I am trying to get the NAL units from an mp4 file using C. I got inside the "mdat" atom and tried extracting the NAL units. The first 3 were as "size, data" where size is the size of data in bytes. After that, I continued looking for the next unit. The size was 0xde02004c, which is too big. When I checked it with the hex editor, I saw that that is indeed true. But then I noticed the "Lavc" written right next to it.
00004930 92 43 19 61 93 4e de 02 00 4c 61 76 63 35 38 2e |.C.a.N...Lavc58.|
00004940 35 34 2e 31 30 30 00 42 20 08 c1 18 38 00 00 00 |54.100.B ...8...|
00004950 c9 01 9e 41 79 09 7f 7a 03 ed 3f 54 39 fb c2 01 |...Ay..z..?T9...|
00004960 c4 53 76 51 2d bf 57 5f 04 25 00 b9 fb df 43 67 |.SvQ-.W_.%....Cg|
00004970 f3 27 b9 f5 d7 e7 95 e9 b4 06 14 6b 4a c7 4e ff |.'.........kJ.N.|
00004980 23 ed 8f 17 d0 4d d4 21 a7 b3 84 0e 65 60 41 67 |#....M.!....e`Ag|
00004990 ec db 10 c9 b3 4c 3f 71 df 6b 73 c2 df cd fe 85 |.....L?q.ks.....|
The previous NAL unit ends right before the bytes "de 02 00 4c", so that should be the size of the next one. But it isn't. It looks like codec information. Why?
Edit: The first bytes of the first nalu:
00 00 02 af 06 05 ff ff ┊ ab dc 45 e9 bd e6 d9 48 │00•×••××┊××E××××H│
b7 96 2c d8 20 d9 23 ee ┊ ef 78 32 36 34 20 2d 20 │××,× ×#×┊×x264 - │
the second:
00 00 41 80 65 ┊ 88 84 01 ff 5e e7 6f ea
36 23 b7 5d 16 f8 5f 54 ┊ a3 5d 7c 9e ac d1 9b f6
and the third:
00 04 cb 41 9a 22 6c 5f
6e 75 69 b0 e3 e1 d9 c9 ┊ d4 71 cb 05 a3 60 09 71 ```
Related
After getting data from old software, I can save it to a file with a specific format.
I wanted to extract the data from this file.
Unfortunately, this format is unreadable.
It seems to have specific characters (? or #).
I don't really understand how it is encoded but I have the data in the software to check the answer.
Here is a small sample of the bytes that the file contains:
0000-06f0: 10 db 2f 34-dc 80 c4 3f-8c e7 f7 ae-e6 61 02 40 ../4...? .....a.#
0000-0700: 41 69 af a4-f1 9e c2 3f-d9 e4 52 91-d4 1e 02 40 Ai.....? ..R....#
0000-0710: 50 0f be bc-f0 b5 c3 3f-df 4e 84 c9-0e e0 02 40 P......? .N.....#
0000-0720: 51 fe 42 71-a4 15 c3 3f-52 58 bc ab-ff f5 02 40 Q.Bq...? RX.....#
0000-0730: f6 26 e6 87-3c 27 c3 3f-ef 02 25 a5-db 9b 02 40 .&..<'.? ..%....#
0000-0740: 1e d4 37 19-a1 56 c3 3f-b5 76 c8 6a-34 3c 02 40 ..7..V.? .v.j4<.#
0000-0750: 81 34 51 8c-b0 f8 c4 3f-2e 74 d6 cd-4a 84 01 40 .4Q....? .t..J..#
0000-0760: 14 c7 40 00-7a 93 c5 3f-02 43 07 2b-76 a4 01 40 ..#.z..? .C.+v..#
0000-0770: c9 2d 42 c2-03 51 c6 3f-0c c5 30 d2-b5 38 01 40 .-B..Q.? ..0..8.#
0000-0780: 70 3e bb b0-cb 0a c8 3f-4b b7 12 c7-28 18 00 40 p>.....? K...(..#
0000-0790: 6a ad b4 7a-62 ae c7 3f-90 11 50 41-f1 f2 fd 3f j..zb..? ..PA...?
