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gpgsm decryption with smartcard fails with "Invalid session key"
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Description

I am trying to use a X509 certificate with the private keys on a OpenPGP V2.0
smartcard, but I cannot decrypt messages: gpgsm aborts with the error "Invalid
session key".

If I manually decrypt the RSA-encrypted session key by talking to scdaemon
directly, I can successfully decode the AES-encrypted message block to the
cleartext I put in at the beginning.

What is going wrong here?

Here is a complete transcript:

lorenz@host:~/gpgsm_problem> gpgsm -K mail@example.com

/home/lorenz/.gnupg/pubring.kbx

       ID: 0xA2D76777
      S/N: 52DF665BB71FAF4F
   Issuer: /CN=mail@example.com
  Subject: /CN=mail@example.com
      aka: mail@example.com
 validity: 2016-01-27 15:35:46 through 2063-04-05 17:00:00
 key type: 4096 bit RSA
key usage: digitalSignature nonRepudiation keyEncipherment dataEncipherment

chain length: unlimited

fingerprint: A2:A0:4A:AA:7A:16:32:B5:82:FD:20:54:F7:5F:DE:AB:A2:D7:67:77
   card s/n: D27600012401020000050000280D0000

lorenz@host:~/gpgsm_problem> cat cleartext
0123456789abcdef0123
lorenz@host:~/gpgsm_problem> gpgsm --no-encrypt-to -e -r mail@example.com >
gpgsm_encrypted < cleartext
gpgsm: CRLs not checked due to --disable-crl-checks option
gpgsm: encrypted data created
lorenz@host:~/gpgsm_problem> gpgsm -d gpgsm_encrypted
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: CRLs not checked due to --disable-crl-checks option
gpgsm: DBG: recp 0 - issuer: 'CN=mail@example.com'
gpgsm: DBG: recp 0 - serial: 52DF665BB71FAF4F
gpgsm: decrypting session key failed: Invalid session key
gpgsm: message decryption failed: No secret key <GpgSM>
lorenz@host:~/gpgsm_problem>

I cobbled together a small script to manually decrypt the message using
openssl asn1parse, gpg-agent-connect and pycrypto, which works:

lorenz@host:~/gpgsm_problem> ./decode
Files cleartext and - are identical

I attach a tar-ball with all the files used as well as the scripts for the
manual decryption. Also, the decrypted session key for my message. Is there
anything more I could do to help?

Regards,

Lorenz

Related Objects

Event Timeline

lorenz added a project: Bug Report.Jan 27 2016, 5:08 PM
lorenz added a subscriber: lorenz.

757_gpgsm_problem.tar.gz30 KBDownload

• werner added projects: scd, gnupg.Jan 28 2016, 12:07 PM
• werner added a subscriber: • werner.Jan 28 2016, 12:11 PM

Which OS and which gnupg version are you using?

Use

gpgsm --debug 4 -d gpgsm_encrypted

to see the session key before gpgsm detects thaty it is invalid.

lorenz added a comment.Jan 28 2016, 12:23 PM

Thanks for looking at this!

I am on openSUSE (Tumbleweed), my gnupg version is
lorenz@host:~/gpgsm_problem> gpgsm --version
gpgsm (GnuPG) 2.1.10
libgcrypt 1.6.4
libksba 1.3.3
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Home: ~/.gnupg
Supported algorithms:
Cipher: 3DES, AES128, AES192, AES256, SERPENT128, SERPENT192, SERPENT256, SEED,
CAMELLIA128, CAMELLIA192, CAMELLIA256
Pubkey: RSA, ECC
Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224, WHIRLPOOL

If I run

  gpgsm --debug 4 -d gpgsm_encrypted

the same session key is printed that my script got

Here is a full transcript:

