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Revamp "Verifying signatures" and "Qubes security pack"

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- Standardize syntax, formatting, and orthography
- Update links
- Clarify and improve language
- Deduplicate content
- Add info regarding keys not directly signed by the QMSK
  (https://github.com/QubesOS/qubes-doc/pull/1180#discussion_r672939404)
- Add general info about digital signature use
- Improve page organization (#1179)
- Update info and instructions regarding the QMSK
- Miscelanneous fixes and improvements
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parent 39d4be00cc
commit 05dcacd7b5
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225
project-security/security-pack.md
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@ -18,177 +18,130 @@ ref: 213
title: Qubes security pack (qubes-secpack)
---
The **Qubes Security Pack** (`qubes-secpack`) is a Git repository that
contains:
The **Qubes Security Pack** (qubes-secpack) is a Git repository that contains:
* [Qubes Security Bulletins (QSBs)](/security/qsb/)
* [Qubes Canaries](/security/canary/)
* [Signed Qubes ISO digests](/security/verifying-signatures/#how-to-verify-qubes-iso-digests)
* [Qubes fund information](https://github.com/QubesOS/qubes-secpack/tree/master/fund)
* [Qubes PGP keys](https://keys.qubes-os.org/keys/)
* Security-related information and announcements (e.g., key revocations)
- [Qubes security bulletins (QSBs)](/security/qsb/)
- [Qubes canaries](/security/canary/)
- [Qubes ISO cryptographic hash values](/security/verifying-signatures/#how-to-verify-the-cryptographic-hash-values-of-qubes-isos)
- [Qubes fund information](https://github.com/QubesOS/qubes-secpack/tree/master/fund)
- [Qubes PGP keys](https://keys.qubes-os.org/keys/)
- Security-related information and announcements (e.g., key revocations)
While `qubes-secpack` itself is independent of any particular host, its current
While qubes-secpack itself is independent of any particular host, its current
official location is:
<https://github.com/QubesOS/qubes-secpack>
## How to obtain, verify, and read
The following example demonstrates one method of obtaining the `qubes-secpack`,
verifying its contents, and reading them.
The following example demonstrates one method of obtaining the qubes-secpack,
verifying its authenticity, and reading the contents.
1. Clone the `qubes-secpack` repo.
1. Use Git to clone the qubes-secpack repo.
```shell_session
$ git clone https://github.com/QubesOS/qubes-secpack.git
Cloning into 'qubes-secpack'...
remote: Counting objects: 195, done.
remote: Total 195 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (195/195), 130.94 KiB | 207.00 KiB/s, done.
Resolving deltas: 100% (47/47), done.
Checking connectivity... done.
```
```shell_session
$ git clone https://github.com/QubesOS/qubes-secpack.git
Cloning into 'qubes-secpack'...
remote: Counting objects: 195, done.
remote: Total 195 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (195/195), 130.94 KiB | 207.00 KiB/s, done.
Resolving deltas: 100% (47/47), done.
Checking connectivity... done.
```
2. Import the included PGP keys.
```shell_session
$ gpg --import qubes-secpack/keys/*/*
gpg: directory `/home/user/.gnupg' created
gpg: new configuration file `/home/user/.gnupg/gpg.conf' created
gpg: WARNING: options in `/home/user/.gnupg/gpg.conf' are not yet active during this run
gpg: keyring `/home/user/.gnupg/secring.gpg' created
gpg: keyring `/home/user/.gnupg/pubring.gpg' created
gpg: /home/user/.gnupg/trustdb.gpg: trustdb created
gpg: key C37BB66B: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 1E30A75D: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 74EADABC: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 65EF29CA: public key "Joanna Rutkowska (Qubes OS Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key 34898310: public key "Joanna Rutkowska (Qubes OS Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key B298547C: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@mimuw.edu.pl>" imported
gpg: key AB5EEF90: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key A603BCB6: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key 42CFA724: public key "Marek Marczykowski-Górecki (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key 15CE40BF: public key "Wojciech Zygmunt Porczyk (Qubes OS signing key) <woju@invisiblethingslab.com>" imported
gpg: key 36879494: public key "Qubes Master Signing Key" imported
gpg: key 211093A7: public key "Qubes OS Release 1 Signing Key" imported
gpg: key 0A40E458: public key "Qubes OS Release 2 Signing Key" imported
gpg: key 03FA5082: public key "Qubes OS Release 3 Signing Key" imported
gpg: key 92C7B3DC: public key "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key 1830E06A: public key "Marek Marczykowski-Górecki (Qubes security pack) <marmarek@invisiblethingslab.com>" imported
gpg: key 3F48CB21: public key "Qubes OS Security Team <security@qubes-os.org>" imported
gpg: Total number processed: 17
gpg: imported: 17 (RSA: 17)
gpg: no ultimately trusted keys found
```
```shell_session
$ gpg --import qubes-secpack/keys/*/*
gpg: directory `/home/user/.gnupg' created
gpg: new configuration file `/home/user/.gnupg/gpg.conf' created
gpg: WARNING: options in `/home/user/.gnupg/gpg.conf' are not yet active during this run
gpg: keyring `/home/user/.gnupg/secring.gpg' created
gpg: keyring `/home/user/.gnupg/pubring.gpg' created
gpg: /home/user/.gnupg/trustdb.gpg: trustdb created
gpg: key C37BB66B: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 1E30A75D: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 74EADABC: public key "Joanna Rutkowska (Qubes OS signing key) <joanna@invisiblethingslab.com>" imported
gpg: key 65EF29CA: public key "Joanna Rutkowska (Qubes OS Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key 34898310: public key "Joanna Rutkowska (Qubes OS Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key B298547C: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@mimuw.edu.pl>" imported
gpg: key AB5EEF90: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key A603BCB6: public key "Marek Marczykowski (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key 42CFA724: public key "Marek Marczykowski-Górecki (Qubes OS signing key) <marmarek@invisiblethingslab.com>" imported
gpg: key 15CE40BF: public key "Wojciech Zygmunt Porczyk (Qubes OS signing key) <woju@invisiblethingslab.com>" imported
gpg: key 36879494: public key "Qubes Master Signing Key" imported
gpg: key 211093A7: public key "Qubes OS Release 1 Signing Key" imported
gpg: key 0A40E458: public key "Qubes OS Release 2 Signing Key" imported
gpg: key 03FA5082: public key "Qubes OS Release 3 Signing Key" imported
gpg: key 92C7B3DC: public key "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>" imported
gpg: key 1830E06A: public key "Marek Marczykowski-Górecki (Qubes security pack) <marmarek@invisiblethingslab.com>" imported
gpg: key 3F48CB21: public key "Qubes OS Security Team <security@qubes-os.org>" imported
gpg: Total number processed: 17
gpg: imported: 17 (RSA: 17)
gpg: no ultimately trusted keys found
```
3. Verify and trust the Qubes Master Signing Key.
3. [Authenticate and set the trust level of the Qubes Master Signing Key
(QMSK).](#how-to-import-and-authenticate-the-qubes-master-signing-key)
```shell_session
$ gpg --edit-key 36879494
gpg (GnuPG) 1.4.18; Copyright (C) 2014 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.
