Object reference not set to an instance of the object

By Agg , 7 March, 2024
Forums
DLMSDirector

I can use the ECDSA suite1 and One-Pass Diffie-Hellman connect to the meter. But when I read the data from the objects,it shows "Object reference not set to an instance of the object. "
And I try to change the key agreement from one-pass to none，then I can read the data successfully. So Why does this error occur？

The log is below:

GXDLMSDirector 9.0.2311.1001
Log created 21:15:53
21:15:56 Initializing Network connection.
21:15:57 Send SNRM request.
7E A0 07 03 03 93 8C 11 7E
21:15:57
7E A0 1E 03 03 73 40 CC 81 80 12 05 01 80 06 01 80 07 04 00 00 00 01 08 04 00 00 00 01 53 3B 7E
21:15:57 Parsing UA reply succeeded.
21:15:57 Send AARQ request.
7E A0 7B 03 03 10 6E 6A E6 E6 00 60 6D A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 00 00 00 8A 02 07 80 8B 07 60 85 74 05 08 02 07 AC 22 80 20 63 6D 68 0E 58 76 5B 65 4F 5D 1F 4D 44 53 6A 69 65 2A 44 67 13 60 77 14 75 0F 63 77 06 5F 36 1F BE 23 04 21 21 1F 31 00 00 00 00 C8 78 0A 70 91 93 CB 02 83 8A 83 D2 6E DF BC 72 DB 95 2C BD 20 E3 25 F0 C0 F3 8A 8A 7E
21:15:57
7E A0 83 03 03 30 9F D9 E6 E7 00 61 75 A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 00 00 01 A2 03 02 01 00 A3 05 A1 03 02 01 0E A4 0A 04 08 4D 4D 4D 00 00 00 00 01 88 02 07 80 89 07 60 85 74 05 08 02 07 AA 12 80 10 62 1B 02 11 71 0A 12 09 03 16 55 31 3C 3E 48 00 BE 23 04 21 28 1F 31 00 00 00 00 C9 50 5D D6 FC 61 08 89 B3 04 90 03 C8 79 58 F0 EA 7D 35 98 9D BF 77 3A 27 CA 12 59 7E
21:15:57 Parsing AARE reply succeeded.
21:15:57 Authenticating.
7E A0 6E 03 03 32 88 C5 E6 E6 00 CB 60 31 00 00 00 01 BD BB 1B A6 AC 9E 2D 5B 2B C7 20 A7 1F 14 71 C5 C8 F6 9F 74 D1 D7 79 57 2C 41 20 2A 14 62 8C A2 1E 81 26 82 0A F8 11 34 10 94 86 E8 49 65 BD D2 52 FD 06 FB 58 83 85 95 B0 16 62 AE A5 1E 89 AD 1C 09 1B 50 CC D3 FB 27 D0 6E 11 12 EC 45 F9 D2 F5 0E E2 88 1E 05 40 D2 07 3B 2D FD 16 7E
21:15:57
7E A0 67 03 03 52 ED 5F E6 E7 00 CF 59 31 00 00 00 01 5F 44 6A 0E 50 56 63 88 56 14 05 80 C2 8A 0D 84 9B 3B A7 B7 29 F7 CA 63 2C 19 D1 28 43 0F 41 58 AB 99 AC 30 77 A7 01 F9 52 D4 80 65 2B 4A 18 E1 C4 E3 20 07 3A 75 31 1B 1D CA 03 3B FA 74 B1 BF C5 A1 36 5D 19 AB 7A EC 54 74 1E 61 8E CA FA 62 C2 8A B0 68 CD 4C 7E
System.NullReferenceException: Object reference not set to an instance of the object.
in Gurux.DLMS.GXDLMS.Cipher1(GXDLMSLNParameters p, Byte[] data, Boolean sign)
in Gurux.DLMS.GXDLMS.GetLNPdu(GXDLMSLNParameters p, GXByteBuffer reply)
in Gurux.DLMS.GXDLMS.GetLnMessages(GXDLMSLNParameters p)
in Gurux.DLMS.GXDLMSClient.Read(Object name, ObjectType objectType, Int32 attributeOrdinal, GXByteBuffer data, Int32 mode)
in Gurux.DLMS.GXDLMSClient.Read(GXDLMSObject item, Int32 attributeOrdinal)
in GXDLMSDirector.GXDLMSCommunicator.Read(Object sender, GXDLMSObject obj, Boolean forceRead)
in GXDLMSDirector.MainForm.Read(Object sender, GXAsyncWork work, Object[] parameters)

Agg

2 years 3 months ago

secured

Image

Kurumi

2 years 3 months ago

Hi,

I need to check this. I don't know any meter that uses One-Pass Diffie-Hellman and has not been used for a long time. All the ECDSA meters are using GeneralSigning.