lorenz@host:~/gpgsm_problem> gpgsm --debug 4 -d gpgsm_encrypted
gpgsm: reading options from '/home/lorenz/.gnupg/gpgsm.conf'
gpgsm: enabled debug flags: crypto
gpgsm: failed to open '/home/lorenz/.gnupg/policies.txt': No such file or directory
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: DBG: signature value: 28 37 3A 73 69 67 2D 76 61 6C 28 33 3A 72 73 61 28
31 3A 73 32 35 36 3A 75 46 91 66 A9 B6 A0 46 03 85 68 F1 E8 A5 37 14 30 BA E5 B6
A2 D6 5C E8 26 31 C7 9A AF 27 96 54 CD 6D 73 8C 70 73 CA C9 E9 73 9C E2 B3 5E 50
9B 7D 6A 5E C7 9E C4 34 FE 1B E1 9C DC 14 56 3F F4 29 A2 07 47 9D A5 5D 0E BE C3
F3 6E E6 49 3C 96 BB 43 3A 5B 1C 56 10 E3 3B 0C 3F 67 2F 31 B9 BF B7 38 4F CA C7
55 20 AC 50 76 6A CB FC C9 15 29 D5 10 89 31 88 A9 87 ED DC 2B A3 7C 22 E5 04 4F
16 A8 32 DF 62 56 B1 88 C8 80 0B 4B 93 E7 8A D4 35 D3 14 62 40 FB 87 82 EF E3 4F
DE ED 27 BF 0B 01 B1 49 C5 20 03 1A 04 87 31 55 14 7F B3 91 31 8A A8 E5 0C CF CE
25 77 6C A1 5C 5D EB 74 D5 28 4D DB 90 6A 87 B3 91 48 A0 72 10 2C C7 DD DA 2F E0
2E AA D1 BD D0 16 50 DB 30 12 08 C4 3A 62 DB 4F 77 E1 5E 18 ED 22 C1 70 32 2F C3
6A DE 66 B2 47 52 48 B2 86 B1 32 6C 6E 27 04 12 A8 E1 48 8A 29 29 28 34 3A 68 61
73 68 36 3A 73 68 61 32 35 36 29 29
gpgsm: DBG: encoded hash: 00 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 00 30 31
30 0D 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 82 A4 B2 5B 4E 14 77 27 0B 73
12 97 8F 56 FC 61 42 7E 37 3F 8B 74 3F 4E 40 2D 38 C1 08 47 32 6C
DBG: rsa_verify
data:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d06096086480165030402010500042082 \
DBG: a4b25b4e1477270b7312978f56fc61427e373f8b743f4e402d38c10847326c
DBG: rsa_verify
sig:+75469166a9b6a046038568f1e8a5371430bae5b6a2d65ce82631c79aaf279654 \
DBG:
cd6d738c7073cac9e9739ce2b35e509b7d6a5ec79ec434fe1be19cdc14563ff4 \
DBG:
29a207479da55d0ebec3f36ee6493c96bb433a5b1c5610e33b0c3f672f31b9bf \
DBG:
b7384fcac75520ac50766acbfcc91529d510893188a987eddc2ba37c22e5044f \
DBG:
16a832df6256b188c8800b4b93e78ad435d3146240fb8782efe34fdeed27bf0b \
DBG:
01b149c520031a04873155147fb391318aa8e50ccfce25776ca15c5deb74d528 \
DBG:
4ddb906a87b39148a072102cc7ddda2fe02eaad1bdd01650db301208c43a62db \
DBG:
4f77e15e18ed22c170322fc36ade66b2475248b286b1326c6e270412a8e1488a
DBG: rsa_verify
n:+d851729ea0d4cb8241b06da9e2e2b96e6b98f39732127c79da8ffe6a4be9a88d \
DBG:
0a80fde61ad1b1ae732955e61c90bb2273edde2045c91d84c0d5f03648c44454 \
DBG:
22c1655c58fa1c61e36998e58481dba384b5d868cb8531f9619dfb3bb307570d \
DBG:
0bfc9861cd423111233565f453ff12ea873da27496234fdf16f4e16fccf813d3 \
DBG:
2add89e33390b533e57fdfa58f0cbb26018319dd741251c3a66d9617429a5e05 \
DBG:
f10df9a526fc276a80362c2e255bb75824e02ffc9da37780f2f0e278c319ecef \
DBG:
8bd700270b305b1c08c9e47eb153507b9a5c26bbb577a53a0a3e07169a53b41d \
DBG:
c4e96baf0c70d4c61a263ca4ed3f467d5f5e4a8361ff33d253dd5945b16ccd51
DBG: rsa_verify e:+010001
DBG: rsa_verify
cmp:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d06096086480165030402010500042082 \
DBG: a4b25b4e1477270b7312978f56fc61427e373f8b743f4e402d38c10847326c
DBG: rsa_verify => Good
gpgsm: certificate is good
gpgsm: failed to open '/home/lorenz/.gnupg/policies.txt': No such file or directory
