OpenBSD is back! Now with GnuPG

Another friend, another animal, a gnu.

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And yes, this gnu is special. First of all is a capital letters GNU, he likes free software, and our special one also like electronic music. But not only free software, he is specialized also in privacy, he can be the guardian of our privacy! Because one of the hottest applications in this wonderful GNU world is GnuPG a mature piece of open source software:

GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP). GnuPG allows you to encrypt and sign your data and communications; it features a versatile key management system, along with access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. GnuPG also provides support for S/MIME and Secure Shell (ssh).
Since its introduction in 1997, GnuPG is Free Software (meaning that it respects your freedom). It can be freely used, modified and distributed under the terms of the GNU General Public License .

OpenBSD want your pretty good privacy

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Speaking about pretty obviously my first tough is a wonderful woman. And doing a simple association my connected brain has elaborated this image, a wonderful Julia Roberts singing a song in the set's bathroom of pretty woman, do you remember it?
But you have to understand that pretty have to be also our privacy in a interconnected world, the Internet. Every single man and woman (child i don't think that have to use it) in the world have access to the Internet, but only a little part know how to protect him/her privacy from what we've previously named the privacy cannibals.
Today we add another friend to our great guarantees of privacy, a cool dude that follow the OpenPGP standard that you can freely study reading the RFC 4880.

Create the perfect pgp keypair with OpenBSD

Ok let's go deep and start the configuration of our GNU PGP.
Install the software from ports repository:

$ rm -rf .gnupg
$ mkdir .gnupg
$ chmod -R go-rwx .gnupg
$ doas pkg_add -U gnupg-2.1.23

We've deleted possible previous gnupg configuration, recreate the user directory of the program, assign to it the correct permissions and install the version 2 of the gnupg collection.

$ cat << EOF > ~/.gnupg/gpg.conf
use-agent
personal-cipher-preferences AES256 AES192 AES CAST5
personal-digest-preferences SHA512 SHA384 SHA256 SHA224
default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed
cert-digest-algo SHA512
s2k-digest-algo SHA512
s2k-cipher-algo AES256
charset utf-8
fixed-list-mode
no-comments
no-emit-version
keyid-format 0xlong
list-options show-uid-validity
verify-options show-uid-validity
with-fingerprint
EOF

Create the bootstrap gpg configuration file in our previously created directory.

$ gpg2 --full-generate-key
gpg (GnuPG) 2.1.23; Copyright (C) 2017 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Please select what kind of key you want:
   (1) RSA and RSA (default)
   (2) DSA and Elgamal
   (3) DSA (sign only)
   (4) RSA (sign only)
Your selection? 4
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 0
Key does not expire at all
Is this correct? (y/N) y

GnuPG needs to construct a user ID to identify your key.

Real name: No Place No Address
Email address: [email protected]
Comment: No Place No Address
You selected this USER-ID:
    "No Place No Address (No Place No Address) <[email protected]>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
gpg: /home/taglio/.gnupg/trustdb.gpg: trustdb created
gpg: key 0xAD8E487FF2F05FDE marked as ultimately trusted
gpg: directory '/home/taglio/.gnupg/openpgp-revocs.d' created
gpg: revocation certificate stored as '/home/taglio/.gnupg/openpgp-revocs.d/6ACFBE8E6C24EA903F5B9F49AD8E487FF2F05FDE.rev'
public and secret key created and signed.

Note that this key cannot be used for encryption.  You may want to use
the command "--edit-key" to generate a subkey for this purpose.
pub   rsa4096/0xAD8E487FF2F05FDE 2018-02-23 [SC]
      Key fingerprint = 6ACF BE8E 6C24 EA90 3F5B  9F49 AD8E 487F F2F0 5FDE
uid                              No Place No Address (No Place No Address) <[email protected]>

We're creating a no expiring master key in our home directory, using RSA sign only option with the maximum key size that is 4096 bits . In gpg every key is associated with a user ID, in our case is [email protected]. Remember to use a strong unpredictable password and to anote and store it in a secure place (¿do you remember what is a pen and what is a paper?). It's important for the rest of the configuration know the result keyid, for our case is 0xAD8E487FF2F05FDE. Go ahead with the deep configuration:

$ gpg2 --expert --edit-key 0xAD8E487FF2F05FDE
gpg (GnuPG) 2.1.23; Copyright (C) 2017 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Secret key is available.

gpg: checking the trustdb
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
sec  rsa4096/0xAD8E487FF2F05FDE
     created: 2018-02-23  expires: never       usage: SC  
     trust: ultimate      validity: ultimate
[ultimate] (1). No Place No Address (No Place No Address) <[email protected]>

gpg> addkey
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
  (10) ECC (sign only)
  (11) ECC (set your own capabilities)
  (12) ECC (encrypt only)
  (13) Existing key
Your selection? 6
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

sec  rsa4096/0xAD8E487FF2F05FDE
     created: 2018-02-23  expires: never       usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0x3C423C42DE438790
     created: 2018-02-23  expires: never       usage: E   
[ultimate] (1). No Place No Address (No Place No Address) <[email protected]>

Now we've entered in the gpg shell! Look at the new prompt gpg>. From there we can access to all the possible commands of our GNU privacy suite.

gpg> addkey
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
Your selection? 6
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

sec  rsa4096/0x17B9BD907F897DD1
     created: 2018-02-23  expires: never       usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xEF0998EA8BB3F32B
     created: 2018-02-23  expires: never       usage: E   
[ultimate] (1). No Place No Address (No Place No Address) <[email protected]>

We've created a key that depend from our master key, selecting RSA for encrypt only. This is our encryption key.

