Project

General

Profile

PublicKey Info Base » History » Version 51

Yingdi Yu, 07/18/2014 10:31 AM

1 1 Yingdi Yu
Public key Info Base (PIB) Service
2
==================================
3
4
## Public Key Info Management 
5
6
NDN data packets are secured through digital signatures.
7 2 Yingdi Yu
In order to generate a valid signature, an NDN application needs to know not only the correct key to use but also the correct public key information that should be put into the `KeyLocator` of a data packet. 
8
The information needs to be managed locally on the system where the application is running.
9
10
The information related to keys is managed at three granularities: identities, keys, and certificates. 
11
A key is always associated with a namespace, called "identity".
12 4 Yingdi Yu
An identity however may have more than one keys.
13
Each key is named as `/<Identity>/[KeyId]`. 
14
The `KeyId` uniquely identifies a key which belongs to the `Identity`.
15 2 Yingdi Yu
Among these keys, only one is the default key of the identity.
16
If only identity is provided when signing a packet, the default key of the identity will be used to sign the packet.
17
18
A certificate is always associated with the key in the certificate
19
If a certificate is provided when signing a packet, the corresponding private key should be used to sign the packet 
20
and the name of the certificate name may be put into the `KeyLocator` of the packet.
21
22
A key may have more than one certificates (e.g., certificates may be issued by different parties).
23
Among these certificates, only one is the default certificate of the key.
24
The default certificate of the default key of an identity is the default certificate of the identity.
25
If only identity is provided when signing a packet, the name of the default certificate of the identity may be put into the `KeyLocator` of the packet.
26
27 3 Yingdi Yu
All the information above may be accessed by different APIs and applications on the same system, 
28
therefore it is desirable to make the information provisioning as a system service. 
29 1 Yingdi Yu
30 3 Yingdi Yu
Since public keys and certificates are supposed to be publicly available, 
31
the service also serves as a local storage of certificate and public keys, 
32
besides providing the public key related information.
33 1 Yingdi Yu
34 3 Yingdi Yu
## PIB management model
35 1 Yingdi Yu
36 3 Yingdi Yu
The public key information of each system user is managed separately in PIB.
37
For now, PIB service is a system service (i.e., run by root).
38
PIB service may be separated into several user services (i.e., run by each user) in the future.
39 1 Yingdi Yu
40 3 Yingdi Yu
Each user has three tables in PIB: identity table, key table, and certificate table.
41 1 Yingdi Yu
The public key information of a user is managed in these tables.
42 4 Yingdi Yu
Identity table consists of two columns: `identity` (primary key) and `default_key_id`.
43 16 Yingdi Yu
Identity table schema:
44
45 17 Yingdi Yu
    User_[UserName]_ID(
46 16 Yingdi Yu
        identity             BLOB NOT NULL,        
47
        default_key_id       BLOB,
48
                     
49
        PRIMARY KEY (identity)                     
50
    );                                             
51
52 4 Yingdi Yu
Key Table consists of five columns: `identity`, `key_id`, `key_type`, `key_bits`, and `default_cert_name`. 
53
The combination of `identity` and `key_id` is the primary key of key table.
54 18 Yingdi Yu
Key table schema:
55
56
    User_[UserName]_KEY(
57
        identity             BLOB NOT NULL,        
58
        key_id               BLOB NOT NULL,        
59
        key_type             INTEGER NOT NULL,     
60
        key_bits             BLOB NOT NULL,        
61
        default_cert_name    BLOB,                 
62
        PRIMARY KEY (identity, key_id)             
63
    );
64
65 4 Yingdi Yu
Certificate table consists of four columns: `certificate_name` (primary key), `identity`, `key_id`, and `certificate_data`.
66 18 Yingdi Yu
Certificate table schema:
67
68
    User_[UserName]_CERT(
69
        certificate_name     BLOB NOT NULL,        
70
        identity             BLOB NOT NULL,        
71
        key_id               BLOB NOT NULL,        
72
        certificate_data     BLOB NOT NULL,        
73
        PRIMARY KEY (certificate_name)             
74
    );
75 4 Yingdi Yu
76
Besides the tables for each user, PIB has two more management tables: user table and certificate_publishing table.
77
User table stores user's local management key (we will discuss it later) and user's default identity
78 3 Yingdi Yu
Each user has its own default identity. 
79
From the default identity, the default key and certificate of the user can be derived.
80 1 Yingdi Yu
81 14 Yingdi Yu
User table schema:
82
83
    User(                                       
84
        user_name             BLOB NOT NULL,    
85
        has_default_identity  INTEGER DEFAULT 0,
86
        default_identity      BLOB,             
87
        local_management_cert BLOB NOT NULL,    
88
                                                