0000-07a0: 3a e9 01 1a-a7 f4 c7 3f-96 7b d0 a5-33 40 fd 3f :......? .{..3#.?
0000-07b0: 87 a1 ac 47-6c c0 c6 3f-90 78 3d 69-07 43 fe 3f ...Gl..? .x=i.C.?
0000-07c0: 36 d7 1c 39-43 27 c8 3f-d4 a3 47 47-80 df fd 3f 6..9C'.? ..GG...?
If someone knows how to decode it to get, it could be super useful.
Thanks.
Recently I was porting dmidecode to Windows, and was looking into SMBIOS table. I thought that will be straightforward task, just remove Linux dependent stuff from dmidecode to make it compile on windows, and instead of getting SMBIOS from memory get it with GetSystemFirmwareTable('RSMB', 0, smBiosData, size1); and feed it to other functions.
But there is a problem, GetSystemFirmwareTable reports not full SMBIOS, it is truncated at the beginning and lack some values in the header, like number of structures(I have ver 2.8 other can differ). the rest of SMBIOS is the same and can be decoded by dmidecode.
Can someone explain why is that? Or am I wrong and doing it wrong(reading SMBIOS in Windows)?
The difference:
SMBIOS from Linux(small part):
5F 53 4D 5F DF 1F 02 08 9A 00 00 00 00 00 00 00 5F 44 4D 49 5F 35 A7 09 20 00 00 00 3B 00 28 00 00 1A 00 00 01 02 00 F0 03 FF 80 98 FB 7F 01 00 00 00 03 0D 05 11 FF FF 20 00 41 6D 65 72 69 63 61 6E 20 4D 65 67 61 74 72 65 6E 64 73 20 49 6E 74 65 72 6E 61 74 69 6F 6E 61 6C 2C 20 4C 4C 43 2E 00 31 2E 44 36 00 30 31 2F 31 32 2F 32 30 32 31 00 00 01 1B 01 00 01 02 03 04 57 87 C5 95 08 81 18 D9 A7 58 00 D8 61 A1 F2 74 06 05 06 4D 69 63 72 6F 2D 53 74 61 72 20 49 6E 74 65 72 6E 61 74 69 6F 6E 61 6C 20 43 6F 2E 2C 20 4C 74 64 2E
SMBIOS from Windows(small part):
00 02 08 00 A7 09 00 00 00 1A 00 00 01 02 00 F0 03 FF 80 98 FB 7F 01 00 00 00 03 0D 05 11 FF FF 20 00 41 6D 65 72 69 63 61 6E 20 4D 65 67 61 74 72 65 6E 64 73 20 49 6E 74 65 72 6E 61 74 69 6F 6E 61 6C 2C 20 4C 4C 43 2E 00 31 2E 44 36 00 30 31 2F 31 32 2F 32 30 32 31 00 00 01 1B 01 00 01 02 03 04 57 87 C5 95 08 81 18 D9 A7 58 00 D8 61 A1 F2 74 06 05 06 4D 69 63 72 6F 2D 53 74 61 72 20 49 6E 74 65 72 6E 61 74 69 6F 6E 61 6C 20 43 6F 2E 2C 20 4C 74 64 2E
If a client connects to SQL Server, and a certificate is used to power TLS encryption, how can i get information about that certificate?
Ideally i want all the details, but i'd be happy with
Issuer: SSL_Self_Signed_Fallback
Issued to: SSL_Self_Signed_Fallback
SHA1 fingerprint: 6640479c9cac2b7ca63c9708c71a9245b951b4c7
Obviously i can't just look at the configuration on the server; as i'm trying to verify no MitM.
Also, i want to verify the correct certificate is being used (especially when no certificate is selected for use in the SQL Server Configuration Manager).
Either way: i want the client to be able to verify the certificate.
How can i get information about the certificate.
Assume:
ADO.net (SqlClient provider)
ADO (SQLOLEDB Provider)
OLEDB (SQLOLEDB Provider)
Whichever helps.
