private static bool TryDecode(
ReadOnlyMemory <byte> source,
bool ownsMemory,
out Rfc3161TstInfo tstInfo,
out int bytesConsumed,
out byte[] copiedBytes)
{
// https://tools.ietf.org/html/rfc3161#section-2.4.2
// The eContent SHALL be the DER-encoded value of TSTInfo.
AsnReader reader = new AsnReader(source, AsnEncodingRules.DER);
try
{
ReadOnlyMemory <byte> firstElement = reader.PeekEncodedValue();
if (ownsMemory)
{
copiedBytes = null;
}
else
{
// Copy the data so no ReadOnlyMemory values are pointing back to user data.
copiedBytes = firstElement.ToArray();
firstElement = copiedBytes;
}
Rfc3161TstInfo parsedInfo = AsnSerializer.Deserialize <Rfc3161TstInfo>(
firstElement,
AsnEncodingRules.DER);
// The deserializer doesn't do bounds checks.
// Micros and Millis are defined as (1..999)
// Seconds doesn't define that it's bounded by 0,
// but negative accuracy doesn't make sense.
//
// (Reminder to readers: a null int? with an inequality operator
// has the value false, so if accuracy is missing, or millis or micro is missing,
// then the respective checks return false and don't throw).
if (parsedInfo.Accuracy?.Micros > 999 ||
parsedInfo.Accuracy?.Micros < 1 ||
parsedInfo.Accuracy?.Millis > 999 ||
parsedInfo.Accuracy?.Millis < 1 ||
parsedInfo.Accuracy?.Seconds < 0)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
tstInfo = parsedInfo;
bytesConsumed = firstElement.Length;
return(true);
}
catch (CryptographicException)
{
tstInfo = null;
bytesConsumed = 0;
copiedBytes = null;
return(false);
}
}
private Rfc3161TimestampTokenInfo(byte[] copiedBytes, Rfc3161TstInfo tstInfo)
{
_encodedBytes = copiedBytes;
_parsedData = tstInfo;
}
private static byte[] Encode(
Oid policyId,
Oid hashAlgorithmId,
ReadOnlyMemory <byte> messageHash,
ReadOnlyMemory <byte> serialNumber,
DateTimeOffset timestamp,
bool isOrdering,
long?accuracyInMicroseconds,
ReadOnlyMemory <byte>?nonce,
ReadOnlyMemory <byte>?tsaName,
X509ExtensionCollection?extensions)
{
if (policyId == null)
{
throw new ArgumentNullException(nameof(policyId));
}
if (hashAlgorithmId == null)
{
throw new ArgumentNullException(nameof(hashAlgorithmId));
}
var tstInfo = new Rfc3161TstInfo
{
// The only legal value as of 2017.
Version = 1,
Policy = policyId,
MessageImprint =
{
HashAlgorithm =
{
Algorithm = hashAlgorithmId,
Parameters = AlgorithmIdentifierAsn.ExplicitDerNull,
},
HashedMessage = messageHash,
},
SerialNumber = serialNumber,
GenTime = timestamp,
Ordering = isOrdering,
Nonce = nonce,
};
if (accuracyInMicroseconds != null)
{
tstInfo.Accuracy = new Rfc3161Accuracy(accuracyInMicroseconds.Value);
}
if (tsaName != null)
{
tstInfo.Tsa = GeneralNameAsn.Decode(tsaName.Value, AsnEncodingRules.DER);
}
if (extensions != null)
{
tstInfo.Extensions = extensions.OfType <X509Extension>().
Select(ex => new X509ExtensionAsn(ex)).ToArray();
}
using (AsnWriter writer = new AsnWriter(AsnEncodingRules.DER))
{
tstInfo.Encode(writer);
return(writer.Encode());
}
}