// Convert an ASN.1 buffer into DSA public parameters.
internal void ASN1ToPublic(ASN1Parser parser)
{
parser = parser.GetSequence();
if (parser.Type == ASN1Type.Sequence)
{
// This looks like it may be a "SubjectPublicKeyInfo"
// from an X.509 certificate. Validate the algorithm ID.
ASN1Parser alg = parser.GetSequence();
byte[] objid = alg.GetObjectIdentifier();
if (!ASN1Parser.IsObjectID(objid, dsaID))
{
throw new CryptographicException
(_("Crypto_InvalidASN1"));
}
// Get the common P, Q, and G parameters.
ASN1Parser algParams = alg.GetSequence();
P = algParams.GetBigInt();
Q = algParams.GetBigInt();
G = algParams.GetBigInt();
algParams.AtEnd();
alg.AtEnd();
// Get the public key information (Y).
ASN1Parser bitString = parser.GetBitStringContents();
Y = bitString.GetBigInt();
bitString.AtEnd();
parser.AtEnd();
}
else
{
// This looks like a bare list of DSA parameters.
P = parser.GetBigInt();
Q = parser.GetBigInt();
G = parser.GetBigInt();
Y = parser.GetBigInt();
if (!parser.IsAtEnd())
{
// It looks like we have private DSA parameters also.
J = parser.GetBigInt();
X = parser.GetBigInt();
Seed = parser.GetBigInt();
Counter = parser.GetInt32();
}
parser.AtEnd();
}
}
// Convert an ASN.1 buffer into RSA public parameters.
internal void ASN1ToPublic(ASN1Parser parser)
{
parser = parser.GetSequence();
if (parser.Type == ASN1Type.Sequence)
{
// This looks like it may be a "SubjectPublicKeyInfo"
// from an X.509 certificate. Validate the algorithm ID.
ASN1Parser alg = parser.GetSequence();
byte[] objid = alg.GetObjectIdentifier();
if (!ASN1Parser.IsObjectID(objid, rsaID))
{
throw new CryptographicException
(_("Crypto_InvalidASN1"));
}
alg.GetNull();
alg.AtEnd();
// Get the public key information.
ASN1Parser bitString = parser.GetBitStringContents();
ASN1Parser inner = bitString.GetSequence();
Modulus = inner.GetBigInt();
Exponent = inner.GetBigInt();
inner.AtEnd();
bitString.AtEnd();
parser.AtEnd();
}
else if (parser.Type == ASN1Type.Integer &&
parser.Length == 1)
{
// This looks like a list of private RSA parameters.
ASN1ToPrivate(parser);
}
else
{
// This looks like a bare list of RSA parameters.
Modulus = parser.GetBigInt();
Exponent = parser.GetBigInt();
parser.AtEnd();
}
}