Bonus - Decoding network traffic
You can spy on the network traffic, and view the raw TLS handshake:
16 03 01 04 d0 02 00 00 51 03 01 5d a7 35 91 e7 c2 8d f3 3e d5 e4 6d ec 9a b9 7f af c1 43 ad d3 51 41 b7 44 4f 57 4e 47 52 44 00 20 d1 03 00 00 5b 82 d8 85 fe e2 b6 9a 6c ec 88 69 fc ee d3 61
23 e4 ae 17 3b be 1a e2 8f 29 23 ca c0 14 00 00 09 00 17 00 00 ff 01 00 01 00 0b 00 03 08 00 03 05 00 03 02 30 82 02 fe 30 82 01 e6 a0 03 02 01 02 02 10 20 9e 8f 8c 08 72 c1 bf 45 ad f8 df 73
1f 21 47 30 0d 06 09 2a 86 48 86 f7 0d 01 01 0b 05 00 30 3b 31 39 30 37 06 03 55 04 03 1e 30 00 53 00 53 00 4c 00 5f 00 53 00 65 00 6c 00 66 00 5f 00 53 00 69 00 67 00 6e 00 65 00 64 00 5f 00
46 00 61 00 6c 00 6c 00 62 00 61 00 63 00 6b 30 1e 17 0d 31 39 31 30 31 36 31 34 30 31 30 36 5a 17 0d 34 39 31 30 31 36 31 34 30 31 30 36 5a 30 3b 31 39 30 37 06 03 55 04 03 1e 30 00 53 00 53
00 4c 00 5f 00 53 00 65 00 6c 00 66 00 5f 00 53 00 69 00 67 00 6e 00 65 00 64 00 5f 00 46 00 61 00 6c 00 6c 00 62 00 61 00 63 00 6b 30 82 01 22 30 0d 06 09 2a 86 48 86 f7 0d 01 01 01 05 00 03
82 01 0f 00 30 82 01 0a 02 82 01 01 00 b6 dc 05 25 3e 1e 41 82 f6 b4 bc 97 1c c5 1e 02 a6 bb 1a c7 34 ed 51 cc 65 a6 60 72 0c 3c 0e ac 57 df 4f df 18 15 14 6f e0 9c d4 39 36 a1 8e 5b 17 85 0a
93 c2 78 02 70 89 f5 35 18 55 37 14 b0 6e 4c cd 0d e7 a0 81 33 c8 42 bc 55 f6 71 fa 4e d2 98 5e 63 5b 32 a6 c3 04 21 3d 22 df 8c ee a7 6e 53 4b be 3d e6 39 c9 90 c6 a9 ed df 7a a8 46 83 b9 7c
f1 03 7c 45 b1 be 42 ee 71 aa bc d6 7b 27 41 f3 b8 c4 16 2a 18 8a 38 4c 19 51 25 78 56 ce 12 75 d0 eb 29 19 c5 70 b1 c0 13 18 77 77 a6 9b 47 1f fe 1f 27 5a 50 fb 3f 73 03 c3 a0 5d 2f f4 dd 37
fd df 87 f0 80 e9 de a7 16 df ee b8 00 c2 1e 68 49 19 ce 44 f4 af ac bf d3 5f b8 1c 64 d5 95 1f 8b 32 c1 5a 80 a8 21 2d 2c 66 b8 7e 29 13 11 f8 1f e1 e9 0f 68 4e 0a b8 1b 3c f3 28 6f b7 46 85
b1 17 c9 c6 82 e4 3c 28 d4 6d d9 5b dd 02 03 01 00 01 30 0d 06 09 2a 86 48 86 f7 0d 01 01 0b 05 00 03 82 01 01 00 3e f8 c8 54 30 c1 c1 12 5e eb 01 e5 50 41 57 55 de 9e 2e 69 2a 14 fa 9a 5a 9f
d3 c3 1c 28 49 28 b2 c2 e0 cf 3d 7f 48 88 3c 25 e3 30 b7 93 e1 5c a5 9c 6f 41 b0 fb 55 67 69 e5 c5 0e 46 7c e6 2b b4 2b d8 ac 42 62 1e 18 01 69 cd e0 85 59 77 19 bd f9 17 fc 1d 10 ba 8a 93 aa
88 8e e9 73 2c 56 2e d1 5e 22 ca 20 61 4c 03 f0 70 9f a7 a7 ed 16 3a fa 00 0e 9e 39 e8 6b 99 a1 72 cb 48 b8 88 26 2d 9d 3f d6 48 70 f0 a5 51 ee c0 a9 0a e8 cf e6 ed 27 79 4d f1 23 a6 f4 64 a0