pub 4096R/36879494 created: 2010-04-01 expires: never usage: SC
trust: unknown validity: unknown
[ unknown] (1). Qubes Master Signing Key
gpg> fpr
pub 4096R/36879494 2010-04-01 Qubes Master Signing Key
Primary key fingerprint: 427F 11FD 0FAA 4B08 0123 F01C DDFA 1A3E 3687 9494
gpg> trust
pub 4096R/36879494 created: 2010-04-01 expires: never usage: SC
trust: unknown validity: unknown
[ unknown] (1). Qubes Master Signing Key
Please decide how far you trust this user to correctly verify other users' keys
(by looking at passports, checking fingerprints from different sources, etc.)
1 = I don't know or won't say
2 = I do NOT trust
3 = I trust marginally
4 = I trust fully
5 = I trust ultimately
m = back to the main menu
Your decision? 5
Do you really want to set this key to ultimate trust? (y/N) y
pub 4096R/36879494 created: 2010-04-01 expires: never usage: SC
trust: ultimate validity: unknown
[ unknown] (1). Qubes Master Signing Key
Please note that the shown key validity is not necessarily correct
unless you restart the program.
gpg> q
```
**Important!**
In order to verify the authenticity of the Qubes Master Signing Key prior to
trusting it, you should obtain the Qubes Master Signing Key fingerprint from
a trustworthy source (ideally, multiple sources) *other than* this website
and visually compare it (them) to the fingerprint displayed in the preceding
step, ensuring they match. You can read more about digital signatures and
key verification [here](/security/verifying-signatures/).
**Note:** Only some keys in the qubes-secpack are signed by the QMSK. Keys
that are not signed directly by the QMSK are still signed indirectly by
virtue of being included in the qubes-secpack, which is itself signed (via
Git tags and/or commits) by keys that are in turn signed by the QMSK.
4. Verify signed Git tags.
```shell_session
$ cd qubes-secpack/
$ git tag -v `git describe`
object 2bb7f0b966593d8ed74e140a04d60c68b96b164e
type commit
tag joanna_sec_2bb7f0b9
tagger Joanna Rutkowska <joanna@invisiblethingslab.com> 1468335706 +0000
```shell_session
$ cd qubes-secpack/
$ git tag -v `git describe`
object 2bb7f0b966593d8ed74e140a04d60c68b96b164e
type commit
tag joanna_sec_2bb7f0b9
tagger Joanna Rutkowska <joanna@invisiblethingslab.com> 1468335706 +0000
Tag for commit 2bb7f0b966593d8ed74e140a04d60c68b96b164e
gpg: Signature made 2016-07-12T08:01:46 PDT
gpg: using RSA key 0x4E6829BC92C7B3DC
gpg: Good signature from "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>" [full]
```
Tag for commit 2bb7f0b966593d8ed74e140a04d60c68b96b164e
gpg: Signature made 2016-07-12T08:01:46 PDT
gpg: using RSA key 0x4E6829BC92C7B3DC
gpg: Good signature from "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>" [full]
```
(The final line of output confirms that the signature is good.)
The final line of output confirms that the signature is good.
5. Verify detached PGP signatures.
```shell_session
$ cd canaries/
$ gpg --verify canary-001-2015.txt.sig.joanna canary-001-2015.txt
gpg: Signature made Mon Jan 5 20:21:40 2015 UTC using RSA key ID 92C7B3DC
gpg: Good signature from "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>"
$ gpg --verify canary-001-2015.txt.sig.marmarek canary-001-2015.txt
gpg: Signature made Mon Jan 5 20:13:37 2015 UTC using RSA key ID 1830E06A
gpg: Good signature from "Marek Marczykowski-Górecki (Qubes security pack) <marmarek@invisiblethingslab.com>"
```
```shell_session
$ cd canaries/
$ gpg --verify canary-001-2015.txt.sig.joanna canary-001-2015.txt
gpg: Signature made Mon Jan 5 20:21:40 2015 UTC using RSA key ID 92C7B3DC
gpg: Good signature from "Joanna Rutkowska (Qubes Security Pack Signing Key) <joanna@invisiblethingslab.com>"
$ gpg --verify canary-001-2015.txt.sig.marmarek canary-001-2015.txt
gpg: Signature made Mon Jan 5 20:13:37 2015 UTC using RSA key ID 1830E06A
gpg: Good signature from "Marek Marczykowski-Górecki (Qubes security pack) <marmarek@invisiblethingslab.com>"
```
(The fourth and final lines of output confirm that the two signatures are
good.)
The fourth and final lines of output confirm that the two signatures are
good.
The same procedures can be applied to any directory or file in the
`qubes-secpack`. Two methods of verification (signed Git tags and detached PGP
qubes-secpack. Two methods of verification (signed Git tags and detached PGP
signatures) are provided to ensure that the system is robust (e.g., against a
potential failure in Git tag-based verification) and to give users more options
to verify the files.
## PGP key inclusion criteria
The `qubes-secpack` generally includes only those PGP keys used to sign some
kind of official project artifact, such as Qubes release ISOs (release signing
keys), Git tags and commits (code signing, doc signing, and security team
keys), and the `qubes-secpack`'s own files and Git tags (security team keys
again). This means that email keys are generally not included, even for
official project email addresses. There is one exception to this rule: the
official [Qubes Security Team](/security/#qubes-security-team) email address,
which is used to report security vulnerabilities in Qubes OS to our security
team.
