public static bool PssVerify()

in TPM Parser/Tpm2Lib/CryptoLib.cs [422:496]
47 lines of code
8 McCabe index (conditional complexity)

        public static bool PssVerify(byte[] m, byte[] em, int sLen, int emBits, TpmAlgId hashAlg)
        {
            var emLen = (int)Math.Ceiling(1.0 * emBits / 8);
            int hLen = CryptoLib.DigestSize(hashAlg);
            // 1 - Skip
            // 2
            byte[] mHash = TpmHash.FromData(hashAlg, m);

            // 3
            if (emLen < hLen + sLen + 2)
            {
                return false;
            }

            // 4
            if (em[em.Length - 1] != 0xbc)
            {
                return false;
            }

            // 5
            byte[] maskedDB = Globs.CopyData(em, 0, emLen - hLen - 1);
            byte[] h = Globs.CopyData(em, emLen - hLen - 1, hLen);

            // 6
            int numZeroBits = 8 * emLen - emBits;
            // First numZero bits is zero in mask
            byte mask = GetByteMask(numZeroBits);
            if ((maskedDB[0] & mask) != maskedDB[0])
            {
                return false;
            }

            // 7
            byte[] dbMask = CryptoLib.MGF(h, emLen - hLen - 1, hashAlg);

            // 8
            byte[] db = XorEngine.Xor(maskedDB, dbMask);

            // 9
            int numZeroBits2 = 8 * emLen - emBits;
            byte mask2 = GetByteMask(numZeroBits2);
            db[0] &= mask2;

            // 10
            for (int j = 0; j < emLen - hLen - sLen - 2; j++)
            {
                if (db[j] != 0)
                {
                    return false;
                }

            }
            if (db[emLen - hLen - sLen - 1 - 1] != 1)
            {
                return false;
            }

            // 11
            byte[] salt = Globs.CopyData(db, db.Length - sLen);

            // 12
            byte[] mPrime = Globs.Concatenate(new[] { Globs.ByteArray(8, 0), mHash, salt});

            // 13
            byte[] hPrime = TpmHash.FromData(hashAlg, mPrime);

            // 14
            bool match = Globs.ArraysAreEqual(h, hPrime);
            if (match == false)
            {
                return false;
            }
            return true;
        }