89
        PRIMARY KEY (user_name)                 
90
    );
91
92 19 Yingdi Yu
Certificate_Publishing table schema:
93
94
    Certificate_Publishing(
95
        user_name             BLOB NOT NULL,
96
        publish_namespace     BLOB NOT NULL,
97
98
        PRIMARY KEY (user_name, publish_namespace)
99
    );  
100
101 1 Yingdi Yu
The read access to a user's public key information is not restricted,
102
while the write access to a user's public key information requires authentication.
103
The write access is expressed as signed commands. 
104 5 Yingdi Yu
The signing key can be authenticated only if the key already exists in the corresponding user's PIB tables.
105 4 Yingdi Yu
Each key has its own write access privilege which is defined as:
106 3 Yingdi Yu
107 4 Yingdi Yu
* The root user has the **root key** of the local system. The root key has the highest privilege, i.e., its owner is allowed to change anything in PIB. The identity of the root key is `/localhost`, and the name of the root key should be `/localhost/[KeyId]`.
108
* Each user has its own **local management key**. The local management key is allowed to change anything in the user's PIB info including the three tables and user's own entry in the user table. The identity of the user local management key is `/localhost/user/[UserName]`, and the name of the key should be `/localhost/user/[UserName]/[KeyId]`. Note that the local management key of the root user is the root key.
109 6 Yingdi Yu
* All the other keys are called **regular keys**. A regular key is allowed to change keys/certificates with identities under the key's own namespace, e.g., a key with the identity `/ndn/ucla/alice` is allowed to change a key with the identity `/ndn/ucla/alice/chat` but is not allowed to change a key with the identity `/ndn/ucla/bob`.
110 3 Yingdi Yu
111
## PIB Service Protocol 
112
113
PIB service provides an interface to NDN applications for public key info lookup. 
114 1 Yingdi Yu
The interface is defined in terms of NDN packets (interest/data).
115 32 Yingdi Yu
Depending on the query type, a query to PIB is expressed as a **[signed interest](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest)** (for Write operation) or normal interest (for Read operation).
116 5 Yingdi Yu
The query interest is defined as:
117
118
    /localhost/pib/[UserName]/[Verb]/[Param]/<signed_interest_security_components>
119 34 Yingdi Yu
                                            |<-- Required for Write operation -->|
120 5 Yingdi Yu
121
`UserName` indicates the tables in which the query should apply.
122
`Verb` indicates the access operation. 
123 42 Yingdi Yu
Five types of operations are defined: 
124 40 Yingdi Yu
125 41 Yingdi Yu
Verb                 | Access Type       | Description
126 42 Yingdi Yu
-------------------- | ----------------- | ----------------------------------------------------------
127
Get                  | Read              | Get a single entity (user, identity, key, or certificate)
128 41 Yingdi Yu
Default              | Read              | Get the default setting of an entity
129
List                 | Read              | List the name of a set of entities
130 1 Yingdi Yu
Update               | Write             | Add/Change an entity
131
Delete               | Write             | Delete an entity
132
133
`Param` is a TLV block containing parameters of the query.
134
Different types of operations have their own parameters.
135
136 42 Yingdi Yu
### Query Responses
137
138
The response to a query interest is a data packet signed by PIB.
139
The public key certificate of PIB is stored in a read-only file and is accessible to all users on the system.
140
141
Several TLVs are defined for the content of query responses.
142
`Identity` TLV:
143
144
    PibIdentity := PIB-IDENTITY-TYPE TLV-LENGTH
145
                   Name
146
147
`PublicKey` TLV:
148
149
    PibPublicKey := PIB-PUBLIC-KEY-TYPE TLV-LENGTH
150
                    Name
151
                    PibBytes
152
153
`Certificate` TLV:
154
155
    PibCertificate := PIB-CERTIFICATE-TYPE TLV-LENGTH
156
                      Data 
157
 