The qubes-secpack generally includes only those PGP keys used to sign some kind
of official project asset, such as Qubes release ISOs (release signing keys),
Git tags and commits (code signing, doc signing, and security team keys), and
the qubes-secpack's own files and Git tags (security team keys again). This
means that email keys are generally not included, even for official project
email addresses. There is one exception to this rule: the official [Qubes
security team](/security/#qubes-security-team) email address, which is used to
report security vulnerabilities in Qubes OS to our security team.
## History and rationale
On 2013-01-05, Joanna Rutkowska announced the `qubes-secpack` and explained its
On 2013-01-05, Joanna Rutkowska announced the qubes-secpack and explained its
rationale in an
[email](https://groups.google.com/d/msg/qubes-devel/twkOEaMLtNI/lZyGx6_jFCEJ)
to the Qubes mailing lists:

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project-security/verifying-signatures.md
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@ -11,7 +11,13 @@ ref: 211
title: Verifying signatures
---
## What Digital Signatures Can and Cannot Prove
The Qubes OS Project uses [digital
signatures](https://en.wikipedia.org/wiki/Digital_signature) to guarantee the
authenticity and integrity of certain important assets. This page explains how
to verify those signatures. It is extremely important for your security to
understand and apply these practices.
## What digital signatures can and cannot prove
Most people --- even programmers --- are confused about the basic concepts
underlying digital signatures. Therefore, most people should read this section,
@ -24,15 +30,15 @@ third party). **Integrity** ensures that the contents of the file have not been
tampered with (i.e., that a third party has not undetectably altered its
contents *en route*).
Digital signatures **cannot** prove any other property, e.g., that the signed
file is not malicious. In fact, there is nothing that could stop someone from
signing a malicious program (and it happens from time to time in reality).
Digital signatures **cannot** prove, e.g., that the signed file is not
malicious. In fact, there is nothing that could stop someone from signing a
malicious program (and it happens from time to time in reality).
The point is that we must decide who we will trust (e.g., Linus Torvalds,
Microsoft, or the Qubes Project) and assume that if a given file was signed by
a trusted party, then it should not be malicious or negligently buggy. The
decision of whether to trust any given party is beyond the scope of digital
signatures. It's more of a sociological and political decision.
signatures. It's more of a social and political decision.
Once we make the decision to trust certain parties, digital signatures are
useful, because they make it possible for us to limit our trust only to those
@ -41,8 +47,8 @@ between us and them, e.g., server compromises (qubes-os.org will surely be
compromised one day, so [don't blindly trust the live version of this
site](/faq/#should-i-trust-this-website)), dishonest IT staff at the hosting
company, dishonest staff at the ISPs, Wi-Fi attacks, etc. We call this
philosophy [Distrusting the
Infrastructure](/faq/#what-does-it-mean-to-distrust-the-infrastructure).
philosophy [distrusting the
infrastructure](/faq/#what-does-it-mean-to-distrust-the-infrastructure).
By verifying all the files we download that purport to be authored by a party
we've chosen to trust, we eliminate concerns about the bad things discussed
@ -52,127 +58,120 @@ them).
However, for digital signatures to make any sense, we must ensure that the
public keys we use for signature verification are indeed the original ones.
Anybody can generate a GPG key pair that purports to belong to "The Qubes
Project," but of course only the key pair that we (i.e., the Qubes developers)
generated is the legitimate one. The next section explains how to verify the
validity of the Qubes signing keys in the process of verifying a Qubes ISO.
(However, the same general principles apply to all cases in which you may wish
to verify a PGP signature, such as [verifying
repos](#how-to-verify-qubes-repos), not just verifying ISOs.)
Anybody can generate a cryptographic key that purports to belong to "The Qubes
OS Project," but of course only the keys that we (the real Qubes developers)
generate are the genuine ones. The next rest of this page explains how to
verify the authenticity of the various keys used in the project and how to use
those keys to verify certain important assets.
## How to Verify Qubes ISO Signatures
## How to obtain and authenticate PGP keys
This section will guide you through the process of verifying a Qubes ISO by
checking its PGP signature. There are three basic steps in this process:
We use [PGP](https://en.wikipedia.org/wiki/Pretty_Good_Privacy) (specifically,
the [OpenPGP](https://en.wikipedia.org/wiki/Pretty_Good_Privacy#OpenPGP)
standard). Before we begin, you'll need software that can manage PGP keys and
verify PGP signatures. Any program that complies with the OpenPGP standard will
do, but here are some examples for popular operating systems:
1. [Get the Qubes Master Signing Key and verify its
authenticity](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)
2. [Get the Release Signing Key](#2-get-the-release-signing-key)
3. [Verify your Qubes ISO](#3-verify-your-qubes-iso)
If you run into any problems, please consult the [Troubleshooting
FAQ](#troubleshooting-faq) below.
### Preparation
Before we begin, you'll need a program that can verify PGP signatures. Any such
program will do, but here are some examples for popular operating systems:
**Windows:** [Gpg4win](https://gpg4win.org/download.html)
([documentation](https://www.gpg4win.org/documentation.html)). Use the Windows
command line (`cmd.exe`) to enter commands.
**Linux:** [GnuPG](https://gnupg.org/download/index.html)
([documentation](https://www.gnupg.org/documentation/)). Open a terminal and
use the `gpg2` command. If you don't already have GnuPG installed, install it
via your distro's package manager or from the website.
**Mac:** [GPG Suite](https://gpgtools.org/)
([documentation](https://gpgtools.tenderapp.com/kb)). Open a terminal to enter
commands.
**Linux:** `gpg2` from your package manager or from
[gnupg.org](https://gnupg.org/download/index.html)
([documentation](https://www.gnupg.org/documentation/)). Open a terminal to
enter commands.
**Windows:** [Gpg4win](https://gpg4win.org/download.html)
([documentation](https://www.gpg4win.org/documentation.html)). Use the Windows
command line (`cmd.exe`) to enter commands.
The commands below will use `gpg2`, but if that doesn't work for you, try `gpg`
instead. If that still doesn't work, please consult the documentation for your
specific program (see links above).
Throughout this page, we'll use GnuPG via the `gpg2` command. If that doesn't
work for you, try `gpg` instead. If that still doesn't work, please consult the
documentation for your specific program (see links above) and the
[troubleshooting FAQ](#troubleshooting-faq) below.
