Database encryption to provide write protection
View Patent ↗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 write request to a database, the write request specifying an original table (OT) name of one of a plurality of tables in the database, a column name of one of a plurality of columns in the OT, and a data entry to be written;
accessing an OT primary key where the data entry is to be written, the OT primary key identifying a row of the OT;
writing the data entry to a first location in the OT corresponding to the column name and the row corresponding to the OT primary key;
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT primary key;
obtaining a cipher text based on the data entry and the AAD;
writing the cipher text to a second location in a cipher text column of an encrypted table (ET) different than the OT, the second location being in a row of the ET where the row also stores the OT name, the column name, and the OT primary key;
accessing the row of the ET corresponding to the OT primary key;
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.
2. The computer implemented method of claim 1 , wherein the write request further comprises the OT primary key, and accessing the primary key of the original table comprises:
extracting the OT primary key from the write request.
3. The computer implemented method of claim 1 , wherein accessing the primary key of the original table comprises:
initiating a transaction state with the database creating a new primary key in the original table and preventing the new primary key from being used outside of the transaction;
responsive to the data entry being written to the first location and the cipher text being written to the second location, exiting the transaction state, thereby allowing free use of the new primary key.
4. 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.
5. The computer implemented method of claim 1 , wherein the AAD further comprises additional information stored in the database but not in the encrypted table.
6. The computer implemented method of claim 1 , further comprising:
deleting the data entry from the original table.
7. The computer implemented method of claim 1 , wherein writing the cipher text to the second location further comprises:
writing the original table name to an original table column in the row of the ET;
writing the column name to a column column in the row of the ET; and
writing the OT primary key to an OT primary key column in the row of the ET.
8. The computer implemented method of claim 1 , wherein writing the cipher text to the second location further comprises:
writing to a key revision column at least one of an identifier for the cryptographic key and an identifier of a generation of a cryptographic key.
9. A computer implemented method comprising:
receiving a write request to a database, the write request including an original table name of one of a plurality of tables in the database, a column name of one of a plurality of columns in the original table, and a data entry to be written;
accessing an original table (OT) primary key, the OT primary key identifying a row of the OT;
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT primary key;
obtaining a cipher text based on the data entry and the AAD; and
writing the cipher text to a location in a cipher text column of an encrypted table (ET) different than the OT, the second location being in a row of the ET where the row also stores the OT name, the column name, and the OT primary key,
wherein the data entry is not written to the OT;
accessing the row of the ET corresponding to the OT primary key;
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.
10. 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 write request to a database, the write request specifying an original table (OT) name of one of a plurality of tables in the database, a column name of one of a plurality of columns in the OT, and a data entry to be written;
accessing an OT primary key where the data entry is to be written, the OT primary key identifying a row of the OT;
writing the data entry to a first location in the OT corresponding to the column name and the row corresponding to the OT primary key;
preparing an additional authenticated data (AAD) comprising the OT name, the column name, and the OT primary key;
obtaining a cipher text based on the data entry and the AAD;
writing the cipher text to a second location in a cipher text column of an encrypted table (ET) different than the OT, the second location being in a row of the ET where the row also stores the OT name, the column name, and the OT primary key;
accessing the row of the ET corresponding to the OT primary key;
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.
11. The non-transitory computer readable medium of claim 10 , wherein the write request further comprises the OT primary key, and accessing the primary key of the original table comprises:
extracting the OT primary key from the write request.
12. The non-transitory computer readable medium of claim 10 , wherein accessing the primary key of the original table comprises:
initiating a transaction state with the database creating a new primary key in the original table and preventing the new primary key from being used outside of the transaction; and
responsive to the data entry being written to the first location and the cipher text being written to the second location, exiting the transaction state, thereby allowing free use of the new primary key.
13. The non-transitory computer readable medium of claim 10 , 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.
14. The non-transitory computer readable medium of claim 10 , wherein the AAD further comprises additional information stored in the database but not in the encrypted table.
15. The non-transitory computer readable medium of claim 10 , further comprising:
deleting the data entry from the original table.
16. The non-transitory computer readable medium of claim 10 , wherein writing the cipher text to the second location further comprises:
writing the original table name to an original table column in the row of the ET;
writing the column name to a column column in the row of the ET; and
writing the OT primary key to an OT primary key column in the row of the ET.
17. The non-transitory computer readable medium of claim 10 , wherein writing the cipher text to the second location further comprises:
writing to a key revision column at least one of an identifier for the cryptographic key and an identifier of a generation of a cryptographic key.