158
A response may also be a error code defined a non-negative integer:
159
160
    ErrorCode := ERROR-CODE-TYPE TLV-LENGTH
161
                 nonNegativeInteger
162
163
Error code                    | Value             | Description
164
----------------------------- | ----------------- | ----------------------------------
165
ERR\_SUCCESS                  | 0                 | No error
166
ERR\_INCOMPLETE\_COMMAND      | 1                 | Incomplete interest
167
ERR\_WRONG\_VERB              | 2                 | Wrong verb in interest
168
ERR\_WRONG\_PARAM             | 3                 | Wrong parameter in interest
169
ERR\_NON\_EXISTING\_USER      | 128               | User does not exist
170
ERR\_NON\_EXISTING\_ID        | 129               | Identity does not exist
171
ERR\_NON\_EXISTING\_KEY       | 130               | Public key does not exist
172
ERR\_NON\_EXISTING\_CERT      | 131               | Certificate does not exist
173
ERR\_NO\_DEFAULT\_ID          | 256               | No default identity is set
174
ERR\_NO\_DEFAULT\_KEY         | 257               | No default public key is set 
175
ERR\_NO\_DEFAULT\_CERT        | 258               | No default certificate is set
176
ERR\_DELETE\_DEFAULT\_SETTING | 384               | Trying to delete default setting
177
178 11 Yingdi Yu
### `Get` Parameters
179 8 Yingdi Yu
For `get` operation, `Param` is defined as:
180 1 Yingdi Yu
181 42 Yingdi Yu
    PibGetParam := PIB-GET-PARAM-TYPE TLV-LENGTH
182
                   PibType
183
                   Name?
184 1 Yingdi Yu
185
`Type` indicates which table the query will be applied eventually.
186
187 42 Yingdi Yu
    PibType := PIB-TYPE-TYPE TLV-LENGTH
188
               nonNegativeInteger
189 22 Yingdi Yu
190 42 Yingdi Yu
Type constant                               | Assigned value    | Assigned value (hex)
191
------------------------------------------- | ----------------- | --------------------
192
USER                                        | 0                 | 0x00
193
ID                                          | 1                 | 0x01
194
KEY                                         | 2                 | 0x02
195
CERT                                        | 3                 | 0x03
196 30 Yingdi Yu
197 5 Yingdi Yu
198 48 Yingdi Yu
`Name` is the name of the queried entity. It is a TLV defined in [NDN-TLV spec](http://named-data.net/doc/ndn-tlv/name.html#name).
199
Name is ignored if type is USER.
200 5 Yingdi Yu
201 42 Yingdi Yu
If error happens during processing the query, the content of the response is an ErrorCode TLV.
202
If no error happens, the content depends on the `Type`.
203
When `Type` is `User`, the content is a list of TLVs:
204 5 Yingdi Yu
205 42 Yingdi Yu
    GetUserContent := CONTENT-TYPE TLV-LENGTH
206
                      PibCertificate // local management certificate
207
                      ...            // Other information to add if exists
208 5 Yingdi Yu
209 42 Yingdi Yu
When `Type` is `ID`, the query is actually invalid. 
210
The response is an ErrorCode with value `ERR_WRONG_PARAM`.
211 1 Yingdi Yu
212 42 Yingdi Yu
For `KEY`, the content is a `PibPublicKey` TLV. 
213 48 Yingdi Yu
For `CERT`, the content is a `PibCertificate` TLV.
214 1 Yingdi Yu
215 42 Yingdi Yu
### `Default` Parameters
216 1 Yingdi Yu
217 42 Yingdi Yu
The parameters of `default` operation is defined as.
218 12 Yingdi Yu
219 42 Yingdi Yu
      PibDefaultParam := PIB-DEFAULT-PARAM-TYPE TLV-LENGTH
220
                         PibType    // target type
221
                         PibType    // origin type
222
                         Name?      // origin name
223 12 Yingdi Yu
224
225 42 Yingdi Yu
The response to a `default` query is the default entity of the "target type" of the "origin".
226 21 Yingdi Yu
227 42 Yingdi Yu
Possible values of target type include `ID`, `KEY`, and `CERT`.
228
Possible values of origin type include `USER`, `ID`, and `KEY`.
229
The target type should be always "below" the origin type (e.g., it is wrong to have a target type `ID` and an origin type `CERT`.)
230
The origin name should be consistent with the origin type.
231
Origin name is ignored if origin type is `USER`.
232
When wrong parameters are supplied, the content of response is an ErrorCode with value `ERR_WRONG_PARAM`.
233 37 Yingdi Yu
234 42 Yingdi Yu