### 1. Get the Qubes Master Signing Key and verify its authenticity
### How to import and authenticate the Qubes Master Signing Key
Every file published by the Qubes Project (ISO, RPM, TGZ files and Git
repositories) is digitally signed by one of the developer keys or Release
Signing Keys. Each such key is signed by the [Qubes Master Signing
Key](https://keys.qubes-os.org/keys/qubes-master-signing-key.asc)
(`0xDDFA1A3E36879494`). The developer signing keys are set to expire after one
year, while the Qubes Master Signing Key and Release Signing Keys have no
expiration date. This Qubes Master Signing Key was generated on and is kept
only on a dedicated, air-gapped "vault" machine, and the private portion will
(hopefully) never leave this isolated machine.
Many important Qubes OS Project assets (e.g., ISOs, RPMs, TGZs, and Git
objects) are digitally signed by an official team member's key or by a release
signing key (RSK). Each such key is, in turn, signed by the [Qubes Master
Signing Key
(QMSK)](https://keys.qubes-os.org/keys/qubes-master-signing-key.asc)
(`0x427F11FD0FAA4B080123F01CDDFA1A3E36879494`). In this way, the QMSK is the
ultimate root of trust for the Qubes OS Project.
There are several ways to get the Qubes Master Signing Key.
The developer signing keys are set to expire after one year, while the QMSK and
RSKs have no expiration date. Th QMSK was generated on and is kept only on a
dedicated, air-gapped "vault" machine, and the private portion will (hopefully)
never leave this isolated machine.
- If you have access to an existing Qubes installation, it's available in every
VM ([except dom0](https://github.com/QubesOS/qubes-issues/issues/2544)):
There are several ways to get the QMSK.
```shell_session
$ gpg2 --import /usr/share/qubes/qubes-master-key.asc
```
- If you're on Qubes OS, it's available in every
qube ([except dom0](https://github.com/QubesOS/qubes-issues/issues/2544)):
- If you're on Fedora, you can get it in the `distribution-gpg-keys` package:
```shell_session
$ gpg2 --import /usr/share/qubes/qubes-master-key.asc
```
- If you're on Fedora, you can get it in the [distribution-gpg-keys](https://github.com/xsuchy/distribution-gpg-keys) package:
```shell_session
$ dnf install distribution-gpg-keys
```
```shell_session
$ dnf install distribution-gpg-keys
$ gpg2 --import /usr/share/distribution-gpg-keys/qubes/*
```
- If you’re on Debian, it may already be included in your keyring.
- Fetch it with GPG:
```shell_session
$ gpg2 --fetch-keys https://keys.qubes-os.org/keys/qubes-master-signing-key.asc
```
- Download it as a
[file](https://keys.qubes-os.org/keys/qubes-master-signing-key.asc), then
import it with GPG:
```shell_session
$ gpg2 --import ./qubes-master-signing-key.asc
```
```shell_session
$ gpg2 --fetch-keys https://keys.qubes-os.org/keys/qubes-master-signing-key.asc
```
- Get it from a public
[keyserver](https://en.wikipedia.org/wiki/Key_server_%28cryptographic%29#Keyserver_examples)
(specified on first use with `--keyserver <URI>` along with keyserver options
to include key signatures), e.g.:
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --keyserver hkp://pool.sks-keyservers.net:11371 --recv-keys 0x427F11FD0FAA4B080123F01CDDFA1A3E36879494
```
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --keyserver hkp://keyserver.ubuntu.com --recv-keys 0x427F11FD0FAA4B080123F01CDDFA1A3E36879494
```
The Qubes Master Signing Key is also available in the [Qubes Security
Pack](/security/pack/) and in the archives of the project's
[developer](https://groups.google.com/d/msg/qubes-devel/RqR9WPxICwg/kaQwknZPDHkJ)
and
[user](https://groups.google.com/d/msg/qubes-users/CLnB5uFu_YQ/ZjObBpz0S9UJ)
[mailing lists](/support/).
- Download it as a file, then import the file.
Once you have obtained the Qubes Master Signing Key, you must verify that it is
authentic rather than a forgery. Anyone can create a PGP key with the name
"Qubes Master Signing Key," so you cannot rely on the name alone. You also
Here are some example download locations:
- [Qubes security pack](/security/pack/)
- [Qubes keyserver](https://keys.qubes-os.org/keys/qubes-master-signing-key.asc)
- [Email to qubes-devel](https://groups.google.com/d/msg/qubes-devel/RqR9WPxICwg/kaQwknZPDHkJ)
- [Email to qubes-users](https://groups.google.com/d/msg/qubes-users/CLnB5uFu_YQ/ZjObBpz0S9UJ)
Once you have the key as a file, import it:
```shell_session
$ gpg2 --import /<PATH_TO_FILE>/qubes-master-signing-key.asc
```
Once you've obtained the QMSK, you must verify that it's authentic rather than
a forgery. Anyone can create a PGP key with the name "Qubes Master Signing Key"
and the short key ID `0x36879494`, so you cannot rely on these alone. You also
should not rely on any single website, not even over HTTPS.
So, what *should* you do? One option is to use the PGP [Web of
Trust](https://en.wikipedia.org/wiki/Web_of_trust). In addition, some operating
systems include the means to acquire the Qubes Master Signing Key in a secure
way. For example, on Fedora, `dnf install distribution-gpg-keys` will get you
the Qubes Master Signing Key along with several other Qubes keys. On Debian,
your keyring may already contain the necessary keys.
systems include the means to acquire the QMSK in a secure way. For example, on
Fedora, `dnf install distribution-gpg-keys` will get you the QMSK along with
several other Qubes keys. On Debian, your keyring may already contain the
necessary keys.
Another option is to rely on the key's fingerprint. Every PGP key has a
fingerprint that uniquely identifies it among all PGP keys (viewable with `gpg2
--fingerprint <KEY_ID>`). Therefore, if you know the genuine Qubes Master
Signing Key fingerprint, then you always have an easy way to confirm whether
any purported copy of it is authentic, simply by comparing the fingerprints.
Perhaps the most common route is to rely on the key's fingerprint. Every PGP
key has a fingerprint that uniquely identifies it among all PGP keys (viewable
with `gpg2 --fingerprint <KEY_ID>`). Therefore, if you know the genuine QMSK
fingerprint, then you always have an easy way to confirm whether any purported
copy of it is authentic, simply by comparing the fingerprints.