72 04 2a 3a b9 30 aa 84 e4 d2 26 9d 8c 3e b5 fe 87 ef 2c 21 c7 4e 38 1f b7 b1 25 69 68 d8 42 b1 8d 25 f3 90 14 78 d2 39 9f 0f 17 2a fc 24 2e 3b 3b 40 99 c6 fb c9 0a b0 af cd 66 f1 c9 84 c5 be
dc e9 38 bb 36 2d be 6b db db 86 95 96 c6 84 4b 7d b0 a1 ea f7 42 b2 56 93 ec e9 fd 86 8f a5 ad f0 57 63 78 d0 5a 0c 00 01 67 03 00 18 61 04 6d f6 56 8c e9 8a 82 29 0a d4 da ea be 89 52 30 bf
cd 49 66 77 7f 18 12 b1 75 44 96 d1 9e 6d 15 da 69 ba a7 7c ee 6f ab 96 ea b0 0d 64 0f c4 22 ba d7 9f 54 71 15 42 84 50 95 a4 ad 16 15 71 56 a7 0a 80 60 2d 83 86 80 0a 96 7b 30 6a aa b7 be 8f
45 9b 96 1a 5c b2 d3 e6 28 6f c4 e4 bb 70 ce 01 00 23 e6 8d 9e bf fc 90 66 f8 07 b6 6b 44 bb 03 b5 3b fd 72 fe 7b 5a e6 15 5d 10 d6 51 22 b8 44 8d 27 85 20 53 04 fb 06 32 b7 03 9e ba 7a 32 62
f1 61 25 8a c4 42 3a 02 1f be cf 92 4d 6e 48 d3 48 8b 8f 03 dc 66 d8 8b 63 21 be 6f b0 53 1c 00 37 4e 7e 4f e8 1e ba d2 c4 45 0f c0 13 ed 71 ee 47 f3 4c 0d 1d af d5 d5 bb 52 78 4b b3 55 70 4e
bc a4 f1 da 4a ec 60 7a af 81 23 49 16 57 db 8e 8b 22 65 91 3f 5b 1c 0a 13 d0 e4 b0 a4 d3 10 33 a3 bd c9 39 b6 ea 9b 73 67 11 49 ed 4f 6d 71 ae ce a3 2a 3a 6d 07 d9 d6 24 89 27 2d e6 5a e9 e1
e0 6c 47 5c c1 c0 72 01 e6 63 a6 06 7f 0d b0 16 68 7d 82 49 86 df 38 9b b4 95 5a 95 f8 e8 03 e9 63 83 7c c4 07 62 a1 f5 ce 48 0a 0c 6e 9c da e5 bf 5e e4 56 a1 de 98 80 e5 65 df eb 25 7c 38 97
8a e1 8d a3 c9 a8 a6 f8 bb 77 06 16 ec 21 8a 5c 0e 0e 00 00 00
Which can then be decoded:
Record Header
16 ; type 0x16 (22) = Handshake record
03 01 ; protocol version { 3, 1 } TLS 1.0
04 d0 ; 0x04d0 bytes of handshake message follows
Handshake
02 ; Handshake type 0x02 (2=server_hello)
00 51 ; bytes in message 0x0051 (88-bytes)
03 01 ; server_version { 3, 1 } (TLS 1.0)
5d a7 35 91 ; random.gmt_unix_time (1571239313 = 10/16/2019 3:21pm UTC)
e7 c2 8d f3 3e d5 e4 6d ; random.random_bytes 28-bytes
ec 9a b9 7f af c1 43 ad
d3 51 41 b7 44 4f 57 4e
47 52 44 00 20 d1 03 00 ; "çÂ.ó>Õämìš¹¯ÁCÓQA·DOWNGRD\0"
00 5b 82 d8 85 fe e2 b6 ; SessionID (variable length 2..32-bytes)
9a 6c ec 88 69 fc ee d3
61 23 e4 ae 17 3b be 1a
e2 8f 29 23 ca c0 14 00
00 09 ; CipherSuite { 0, 9} (TLS_RSA_WITH_DES_CBC_SHA)
00 17 ; CipherSuite { 0, 0x17 } = (TLS_DH_anon_EXPORT_WITH_RC4_40_MD5)
00 00 ; CipherSuite { 0, 0 } (TLS_NULL_WITH_NULL_NULL)
ff ; compression_method 0xff
01 ; compression_method 0x01
00 ; compression_method 0x00 (0=null)
01 00 ; ???