If no error happens in processing the query, the response could be `PibIdentity`, `PibPublicKey`, or `PibCertificate`, depending on the target type.
235 37 Yingdi Yu
236 42 Yingdi Yu
### `List` Parameters
237 36 Yingdi Yu
238 42 Yingdi Yu
The parameters of `list` operation are defined as: 
239 36 Yingdi Yu
240 42 Yingdi Yu
    PibListParam := PIB-LIST-PARAM-TYPE TLV-LENGTH
241
                    PibType // origin type
242
                    Name?   // origin name
243 36 Yingdi Yu
244 42 Yingdi Yu
The response to the `list` query is a list of `Name`, depending on the origin type.
245
Possible values of origin type include `USER`, `ID`, and `KEY`.
246
Origin name is ignored if origin type is `USER`.
247
If the origin type is `USER`, the response is a list of identities of the user.
248
If the origin type is `ID`, the response is a list of names of keys of the identity.
249
If the origin type is `KEY`, the response is a list of names of certificates of the key.
250 1 Yingdi Yu
251 50 Yingdi Yu
    PibNameList := PIB-NAME-LIST-TYPE TLV-LENGTH
252
                   Name+
253
254 42 Yingdi Yu
### `Update` Parameters
255 1 Yingdi Yu
256 42 Yingdi Yu
The parameters of `update` operation are defined as: 
257 1 Yingdi Yu
258 45 Yingdi Yu
    PibUpdateParam := PIB-UPDATE-PARAM-TYPE TLV-LENGTH
259
                      (PibIdentity | PibPublicKey | PibCertificate)
260 42 Yingdi Yu
                      PibDefaultOpt
261 1 Yingdi Yu
262 42 Yingdi Yu
`DefaultOpt` is the default option:
263 1 Yingdi Yu
264
265 42 Yingdi Yu
    PibDefaultOpt := PIB-DEFAULT-OPT-TYPE TLV-LENGTH
266
                     nonNegativeInteger
267
268
DefaultOpt constant                         | Assigned value    | Assigned value (hex)
269 1 Yingdi Yu
------------------------------------------- | ----------------- | --------------------
270 46 Yingdi Yu
DEFAULT\_OPT\_NO                              | 0                 | 0x00
271
DEFAULT\_OPT\_USER                            | 1                 | 0x01
272
DEFAULT\_OPT\_ID                              | 2                 | 0x02
273
DEFAULT\_OPT\_KEY                             | 3                 | 0x03
274 1 Yingdi Yu
275 42 Yingdi Yu
The operation, once validated, will add a new entry in the corresponding table if no such an entry exists or update the existing entry,
276
and change the default setting according to `PibDefaultOpt`.
277 1 Yingdi Yu
278 42 Yingdi Yu
The response is always an ErrorCode: `ERR_SUCCESS` for a successful operation, others for failure.
279 1 Yingdi Yu
280 42 Yingdi Yu
### `Delete` Parameters
281 1 Yingdi Yu
282 42 Yingdi Yu
The parameters of `delete` operation are defined as: 
283
284 44 Yingdi Yu
    PibDeleteParam := PIB-DELETE-PARAM-TYPE TLV-LENGTH
285
                      PibType
286 42 Yingdi Yu
                      Name
287
288
The entity and its belonging entities will be deleted once the operation is validated.
289
290
The response is always an ErrorCode: `ERR_SUCCESS` for a successful deletion, others for failure.
291
292
### TLV-TYPE assignments
293
294
Type                                            | Assigned value    | Assigned value (hex)
295
----------------------------------------------- | ----------------- | --------------------
296
PibGetParam                                     | 128               | 0x80
297
PibDefaultParam                                 | 129               | 0x81
298 49 Yingdi Yu
PibListParam                                    | 130               | 0x82
299
PibUpdateParam                                  | 131               | 0x83
300
PibDeleteParam                                  | 132               | 0x84
301 43 Yingdi Yu
PibType                                         | 144               | 0x90
302
PibIdentity                                     | 145               | 0x91
303
PibPublicKey                                    | 146               | 0x92
304
PibCertificate                                  | 147               | 0x93
305
PibBytes                                        | 148               | 0x94 
306
PibDefaultOpt                                   | 149               | 0x95
307 51 Yingdi Yu
PibDefaultOpt                                   | 150               | 0x96
308 47 Yingdi Yu
PibErrorCode                                    | 252               | 0xfc