For example, here is the Qubes Master Signing Key fingerprint:
For example, here is the QMSK fingerprint:
```
pub 4096R/36879494 2010-04-01
@ -213,12 +212,12 @@ Here are some ideas for how to do that:
Once you've obtained the fingerprint from enough independent sources in enough
different ways that you feel confident that you know the genuine fingerprint,
keep it in a safe place. Every time you need to check whether a key claiming to
be the Qubes Master Signing Key is authentic, compare that key's fingerprint to
your trusted copy and confirm they match.
be the QMSK is authentic, compare that key's fingerprint to your trusted copy
and confirm they match.
Now that you've imported the authentic Qubes Master Signing Key, set its trust
level to "ultimate" so that it can be used to automatically verify all the keys
signed by the Qubes Master Signing Key (in particular, Release Signing Keys).
Now that you've imported the authentic QMSK, set its trust level to "ultimate"
so that it can be used to automatically verify all the keys signed by the QMSK
(in particular, RSKs).
```
$ gpg2 --edit-key 0x427F11FD0FAA4B080123F01CDDFA1A3E36879494
@ -261,16 +260,11 @@ unless you restart the program.
gpg> q
```
Now, when you import any of the legitimate Qubes developer keys and Release
Signing Keys used to sign ISOs, RPMs, TGZs, Git tags, and Git commits, they
will already be trusted in virtue of being signed by the Qubes Master Signing
Key.
Now, when you import any of the release signing keys and many Qubes team member
keys, they will already be trusted in virtue of being signed by the QMSK.
Before proceeding to the next step, make sure the Qubes Master Signing Key is
in your keyring with the correct trust level. (Note: We have already verified
the authenticity of the key, so this final check is not about security. Rather,
it's just a sanity check to make sure that we've imported the key into our
keyring correctly.)
Before proceeding to the next step, let's do a final sanity check to make sure
the QMSK is in your keyring with the correct trust level.
```
$ gpg2 -k "Qubes Master Signing Key"
@ -279,46 +273,53 @@ pub rsa4096 2010-04-01 [SC]
uid [ultimate] Qubes Master Signing Key
```
If you don't see the Qubes Master Signing Key here with a trust level of
"ultimate," go back and follow the instructions in this section carefully.
If you don't see the QMSK here with a trust level of "ultimate," go back and
follow the instructions in this section carefully and consult the
[troubleshooting FAQ](#troubleshooting-faq) below.
### 2. Get the Release Signing Key
### How to import and authenticate release signing keys
The filename of the Release Signing Key for your version is usually
`qubes-release-X-signing-key.asc`, where `X` is the major version number of
your Qubes release. There are several ways to get the Release Signing Key for
your Qubes release.
Every Qubes OS release is signed by a **release signing key (RSK)**, which is
in turn signed by the Qubes Master Signing Key (QMSK). Before we proceed, you
must first [import and authenticate the Qubes Master Signing
Key](#how-to-import-and-authenticate-the-qubes-master-signing-key).
The first step is to obtain the correct RSK. The filename of the RSK for your
Qubes OS release is usually `qubes-release-X-signing-key.asc`, where `X` is the
major version number of your Qubes release. There are several ways to get the
RSK for your Qubes release.
- If you have access to an existing Qubes installation, the release keys are
available in dom0 in `/etc/pki/rpm-gpg/RPM-GPG-KEY-qubes-*`. These can be
[copied](/doc/how-to-copy-from-dom0/#copying-from-dom0) into other VMs for
further use. In addition, every other VM contains the release key
[copied](/doc/how-to-copy-from-dom0/#copying-from-dom0) into other qubes for
further use. In addition, every other qube contains the release key
corresponding to that installation's release in
`/etc/pki/rpm-gpg/RPM-GPG-KEY-qubes-*`. If you wish to use one of these keys,
make sure to import it into your keyring, e.g.:
```
$ gpg2 --import /etc/pki/rpm-gpg/RPM-GPG-KEY-qubes-*
```
```
$ gpg2 --import /etc/pki/rpm-gpg/RPM-GPG-KEY-qubes-*
```
- Fetch it with GPG:
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --fetch-keys https://keys.qubes-os.org/keys/qubes-release-X-signing-key.asc
```
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --fetch-keys https://keys.qubes-os.org/keys/qubes-release-X-signing-key.asc
```
- Download it as a file. You can find the Release Signing Key for your Qubes
version on the [Downloads](/downloads/) page. You can also download all the
currently used developers' signing keys, Release Signing Keys, and the Qubes
Master Signing Key from the [Qubes Security Pack](/security/pack/) and the
[Qubes OS Keyserver](https://keys.qubes-os.org/keys/). Once you've downloaded
your Release Signing Key, import it with GPG:
- Download it as a file. You can find the RSK for your Qubes
release on the [downloads](/downloads/) page. You can also download all the
currently used developers' signing keys, RSKs, and the Qubes
Master Signing Key from the [Qubes security pack](/security/pack/) and the
[Qubes keyserver](https://keys.qubes-os.org/keys/). Once you've downloaded
your RSK, import it with GPG:
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --import ./qubes-release-X-signing-key.asc
```
```shell_session
$ gpg2 --keyserver-options no-self-sigs-only,no-import-clean --import ./qubes-release-X-signing-key.asc
```
The Release Signing Key should be signed by the Qubes Master Signing Key:
Now that you have the correct RSK, you simply need to verify that it is signed
by the QMSK:
```shell_session
$ gpg2 --check-signatures "Qubes OS Release X Signing Key"
@ -334,13 +335,14 @@ gpg: 2 good signatures
This is just an example, so the output you receive will not look exactly the
same. What matters is the line that shows that this key is signed by the Qubes
Master Signing Key with a `sig!` prefix. This verifies the authenticity of the
Release Signing Key. Note that the `!` flag after the `sig` tag is important
because it means that the key signature is valid. A `sig-` prefix would
indicate a bad signature and `sig%` would mean that gpg encountered an error
while verifying the signature. It is not necessary to independently verify the
authenticity of the Release Signing Key, since you already verified the
authenticity of the Qubes Master Signing Key. Before proceeding to the next
step, make sure the Release Signing Key is in your keyring:
RSK. Note that the `!` flag after the `sig` tag is important because it means
that the key signature is valid. A `sig-` prefix would indicate a bad signature
and `sig%` would mean that gpg encountered an error while verifying the
signature. It is not necessary to independently verify the authenticity of the
RSK, since you already verified the authenticity of the QMSK.
