Andy LoPresto created NIFI-7668:
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Summary: Add configurable PBE AEAD algorithms to flow encryption
Key: NIFI-7668
URL: https://issues.apache.org/jira/browse/NIFI-7668
Project: Apache NiFi
Issue Type: Improvement
Components: Configuration, Core Framework
Affects Versions: 1.11.4
Reporter: Andy LoPresto
Assignee: Andy LoPresto
NIFI-7638 introduced a single custom PBE algorithm (pair for 128/256-bit keys)
which provided AEAD semantics using Argon2 for key derivation and AES-G/CM for
authenticated encryption. This solution was a stop gap to allow more robust
encryption than AES-CBC without modifying the {{EncryptionMethod}}, which is a
single definition of encryption algorithms and (supposed) KDFs referenced
throughout the codebase.
Introducing changes to {{EncryptionMethod}} would have required massive
regression testing, further support changes to {{EncryptContent}}, encrypted
repository implementations, multiple documentation changes, etc. This change
allows for a single custom algorithm which makes reasonable default decisions
around cost parameters and algorithm selection, meeting the user requirements
without demanding far-reaching changes.
Instead, this ticket proposes an intentional enhancement to the
{{nifi.properties}} structure to add a new {{nifi.sensitive.props.kdf}}
property to complement the existing {{nifi.sensitive.props.algorithm}}
property. This will allow arbitrary secure KDFs (Argon2, bcrypt, scrypt,
PBKDF2) to be specified with custom cost parameters and combined with any keyed
encryption algorithm (AES-CBC, AES-G/CM, AES-CTR) to derive a key and encrypt
the flow sensitive properties.
For backward compatibility, as this is likely to go in a 1.13.0 release, not a
major release, an existing {{nifi.properties}} file will work fine. If the
{{nifi.sensitive.props.kdf}} value is not specified, it will not be used, which
is acceptable for all existing {{EncryptionMethod}} values which are already
supported by the {{StringEncryptor}} class. If a _new_ algorithm is specified
(e.g. one of the raw keyed algorithms), the KDF will need to be present and
will be checked for appropriateness and cost parameter validity. No default
value changes will be made. Thus, this will only affect security-conscious
users who explicitly change those values to reflect more robust key derivation
and data protection algorithm choices.
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