\cfg{winhelp-topic}{pgpfingerprints}
-\I{verifying new versions}We create \i{PGP signatures} for all the PuTTY
+\I{verifying new versions}We create \i{GPG signatures} for all the PuTTY
files distributed from our web site, so that users can be confident
that the files have not been tampered with. Here we identify
our public keys, and explain our signature policy so you can have an
\H{pgpkeys-pubkey} Public keys
-We supply two complete sets of keys. We supply a set of RSA keys,
-compatible with both \W{http://www.gnupg.org/}{GnuPG} and PGP2,
-and also a set of DSA keys compatible with GnuPG.
+We maintain a set of three keys, stored with different levels of
+security due to being used in different ways. See \k{pgpkeys-security}
+below for details.
-In each format, we have three keys:
+The three keys we provide are:
-\b A Development Snapshots key, used to sign the nightly builds.
+\dt Snapshot Key
-\b A Releases key, used to sign actual releases.
+\dd Used to sign routine development builds of PuTTY: nightly
+snapshots, pre-releases, and sometimes also custom diagnostic builds
+we send to particular users.
-\b A Master Key. The Master Key is used to sign the other two keys, and
-they sign it in return.
+\dt Release Key
-Therefore, we have six public keys in total:
+\dd Used to sign manually released versions of PuTTY.
-\b RSA:
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/master-rsa.asc}{Master Key},
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/release-rsa.asc}{Release key},
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/snapshot-rsa.asc}{Snapshot key}
+\dt Master Key
-\lcont{
-Master Key: 1024-bit; \I{PGP key fingerprint}fingerprint:
-\cw{8F\_15\_97\_DA\_25\_30\_AB\_0D\_\_88\_D1\_92\_54\_11\_CF\_0C\_4C}
-}
+\dd Used to tie the other two keys into the GPG web of trust. The
+Master Key signs the other two keys, and other GPG users have signed
+it in turn.
-\b DSA:
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/master-dsa.asc}{Master Key},
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/release-dsa.asc}{Release key},
-\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/snapshot-dsa.asc}{Snapshot key}
+The current issue of those three keys are available for download from
+the PuTTY website, and are also available on PGP keyservers using the
+key IDs listed below.
-\lcont{
-Master Key: 1024-bit; fingerprint:
-\cw{313C\_3E76\_4B74\_C2C5\_F2AE\_\_83A8\_4F5E\_6DF5\_6A93\_B34E}
-}
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/master-2015.asc}{\s{Master Key}}
+
+\dd RSA, 4096-bit. Key ID: \cw{4096R/04676F7C} (long version:
+\cw{4096R/AB585DC604676F7C}). Fingerprint:
+\cw{440D\_E3B5\_B7A1\_CA85\_B3CC\_\_1718\_AB58\_5DC6\_0467\_6F7C}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/release-2015.asc}{\s{Release Key}}
+
+\dd RSA, 2048-bit. Key ID: \cw{2048R/B43434E4} (long version:
+\cw{2048R/9DFE2648B43434E4}). Fingerprint:
+\cw{0054\_DDAA\_8ADA\_15D2\_768A\_\_6DE7\_9DFE\_2648\_B434\_34E4}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/snapshot-2015.asc}{\s{Snapshot Key}}
+
+\dd RSA, 2048-bit. Key ID: \cw{2048R/D15F7E8A} (long version:
+\cw{2048R/EEF20295D15F7E8A}). Fingerprint:
+\cw{0A3B\_0048\_FE49\_9B67\_A234\_\_FEB6\_EEF2\_0295\_D15F\_7E8A}
\H{pgpkeys-security} Security details
section explains what those security levels are, and how far you can
expect to trust each key.
-\S{pgpkeys-snapshot} The Development Snapshots keys
+\S{pgpkeys-snapshot} The Development Snapshots key
-These keys are stored \e{without passphrases}. This is
-necessary, because the snapshots are generated every night without
-human intervention, so nobody would be able to type a passphrase.
+The Development Snapshots private key is stored \e{without a
+passphrase}. This is necessary, because the snapshots are generated
+every night without human intervention, so nobody would be able to
+type a passphrase.
-The actual snapshots are built on a team member's home Windows box.
-The keys themselves are stored on an independently run Unix box
-(the same one that hosts our Git repository). After
-being built, the binaries are uploaded to this Unix box and then
-signed automatically.
+The snapshots are built and signed on a team member's home computers,
+before being uploaded to the web server from which you download them.
-Therefore, a signature from one of the Development Snapshots keys
-\e{DOES} protect you against:
+Therefore, a signature from the Development Snapshots key \e{DOES}
+protect you against:
\b People tampering with the PuTTY binaries between the PuTTY web site
and you.
-But it \e{DOES NOT} protect you against:
+\b The maintainers of our web server attempting to abuse their root
+privilege to tamper with the binaries.
-\b People tampering with the binaries before they are uploaded to the
-independent Unix box.
+But it \e{DOES NOT} protect you against:
-\b The sysadmin of the independent Unix box using his root privilege to
-steal the private keys and abuse them, or tampering with the
-binaries before they are signed.
+\b People tampering with the binaries before they are uploaded to our
+download servers.
-\b Somebody getting root on the Unix box.
+\b People tampering with the build machines so that the next set of
+binaries they build will be malicious in some way.
-Of course, we don't believe any of those things is very likely. We
-know our sysadmin personally and trust him (both to be competent and
-to be non-malicious), and we take all reasonable precautions to
-guard the build machine. But when you see a signature, you should
-always be certain of precisely what it guarantees and precisely what
-it does not.
+\b People stealing the unencrypted private key from the build machine
+it lives on.
