gpg: default to 3072-bit RSA keys.

* agent/command.c (hlp_genkey): update help text to suggest the use of
3072 bits.
* doc/wks.texi: Make example match default generation.
* g10/keygen.c (DEFAULT_STD_KEY_PARAM): update to
rsa3072/cert,sign+rsa3072/encr, and fix neighboring comment,
(gen_rsa, get_keysize_range): update default from 2048 to 3072).
* g10/keyid.c (pubkey_string): update comment so that first example
is the default 3072-bit RSA.

--

3072-bit RSA is widely considered to be 128-bit-equivalent security.
This is a sensible default in 2017.

Signed-off-by: Daniel Kahn Gillmor <[email protected]>

(cherry picked from commit 909fbca19678e6e36968607e8a2348381da39d8c)

Gbp-Pq: Topic from-master
Gbp-Pq: Name gpg-default-to-3072-bit-RSA-keys.patch

4 files changed, 9 insertions, 10 deletions

diff --git a/agent/command.c b/agent/command.c
index c24fc80fd..72b597318 100644
--- a/agent/command.c
+++ b/agent/command.c
@@ -843,7 +843,7 @@ static const char hlp_genkey[] =
   "\n"
   "  C: GENKEY\n"
   "  S: INQUIRE KEYPARAM\n"
-  "  C: D (genkey (rsa (nbits  2048)))\n"
+  "  C: D (genkey (rsa (nbits 3072)))\n"
   "  C: END\n"
   "  S: D (public-key\n"
   "  S: D   (rsa (n 326487324683264) (e 10001)))\n"
diff --git a/doc/wks.texi b/doc/wks.texi
index 119e31ca9..ae6c310fa 100644
--- a/doc/wks.texi
+++ b/doc/wks.texi
@@ -412,10 +412,10 @@ the submission address:
 The output of the last command looks similar to this:
 
 @example
-  sec   rsa2048 2016-08-30 [SC]
+  sec   rsa3072 2016-08-30 [SC]
         C0FCF8642D830C53246211400346653590B3795B
   uid           [ultimate] key-submission@@example.net
-  ssb   rsa2048 2016-08-30 [E]
+  ssb   rsa3072 2016-08-30 [E]
 @end example
 
 Take the fingerprint from that output and manually publish the key:
diff --git a/g10/keygen.c b/g10/keygen.c
index 6042226e2..aa45ff385 100644
--- a/g10/keygen.c
+++ b/g10/keygen.c
@@ -46,11 +46,10 @@
 #include "../common/mbox-util.h"
 
 
-/* The default algorithms.  If you change them remember to change them
-   also in gpg.c:gpgconf_list.  You should also check that the value
+/* The default algorithms.  If you change them, you should ensure the value
    is inside the bounds enforced by ask_keysize and gen_xxx.  See also
    get_keysize_range which encodes the allowed ranges.  */
-#define DEFAULT_STD_KEY_PARAM  "rsa2048/cert,sign+rsa2048/encr"
+#define DEFAULT_STD_KEY_PARAM  "rsa3072/cert,sign+rsa3072/encr"
 #define FUTURE_STD_KEY_PARAM   "ed25519/cert,sign+cv25519/encr"
 
 /* When generating keys using the streamlined key generation dialog,
@@ -1652,7 +1651,7 @@ gen_rsa (int algo, unsigned int nbits, KBNODE pub_root,
 
   if (nbits < 1024)
     {
-      nbits = 2048;
+      nbits = 3072;
       log_info (_("keysize invalid; using %u bits\n"), nbits );
     }
   else if (nbits > maxsize)
@@ -2121,7 +2120,7 @@ get_keysize_range (int algo, unsigned int *min, unsigned int *max)
     default:
       *min = opt.compliance == CO_DE_VS ? 2048: 1024;
       *max = 4096;
-      def = 2048;
+      def = 3072;
       break;
     }
 
diff --git a/g10/keyid.c b/g10/keyid.c
index 5b868cd9c..af9be0761 100644
--- a/g10/keyid.c
+++ b/g10/keyid.c
@@ -73,7 +73,7 @@ pubkey_letter( int algo )
    is copied to the supplied buffer up a length of BUFSIZE-1.
    Examples for the output are:
 
-   "rsa2048"  - RSA with 2048 bit
+   "rsa3072"  - RSA with 3072 bit
    "elg1024"  - Elgamal with 1024 bit
    "ed25519"  - ECC using the curve Ed25519.
    "E_1.2.3.4"  - ECC using the unsupported curve with OID "1.2.3.4".
@@ -83,7 +83,7 @@ pubkey_letter( int algo )
    If the option --legacy-list-mode is active, the output use the
    legacy format:
 
-   "2048R" - RSA with 2048 bit
+   "3072R" - RSA with 3072 bit
    "1024g" - Elgamal with 1024 bit
    "256E"  - ECDSA using a curve with 256 bit