SSHSecure/sshkeys/const.go

/*
   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

// Needed for V1 key format.
const (
	KeyV1Magic string = "openssh-key-v1"
)

// Defaults.
const (
	defCipher     string = CipherAes256Ctr
	defKeyType    string = KeyEd25519
	defKDF        string = KdfBcrypt
	defRounds     uint32 = 100
	defRSABitSize uint32 = 4096
	defSaltLen    int    = 16
	// bcrypt_pbkdf maxes out at 32 for private key gen (sk is actually 64; sk+pk)
	// But per OpenSSH code, we pass a key len of kdfKeyLen + len(salt)
	kdfKeyLen int = 32
	kdfSplit  int = 32
)

// Cipher names. I believe only AES256-CTR is supported upstream currently.
const (
	CipherNull      string = "none"
	CipherAes256Ctr string = "aes256-ctr"
)

var allowedCiphers = [...]string{CipherNull, CipherAes256Ctr}

// Key types.
const (
	KeyEd25519 string = "ssh-ed25519"
	KeyRsa     string = "ssh-rsa"
)

var allowedKeytypes = [...]string{KeyEd25519, KeyRsa}

// KDF names. I believe only bcrypt is supported upstream currently.
const (
	KdfNull   string = "none"
	KdfBcrypt string = "bcrypt"
)

var allowedKdfnames = [...]string{KdfNull, KdfBcrypt}

// Key lengths.
const (
	// ED25519 in OpenSSH uses a static key size of 64 bytes.
	ed25519Len uint32 = 64
)

// Key/Block sizes.
const (
	keyEd25519 uint32 = 32
	// Is this correct? Based on PROTOCOL.key's "padlen % 255", it seems to be.
	blockPad     uint32 = 255
	blockEd25519 uint32 = 16
	// Blocksize for RSA depends on key bits, I think.
	blockNull uint32 = 8
)