// claims are applied in reverse precedence
	return jwt.Signed(j.signer).
		Claims(privateClaims).
		Claims(claims).
		Claims(&jwt.Claims{
			Issuer: j.iss,
		}).
		CompactSerialize()
}

// JWTTokenAuthenticator authenticates tokens as JWT tokens produced by JWTTokenGenerator
// Token signatures are verified using each of the given public keys until one works (allowing key rotation)