BR,
Mikko

Agg

2 years 3 months ago

If I use GeneralSigning. It shows the error "Decrypt failed. invalid authentication tag." So how to solve this problem？

The server log is below：
Client address: 1
Conformance:
[SET, GET, ACTION]
MaxReceivePduSize: 832 MaxSendPduSize: 65535

Security suite: SUITE_1
Security policy: [AUTHENTICATED, ENCRYPTED]
Authentication key: D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 DA DB DC DD DE DF
Block cipher key: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

TCP/IP connection established.
TX: 7E A0 1E 03 03 73 40 CC 81 80 12 05 01 80 06 01 80 07 04 00 00 00 01 08 04 00 00 00 01 53 3B 7E
RX: 7E A0 7B 03 03 10 6E 6A E6 E6 00 60 6D A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 00 00 00 8A 02 07 80 8B 07 60 85 74 05 08 02 07 AC 22 80 20 36 59 64 35 09 4E 2A 43 10 24 43 42 26 07 3C 32 4F 4C 67 6E 66 00 0C 4C 0A 6D 78 64 30 5D 2E 2D BE 23 04 21 21 1F 31 00 00 00 00 C8 78 0A 70 91 93 CB 02 83 8A 83 D2 6E DF BC 72 DB 95 2C BD 20 E3 25 F0 C0 F3 BA E9 7E
TX: 7E A0 83 03 03 30 9F D9 E6 E7 00 61 75 A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 00 00 01 A2 03 02 01 00 A3 05 A1 03 02 01 0E A4 0A 04 08 4D 4D 4D 00 00 00 00 01 88 02 07 80 89 07 60 85 74 05 08 02 07 AA 12 80 10 3C 32 42 66 5D 05 34 1B 2D 04 03 76 14 21 1E 35 BE 23 04 21 28 1F 31 00 00 00 00 C9 50 5D D6 FC 61 08 89 B3 04 90 03 C8 79 58 F0 EA 7D 35 98 9D BF 77 3A 27 CA BB 59 7E
RX: 7E A0 6E 03 03 32 88 C5 E6 E6 00 CB 60 31 00 00 00 01 BD BB 1B A6 AC 9E 2D 5B 2B C7 20 A7 1F 14 71 43 1C 80 10 90 35 04 F6 BE 1E 02 B6 2E BB 90 CD 98 37 1A E0 F8 13 E4 D1 B3 E9 6B DB 1C 15 0F 4C 38 D9 B1 EF AD BE 48 DD 7A 2A C3 50 FA 87 71 CF E8 90 59 F3 F7 CF 88 47 C5 9C 99 9F 58 3D 9D D4 F9 C4 BC 0E 75 41 37 19 AC E7 A3 42 91 88 7E
onPreAction 0.0.40.0.0.255:1
B1 38 7C 42 62 6D 76 E8 DA AF E5 3B 2C FE 87 1A 0A FB 47 02 3D 53 4C 5A 71 52 ED 9D 08 BF F4 0C
TX: 7E A0 67 03 03 52 ED 5F E6 E7 00 CF 59 31 00 00 00 01 5F 44 6A 0E 50 56 63 88 3B A1 D0 2E 94 74 F6 E9 CB BB F5 1D CE 61 9F 0A 67 CB C7 F8 9B CA 2C DB 7F 8B 1A 10 25 39 88 3F C8 1A 51 0B F9 41 83 92 B9 F5 B7 09 25 77 AF DF C3 FC E2 F6 11 8C 14 80 FE 8E 9E 99 09 3D 49 13 59 20 DF 0C 93 81 2C D3 3E 69 73 D5 0C CE 7E
RX: 7E A0 84 03 03 54 9C AB E6 E6 00 DF 00 08 4D 4D 4D 00 00 00 00 00 08 4D 4D 4D 00 00 00 00 01 00 00 20 C8 1E 31 00 00 00 02 CB 4E 5E 20 B5 76 72 53 F3 33 19 28 78 17 0D 5A 52 62 B7 6A 8D 96 73 8B 33 40 10 4D E9 B0 08 5C 8F 04 E9 24 3E 4B D6 CA D3 67 3E FF 25 68 91 30 70 B5 AA AA 5A C8 56 82 4A 77 6C 30 38 1F 3C 18 84 C3 BB B6 7E 90 80 E0 B5 03 A1 DE BA 11 FB 82 D6 D3 9C E1 B8 66 2A 73 3B BD 56 09 7E