Handshake header
0b ; 0x0b (11) handshake message (11=certificate)
00 03 08 ; 0x308 (776) bytes of certificates to follow
Certificates length
00 03 05 ; length of all certificates to follow is 0x305 (773) bytes
Certificate 1 Length
00 03 02 ; certificate 1 length 0x302 (770) bytes
Certificate 1
30 82 02 fe 30 82 01 e6 a0 03 02 01 02 02 10 20 9e 8f 8c 08 72 c1 bf 45 ad f8 df 73 1f 21 47 30 0d 06 09 2a 86 48 86 f7 0d 01 01 0b 05 00 30 3b 31 39 30 37 06 03 55 04 03 1e 30 00
53 00 53 00 4c 00 5f 00 53 00 65 00 6c 00 66 00 5f 00 53 00 69 00 67 00 6e 00 65 00 64 00 5f 00 46 00 61 00 6c 00 6c 00 62 00 61 00 63 00 6b 30 1e 17 0d 31 39 31 30 31 36 31 34 30 31 30 36 5a
17 0d 34 39 31 30 31 36 31 34 30 31 30 36 5a 30 3b 31 39 30 37 06 03 55 04 03 1e 30 00 53 00 53 00 4c 00 5f 00 53 00 65 00 6c 00 66 00 5f 00 53 00 69 00 67 00 6e 00 65 00 64 00 5f 00 46 00 61
00 6c 00 6c 00 62 00 61 00 63 00 6b 30 82 01 22 30 0d 06 09 2a 86 48 86 f7 0d 01 01 01 05 00 03 82 01 0f 00 30 82 01 0a 02 82 01 01 00 b6 dc 05 25 3e 1e 41 82 f6 b4 bc 97 1c c5 1e 02 a6 bb 1a
c7 34 ed 51 cc 65 a6 60 72 0c 3c 0e ac 57 df 4f df 18 15 14 6f e0 9c d4 39 36 a1 8e 5b 17 85 0a 93 c2 78 02 70 89 f5 35 18 55 37 14 b0 6e 4c cd 0d e7 a0 81 33 c8 42 bc 55 f6 71 fa 4e d2 98 5e
63 5b 32 a6 c3 04 21 3d 22 df 8c ee a7 6e 53 4b be 3d e6 39 c9 90 c6 a9 ed df 7a a8 46 83 b9 7c f1 03 7c 45 b1 be 42 ee 71 aa bc d6 7b 27 41 f3 b8 c4 16 2a 18 8a 38 4c 19 51 25 78 56 ce 12 75
d0 eb 29 19 c5 70 b1 c0 13 18 77 77 a6 9b 47 1f fe 1f 27 5a 50 fb 3f 73 03 c3 a0 5d 2f f4 dd 37 fd df 87 f0 80 e9 de a7 16 df ee b8 00 c2 1e 68 49 19 ce 44 f4 af ac bf d3 5f b8 1c 64 d5 95 1f
8b 32 c1 5a 80 a8 21 2d 2c 66 b8 7e 29 13 11 f8 1f e1 e9 0f 68 4e 0a b8 1b 3c f3 28 6f b7 46 85 b1 17 c9 c6 82 e4 3c 28 d4 6d d9 5b dd 02 03 01 00 01 30 0d 06 09 2a 86 48 86 f7 0d 01 01 0b 05
00 03 82 01 01 00 3e f8 c8 54 30 c1 c1 12 5e eb 01 e5 50 41 57 55 de 9e 2e 69 2a 14 fa 9a 5a 9f d3 c3 1c 28 49 28 b2 c2 e0 cf 3d 7f 48 88 3c 25 e3 30 b7 93 e1 5c a5 9c 6f 41 b0 fb 55 67 69 e5
