public ISignatureUnion SignData()

in TPM Parser/Tpm2Lib/CryptoAsym.cs [309:363]
51 lines of code
8 McCabe index (conditional complexity)

        public ISignatureUnion SignData(byte[] data, TpmAlgId sigHash)
        {
            var rsaParams = PublicParms.parameters as RsaParms;
            if (rsaParams != null)
            {
                TpmAlgId sigScheme = rsaParams.scheme.GetUnionSelector();

                switch (sigScheme)
                {
                    case TpmAlgId.Rsassa:
                        {
                            if (sigHash == TpmAlgId.Null)
                            {
                                sigHash = (rsaParams.scheme as SigSchemeRsassa).hashAlg;
                            }
                            byte[] digest = CryptoLib.HashData(sigHash, data);
                            IBuffer sigBuffer = CryptographicEngine.SignHashedData(Key, CryptographicBuffer.CreateFromByteArray(digest));
                            byte[] sig;
                            CryptographicBuffer.CopyToByteArray(sigBuffer, out sig);
                            return new SignatureRsassa(sigHash, sig);
                        }
                    case TpmAlgId.Rsapss:
                        {
                            Globs.Throw<ArgumentException>("SignData(): PSS scheme is not supported");
                            return null;
                        }
                }
                Globs.Throw<ArgumentException>("Unsupported signature scheme");
                return null;
            }

            var eccParms = PublicParms.parameters as EccParms;
            if (eccParms != null)
            {
                if (eccParms.scheme.GetUnionSelector() != TpmAlgId.Ecdsa)
                {
                    Globs.Throw<ArgumentException>("Unsupported ECC sig scheme");
                    return null;
                }
                if (sigHash == TpmAlgId.Null)
                {
                    sigHash = (eccParms.scheme as SigSchemeEcdsa).hashAlg;
                }
                byte[] digest = CryptoLib.HashData(sigHash, data);
                IBuffer buf = CryptographicEngine.SignHashedData(Key, CryptographicBuffer.CreateFromByteArray(digest));
                byte[] sig;
                CryptographicBuffer.CopyToByteArray(buf, out sig);
                int len = sig.Length / 2;
                return new SignatureEcdsa(sigHash, Globs.CopyData(sig, 0, len), Globs.CopyData(sig, len, len));
            }

            // Should never be here
            Globs.Throw("VerifySignature: Unrecognized asymmetric algorithm");
            return null;
        } // SignData()