// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package rsa

var NonZeroRandomBytes = nonZeroRandomBytes
var EMSAPSSEncode = emsaPSSEncode
var EMSAPSSVerify = emsaPSSVerify

	//     maskedDB to zero.

	db[0] &= 0xff >> (8*emLen - emBits)

	// 12. Let EM = maskedDB || H || 0xbc.
	em[emLen-1] = 0xbc

	// 13. Output EM.
	return em, nil
}

func emsaPSSVerify(mHash, em []byte, emBits, sLen int, hash hash.Hash) error {
	// See RFC 8017, Section 9.1.2.

	hLen := hash.Size()
	if sLen == PSSSaltLengthEqualsHash {
		sLen = hLen
	}
	emLen := (emBits + 7) / 8

	if err != nil {
		t.Errorf("Error from emsaPSSEncode: %s\n", err)
	}
	if !bytes.Equal(encoded, expected) {
		t.Errorf("Bad encoding. got %x, want %x", encoded, expected)
	}

	if err = EMSAPSSVerify(hashed, encoded, 1023, len(salt), sha1.New()); err != nil {
		t.Errorf("Bad verification: %s", err)
	}
}

// TestPSSGolden tests all the test vectors in pss-vect.txt from