Patent ID: 11902417
Assignee: PII GUARD APS
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A computer-implemented method for performing format-preserving encryption and decryption of a data object in a first format, the data object having a variable size, the method utilizing an inner encryption algorithm which is capable of taking a variable size input and of outputting, as its output, an encrypted version of the variable size input, the method comprising:
converting the data object to obtain a converted version of the data object in a second format compatible with the inner encryption algorithm;
encrypting, by use of the inner encryption algorithm and at least one of a tweak and a key, the converted version of the data object to obtain an encrypted version of the data object;
deconverting the encrypted version of the data object to obtain a deconverted version of the encrypted version of the data object in a third format;
outputting the deconverted version of the encrypted version of the data object in the third format;
wherein the combined steps of converting, encrypting, and deconverting are format-preserving such that the first format has at least one predetermined attribute which is reproduced or retained in the third format;
wherein the output deconverted version of the encrypted version of the data object in the third format has a different size than the input data object in the first format;
wherein during decryption the data object in the third format is converted into the second format and subsequently decrypted using the same at least one of the tweak and the key used during encryption to obtain a decrypted data object which is subsequently deconverted into the first format.