PreRead 0.0.43.0.0.255:2
TX: 7E A0 7D 03 03 74 D6 04 E6 E7 00 DF 00 08 4D 4D 4D 00 00 00 00 01 08 4D 4D 4D 00 00 00 00 00 00 00 19 CC 17 31 00 00 00 02 1C D9 31 3E 41 74 2B E8 E7 A3 1A 35 D3 EA E7 79 3C 11 40 C1 C5 1E 4F 04 52 BE 0A 0A 67 5B E0 7B 05 05 5C E5 32 0F B8 02 64 38 FA 8D C0 13 9A 39 E3 AE EA 01 B6 EC F2 36 5E 48 80 43 54 1C 68 39 9B 7D 53 84 E5 01 58 FD FE A2 88 59 80 05 FB 44 95 A7 50 7C D4 7E
RX: 7E A0 84 03 03 76 8C A9 E6 E6 00 DF 00 08 4D 4D 4D 00 00 00 00 00 08 4D 4D 4D 00 00 00 00 01 00 00 20 C8 1E 31 00 00 00 03 0A C6 20 BD 9D 19 E9 0D C6 6E 26 BE A2 AE 6A DB 91 FC 41 5C 24 B4 C5 49 A3 40 C3 53 EC 5F 83 97 F8 B6 54 85 73 B1 82 86 3F 8F B2 75 15 D0 93 FF 0D FD 0E 40 CE C5 F4 2C 7B F1 65 F0 7F 56 F4 13 8A 61 0F 68 9A AA AF 92 E2 6C 29 84 DC 8B B6 6F DA 4B 04 1D B6 5B 38 BA B4 AA 1D B8 7E
PreRead 0.0.43.1.4.255:2
TX: 7E A0 80 03 03 96 6E 3C E6 E7 00 DF 00 08 4D 4D 4D 00 00 00 00 01 08 4D 4D 4D 00 00 00 00 00 00 00 1C CC 1A 31 00 00 00 03 67 38 76 AB 20 31 26 37 29 A1 43 94 5A 89 DA 43 8A 46 96 9B 0A 40 FC DD 0F 88 1B CA CE 75 79 C6 35 D2 14 8A EE 2F 9E 97 BB B7 DB 9B E4 32 5A 3F 3B E4 E5 69 29 E8 17 BB A3 4D 03 C5 CF 3B F3 32 5A E7 58 1C 92 C7 37 48 64 E3 BB A3 00 CD 58 3E A1 72 E8 78 81 AA 40 10 7E
RX: 7E A0 84 03 03 98 FC A7 E6 E6 00 DF 00 08 4D 4D 4D 00 00 00 00 00 08 4D 4D 4D 00 00 00 00 01 00 00 20 C8 1E 31 00 00 00 04 6E 69 79 F2 4F FB 4E 9C E7 24 43 85 55 62 29 37 4A EC 45 91 BC 5E 97 56 7B 40 6A 4D 44 10 67 05 48 F4 62 CF 6E 34 46 C2 72 07 0B 69 F8 0D 5B 5D AF 17 F7 57 8C F7 5F CF 63 D9 75 05 75 BE 35 E8 A4 FB 95 03 78 8F 1A 9B 50 E9 60 9D C7 AE 7D C3 24 3B D2 93 1D 5D 3C 50 92 E1 8B D5 7E
PreRead 0.0.43.1.5.255:2
TX: 7E A0 80 03 03 B8 12 F4 E6 E7 00 DF 00 08 4D 4D 4D 00 00 00 00 01 08 4D 4D 4D 00 00 00 00 00 00 00 1C CC 1A 31 00 00 00 04 C4 37 69 65 A3 E5 B7 9F BC F5 8A F3 4F A9 D6 65 1F FE DE D7 D4 40 F4 6F 0F 69 95 FC F7 E0 D4 0D 40 C6 71 7D 4A 81 9C A7 FD 36 E0 8A BF 9C 2B 73 85 2D F4 82 D4 2D 6E 0F 72 72 3E 51 D7 AF C5 F6 6A 9C A3 51 10 B3 C6 E8 9C 17 66 5B 67 63 68 C0 93 3E 57 55 0C 89 57 72 7E

Kurumi

2 years 3 months ago

Hi,

First, you need to check if your meter is supporting ECDSA. Then you need to check in what way the ECDSA is used. Multiple reasons might cause this.