-\S{pgpkeys-release} The Releases keys
+Of course, we take all reasonable precautions to guard the build
+machines. But when you see a signature, you should always be certain
+of precisely what it guarantees and precisely what it does not.
-The Release keys have passphrases and we can be more careful about
-how we use them.
+\S{pgpkeys-release} The Releases key
-The Release keys are kept safe on the developers' own local
-machines, and only used to sign releases that have been built by
-hand. A signature from a Release key protects you from almost any
-plausible attack.
+The Releases key is more secure: because it is only used at release
+time, to sign each release by hand, we can store it encrypted.
-(Some of the developers' machines have cable modem connections and
-might in theory be crackable, but of course the private keys are
-still encrypted, so the crack would have to go unnoticed for long
-enough to steal a passphrase.)
+The Releases private key is kept encrypted on the developers' own
+local machines. So an attacker wanting to steal it would have to also
+steal the passphrase.
\S{pgpkeys-master} The Master Keys
-The Master Keys sign almost nothing. Their purpose is to bind the
-other keys together and certify that they are all owned by the same
-people and part of the same integrated setup. The only signatures
-produced by the Master Keys, \e{ever}, should be the signatures
-on the other keys.
+The Master Key signs almost nothing. Its purpose is to bind the other
+keys together and certify that they are all owned by the same people
+and part of the same integrated setup. The only signatures produced by
+the Master Key, \e{ever}, should be the signatures on the other keys.
-We intend to arrange for the Master Keys to sign each other, to
-certify that the DSA keys and RSA keys are part of the same setup.
-We have not yet got round to this at the time of writing.
+The Master Key is especially long, and its private key and passphrase
+are stored with special care.
-We have collected a few third-party signatures on the Master Keys,
-in order to increase the chances that you can find a suitable trust
-path to them. We intend to collect more. (Note that the keys on the
-keyservers appear to have also collected some signatures from people
-who haven't performed any verification of the Master Keys.)
+We have collected some third-party signatures on the Master Key, in
+order to increase the chances that you can find a suitable trust path
+to them.
We have uploaded our various keys to public keyservers, so that
even if you don't know any of the people who have signed our
keys, you can still be reasonably confident that an attacker would
find it hard to substitute fake keys on all the public keyservers at
once.
+
+\H{pgpkeys-rollover} Key rollover
+
+Our current three keys were generated in September 2015. Prior to
+that, we had a much older set of keys generated in 2000. For each of
+the three key types above, we provided both an RSA key \e{and} a DSA
+key (because at the time we generated them, RSA was not in practice
+available to everyone, due to export restrictions).
+
+The new Master Key is signed with both of the old ones, to show that
+it really is owned by the same people and not substituted by an
+attacker. Also, we have retrospectively signed the old Release Keys
+with the new Master Key, in case you're trying to verify the
+signatures on a release prior to the rollover and can find a chain of
+trust to those keys from any of the people who have signed our new
+Master Key.
+
+Future releases will be signed with the up-to-date keys shown above.
+Releases prior to the rollover are signed with the old Release Keys.
+
+For completeness, those old keys are given here:
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/master-rsa.asc}{\s{Master Key} (original RSA)}
+
+\dd RSA, 1024-bit. Key ID: \cw{1024R/1E34AC41} (long version:
+\cw{1024R/9D5877BF1E34AC41}). Fingerprint:
+\cw{8F\_15\_97\_DA\_25\_30\_AB\_0D\_\_88\_D1\_92\_54\_11\_CF\_0C\_4C}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/master-rsa.asc}{\s{Master Key} (original DSA)}
+
+\dd DSA, 1024-bit. Key ID: \cw{1024D/6A93B34E} (long version:
+\cw{1024D/4F5E6DF56A93B34E}). Fingerprint:
+\cw{313C\_3E76\_4B74\_C2C5\_F2AE\_\_83A8\_4F5E\_6DF5\_6A93\_B34E}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/release-rsa.asc}{\s{Release Key} (original RSA)}
+
+\dd RSA, 1024-bit. Key ID: \cw{1024R/B41CAE29} (long version:
+\cw{1024R/EF39CCC0B41CAE29}). Fingerprint:
+\cw{AE\_65\_D3\_F7\_85\_D3\_18\_E0\_\_3B\_0C\_9B\_02\_FF\_3A\_81\_FE}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/release-rsa.asc}{\s{Release Key} (original DSA)}
+
+\dd DSA, 1024-bit. Key ID: \cw{1024D/08B0A90B} (long version:
+\cw{1024D/FECD6F3F08B0A90B}). Fingerprint:
+\cw{00B1\_1009\_38E6\_9800\_6518\_\_F0AB\_FECD\_6F3F\_08B0\_A90B}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/snapshot-rsa.asc}{\s{Snapshot Key} (original RSA)}
+
+\dd RSA, 1024-bit. Key ID: \cw{1024R/32B903A9} (long version:
+\cw{1024R/FAAED21532B903A9}). Fingerprint:
+\cw{86\_8B\_1F\_79\_9C\_F4\_7F\_BD\_\_8B\_1B\_D7\_8E\_C6\_4E\_4C\_03}
+
+\dt \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/keys/snapshot-rsa.asc}{\s{Snapshot Key} (original DSA)}
+
+\dd DSA, 1024-bit. Key ID: \cw{1024D/7D3E4A00} (long version:
+\cw{1024D/165E56F77D3E4A00}). Fingerprint:
+\cw{63DD\_8EF8\_32F5\_D777\_9FF0\_\_2947\_165E\_56F7\_7D3E\_4A00}
projects / PuTTY.git / commitdiff