As a final sanity check, make sure the RSK is in your keyring with the correct
trust level:
```
$ gpg2 -k "Qubes OS Release"
@ -349,49 +351,48 @@ pub rsa4096 2017-03-06 [SC]
uid [ full ] Qubes OS Release X Signing Key
```
If you don't see the correct Release Signing Key here, go back and follow the
instructions in this section carefully.
If you don't see the correct RSK here with a trust level of "full" or higher,
go back and follow the instructions in this section carefully, and consult the
[troubleshooting FAQ](#troubleshooting-faq) below.
### 3. Verify your Qubes ISO
### How to obtain and authenticate other signing keys
Every Qubes ISO is released with a detached PGP signature file, which you can
find on the [Downloads](/downloads/) page alongside the ISO. If the filename of
your ISO is `Qubes-RX-x86_64.iso`, then the name of the signature file for that
ISO is `Qubes-RX-x86_64.iso.asc`, where `X` is a specific version of Qubes. The
signature filename is always the same as the ISO filename followed by `.asc`.
Please see the [Qubes security pack](/security/pack/) documentation.
Download both the ISO and its signature file. Put both of them in the same
directory, then navigate to that directory. Now, you can verify the ISO by
executing this GPG command in the directory that contains both files:
## How to verify the cryptographic hash values of Qubes ISOs
```shell_session
$ gpg2 -v --verify Qubes-RX-x86_64.iso.asc Qubes-RX-x86_64.iso
gpg: armor header: Version: GnuPG v1
gpg: Signature made Tue 08 Mar 2016 07:40:56 PM PST using RSA key ID 03FA5082
gpg: using PGP trust model
gpg: Good signature from "Qubes OS Release X Signing Key"
gpg: binary signature, digest algorithm SHA256
```
There are two ways to verify Qubes ISO: cryptographic hash values and detached
PGP signatures. Both methods are equally secure. Using just one method is
sufficient to verify your Qubes ISO. Using both methods is not necessary, but
you can do so if you like. One method might be more convenient than another in
certain circumstances, so we provide both. This section covers cryptographic
hash values. For the other method, see [how to verify detached PGP signatures
on Qubes ISOs](#how-to-verify-detached-pgp-signatures-on-qubes-isos).
This is just an example, so the output you receive will not look exactly the
same. What matters is the line that says `Good signature from "Qubes OS Release
X Signing Key"`. This confirms that the signature on the ISO is good.
Before we proceed, you must first complete the following prerequisite steps:
## How to Verify Qubes ISO Digests
1. [Import and authenticate the Qubes Master Signing Key.](#how-to-import-and-authenticate-the-qubes-master-signing-key)
2. [Import and authenticate your release signing key.](#how-to-import-and-authenticate-release-signing-keys)
Each Qubes ISO is also accompanied by a plain text file ending in `.DIGESTS`.
This file contains the output of running several different cryptographic hash
functions on the ISO in order to obtain alphanumeric outputs known as "digests"
or "hash values." These hash values are provided as an alternative verification
method to PGP signatures (though the digest file is itself also PGP-signed ---
see below). If you've already verified the signatures on the ISO directly, then
verifying digests is not necessary. You can find the `.DIGESTS` for your ISO on
the [Downloads](/downloads/) page, and you can always find all the digest files
for every Qubes ISO in the [Qubes Security Pack](/security/pack/).
Each Qubes ISO is accompanied by a set of **cyrptographic hash values**
contained in a plain text file ending in `.DIGESTS`, which can find on the
[downloads](/downloads/) page alongside the ISO. This file contains the output
of running several different cryptographic hash functions on the ISO (a process
known as "hashing") in order to obtain alphanumeric outputs known as "hash
values or "digests."
One convenient property of hash values is that they can be generated on any
computer. This means, for example, that you can download a Qubes ISO on one
computer, hash it, then visually compare that hash value to one you generated
or have saved on a different computer.
In addition to the `.DIGESTS` files on the [downloads](/downloads/) page
alongside each ISO, and you can always find all the digest files for every
Qubes ISO in the [Qubes security pack](/security/pack/).
If the filename of your ISO is `Qubes-RX-x86_64.iso`, then the name of the
digest file for that ISO is `Qubes-RX-x86_64.iso.DIGESTS`, where `X` is a
specific version of Qubes. The digest filename is always the same as the ISO
specific release of Qubes. The digest filename is always the same as the ISO
filename followed by `.DIGESTS`. Since the digest file is a plain text file,
you can open it with any text editor. Inside, you should find text that looks
similar to this:
@ -424,9 +425,9 @@ g8JqGYYptgkxjQdX3YAy9VDsCJ/6EkFc2lkQHbgZxjXqyrEMbgeSXtMltZ7cCqw1
```
Four digests have been computed for this ISO. The hash functions used, in order
from top to bottom, are MD5, SHA1, SHA256, and SHA512. One way to verify that
the ISO you downloaded matches any of these hash values is by using the
respective `*sum` programs:
from top to bottom, are MD5, SHA-1, SHA-256, and SHA-512. One way to verify
that the ISO you downloaded matches any of these hash values is by using the
respective `*sum` command:
```shell_session
$ md5sum -c Qubes-RX-x86_64.iso.DIGESTS
@ -474,51 +475,106 @@ Therefore, we should also verify the authenticity of the listed hash values.
Since `Qubes-RX-x86_64.iso.DIGESTS` is a clearsigned PGP file, we can use GPG
to verify it from the command line:
1. [Get the Qubes Master Signing Key and verify its
authenticity](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)
2. [Get the Release Signing Key](#2-get-the-release-signing-key)
1. [Import and authenticate the Qubes Master Signing Key.](#how-to-import-and-authenticate-the-qubes-master-signing-key)
2. [Import and authenticate your release signing key.](#how-to-import-and-authenticate-release-signing-keys)
3. Verify the signature in the digest file:
```shell_session
$ gpg2 -v --verify Qubes-RX-x86_64.iso.DIGESTS
gpg: armor header: Hash: SHA256
gpg: armor header: Version: GnuPG v2
gpg: original file name=''
gpg: Signature made Tue 20 Sep 2016 10:37:03 AM PDT using RSA key ID 03FA5082
gpg: using PGP trust model
gpg: Good signature from "Qubes OS Release X Signing Key"
gpg: textmode signature, digest algorithm SHA256
```
```shell_session
$ gpg2 -v --verify Qubes-RX-x86_64.iso.DIGESTS
gpg: armor header: Hash: SHA256
gpg: armor header: Version: GnuPG v2
gpg: original file name=''
gpg: Signature made Tue 20 Sep 2016 10:37:03 AM PDT using RSA key ID 03FA5082
gpg: using PGP trust model
gpg: Good signature from "Qubes OS Release X Signing Key"
gpg: textmode signature, digest algorithm SHA256
```
The signature is good. If our copy of the `Qubes OS Release X Signing Key` is
being validated by the authentic Qubes Master Signing Key (see
[above](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)), we
can be confident that these hash values came from the Qubes devs.
