public override byte[] SignData(byte[] data, HashAlgorithmName hashAlgorithm)
{
byte[] ieeeFormat = _key.SignData(data, hashAlgorithm);
Debug.Assert(ieeeFormat.Length % 2 == 0);
int segmentLength = ieeeFormat.Length / 2;
return(DerEncoder.ConstructSequence(
DerEncoder.SegmentedEncodeUnsignedInteger(ieeeFormat, 0, segmentLength),
DerEncoder.SegmentedEncodeUnsignedInteger(ieeeFormat, segmentLength, segmentLength)));
}
protected override PublicKey BuildPublicKey()
{
RSAParameters parameters = _key.ExportParameters(false);
byte[] rsaPublicKey = DerEncoder.ConstructSequence(
DerEncoder.SegmentedEncodeUnsignedInteger(parameters.Modulus),
DerEncoder.SegmentedEncodeUnsignedInteger(parameters.Exponent));
Oid oid = new Oid(Oids.RsaRsa);
// The OID is being passed to everything here because that's what
// X509Certificate2.PublicKey does.
return(new PublicKey(
oid,
// Encode the DER-NULL even though it is OPTIONAL, because everyone else does.
//
// This is due to one version of the ASN.1 not including OPTIONAL, and that was
// the version that got predominately implemented for RSA. Now it's convention.
new AsnEncodedData(oid, new byte[] { 0x05, 0x00 }),
new AsnEncodedData(oid, rsaPublicKey)));
}
private byte[] Encode(X509SignatureGenerator signatureGenerator, HashAlgorithmName hashAlgorithm)
{
// State validation should be runtime checks if/when this becomes public API
Debug.Assert(Subject != null);
Debug.Assert(PublicKey != null);
// Under a public API model we could allow these to be null for a self-signed case.
Debug.Assert(SerialNumber != null);
Debug.Assert(Issuer != null);
List <byte[][]> encodedFields = new List <byte[][]>();
byte version = Version;
if (version != 0)
{
byte[][] encodedVersion = DerEncoder.ConstructSegmentedSequence(
DerEncoder.SegmentedEncodeUnsignedInteger(new[] { version }));
encodedVersion[0][0] = DerSequenceReader.ContextSpecificConstructedTag0;
encodedFields.Add(encodedVersion);
}
encodedFields.Add(DerEncoder.SegmentedEncodeUnsignedInteger(SerialNumber));
// SignatureAlgorithm: Use the specified value, or ask the generator (without mutating the class)
byte[] signatureAlgorithm = SignatureAlgorithm ?? signatureGenerator.GetSignatureAlgorithmIdentifier(hashAlgorithm);
EncodingHelpers.ValidateSignatureAlgorithm(signatureAlgorithm);
encodedFields.Add(signatureAlgorithm.WrapAsSegmentedForSequence());
// For public API allowing self-sign ease-of-use, this could be (Issuer ?? Subject).
encodedFields.Add(Issuer.RawData.WrapAsSegmentedForSequence());
encodedFields.Add(
DerEncoder.ConstructSegmentedSequence(
EncodeValidityField(NotBefore, nameof(NotBefore)),
EncodeValidityField(NotAfter, nameof(NotAfter))));
encodedFields.Add(Subject.RawData.WrapAsSegmentedForSequence());
encodedFields.Add(PublicKey.SegmentedEncodeSubjectPublicKeyInfo());
// Issuer and Subject Unique ID values would go here, if they were supported.
if (Extensions.Count > 0)
{
Debug.Assert(version >= 2);
List <byte[][]> encodedExtensions = new List <byte[][]>(Extensions.Count);
// extensions[3] Extensions OPTIONAL
//
// Since this doesn't say IMPLICIT, it will look like
//
// A3 [length]
// 30 [length]
// First Extension
// Second Extension
// ...