gpg>addkey
addkey
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
  (10) ECC (sign only)
  (11) ECC (set your own capabilities)
  (12) ECC (encrypt only)
  (13) Existing key
Your selection? 4
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

sec  rsa4096/0xAD8E487FF2F05FDE
     created: 2018-02-23  expires: never       usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0x3C423C42DE438790
     created: 2018-02-23  expires: never       usage: E   
ssb  rsa4096/0x5DC3DAEF3359F361
     created: 2018-02-23  expires: never       usage: S   
[ultimate] (1). No Place No Address (No Place No Address) <[email protected]>

Now we've created another sub key. This time to sign only, always with the RSA protocol. His size is as usual 4096 bits.

addkey
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
  (10) ECC (sign only)
  (11) ECC (set your own capabilities)
  (12) ECC (encrypt only)
  (13) Existing key
Your selection? 8

Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Sign Encrypt 

   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished

Your selection? S

Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Encrypt 

   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished

Your selection? E

Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: 

   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished

Your selection? A

Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Authenticate 

   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished

Your selection? Q
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 4096
Requested keysize is 4096 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

sec  rsa4096/0xAD8E487FF2F05FDE
     created: 2018-02-23  expires: never       usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0x3C423C42DE438790
     created: 2018-02-23  expires: never       usage: E   
ssb  rsa4096/0x5DC3DAEF3359F361
     created: 2018-02-23  expires: never       usage: S   
ssb  rsa4096/0x52E923E51A16A5E9
     created: 2018-02-23  expires: never       usage: A   
[ultimate] (1). No Place No Address (No Place No Address) <[email protected]>
gpg> save

At last we've created a sub key for authentication purpose. Thanks to the --expert option that we've used we can edit like a pro our last RSA key using the (8) option in our gpg shell. Follow the commands and we've finished! Don't leave the last save if you don't launch it you will loose all! Review the created keys with:

$ gpg2 --list-secret-keys
/home/taglio/.gnupg/pubring.kbx
-------------------------------
sec   rsa4096/0xAD8E487FF2F05FDE 2018-02-23 [SC]
      Key fingerprint = 6ACF BE8E 6C24 EA90 3F5B  9F49 AD8E 487F F2F0 5FDE
uid                   [ultimate] No Place No Address (No Place No Address) <[email protected]>
ssb   rsa4096/0x3C423C42DE438790 2018-02-23 [E]
ssb   rsa4096/0x5DC3DAEF3359F361 2018-02-23 [S]
ssb   rsa4096/0x52E923E51A16A5E9 2018-02-23 [A]

Export to an encrypted USB stick

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Ok, we've have created our 4 gpg2 keys, one master with 3 slaves, encryption, sign and authentication .
Let's prepare an encrypted fresh USB stick to backup them!

$ doas su
#fdisk -yig sd2 
Writing MBR at offset 0.
Writing GPT.
# disklabel -E sd2
Label editor (enter '?' for help at any prompt)
> ?
Available commands:
 ? | h    - show help                 n [part] - set mount point
 A        - auto partition all space  p [unit] - print partitions
 a [part] - add partition             q        - quit & save changes
 b        - set OpenBSD boundaries    R [part] - resize auto allocated partition
 c [part] - change partition size     r        - display free space
 D        - reset label to default    s [path] - save label to file
 d [part] - delete partition          U        - undo all changes
 e        - edit drive parameters     u        - undo last change
 g [d|u]  - [d]isk or [u]ser geometry w        - write label to disk
 i        - modify disklabel UID      X        - toggle expert mode
 l [unit] - print disk label header   x        - exit & lose changes
 M        - disklabel(8) man page     z        - delete all partitions
 m [part] - modify partition

Suffixes can be used to indicate units other than sectors:
 'b' (bytes), 'k' (kilobytes), 'm' (megabytes), 'g' (gigabytes) 't' (terabytes)
 'c' (cylinders), '%' (% of total disk), '&' (% of free space).
Values in non-sector units are truncated to the nearest cylinder boundary.
> l
# /dev/rsd2c:
type: SCSI
disk: SCSI disk
label: Flash Disk      
duid: 0000000000000000
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 255
sectors/cylinder: 16065
cylinders: 16
total sectors: 257536
boundstart: 64
boundend: 257473
drivedata: 0 
> > a a
offset: [64] 
size: [257409] 
FS type: [4.2BSD] RAID
> w
> q
No label changes.
# 

We've initialized the USB stick with the OpenBSD fdisk with a GPT partition table and the we add a single RAID partition to it with disklabel. We use RAID because this is the manner that use OpenBSD to do it.

# bioctl -c C -l /dev/sd2a softraid0  
New passphrase: 
Re-type passphrase: 
softraid0: CRYPTO volume attached as sd3
# 

We've encrypted the first partition label of our USB stick with the command bioctl that result in the creation of the pseudo device sd3.

# newfs sd3c         
newfs: reduced number of fragments per cylinder group from 16048 to 15984 to enlarge last cylinder group
/dev/rsd3c: 125.4MB in 256880 sectors of 512 bytes
5 cylinder groups of 31.22MB, 1998 blocks, 4096 inodes each
super-block backups (for fsck -b #) at:
 32, 63968, 127904, 191840, 255776,
# mkdir /mnt/encrypted_usb && mount dev/sd3c /mnt/encrypted_usb

Create an ufs2 filesystem in the pseudo device disk label c, that is the one that indicate all the disk. Create a partition where to mount it and mount it!

# gpg2 --homedir /home/taglio/.gnupg --armor --export-secret-keys 0xAD8E487FF2F05FDE > /mnt/encrypted_usb/mastersub.key
# gpg2 --homedir /home/taglio/.gnupg --armor --export-secret-subkeys 0xAD8E487FF2F05FDE > /mnt/encrypted_usb/sub.key
# umount /mnt/encrypted_usb
# 

Greetings

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Bye Bye little loves, i love you.