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: DBG: signature value: 28 37 3A 73 69 67 2D 76 61 6C 28 33 3A 72 73 61 28
31 3A 73 32 35 36 3A 3F DC 77 C2 D3 F0 64 6C AE 20 91 39 59 AF F4 E8 EC B3 F2 B4
BA 19 9A 85 9D 7B 8D 07 59 B8 F8 38 FF 54 7D 5D 80 5D 5B 7C B2 9B 86 48 61 6B DB
ED 8B DD 8E 78 1B 5D 62 0F E6 CF CA AF 78 52 64 7E B7 74 5C F0 57 FF 15 EA 7E DE
E7 A5 CA 73 DE F6 F5 B4 1D B9 39 C0 B3 EF 98 4F 15 14 CB 4E 69 16 76 B8 EC DB FD
04 26 E2 4B 91 13 5D 42 99 3C C2 09 03 4D 57 C0 0E F2 5E 41 4F F9 B4 5D 98 94 6C
16 7F 30 78 A6 E3 9C E1 35 76 6E B8 B5 7E AE A5 F3 F5 37 C8 56 90 67 EC 23 0C 8E
D8 DE 3B 49 31 EB BF 4F D5 3E 51 E1 2B 16 1D 2D 64 34 EE A6 C4 D6 9F C8 BD 05 B2
98 84 90 7B 02 C1 8E 63 BB DA 05 81 E2 87 06 03 67 D3 AC 3E F7 C2 7D BD 5F 86 6C
47 51 E7 D3 9C 62 E8 F2 D0 D3 A1 D0 3B 11 91 AD 2F 5E 10 3D 14 42 81 D8 CD FD 45
D1 AD E8 FB 36 3A 3A 7C 8D 69 C0 A6 77 85 6B 60 67 52 B4 1C 29 29 28 34 3A 68 61
73 68 36 3A 73 68 61 32 35 36 29 29
gpgsm: DBG: encoded hash: 00 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 00 30 31
30 0D 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 AC 84 B9 EC BF F8 15 90 76 00
F8 4A 76 2E 6E 51 C9 40 2B 43 D9 FB 28 C4 C1 E1 94 EC D5 14 4B D0
DBG: rsa_verify
data:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d060960864801650304020105000420ac \
DBG: 84b9ecbff815907600f84a762e6e51c9402b43d9fb28c4c1e194ecd5144bd0
DBG: rsa_verify
sig:+3fdc77c2d3f0646cae20913959aff4e8ecb3f2b4ba199a859d7b8d0759b8f838 \
DBG:
ff547d5d805d5b7cb29b8648616bdbed8bdd8e781b5d620fe6cfcaaf7852647e \
DBG:
b7745cf057ff15ea7edee7a5ca73def6f5b41db939c0b3ef984f1514cb4e6916 \
DBG:
76b8ecdbfd0426e24b91135d42993cc209034d57c00ef25e414ff9b45d98946c \
DBG:
167f3078a6e39ce135766eb8b57eaea5f3f537c8569067ec230c8ed8de3b4931 \
DBG:
ebbf4fd53e51e12b161d2d6434eea6c4d69fc8bd05b29884907b02c18e63bbda \
DBG:
0581e287060367d3ac3ef7c27dbd5f866c4751e7d39c62e8f2d0d3a1d03b1191 \
DBG:
ad2f5e103d144281d8cdfd45d1ade8fb363a3a7c8d69c0a677856b606752b41c
DBG: rsa_verify
n:+e99bc36785f90daef58d54c39650353d62e96e4ced94d7005b952274d420eb34 \
DBG:
8fd6ecc031040b9981e2a614d252a02823848b7489045e5be0e278c178cb16cb \
DBG:
2835397b2d9045d0eda0007a7cbf4a0e1b00c386e95c2b31117b0cf38224438c \
DBG:
1c388b6a68009aeedc4f78abd2c6139b76adeede26e8ef01af740fc109a2f66b \
DBG:
cebdd3cd14304ff5e5e3a4c8629b821a0327300d0265604dedd109232a963558 \
DBG:
27d376c671b6901dc4edff35867d6f33b3db0fc511c28a83a1945d416bd8d210 \
DBG:
f54cfdca51acd9bdef9283bbdaeb8b16565643cfe1d5133da61f2730cd4954db \
DBG:
c913349a7175c56ceaa70b98f9219d27af3ea33939486a8cadc999fbc312f2bd
DBG: rsa_verify e:+010001
DBG: rsa_verify
cmp:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d060960864801650304020105000420ac \
DBG: 84b9ecbff815907600f84a762e6e51c9402b43d9fb28c4c1e194ecd5144bd0
DBG: rsa_verify => Good
gpgsm: intermediate certificate is good
gpgsm: failed to open '/home/lorenz/.gnupg/policies.txt': No such file or directory
gpgsm: Note: non-critical certificate policy not allowed
gpgsm: DBG: signature value: 28 37 3A 73 69 67 2D 76 61 6C 28 33 3A 72 73 61 28
31 3A 73 32 35 36 3A 63 20 28 FD 9C 21 86 72 BE 39 46 59 39 32 25 BC A9 01 9B 0D