// An interesting quirk of skipping null values here is that
// Extensions.Count == 0 => no extensions
// Extensions.ContainsOnly(null) => empty extensions list
HashSet <string> usedOids = new HashSet <string>(Extensions.Count);
foreach (X509Extension extension in Extensions)
{
if (extension == null)
{
continue;
}
if (!usedOids.Add(extension.Oid.Value))
{
throw new InvalidOperationException(
SR.GetString(SR.Cryptography_CertReq_DuplicateExtension, extension.Oid.Value));
}
encodedExtensions.Add(extension.SegmentedEncodedX509Extension());
}
byte[][] extensionField = DerEncoder.ConstructSegmentedSequence(
DerEncoder.ConstructSegmentedSequence(encodedExtensions));
extensionField[0][0] = DerSequenceReader.ContextSpecificConstructedTag3;
encodedFields.Add(extensionField);
}
return(DerEncoder.ConstructSequence(encodedFields));
}
public override byte[] GetSignatureAlgorithmIdentifier(HashAlgorithmName hashAlgorithm)
{
// If we ever support options in PSS (like MGF-2, if such an MGF is ever invented)
// Or, more reasonably, supporting a custom value for the salt size.
if (_padding != RSASignaturePadding.Pss)
{
throw new CryptographicException(SR.Cryptography_InvalidPaddingMode);
}
uint cbSalt;
string digestOid;
if (hashAlgorithm == HashAlgorithmName.SHA256)
{
cbSalt = 256 / 8;
digestOid = Oids.Sha256;
}
else if (hashAlgorithm == HashAlgorithmName.SHA384)
{
cbSalt = 384 / 8;
digestOid = Oids.Sha384;
}
else if (hashAlgorithm == HashAlgorithmName.SHA512)
{
cbSalt = 512 / 8;
digestOid = Oids.Sha512;
}
else
{
throw new ArgumentOutOfRangeException(
nameof(hashAlgorithm),
hashAlgorithm,
SR.Format(SR.Cryptography_UnknownHashAlgorithm, hashAlgorithm.Name));
}
// RSASSA-PSS-params comes from RFC 4055, section 3.1:
// https://tools.ietf.org/html/rfc4055#section-3.1
//
// RSASSA-PSS-params ::= SEQUENCE {
// hashAlgorithm [0] HashAlgorithm DEFAULT sha1Identifier,
// maskGenAlgorithm [1] MaskGenAlgorithm DEFAULT mgf1SHA1Identifier,
// saltLength [2] INTEGER DEFAULT 20,
// trailerField [3] INTEGER DEFAULT 1 }
//
// mgf1SHA1Identifier AlgorithmIdentifier ::= { id-mgf1, sha1Identifier }
// sha1Identifier AlgorithmIdentifier ::= { id-sha1, NULL }
// (and similar for SHA256/384/512)
//
// RFC 5754 says that the NULL for SHA2 (256/384/512) MUST be omitted
// (https://tools.ietf.org/html/rfc5754#section-2) (and that you MUST
// be able to read it even if someone wrote it down)
// Since we
// * don't support SHA-1 in this class
// * only support MGF-1
// * don't support the MGF PRF being different than hashAlgorithm
// * use saltLength==hashLength
// * don't allow custom trailer
// we don't have to worry about any of the DEFAULTs. (specify, specify, specify, omit).
byte[][] hashAlgorithmAlgId = DerEncoder.ConstructSegmentedSequence(
DerEncoder.SegmentedEncodeOid(digestOid));
byte[][] hashAlgorithmField = DerEncoder.ConstructSegmentedSequence(hashAlgorithmAlgId);
hashAlgorithmField[0][0] = DerSequenceReader.ContextSpecificConstructedTag0;
byte[][] maskGenField = DerEncoder.ConstructSegmentedSequence(
DerEncoder.ConstructSegmentedSequence(
DerEncoder.SegmentedEncodeOid(Oids.Mgf1),
hashAlgorithmAlgId));
maskGenField[0][0] = DerSequenceReader.ContextSpecificConstructedTag1;
byte[][] saltLengthField = DerEncoder.ConstructSegmentedSequence(
DerEncoder.SegmentedEncodeUnsignedInteger(cbSalt));
saltLengthField[0][0] = DerSequenceReader.ContextSpecificConstructedTag2;
return(DerEncoder.ConstructSequence(
DerEncoder.SegmentedEncodeOid(Oids.RsaSsaPss),
// RSASSA-PSS-params
DerEncoder.ConstructSegmentedSequence(
hashAlgorithmField,
maskGenField,
saltLengthField)));
}