BR,
Mikko

Agg

2 years 3 months ago

Hi，
I use the simulator meter and it supports ECDSA.When I set the key agreement "None",director can read the data. But when I use GeneralSigning. It shows the error "Decrypt failed. invalid authentication tag."

Agg

2 years 3 months ago

I translate the message,it shows " Decrypt failed. Different block cipher or authentiocation key is used to generate this".

Kurumi

2 years 3 months ago

Hi,

Are you using Gurux simulator? Is that Java or C# version? Your client and meter are using different block cipher or authentication keys.
You need to set the same keys for the meter and client.

BR,
Mikko

Agg

2 years 3 months ago

Yes，I use the Java version.I check that the client and meter are using the same key.But the problem still exists. Will it be related to the certificate or private key？

Image

Agg

2 years 3 months ago

the server log is below：

Client address: 1
Conformance:
[SET, GET, ACTION]
MaxReceivePduSize: 832 MaxSendPduSize: 65535

Security suite: SUITE_1
Security policy: []
Authentication key: D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 DA DB DC DD DE DF
Block cipher key: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

TCP/IP connection established.
TX: 7E A0 1E 03 03 73 40 CC 81 80 12 05 01 80 06 01 80 07 04 00 00 00 01 08 04 00 00 00 01 53 3B 7E
RX: 7E A0 7B 03 03 10 6E 6A E6 E6 00 60 6D A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 BC 61 4E 8A 02 07 80 8B 07 60 85 74 05 08 02 07 AC 22 80 20 0A 44 05 3F 10 0C 39 3F 0F 3F 6D 09 0D 5E 33 0A 3D 77 70 59 04 34 17 72 15 40 00 57 16 55 4A 62 BE 23 04 21 21 1F 31 00 00 00 00 69 48 AF 77 68 5E 7E 08 5A CF BD 82 4D E6 C8 04 29 DC 72 78 C0 90 ED CF 89 3F 96 AC 7E
TX: 7E A0 83 03 03 30 9F D9 E6 E7 00 61 75 A1 09 06 07 60 85 74 05 08 01 03 A6 0A 04 08 4D 4D 4D 00 00 00 00 02 A2 03 02 01 00 A3 05 A1 03 02 01 0E A4 0A 04 08 4D 4D 4D 00 00 00 00 02 88 02 07 80 89 07 60 85 74 05 08 02 07 AA 12 80 10 34 40 54 14 3B 53 44 3F 20 57 54 49 41 62 71 65 BE 23 04 21 28 1F 31 00 00 00 00 98 08 2A 43 12 39 FC 95 52 83 B2 1B 93 E9 48 1C 8F 2C 23 7D 88 07 E3 46 52 CC F2 D1 7E
RX: 7E A0 6E 03 03 32 88 C5 E6 E6 00 CB 60 31 00 00 00 01 12 60 C1 0A 0D B3 7E 79 71 84 2B 0A 88 54 31 B0 06 DF 12 7D EF A9 85 49 EA 3A BB 22 0E 81 63 C9 BB 5E 1D 78 DD 14 9E 10 DC 39 B6 6E A4 35 08 CB E6 F8 54 83 32 61 5E 8A 68 E9 2A 22 7E 64 83 66 8B 87 62 9E 5D B5 86 0D 2F A1 27 63 B2 3D 17 35 30 04 08 85 72 87 C7 D6 68 1B B8 B4 B5 7E
onPreAction 0.0.40.0.0.255:1
