/*
   SSHSecure - a program to harden OpenSSH from defaults
   Copyright (C) 2020  Brent Saner

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

package sshkeys

import (
	"bytes"
	"crypto/cipher"
)

// EncryptedSSHKeyV1 represents an encrypted private key.
type EncryptedSSHKeyV1 struct {
	SSHKeyV1
	Crypt      SSHCrypt
	KDFOpts    SSHKDFOpts
	Passphrase []byte
}

// SSHCrypt contains the encryption object Stream, the cipher object Cipher, the ephemeral salt (CryptSalt), and the ephemeral key (CryptKey).
// the Cipher, and the stream.
type SSHCrypt struct {
	Stream     cipher.Stream
	Cipher     cipher.Block
	PrivateKey []byte  // encryption key
	CryptSalt  []byte  // ephemeral salt
	CryptKey   []byte  // ephemeral key (not really used)
}

// SSHKDFOpts contains a set of KDF options.
type SSHKDFOpts struct {
	Salt   []byte // Also referred to as IV (initialization vector). (https://en.wikipedia.org/wiki/Initialization_vector)
	Rounds uint32 // Also referred to as work factor.
}

// SSHKeyV1 represents a private key.
// We don't bother with the legacy (pre v1) keys. Sorry not sorry.
// Patch your shit.
type SSHKeyV1 struct {
	Magic      string
	DefKeyType string
	KDFName    string
	CipherName string
	KeySize    uint32
	Keys       []SSHPrivKey // 1 by default.
	Buffer     bytes.Buffer
}

// SSHPubKey contains the Public key of an SSH Keypair.
type SSHPubKey struct {
	KeyType string
	Key     interface{}
}

// SSHPrivKey contains the Private key of an SSH Keypair.
type SSHPrivKey struct {
	PublicKey *SSHPubKey
	BitSize   uint32
	BlockSize int
	Key       interface{}
	// ED25519 keys are actually "sk + pk", where sk is the secret key and pk is the pubkey.
	// We store that here.
	KeyAlt   []byte
	Checksum []byte
	Comment  string
}