This is just an example, so the output you receive will not look exactly the
same. What matters is the line that says `Good signature from "Qubes OS Release
X Signing Key"`. This confirms that the signature on digest file is good.
## How to Verify Qubes Repos
If you don't see a good signature here, go back and follow the instructions in
this section carefully, and consult the [troubleshooting
FAQ](#troubleshooting-faq) below.
## How to verify detached PGP signatures on Qubes ISOs
There are two ways to verify Qubes ISO: cryptographic hash values and detached
PGP signatures. Both methods are equally secure. Using just one method is
sufficient to verify your Qubes ISO. Using both methods is not necessary, but
you can do so if you like. One method might be more convenient than another in
certain circumstances, so we provide both. This section covers detached PGP
signatures. For the other method, see [how to verify the cryptographic hash
values of Qubes
ISOs](#how-to-verify-the-cryptographic-hash-values-of-qubes-isos).
Before we proceed, you must first complete the following prerequisite steps:
1. [Import and authenticate the Qubes Master Signing Key.](#how-to-import-and-authenticate-the-qubes-master-signing-key)
2. [Import and authenticate your release signing key.](#how-to-import-and-authenticate-release-signing-keys)
Every Qubes ISO is released with a **detached PGP signature** file, which you
can find on the [downloads](/downloads/) page alongside the ISO. If the
filename of your ISO is `Qubes-RX-x86_64.iso`, then the name of the signature
file for that ISO is `Qubes-RX-x86_64.iso.asc`, where `X` is a specific release
of Qubes. The signature filename is always the same as the ISO filename
followed by `.asc`.
Download both the ISO and its signature file. Put both of them in the same
directory, then navigate to that directory. Now, you can verify the ISO by
executing this GPG command in the directory that contains both files:
```shell_session
$ gpg2 -v --verify Qubes-RX-x86_64.iso.asc Qubes-RX-x86_64.iso
gpg: armor header: Version: GnuPG v1
gpg: Signature made Tue 08 Mar 2016 07:40:56 PM PST using RSA key ID 03FA5082
gpg: using PGP trust model
gpg: Good signature from "Qubes OS Release X Signing Key"
gpg: binary signature, digest algorithm SHA256
```
This is just an example, so the output you receive will not look exactly the
same. What matters is the line that says `Good signature from "Qubes OS Release
X Signing Key"`. This confirms that the signature on the ISO is good.
If you don't see a good signature here, go back and follow the instructions in
this section carefully, and consult the [troubleshooting
FAQ](#troubleshooting-faq) below.
## How to verify signatures on Git repository tags and commits
Whenever you use one of the [Qubes repositories](https://github.com/QubesOS),
you should use Git to verify the PGP signature in a tag on the latest commit or
on the latest commit itself. (One or both may be present, but only one is
required.) If there is no trusted signed tag or commit on top, any commits after
the latest trusted signed tag or commit should **not** be trusted. If you come
across a repo with any unsigned commits, you should not add any of your own
signed tags or commits on top of them unless you personally vouch for the
required.) If there is no trusted signed tag or commit on top, any commits
after the latest trusted signed tag or commit should **not** be trusted. If you
come across a repo with any unsigned commits, you should not add any of your
own signed tags or commits on top of them unless you personally vouch for the
trustworthiness of the unsigned commits. Instead, ask the person who pushed the
unsigned commits to sign them.
You should always perform this verification on a trusted local machine with
properly validated keys (which are available in the [Qubes Security
Pack](/security/pack/)) rather than relying on a third party, such as GitHub.
While the GitHub interface may claim that a commit has a verified signature
from a member of the Qubes team, this is only trustworthy if GitHub has
performed the signature check correctly, the account identity is authentic, the
user's key has not been replaced by an admin, GitHub's servers have not been
compromised, and so on. Since there's no way for you to be certain that all
such conditions hold, you're much better off verifying signatures yourself.
properly authenticated keys rather than relying on a third party, such as
GitHub. While the GitHub interface may claim that a commit has a verified
signature from a member of the Qubes team, this is only trustworthy if GitHub
has performed the signature check correctly, the account identity is authentic,
the user's key has not been replaced by an admin, GitHub's servers have not
been compromised, and so on. Since there's no way for you to be certain that
all such conditions hold, you're much better off verifying signatures yourself.
(Also see: [distrusting the
infrastructure](/faq/#what-does-it-mean-to-distrust-the-infrastructure).)
Also see: [Distrusting the
Infrastructure](/faq/#what-does-it-mean-to-distrust-the-infrastructure)
Before we proceed, you must first complete the following prerequisite steps:
1. [Import and authenticate the Qubes Master Signing Key.](#how-to-import-and-authenticate-the-qubes-master-signing-key)
2. [Import and authenticate keys from the Qubes security pack (qubes-secpack)](/security/pack/)
**Note:** Only some keys in the qubes-secpack are signed by the QMSK. Keys that
are not signed directly by the QMSK are still signed indirectly by virtue of
being included in the qubes-secpack, which is itself signed (via Git tags
and/or commits) by keys that are in turn signed by the QMSK. If a key is not
signed directly by the QMSK, you may need to set its trust level directly.
To verify a signature on a Git tag:
@ -548,17 +604,18 @@ $ git verify-commit <commit ID>
### Why am I getting "Can't check signature: public key not found"?
You don't have the correct [Release Signing
Key](#2-get-the-release-signing-key).
You don't have the correct [release signing
key](#how-to-import-and-authenticate-release-signing-keys).
### Why am I getting "BAD signature from 'Qubes OS Release X Signing Key'"?
The problem could be one or more of the following:
- You're trying to verify the wrong file(s). Read this page again carefully.
- You're using the wrong GPG command. Follow the examples in [Verify your Qubes
ISO](#3-verify-your-qubes-iso) carefully.
- The ISO or [signature file](#3-verify-your-qubes-iso) is bad (e.g.,
- You're using the wrong GPG command. Follow the provided examples carefully,
or try using `gpg` instead of `gpg2` (or vice versa).