c5 0e 46 7c e6 2b b4 2b d8 ac 42 62 1e 18 01 69 cd e0 85 59 77 19 bd f9 17 fc 1d 10 ba 8a 93 aa 88 8e e9 73 2c 56 2e d1 5e 22 ca 20 61 4c 03 f0 70 9f a7 a7 ed 16 3a fa 00 0e 9e 39 e8 6b 99 a1
72 cb 48 b8 88 26 2d 9d 3f d6 48 70 f0 a5 51 ee c0 a9 0a e8 cf e6 ed 27 79 4d f1 23 a6 f4 64 a0 72 04 2a 3a b9 30 aa 84 e4 d2 26 9d 8c 3e b5 fe 87 ef 2c 21 c7 4e 38 1f b7 b1 25 69 68 d8 42 b1
8d 25 f3 90 14 78 d2 39 9f 0f 17 2a fc 24 2e 3b 3b 40 99 c6 fb c9 0a b0 af cd 66 f1 c9 84 c5 be dc e9 38 bb 36 2d be 6b db db 86 95 96 c6 84 4b 7d b0 a1 ea f7 42 b2 56 93 ec e9 fd 86 8f a5 ad
f0 57 63 78 d0 5a 0c 00 01 67 03 00 18 61 04 6d f6 56 8c e9 8a 82 29 0a d4 da ea be 89 52 30 bf cd 49 66 77 7f 18 12 b1 75 44 96 d1 9e 6d 15 da 69 ba a7 7c ee 6f ab 96 ea b0 0d 64 0f c4 22 ba
d7 9f 54 71 15 42 84 50 95 a4 ad 16 15 71 56 a7 0a 80 60 2d 83 86 80 0a 96 7b 30 6a aa b7 be 8f 45 9b 96 1a 5c b2 d3 e6 28 6f c4 e4 bb 70 ce 01 00 23 e6 8d 9e bf fc 90 66 f8 07 b6 6b 44 bb 03
b5 3b fd 72 fe 7b 5a e6 15 5d 10 d6 51 22 b8 44 8d 27 85 20 53 04 fb 06 32 b7 03 9e ba 7a 32 62 f1 61 25 8a c4 42 3a 02 1f be cf 92 4d 6e 48 d3 48 8b 8f 03 dc 66 d8 8b 63 21 be 6f b0 53 1c 00
37 4e 7e 4f e8 1e ba d2 c4 45 0f c0 13 ed 71 ee 47 f3 4c 0d 1d af d5 d5 bb 52 78 4b b3 55 70 4e bc a4 f1 da 4a ec 60 7a af 81 23 49 16 57 db 8e 8b 22 65 91 3f 5b 1c 0a 13 d0 e4 b0 a4 d3 10 33
a3 bd c9 39 b6 ea 9b 73 67 11 49 ed 4f 6d 71 ae ce a3 2a 3a 6d 07 d9 d6 24 89 27 2d e6 5a e9 e1 e0 6c 47 5c c1 c0 72 01 e6 63 a6 06 7f 0d b0 16 68 7d 82 49 86 df 38 9b b4 95 5a 95 f8 e8 03 e9
63 83 7c c4 07 62 a1 f5 ce 48 0a 0c 6e 9c da e5 bf 5e e4 56 a1 de 98 80 e5 65 df eb 25 7c 38 97 8a e1 8d a3 c9 a8 a6 f8 bb 77 06 16 ec 21 8a 5c 0e 0e 00 00 00
The certificate can then be decoded:
Issued by: SSL_Self_Signed_Fallback
Issued to: SSL_Self_Signed_Fallback
Valid from: 2019-10-16 14:01:06 UTC
Valid to: 2049-10-16 14:01:06 UTC
SHA1 fingerprint: 6640479c9cac2b7ca63c9708c71a9245b951b4c7
Of course that requires a network spying tool, and a lot of work.
