CryptoReplaceFfxFpeConfig(mapping=None, *, ignore_unknown_fields=False, **kwargs)Replaces an identifier with a surrogate using Format Preserving
Encryption (FPE) with the FFX mode of operation; however when used
in the ReidentifyContent API method, it serves the opposite
function by reversing the surrogate back into the original
identifier. The identifier must be encoded as ASCII. For a given
crypto key and context, the same identifier will be replaced with
the same surrogate. Identifiers must be at least two characters
long. In the case that the identifier is the empty string, it will
be skipped. See https://cloud.google.com/dlp/docs/pseudonymization
to learn more.
Note: We recommend using CryptoDeterministicConfig for all use cases which do not require preserving the input alphabet space and size, plus warrant referential integrity.
Attributes | |
|---|---|
| Name | Description |
crypto_key |
Required. The key used by the encryption algorithm. |
context |
The 'tweak', a context may be used for higher security since the same identifier in two different contexts won't be given the same surrogate. If the context is not set, a default tweak will be used. If the context is set but: 1. there is no record present when transforming a given value or 2. the field is not present when transforming a given value, a default tweak will be used. Note that case (1) is expected when an InfoTypeTransformation is applied to both structured and
non-structured ContentItem\ s. Currently, the referenced
field may be of value type integer or string.
The tweak is constructed as a sequence of bytes in big
endian byte order such that:
- a 64 bit integer is encoded followed by a single byte of
value 1
- a string is encoded in UTF-8 format followed by a single
byte of value 2
|
common_alphabet |
Common alphabets. |
custom_alphabet |
str
This is supported by mapping these to the alphanumeric characters that the FFX mode natively supports. This happens before/after encryption/decryption. Each character listed must appear only once. Number of characters must be in the range [2, 95]. This must be encoded as ASCII. The order of characters does not matter. The full list of allowed characters is: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz ```!@#$%^&*()_-+={[}]|:;"'<,>.?/ |
radix |
int
The native way to select the alphabet. Must be in the range [2, 95]. |
surrogate_info_type |
The custom infoType to annotate the surrogate with. This annotation will be applied to the surrogate by prefixing it with the name of the custom infoType followed by the number of characters comprising the surrogate. The following scheme defines the format: info_type_name(surrogate_character_count):surrogate For example, if the name of custom infoType is 'MY_TOKEN_INFO_TYPE' and the surrogate is 'abc', the full replacement value will be: 'MY_TOKEN_INFO_TYPE(3):abc' This annotation identifies the surrogate when inspecting content using the custom infoType `` SurrogateType __.
This facilitates reversal of the surrogate when it occurs in
free text.
In order for inspection to work properly, the name of this
infoType must not occur naturally anywhere in your data;
otherwise, inspection may find a surrogate that does not
correspond to an actual identifier. Therefore, choose your
custom infoType name carefully after considering what your
data looks like. One way to select a name that has a high
chance of yielding reliable detection is to include one or
more unicode characters that are highly improbable to exist
in your data. For example, assuming your data is entered
from a regular ASCII keyboard, the symbol with the hex code
point 29DD might be used like so: ⧝MY_TOKEN_TYPE
|
Classes
FfxCommonNativeAlphabet
FfxCommonNativeAlphabet(value)These are commonly used subsets of the alphabet that the FFX mode natively supports. In the algorithm, the alphabet is selected using the "radix". Therefore each corresponds to particular radix.