CC CA 7D 41 9C 86 6D 0A 6E 2C B3 13 59 75 B1 33 92 1B 61 27 16 FF C3 B2 D5 35 82
FB 84 2A 01 49 BD 66 BB 66 2F B2 C2 06 5D 6E 3F 6E E3 01 5A 5B CA 43 63 5C 95 B6
E1 31 A7 1F D5 07 5F 4D E6 65 82 4E 32 F9 C3 7C 7A 4B CD 4D 5C 74 EE 21 F2 75 02
EC 52 3E D2 C9 6A D3 90 23 6E 49 67 35 BE 7F 4D 56 A4 EC CC 2F CF B7 A1 97 A8 72
3E C9 BC 40 D6 5A A4 08 3D D6 BC 82 C3 B7 B7 32 8E B1 2C 8E 6A 6D B7 35 02 19 CF
F5 39 44 58 63 A7 24 00 10 B0 BB FC 4E AF 6E 2F 38 BB A5 57 49 3F D8 6E 50 6F 2C
97 96 DC 1D 46 9A 65 89 CF AE CC F2 E5 D9 9F 53 B3 3E A1 2F 92 A9 D8 0B C6 84 1F
04 C6 EB 1E E8 9F 7D B5 7B A5 02 F1 24 C5 24 63 11 34 CC 5A 93 20 2A 79 88 3A 25
42 90 A9 65 3B 7C 86 D3 12 15 23 29 FC 2C DA CC 39 5B 54 17 29 29 28 34 3A 68 61
73 68 36 3A 73 68 61 32 35 36 29 29
gpgsm: DBG: encoded hash: 00 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 00 30 31
30 0D 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 DF 7B C9 01 35 70 5A 34 2B 30
ED 96 C6 35 7F 80 51 5A 56 9C B6 89 F2 9D 69 DE E4 02 3F 5E 7C 9A
DBG: rsa_verify
data:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d060960864801650304020105000420df \
DBG: 7bc90135705a342b30ed96c6357f80515a569cb689f29d69dee4023f5e7c9a
DBG: rsa_verify
sig:+632028fd9c218672be394659393225bca9019b0dccca7d419c866d0a6e2cb313 \
DBG:
5975b133921b612716ffc3b2d53582fb842a0149bd66bb662fb2c2065d6e3f6e \
DBG:
e3015a5bca43635c95b6e131a71fd5075f4de665824e32f9c37c7a4bcd4d5c74 \
DBG:
ee21f27502ec523ed2c96ad390236e496735be7f4d56a4eccc2fcfb7a197a872 \
DBG:
3ec9bc40d65aa4083dd6bc82c3b7b7328eb12c8e6a6db7350219cff539445863 \
DBG:
a7240010b0bbfc4eaf6e2f38bba557493fd86e506f2c9796dc1d469a6589cfae \
DBG:
ccf2e5d99f53b33ea12f92a9d80bc6841f04c6eb1ee89f7db57ba502f124c524 \
DBG:
631134cc5a93202a79883a254290a9653b7c86d312152329fc2cdacc395b5417
DBG: rsa_verify
n:+ab0ba335e08b2914b11485af3c10e4396f355d4aaeddea618d9549f46f64a31a \
DBG:
6066a4a9402284d9d4a5e578930e6801adb94d5c3aced3b8a84240dfcfa3ba82 \
DBG:
596a921bac1c9ada082b2527f9692347f1e0eb2c7a9bf51302d07e347cc29e3c \
DBG:
0059abf5da0cf5323c2bac50dad6c3de8394caa80c99320e0848565b6afbdae1 \
DBG:
585801495f72413c1506018e5dadaab893b4cd9eeba7e86a2d5234db3aef5c75 \
DBG:
51dadbf331f9ee719832c45415440cf99b55edaddf1808a0a3868a49ee53058f \
DBG:
194cd5de58799bd26a1c42abc5d5a7cf680f96e4e161987661c8917cd63e00e2 \
DBG:
915087e19d0ae6ad97d21dc63a7dcbbcda0334d58e5b01f56a07b716b66e4a7f
DBG: rsa_verify e:+010001
DBG: rsa_verify
cmp:+01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff \
DBG:
ffffffffffffffffffffff003031300d060960864801650304020105000420df \
DBG: 7bc90135705a342b30ed96c6357f80515a569cb689f29d69dee4023f5e7c9a
DBG: rsa_verify => Good
gpgsm: root certificate is good
gpgsm: CRLs not checked due to --disable-crl-checks option
gpgsm: validation model used: shell
gpgsm: DBG: recp 0 - issuer: 'CN=mail@example.com'
gpgsm: DBG: recp 0 - serial: 52DF665BB71FAF4F
gpgsm: DBG: pkcs1 encoded session key: 11 E8 C4 40 93 A8 24 35 16 57 93 8D 03 00
63 5F
gpgsm: decrypting session key failed: Invalid session key
gpgsm: message decryption failed: No secret key <GpgSM>
secmem usage: 0/16384 bytes in 0 blocks