- The ISO or [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos) is bad (e.g.,
incomplete or corrupt download). Try downloading the signature file again
from a different source, then try verifying again. If you still get the same
result, try downloading the ISO again from a different source, then try
@ -567,7 +624,8 @@ The problem could be one or more of the following:
### Why am I getting "bash: gpg2: command not found"?
You don't have `gpg2` installed. Please install it using the method appropriate
for your environment (e.g., via your package manager).
for your environment (e.g., via your package manager), or try using `gpg`
instead.
### Why am I getting "No such file or directory"?
@ -575,38 +633,41 @@ Your working directory does not contain the required files. Go back and follow
the instructions more carefully, making sure that you put all required files in
the same directory *and* navigate to that directory.
### Why am I getting "can't open signed data `Qubes-RX-x86_64.iso' / can't hash datafile: file open error"?
### Why am I getting "can't open signed data 'Qubes-RX-x86\_64.iso' / can't hash datafile: file open error"?
The correct ISO is not in your working directory.
### Why am I getting "can't open `Qubes-RX-x86_64.iso.asc' / verify signatures failed: file open error"?
### Why am I getting "can't open 'Qubes-RX-x86\_64.iso.asc' / verify signatures failed: file open error"?
The correct [signature file](#3-verify-your-qubes-iso) is not in your working
directory.
The correct [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos) is not in your
working directory.
### Why am I getting "no valid OpenPGP data found"?
Either you don't have the correct [signature file](#3-verify-your-qubes-iso),
or you inverted the arguments to `gpg2`. ([The signature file goes
first.](#3-verify-your-qubes-iso))
Either you don't have the correct [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos), or you inverted
the arguments to `gpg2`. (The signature file goes first.)
### Why am I getting "WARNING: This key is not certified with a trusted signature! There is no indication that the signature belongs to the owner."?
Several possibilities:
* you don't have the [Qubes Master Signing
Key](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)
* you didn't [set its trust level
correctly](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)
* in the case of verifying a Git commit or tag, you haven't yet chosen to
place ultimate PGP trust in the individual signer's key
There are several possibilities:
- You don't have the [Qubes Master Signing
Key](#how-to-import-and-authenticate-the-qubes-master-signing-key).
- [You have not set the Qubes Master Signing Key's trust level
correctly.](#how-to-import-and-authenticate-the-qubes-master-signing-key)
- [In the case of a key that is not directly signed by the Qubes Master Signing
Key, you have not set that key's trust level
correctly.](#how-to-verify-signatures-on-git-repository-tags-and-commits)
### Why am I getting "X signature not checked due to a missing key"?
You don't have the keys that created those signatures in your keyring. For
present purposes, you don't need them as long as you have the [Qubes Master
Signing Key](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity)
and the [Release Signing Key](#2-get-the-release-signing-key) for your Qubes
version.
You don't have the keys that created those signatures in your keyring. For the
purpose of verifying a Qubes ISO, you don't need them as long as you have the
[Qubes Master Signing
Key](#how-to-import-and-authenticate-the-qubes-master-signing-key) and the
[release signing key](#how-to-import-and-authenticate-release-signing-keys) for
your Qubes release.
### Why am I seeing additional signatures on a key with "[User ID not found]" or from a revoked key?
@ -618,32 +679,33 @@ keys.
### Why am I getting "verify signatures failed: unexpected data"?
You're not verifying against the correct [signature
file](#3-verify-your-qubes-iso).
You're not verifying against the correct [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos).
### Why am I getting "not a detached signature"?
You're not verifying against the correct [signature
file](#3-verify-your-qubes-iso).
You're not verifying against the correct [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos).
### Why am I getting "CRC error; [...] no signature found [...]"?
You're not verifying against the correct [signature
file](#3-verify-your-qubes-iso), or the signature file has been modified. Try
downloading it again or from a different source.
You're not verifying against the correct [detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos), or the signature
file has been modified. Try downloading it again or from a different source.
### Do I have to verify the ISO against both the [signature file](#3-verify-your-qubes-iso) and the [digest file](#how-to-verify-qubes-iso-digests)?
### Do I have to verify both the [detached PGP signature file](#how-to-verify-detached-pgp-signatures-on-qubes-isos) and the [cryptographic hash values](#how-to-verify-the-cryptographic-hash-values-of-qubes-isos)?
No, either method is sufficient by itself.
No, either method is sufficient by itself, but you can do both if you like.
### Why am I getting "no properly formatted X checksum lines found"?
You're not checking the correct [digest
file](#how-to-verify-qubes-iso-digests).
You're not checking the correct [cryptographic hash
values](#how-to-verify-the-cryptographic-hash-values-of-qubes-isos).
### Why am I getting "WARNING: X lines are improperly formatted"?
Read [How to Verify Qubes ISO Digests](#how-to-verify-qubes-iso-digests) again.
Read [how to verify the cryptographic hash values of Qubes
ISOs](#how-to-verify-the-cryptographic-hash-values-of-qubes-isos) again.
### Why am I getting "WARNING: 1 listed file could not be read"?
@ -653,11 +715,13 @@ The correct ISO is not in your working directory.
Carefully read this page again to be certain that you didn't skip any steps. In
particular, make sure you have the [Qubes Master Signing
Key](#1-get-the-qubes-master-signing-key-and-verify-its-authenticity), the
[Release Signing Key](#2-get-the-release-signing-key), *and* the [signature
file](#3-verify-your-qubes-iso) and/or [digest
file](#how-to-verify-qubes-iso-digests) all for the *correct* Qubes OS version.
If your question is about GPG, please see the [GPG
documentation](https://www.gnupg.org/documentation/). Still have question?
Please see [Help, Support, Mailing Lists, and Forum](/support/) for places
where you can ask!
Key](#how-to-import-and-authenticate-the-qubes-master-signing-key), the
[release signing key](#how-to-import-and-authenticate-release-signing-keys) for
your Qubes release, *and* the [cryptographic hash
values](#how-to-verify-the-cryptographic-hash-values-of-qubes-isos) and/or
[detached PGP signature
file](#how-to-verify-detached-pgp-signatures-on-qubes-isos), all for the
*correct* Qubes OS release. If your question is about GPG, please see the
[GnuPG documentation](https://www.gnupg.org/documentation/). Still have
question? Please see [help, support, mailing lists, and forum](/support/) for
places where you can ask!