DD 23 74 30 88 31 EA 75 DA E1 A5 3C 54 A7 D8 DB 05 CC 41 83 8C 50 44 35 73 8B 48 C7 00 66 D4 E6
TX: 7E A0 67 03 03 52 ED 5F E6 E7 00 CF 59 31 00 00 00 01 8A 88 24 66 9A 86 59 35 5F D4 0B 3C E3 0F 92 CA 72 96 B4 C0 A4 A6 DE EB DD 87 09 0C E4 12 6E BA BD A7 AF A9 CB 95 E1 FD E8 78 91 6C FE 9E 9F FE 68 6A A3 F8 A0 CE 85 66 25 1C 54 FE 7A 72 D5 1F 73 60 26 8A DC B8 EB 06 FE EE 14 FF 9D 20 2F A6 6F 3A 30 EC 0E 6B 7E
RX: 7E A0 84 03 03 54 9C AB E6 E6 00 DF 00 08 4D 4D 4D 00 00 BC 61 4E 08 4D 4D 4D 00 00 00 00 02 00 00 20 C8 1E 31 00 00 00 02 30 CA 3F F2 CC E0 65 A3 FF 7B 09 3F E2 25 E9 87 65 0B AB 15 20 A5 ED 27 C6 40 28 14 FA 3D 37 AE 29 0F 01 15 CA 1E 08 C0 9F 9C 24 4D B5 DC 76 20 CF C7 7A 9D 83 73 97 0E B5 C7 5B 34 80 C3 77 CD 31 42 30 A6 7B 4D EA 4A FA 3F 9B 72 30 62 47 0D 39 FE 78 46 7C C6 DC DC 09 CC 97 97 7E
PreRead 0.0.43.1.4.255:2
TX: 7E A0 80 03 03 74 72 F8 E6 E7 00 DF 00 08 4D 4D 4D 00 00 00 00 02 08 4D 4D 4D 00 00 BC 61 4E 00 00 1C CC 1A 31 00 00 00 02 8F 16 31 2F 3B F5 E3 95 85 E0 6F AE 98 C6 70 A0 AC B5 D7 5D EF 40 B6 0F DB 4D 98 F0 29 CC E9 EB 6E FD B7 24 88 54 1F B3 80 4D 4C 0E 44 10 40 94 6E D2 70 BE 0F 3A 97 55 05 93 0E C3 20 38 E5 2F E5 2E 21 79 9B FA 04 F8 2F 05 67 1E 74 61 E7 30 FD 45 1C 23 FD 3D 32 5F 7E
RX: 7E A0 84 03 03 76 8C A9 E6 E6 00 DF 00 08 4D 4D 4D 00 00 BC 61 4E 08 4D 4D 4D 00 00 00 00 02 00 00 20 C8 1E 31 00 00 00 03 BB C2 9B B9 9B 74 63 5F DD 67 AD 5D 56 1E 75 07 39 DD 19 45 09 EB 8A 34 95 40 40 79 D8 62 20 E5 C1 1A 26 8F 5F B7 3F A9 05 AC 2E 21 E3 77 2C F4 7C 4D F0 91 18 42 9A 3F 22 88 62 18 4A 1E D2 DC 76 5E AB 34 3D 1C 51 47 48 8E 2D 0C 62 39 2A 48 69 6F 4A D2 17 98 EF E2 80 33 B1 CE 7E
PreRead 0.0.96.1.0.255:2
TX: 7E A0 86 03 03 96 F4 77 E6 E7 00 DF 00 08 4D 4D 4D 00 00 00 00 02 08 4D 4D 4D 00 00 BC 61 4E 00 00 22 CC 20 31 00 00 00 03 EA 06 16 9A 27 12 D5 80 47 CF B9 D1 C4 7C 41 44 15 58 9F EC BA FD AC C1 70 E9 CF 40 60 D5 7B 3E 37 9A BA 03 31 73 FE 03 B9 71 95 B4 79 E8 9A F6 EC 32 D2 86 BF B0 B7 C6 7D 50 9D C7 CC 00 5E A8 92 DB 3E CE 11 1E 7B 88 C8 73 18 42 F4 FD 9D 67 27 CD BC B3 12 8E EC B2 76 A3 33 28 C1 F0 7E

Kurumi

2 years 3 months ago

Hi,

I believe that the private key is not yet used. Do you have a meter that you can read to get the correct ECDSA settings?

ECDSA is very complicated and if one of your settings is not what is expected the connection is not working.

BR,
Mikko

Agg

2 years 3 months ago

Hi,
Unfortunately, I don't have a real device. Could you give me an example of the correct ECDSA settings ? Using suite1 and general signing.
If possible, I would greatly appreciate it