public override DSAParameters ExportParameters(bool includePrivateParameters)
{
SecKeyPair keys = GetKeys();
if (keys.PublicKey == null ||
(includePrivateParameters && keys.PrivateKey == null))
{
throw new CryptographicException(SR.Cryptography_OpenInvalidHandle);
}
DSAParameters parameters = new DSAParameters();
DerSequenceReader publicKeyReader =
Interop.AppleCrypto.SecKeyExport(keys.PublicKey, exportPrivate: false);
publicKeyReader.ReadSubjectPublicKeyInfo(ref parameters);
if (includePrivateParameters)
{
DerSequenceReader privateKeyReader =
Interop.AppleCrypto.SecKeyExport(keys.PrivateKey, exportPrivate: true);
privateKeyReader.ReadPkcs8Blob(ref parameters);
}
KeyBlobHelpers.TrimPaddingByte(ref parameters.P);
KeyBlobHelpers.TrimPaddingByte(ref parameters.Q);
KeyBlobHelpers.PadOrTrim(ref parameters.G, parameters.P.Length);
KeyBlobHelpers.PadOrTrim(ref parameters.Y, parameters.P.Length);
if (includePrivateParameters)
{
KeyBlobHelpers.PadOrTrim(ref parameters.X, parameters.Q.Length);
}
return parameters;
}
private byte[] ConvertToApiFormat(byte[] input, int inputOffset, int inputCount)
{
int size = GetSignatureFieldSize();
try
{
DerSequenceReader reader = new DerSequenceReader(input, inputOffset, inputCount);
byte[] rDer = reader.ReadIntegerBytes();
byte[] sDer = reader.ReadIntegerBytes();
byte[] response = new byte[2 * size];
CopySignatureField(rDer, response, 0, size);
CopySignatureField(sDer, response, size, size);
return response;
}
catch (InvalidOperationException e)
{
throw new CryptographicException(SR.Arg_CryptographyException, e);
}
}
internal static void ReadPkcs8Blob(this DerSequenceReader reader, ref ECParameters parameters)
{
// OneAsymmetricKey ::= SEQUENCE {
// version Version,
// privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
// privateKey PrivateKey,
// attributes [0] Attributes OPTIONAL,
// ...,
// [[2: publicKey [1] PublicKey OPTIONAL ]],
// ...
// }
//
// PrivateKeyInfo ::= OneAsymmetricKey
//
// PrivateKey ::= OCTET STRING
int version = reader.ReadInteger();
// We understand both version 0 and 1 formats,
// which are now known as v1 and v2, respectively.
if (version > 1)
{
throw new CryptographicException();
}
{
// Ensure we're reading EC Public Key (well, Private, but the OID says Public)
DerSequenceReader algorithm = reader.ReadSequence();
string algorithmOid = algorithm.ReadOidAsString();
if (algorithmOid != s_idEcPublicKey.Value)
{
throw new CryptographicException();
}
}
byte[] privateKeyBlob = reader.ReadOctetString();
try
{
// ECPrivateKey{CURVES:IOSet} ::= SEQUENCE {
// version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
// privateKey OCTET STRING,
// parameters [0] Parameters{{IOSet}} OPTIONAL,
// publicKey [1] BIT STRING OPTIONAL
// }
DerSequenceReader keyReader = new DerSequenceReader(privateKeyBlob);
version = keyReader.ReadInteger();
// We understand the version 1 format
if (version > 1)
{
throw new CryptographicException();
}
parameters.D = keyReader.ReadOctetString();
// Check for context specific 0
const byte ConstructedContextSpecific =
DerSequenceReader.ContextSpecificTagFlag | DerSequenceReader.ConstructedFlag;
const byte ConstructedContextSpecific0 = (ConstructedContextSpecific | 0);
const byte ConstructedContextSpecific1 = (ConstructedContextSpecific | 1);
if (keyReader.PeekTag() != ConstructedContextSpecific0)
{
throw new CryptographicException();
}
// Parameters ::= CHOICE {
// ecParameters ECParameters,
// namedCurve CURVES.&id({ CurveNames}),
// implicitlyCA NULL
// }
DerSequenceReader parametersReader = keyReader.ReadSequence();
if (parametersReader.PeekTag() != (int)DerSequenceReader.DerTag.ObjectIdentifier)
{
throw new PlatformNotSupportedException(SR.Cryptography_ECC_NamedCurvesOnly);
}
parameters.Curve = ECCurve.CreateFromValue(parametersReader.ReadOidAsString());
// Check for context specific 1
if (keyReader.PeekTag() != ConstructedContextSpecific1)
{
throw new CryptographicException();
}
keyReader = keyReader.ReadSequence();
byte[] encodedPoint = keyReader.ReadBitString();
ReadEncodedPoint(encodedPoint, ref parameters);
// We don't care about the rest of the blob here, but it's expected to not exist.
}
finally
{
Array.Clear(privateKeyBlob, 0, privateKeyBlob.Length);
}
}
internal DerSequenceReader ReadSequence()
{
// DerSequenceReader wants to read its own tag, so don't EatTag here.
CheckTag(DerTag.Sequence, _data, _position);
int lengthLength;
int contentLength = ScanContentLength(_data, _position + 1, out lengthLength);
int totalLength = 1 + lengthLength + contentLength;
DerSequenceReader reader = new DerSequenceReader(_data, _position, totalLength);
_position += totalLength;
return reader;
}
/// <summary>
/// Convert Der format of (r, s) to Ieee1363 format
/// </summary>
public static byte[] ConvertDerToIeee1363(byte[] input, int inputOffset, int inputCount, int fieldSizeBits)
{
int size = BitsToBytes(fieldSizeBits);
try
{
DerSequenceReader reader = new DerSequenceReader(input, inputOffset, inputCount);
byte[] rDer = reader.ReadIntegerBytes();
byte[] sDer = reader.ReadIntegerBytes();
byte[] response = new byte[2 * size];
CopySignatureField(rDer, response, 0, size);
CopySignatureField(sDer, response, size, size);
return response;
}
catch (InvalidOperationException e)
{
throw new CryptographicException(SR.Arg_CryptographyException, e);
}
}