As opposed to most of TLS clients (e.g. http, smtp, pop3, ftp, InternetQueryOption) allow you to view the client certificate directly:
Bonus Chatter - The TLS Nonce Easter Egg
The random 28-byte NONCE, generated by SQL Server and sent to the client, contains an easter-egg (of sorts):
; random.random_bytes 28-bytes
e7 c2 8d f3 3e d5 e4 6d ec 9a b9 7f af c1 çÂ.ó>Õämìš¹.¯Á
43 ad d3 51 41 b7 44 4f 57 4e 47 52 44 00 C.ÓQA·DOWNGRD.
It ends with "DOWNGRD\0".
That's a feature of TLS 1.3 designed to help a client detect a downgrade attack.
If the server is capable of supporting TLS 1.3, but it has been asked by the client to use something lower, it adds "DOWNGRD" to the random nonce:
DOWNGRD\0: If the server was asked to negotiate TLS 1.1 or earlier
DOWNGRD\1: If the server was asked to negotiate TLS 1.2
This way the client can detect if a man-in-the-middle intercepted the client, and altered the list of protocols supposedly supported by the client to trick the client into using TLS 1.2 (weaker), or TLS 1.1 or earlier (broken).
Bonus Reading
How does TLS 1.3 protect against downgrade attacks? 🕗
OpenSSL: Fetching SQL Server public certificate (asking about OpenSSL)
How can client retrieve SQL Server public SSL certificate? (Asking for anything; including network sniffing)
p.s. And, of course, this question does not belong on dba.stackexchange.com because this is a programming question (e.g. ADO.net, OLEDB), and not a DBA question.
I am working on developing an application for a smart card reader, using the Visa test kit in the C language. On reading card number 2, am getting the following Issuer Public Key Certificate after reading the card:
uint8_t ISSUER_PK_CERTIFICATE[] = {41 03 b1 61 f7 dd 14 34 85 79 1b f6 01 04 ea 10 08 06 9d 16 b6 c3 b3 5b 4e 37 ed 20 25 66 d8 77 6f 48 02 28 32 0a 90 31 ae 28 28 75 fa 1b 3a bf c7 6d 15 6f f4 b5 08 4a fd 9c b0 ef b0 8a 8e 5b 41 fa be 99 3b 04 fe 1b 76 8d ef b6 eb ae d1 77 4d d0 5e 7f f7 0c 45 86 42 85 e6 d0 06 2d 86 65 4e 7a 88 5f 49 f9 f3 11 9f 24 35 18 4c 28 1c 14 93 d2 ac 69 ec c7 88 da c0 75 9a 73 ec d5 f0 28 b3 27 a1 e5 1d c5 cb 43 53 7b 1d 2a a7 04 62 cd a3 c8 74 a5 7c 45 8e 52 15 09 ff 98 73 71 d6 da 8d 7a 4f f5 6f 10 87 89 68 86 33 17 1e f1 d6 9d},
...(ignoring the specifics of formatting in C arrays) where the modulus is 176 and from Visa, I have the following CA Public Key Modulus. The cards are test cards, thus I have no problem sharing the output publicly:
uint8_t VISA_PK_MODULUS[] = {99 6A F5 6F 56 91 87 D0 92 93 C1 48 10 45 0E D8 EE 33 57 39 7B 18 A2 45 8E FA A9 2D A3 B6 DF 65 14 EC 06 01 95 31 8F D4 3B E9 B8 F0 CC 66 9E 3F 84 40 57 CB DD F8 BD A1 91 BB 64 47 3B C8 DC 9A 73 0D B8 F6 B4 ED E3 92 41 86 FF D9 B8 C7 73 57 89 C2 3A 36 BA 0B 8A F6 53 72 EB 57 EA 5D 89 E7 D1 4E 9C 7B 6B 55 74 60 F1 08 85 DA 16 AC 92 3F 15 AF 37 58 F0 F0 3E BD 3C 5C 2C 94 9C BA 30 6D B4 4E 6A 2C 07 6C 5F 67 E2 81 D7 EF 56 78 5D C4 D7 59 45 E4 91 F0 19 18 80 0A 9E 2D C6 6F 60 08 05 66 CE 0D AF 8D 17 EA D4 6A D8 E3 0A 24 7C 9F},
