Property MaxKeyDerivationSpinCount

Namespace

DocWright.Core

Assembly

DocWright.Core.dll

MaxKeyDerivationSpinCount

Gets or sets the largest key-derivation iteration count ("spin count") DocWright will honour from an encrypted document, or null for unlimited.

This is the one limit that is on by default (DefaultMaxKeyDerivationSpinCount), because the value it caps is chosen by whoever wrote the file. ECMA-376 agile encryption stores its spin count in the plaintext EncryptionInfo descriptor, so a hostile document can simply ask for ten million rounds of SHA-512 and be honoured — a denial of service that needs no exploit, only a text editor. Every other limit here defaults to unlimited because its worst case is bounded by input size; this one is not.

A document declaring more than the cap raises ResourceLimitExceededException before any hashing is done, so the cost of rejecting it does not depend on the value it asked for.

public int? MaxKeyDerivationSpinCount { get; set; }

Property Value

int?

Exceptions

ArgumentOutOfRangeException

The value is not positive.