• werner added a comment.Jan 29 2016, 9:36 AM

Look here:

gpgsm: DBG: pkcs1 encoded session key: 11 E8 C4 40 93 A8 24 35 16 57 93 8D 03 00
63 5F
gpgsm: decrypting session key failed: Invalid session key

This is clearly not a PKCS#1 encoded session key but a plain session key. This
is likey due to the card already decoding the pkcs#1 - we need to look closer at
this use case.

• werner added a project: S/MIME.Jan 29 2016, 9:37 AM
lorenz added a comment.Jan 29 2016, 10:31 AM

This is likey due to the card already decoding the pkcs#1 - we need to look
closer at this use case.

For reference, I have a OpenPGP v2.0 card from "ZeitControl".

I think the card will always remove the encoding internally and only return the
plaintext, as far as I can tell from
http://g10code.com/docs/openpgp-card-2.0.pdf, Section 7.2.9

lorenz added a comment.Feb 24 2016, 4:05 PM

For what it's worth, with the following trivial patch the decryption works:

diff --git a/sm/decrypt.c b/sm/decrypt.c
index a560272..aa6e874 100644

  • a/sm/decrypt.c

+++ b/sm/decrypt.c
@@ -74,9 +74,9 @@ prepare_decryption (ctrl_t ctrl, const char *hexkeygrip, const
char *desc,

    log_printhex ("pkcs1 encoded session key:", seskey, seskeylen);

  n=0;
  • if (seskeylen == 24)

+ if (seskeylen == 24 || seskeylen == 16)

{
  • /* Smells like a 3-des key. This might happen because a SC has

+ /* Smells like a 3-des or AES key. This might happen because a SC has

          already done the unpacking. */
     }
   else

I am not sure this is a good solution, though, it is probably better to somehow
pass along the information whether the padding is already stripped or not.

Kind regards,

Lorenz
lorenz added a comment.May 13 2016, 10:12 AM

Anything else I can do to help?

lorenz added a comment.Nov 29 2016, 4:58 PM

What about putting in the suggested patch as an intermediate step towards a full
solution?

• werner added a comment.Nov 29 2016, 7:51 PM

Yeah, lets do that. Commit 8489b12 to go into 2.1.17. Thanks.

• werner added a project: Restricted Project.Nov 29 2016, 7:51 PM
• werner closed this task as Resolved.Apr 3 2017, 10:51 PM
• werner claimed this task.

we are now at 2.1.20 - time to mark this one as resolved.