/// <summary>
/// Determines until when the signature will be valid if ever.
/// The date may lay in the past if it is not valid any more.
/// </summary>
/// <param name="objectData">Data to check against.</param>
/// <param name="certificateStorage">Storage of certificates.</param>
/// <param name="date">Date at which the signers certificate must be valid.</param>
/// <returns>Date after which the signature expires.</returns>
public DateTime ExpectedValidUntil(byte[] objectData, ICertificateStorage certificateStorage, DateTime date)
{
if (certificateStorage.Has(SignerId))
{
Certificate signer = certificateStorage.Get(SignerId);
if (signer.VerifySimple(AssmblySigningData(objectData), Data))
{
if (signer.Validate(certificateStorage, date) == CertificateValidationResult.Valid)
{
return ValidUntil;
}
else
{
return DateTime.MinValue;
}
}
else
{
return DateTime.MinValue;
}
}
else
{
return DateTime.MinValue;
}
}
/// <summary>
/// Verifies a signature.
/// </summary>
/// <remarks>
/// Also check the validity of the signer's certificate.
/// </remarks>
/// <param name="objectData">Data to check against.</param>
/// <param name="certificateStorage">Storage of certificates.</param>
/// <param name="date">Date at which the signature must be valid.</param>
/// <returns>Is the signature valid.</returns>
public CertificateValidationResult Verify(byte[] objectData, ICertificateStorage certificateStorage, DateTime date)
{
if (ValidFrom.Date <= date.Date)
{
if (ValidUntil.Date >= date.Date)
{
if (certificateStorage.Has(SignerId))
{
Certificate signer = certificateStorage.Get(SignerId);
if (signer.VerifySimple(AssmblySigningData(objectData), Data))
{
if (signer.Validate(certificateStorage, date) == CertificateValidationResult.Valid)
{
return CertificateValidationResult.Valid;
}
else
{
return CertificateValidationResult.SignerInvalid;
}
}
else
{
return CertificateValidationResult.SignatureDataInvalid;
}
}
else
{
return CertificateValidationResult.UnknownSigner;
}
}
else
{
return CertificateValidationResult.Outdated;
}
}
else
{
return CertificateValidationResult.NotYetValid;
}
}
/// <summary>
/// Determines until when the signature will become valid.
/// </summary>
/// <param name="certificateStorage">Storage of certificates.</param>
/// <param name="date">Date at which the signers certificate must be valid.</param>
/// <returns>Date after which the signature expires.</returns>
public DateTime ExpectedValidFrom(byte[] objectData, ICertificateStorage certificateStorage)
{
if (certificateStorage.Has(SignerId))
{
Certificate signer = certificateStorage.Get(SignerId);
if (signer.VerifySimple(AssmblySigningData(objectData), Data))
{
return ValidFrom;
}
else
{
return DateTime.MaxValue;
}
}
else
{
return DateTime.MaxValue;
}
}