also ignoring the formatting (I have written it like that here for simplicity),
where the modulus is also 176. The CA Public Key index is 5 and the exponent is 3, that's how I retrieved the above key. Now, I have written the following function to implement the RSA decryption algorithm to be able to verify the signature of the certificate:
uint32_t buffer[ISSUER_PK_CERTIFICATE_LENGTH]; //this holds the "decrypted" data
void decryptCertificate(uint8_t exponent)
{
uint32_t buffer[ISSUER_PK_CERTIFICATE_LENGTH]; //the length is in hex
for(int i = 0; i < hexToDecimal(ISSUER_PK_CERTIFICATE_LENGTH); i++) //conversion to integer for my convenience
{
uint32_t powered = pow(ISSUER_PK_CERTIFICATE[i], exponent);
uint32_t remainder = powered / VISA_PK_MODULUS[i];
uint32_t multiplied = remainder * VISA_PK_MODULUS[i];
uint32_t original = powered - multiplied;
buffer[i] = original;
}
}
but the final "decrypted" array does not fit the requirements of the Validation test specified by VISA. Anyone see where I could have gone wrong in the implementation of the above algorithm or can someone point me in the right direction if I have gone wrong? the output of the decryption is as shown:
8f 1b 94 1f 2d 3d 23 00 8b 40 be 00 01 40 06 d0 24 0c 2e 2e 5c 03 35 16 82 7d 5c 08 7b 94 67 4b 0b 84 02 00 8a 14 01 c9 20 9e 98 5d 1c 63 8c 08 43 35 27 14 0c 3d 86 94 61 81 4c 27 3a 48 d0 31 05 01 20 3f b3 40 a1 77 1b 4b ef 5b ab 60 36 38 31 1c 18 01 3d 01 45 e0 43 13 6e 43 d8 4e 6e 29 7a 08 70 41 48 27 37 11 28 00 32 5a 0a 10 34 3e 00 00 0d 49 b0 c7 36 08 30 4d 00 1b 08 99 00 11 b3 27 3d 19 01 35 0c 03 07 2a 5e ed 2f 40 20 8d 02 39 2f 45 13 bd 0d 10 2d 09 41 08 25 08 58 00 01 2c 51 05 06 07 13 a1 cc 0a 1b 88 00 01 04 97
NB: The Visa Specification states the Recovery function as: X = Recover(PK)[S] = Se mod n, given a digital Signature S and public key PK
It appears that you're trying to perform RSA decryption on each byte individually. This is incorrect — the certificate and modulus arrays each represent a single big integer. You will need to use a big-integer math library (or a special-purpose crypto library) to perform this decryption.
As a general comment OpenSSL may be a good fit for you. If its overhead or library size is too large for the card reader, there are other libraries specifically designed for embedded device environments. Check out the crypto library modules on the wiki (Crypto Libraries) and among them CyaSSL, MatrixSSL, PolarSSL, and SharkSSL are known to be for embedded devices.
This is the data it displays:
http://krill.larvit.se/resihop_dev/style.css
HTTP/1.1 200 OK
Date: Tue, 17 Jul 2012 20:36:17 GMT
Server: Apache/2.2.16 (Debian)
Last-Modified: Mon, 16 Jul 2012 23:33:42 GMT
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Accept-Ranges: bytes
Vary: Accept-Encoding
Content-Encoding: gzip
Content-Length: 871
Content-Type: text/css
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