DVFieldCipher class
AES-256-GCM over a server-held keyring, for model fields stored in a database.
Separate from DVAppKeyCipher because the threat models do not overlap. That key belongs to one device and is held by the OS key store of the person using it; this one belongs to a server process and protects rows that many people's requests read. Handing either job to the other key is how a device key ends up in a shared database, or a server key in an application bundle.
The column and the model name are authenticated alongside the value, so a ciphertext copied into a different column, or into the same column of a different model's table, fails to open rather than decrypting into a place it was never written for. It does not bind the row: an attacker who can write to the database can still swap two rows' values within one column, and stopping that needs a per-row identity that survives an update, which a generated model does not currently have.
Constructors
- DVFieldCipher(DVFieldKeyring keyring, {Random? random})
-
randomis for tests that need a repeatable nonce, and for nothing else. - DVFieldCipher.secure(DVFieldKeyring keyring)
- The cipher an application uses: nonces from the platform's secure source, with no way to ask for anything else.
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- keyring → DVFieldKeyring
-
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
decrypt(
{required String model, required String field, required String ciphertext}) → String - Opens a value written by encrypt for the same model and column.
-
encrypt(
{required String model, required String field, required String plaintext}) → String -
Seals
plaintextasdvf1:<key id>:<base64 nonce||ciphertext>. -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited