cipher text to the ET location further comprises:
writing the OT name to an original table column in the row of the ET;
writing the column name to a column name column in the row of the ET; and
writing the OT row identifier to an OT primary key column in the row of the ET.
8. A computer implemented method comprising:
receiving a read request to a database, the read request specifying an original table (OT) name of one of a plurality of tables in the database and a column name of one of a plurality of columns in the OT;
determining an OT row identifier identifying a row of the OT where a data entry was to be read from;
determining, based on the OT name, column name, and OT row identifier, a row of an encrypted table (ET) which is different than the OT, the row of the ET associated with the read request;
responsive to determining that an encrypted data entry, corresponding to the read request, does exist in the ET:
reading, from the row of the ET, a cipher text from a cipher text column; and
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT row identifier;
obtaining an ET data entry based on the cipher text and the AAD; and
returning the ET data entry in response to the read request.
9. The computer implemented method of claim 8 , further comprising:
retrieving an OT data entry from a first location in the OT corresponding to the column name and the OT row identifier;
comparing the ET data entry and the OT data entry; and
responsive to determining, based on the comparing, that the ET data entry matches the OT data entry, validating the encryption as successful.
10. The computer implemented method of claim 9 , further comprising:
responsive to determining, based on the comparing, that the ET data entry does not match the OT data entry, reporting that the encryption was unsuccessful or that a write attack has occurred.
11. The computer implemented method of claim 9 , further comprising:
deleting the data entry from the OT.
12. The computer implemented method of claim 8 , wherein the OT row identifier is an OT primary key identifying a row of the OT.
13. The computer implemented method of claim 8 , wherein the row of the ET also stores the OT name, the column name, and the OT row identifier.
14. The computer implemented method of claim 8 , wherein obtaining the ET data entry comprises:
communicating a decryption request comprising the cipher text, the AAD, and an identification of a cryptographic key to a cryptography service; and
responsive to the decryption request, receiving the ET data entry from the cryptography service.
15. A non-transitory computer readable medium comprising instructions that, when executed by a processor of a device, cause the processor to perform the steps of:
receiving a read request to a database, the read request specifying an original table (OT) name of one of a plurality of tables in the database and a column name of one of a plurality of columns in the OT;
determining an OT row identifier identifying a row of the OT where a data entry was to be read from;
determining, based on the OT name, column name, and row identifier, that an encrypted data entry corresponding to the read request does not exist in an encrypted table (ET) which is different than the OT;
responsive to determining that an encrypted data entry, corresponding to the read request, does not exist in the ET:
retrieving the data entry from a first location in the OT corresponding to the column name and the OT row identifier; and
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT row identifier;
obtaining a cipher text based on the data entry and the AAD, wherein the cipher text encodes the data entry and the AAD together;
writing the cipher text to an ET location in a cipher text column of the ET, the ET location in a row of the ET also storing the OT name, the column name, and the OT row identifier; and
returning the data entry in response to the read request.
16. The non-transitory computer readable medium of claim 15 , wherein the OT row identifier is an OT primary key identifying a row of the OT.
17. The non-transitory computer readable medium of claim 15 , wherein the steps further comprise:
deleting the data entry from the OT.
18. The non-transitory computer readable medium of claim 15 , wherein determining that an encrypted data entry corresponding to the read request does not exist in the ET comprises checking if a row of the ET matches a tuple of the OT name, column name, and OT row identifier.
19. The non-transitory computer readable medium of claim 15 , wherein obtaining the cipher text comprises:
communicating the data entry, the AAD, and an identification of a cryptographic key to a cryptography service; and
responsive to the communication, receiving a cipher text from the cryptography service.
20. The non-transitory computer readable medium of claim 15 , wherein the steps further comprise:
accessing the row of the ET corresponding to the OT row identifier;
creating a second AAD based on at least some of the contents of the row other than the cipher text;
communicating the cipher text and the second AAD to a cryptography service;
responsive to the cryptography service returning the data entry, validating the encryption as successful; and
responsive to the cryptography service returning a decryption error, reporting that the encryption was unsuccessful or that a write attack has occurred.