}
	if ctxt != nil {
		ctxts = append(ctxts, ctxt)
	}
	assert(len(ctxts) > 0)

	// Compute all hashes; hashes may differ across contexts due to different
	// unique IDs for Named types within the hasher.
	hashes := make([]string, len(ctxts))
	for i, ctxt := range ctxts {
		hashes[i] = ctxt.instanceHash(orig, targs)
	}

	// Record the result in all contexts.

	}
	if ctxt != nil {
		ctxts = append(ctxts, ctxt)
	}
	assert(len(ctxts) > 0)

	// Compute all hashes; hashes may differ across contexts due to different
	// unique IDs for Named types within the hasher.
	hashes := make([]string, len(ctxts))
	for i, ctxt := range ctxts {
		hashes[i] = ctxt.instanceHash(orig, targs)
	}

	// Record the result in all contexts.

If your database is stolen, the thief won't have your users' plaintext passwords, only the hashes.

So, the thief won't be able to try to use that password in another system (as many users use the same password everywhere, this would be dangerous).

## Install `passlib`

PassLib is a great Python package to handle password hashes.

It supports many secure hashing algorithms and utilities to work with them.

	}
	indexes := subTreeIndex(0, n, nil)
	hashes, err := r.ReadHashes(indexes)
	if err != nil {
		return Hash{}, err
	}
	if len(hashes) != len(indexes) {
		return Hash{}, fmt.Errorf("tlog: ReadHashes(%d indexes) = %d hashes", len(indexes), len(hashes))
	}
	hash, hashes := subTreeHash(0, n, hashes)
	if len(hashes) != 0 {
		panic("tlog: bad index math in TreeHash")
	}
	return hash, nil
}

            hasher.putInt(bytes.length);
            hasher.putBytes(bytes);
        }

        @Override
        public void putBytes(byte[] bytes, int off, int len) {
            hasher.putInt(len);
            hasher.putBytes(bytes, off, len);
        }

        @Override
        public void putHash(HashCode hashCode) {
            hasher.putInt(hashCode.length());
            hasher.putHash(hashCode);

    }

    @Override
    public String toString() {
        return primitiveType.toString(array);
    }

    @Override
    public void appendToHasher(Hasher hasher) {
        primitiveType.appendTo(hasher, array);
    }

    @Override
    public ValueSnapshot snapshot(@Nullable Object value, ValueSnapshotter snapshotter) {
        PrimitiveType valueType = PrimitiveType.maybeOfValue(value);

	priv, _ := GenerateKey(c, rand.Reader)

	hashed := []byte("testing")
	r, s, err := Sign(rand.Reader, priv, hashed)
	if err != nil {
		t.Errorf("error signing: %s", err)
		return
	}

	if !Verify(&priv.PublicKey, hashed, r, s) {
		t.Errorf("Verify failed")
	}

	hashed[0] ^= 0xff
	if Verify(&priv.PublicKey, hashed, r, s) {
		t.Errorf("Verify always works!")
	}
}

include::{snippetsPath}/workerApi/md5CustomTask/tests/md5Task1.out[]
----

In the `build/md5` directory, you should now see corresponding files with an `md5` extension containing MD5 hashes of the files from the `src` directory.
Notice that the task takes at least 9 seconds to run because it hashes each file one at a time (i.e., three files at ~3 seconds apiece).

[[converting_to_worker_api]]
=== Step 2. Convert to the Worker API

}

// Hash64 returns the i-th short hashed symbol's hash.
// Note: here i is the index of short hashed symbols, not all symbols
// (unlike other accessors).
func (r *Reader) Hash64(i uint32) uint64 {
	off := r.h.Offsets[BlkHash64] + uint32(i*Hash64Size)
	return r.uint64At(off)
}

// Hash returns a pointer to the i-th hashed symbol's hash.
// Note: here i is the index of hashed symbols, not all symbols

		return C._goboringcrypto_RSA_sign_pss_mgf1(key, &outLen, base(out), C.size_t(len(out)),
			base(hashed), C.size_t(len(hashed)), md, nil, C.int(saltLen))
	}) == 0 {
		return nil, fail("RSA_sign_pss_mgf1")
	}

	return out[:outLen], nil
}

func VerifyRSAPSS(pub *PublicKeyRSA, h crypto.Hash, hashed, sig []byte, saltLen int) error {
	md := cryptoHashToMD(h)
	if md == nil {