Unexpected verification failures w\ YubiHSM2-generated signatures

[tarcieri]

I've been using this crate to test ECDSA over secp256k1 signatures generated by YubiHSM2 hardware devices, and encountering sporadic failures. Not sure exactly where the problem lies, but things seem to be working rather sporadically.

Here are 3 batches of signatures generated by the YubiHSM2, with two signatures over the same message each under a different private key, and whether or not they verify or fail. All of the signatures are ASN.1 DER encoded (verbatim as generated by the HSM).

Test Message

54:68:65:20:45:6c:6c:69:70:74:69:63:20:43:75:72:76:65:20:44:69:67:69:74:61:6c:20:53:69:67:6e:61:74:75:72:65:20:41:6c:67:6f:72:69:74:68:6d:20:28:45:43:44:53:41:29:20:69:73:20:61:20:76:61:72:69:61:6e:74:20:6f:66:20:74:68:65:20:44:69:67:69:74:61:6c:20:53:69:67:6e:61:74:75:72:65:20:41:6c:67:6f:72:69:74:68:6d:20:28:44:53:41:29:20:77:68:69:63:68:20:75:73:65:73:20:65:6c:6c:69:70:74:69:63:20:63:75:72:76:65:20:63:72:79:70:74:6f:67:72:61:70:68:79:2e

Key 1

Public Key:

04:48:04:8e:c0:3c:5b:83:cb:25:0b:86:14:d1:ec:ad:5e:1e:ed:2e:78:c7:57:53:95:c7:81:9c:6c:89:1d:41:8a:12:ab:b6:f8:80:cd:f6:c8:5b:93:8c:78:f3:85:82:72:e3:1e:c1:58:39:ab:e1:12:7e:71:9a:87:ab:07:d6:48

Sig 1 [OK]

30:45:02:21:00:a5:2c:6e:0e:08:7b:f1:a9:9f:dc:2f:fd:c8:55:a1:20:d6:15:ee:e2:02:6f:f7:ae:e6:0f:ba:17:f0:9f:fe:2c:02:20:78:74:d2:10:a2:37:41:80:34:bb:c1:5c:0f:c0:d6:3f:a9:cd:49:93:83:5e:ce:ef:53:04:e5:cd:a1:47:43:80

Sig 2 [OK]

30:45:02:21:00:da:3c:23:b0:ce:80:d5:78:3c:87:fd:5c:fe:ca:ab:11:8d:ab:94:9e:79:46:b3:95:6f:58:27:c3:54:fc:1b:34:02:20:40:6d:a2:0e:a1:2c:66:92:f7:9e:bc:19:83:aa:b2:17:18:bc:66:11:55:55:f5:48:ac:07:a7:49:70:9e:c2:a0

Key 2

Public Key:

04:b0:25:84:9f:ad:1a:e5:55:d2:64:a7:b3:2e:8a:fd:0f:69:ba:26:ec:31:1f:c8:ab:bb:86:54:a4:d5:f5:1a:82:33:5d:ff:37:31:e6:c9:93:ee:a5:0c:be:ed:86:fc:e7:a7:58:fb:c6:38:35:1b:70:f9:fc:81:e7:c1:6f:af:15

Sig 1 [OK]:

30:45:02:21:00:ef:a4:28:48:af:03:59:61:7e:72:d1:39:e0:e6:e1:8d:a0:7e:39:84:88:4d:4a:d8:e5:85:89:84:e0:c9:f5:1d:02:20:5e:3a:df:15:a2:de:ff:ed:a8:4f:76:62:9a:28:34:a5:a1:b2:f2:0f:25:6d:f8:84:7f:c3:28:86:58:26:b2:6b

Sig 2 [FAIL]:

30:46:02:21:00:8b:79:67:4d:5d:37:43:ea:22:23:d0:7a:7c:f2:82:d9:67:29:f4:92:53:e6:a6:c7:12:b0:d4:bb:c8:1b:ef:80:02:21:00:b1:21:78:cf:c5:e5:e9:c7:14:3d:e4:c9:81:a5:85:6b:31:21:9a:28:d3:18:8b:c2:b0:32:0d:66:7e:1d:fe:3d

Key 3

Public Key:

04:34:c2:a4:a9:e8:b3:e5:30:66:de:48:a5:e3:9f:97:a1:98:5a:3a:10:4a:21:4e:65:57:40:c1:cf:44:e2:48:39:5f:c9:42:d5:8b:00:5c:0d:20:7a:0e:7d:0e:41:bf:fa:92:de:4d:e9:90:1e:f0:a9:26:96:a5:7f:11:c8:75:f0

Sig 1 [FAIL]:

30:45:02:20:17:a5:6a:e5:d7:d3:dc:2c:4f:b8:ad:e0:1b:d9:2e:e3:12:46:b4:80:38:e4:c5:9c:12:9e:e3:44:bc:11:1a:9d:02:21:00:e0:56:a4:b1:6a:cb:15:4e:3b:03:61:84:ce:c9:5e:00:d4:54:e3:77:1a:20:43:33:90:ae:87:94:3c:cd:4d:9b

Sig 2 [FAIL]:

30:45:02:20:12:94:9e:42:cd:54:fb:9f:da:6e:5f:05:b4:1a:c4:ea:c8:1d:4f:81:38:6e:f2:86:fe:96:57:2a:65:80:82:05:02:21:00:9e:a5:3d:e8:bc:3b:0c:8d:d5:7a:1e:94:93:71:cf:b1:28:d2:43:4e:2c:a7:d1:7c:aa:39:66:4b:01:38:d8:f2

[apoelstra]

Can you try running Signature::normalize_s on the bad signatures and see if that fixes it?

[tarcieri]

That fixed it, thanks.