wip: provisional biscuit v2 protobuf

[divarvel]

Propositions for the biscuit v2 wire format. See #73

• support for new crypto scheme
• cleanup of V0 stuff
• support for signature operations

idk if there are more things to cleanup, based on the experience with biscuit v0 and v1

--- schema.proto	2021-04-17 12:43:36.306961544 +0200
+++ schema2.proto	2021-09-02 14:59:55.822623022 +0200
@@ -3,194 +3,56 @@
 package biscuit.format.schema;
 
 message Biscuit {
-  required bytes authority = 1;
-  repeated bytes blocks = 2;
-  repeated bytes keys = 3;
-  required Signature signature = 4;
+  optional uint32 rootKeyId = 1;
+  required SignedBlock authority = 2;
+  repeated SignedBlock blocks = 3;
+  required Proof proof = 4;
 }
 
-message SealedBiscuit {
-  required bytes authority = 1;
-  repeated bytes blocks = 2;
+message SignedBlock {
+  required bytes block = 1;
+  required bytes nextKey = 2;
   required bytes signature = 3;
 }
 
-message Signature {
-  repeated bytes parameters = 1;
-  required bytes z = 2;
+message Proof {
+  oneof Content {
+    bytes nextSecret = 1;
+    bytes finalSignature = 2;
+  }
 }
 
 message Block {
   required uint32 index = 1;
+  // ^ is this still useful?
   repeated string symbols = 2;
-  repeated FactV0 facts_v0 = 3;
-  repeated RuleV0 rules_v0 = 4;
-  repeated CaveatV0 caveats_v0 = 5;
-  optional string context = 6;
-  optional uint32 version = 7;
-  repeated FactV1 facts_v1 = 8;
-  repeated RuleV1 rules_v1 = 9;
-  repeated CheckV1 checks_v1 = 10;
+  optional string context = 3;
+  optional uint32 version = 4;
+  repeated FactV2 facts_v2 = 5;
+  repeated RuleV2 rules_v2 = 6;
+  repeated CheckV2 checks_v2 = 7;
 }
 
-message FactV0 {
-  required PredicateV0 predicate = 1;
+message FactV2 {
+  required PredicateV2 predicate = 1;
 }
 
-message RuleV0 {
-  required PredicateV0 head = 1;
-  repeated PredicateV0 body = 2;
-  repeated ConstraintV0 constraints = 3;
+message RuleV2 {
+  required PredicateV2 head = 1;
+  repeated PredicateV2 body = 2;
+  repeated ExpressionV2 expressions = 3;
 }
 
-message CaveatV0 {
-  repeated RuleV0 queries = 1;
+message CheckV2 {
+  repeated RuleV2 queries = 1;
 }
 
-message PredicateV0 {
+message PredicateV2 {
   required uint64 name = 1;
-  repeated IDV0 ids = 2;
-}
-
-message IDV0 {
-  enum Kind {
-    SYMBOL = 0;
-    VARIABLE = 1;
-    INTEGER = 2;
-    STR = 3;
-    DATE = 4;
-    BYTES = 5;
-  }
-
-  required Kind kind = 1;
-  optional uint64 symbol = 2;
-  optional uint32 variable = 3;
-  optional int64 integer = 4;
-  optional string str = 5;
-  optional uint64 date = 6;
-  optional bytes bytes = 7;
-}
-
-message ConstraintV0 {
-  required uint32 id = 1;
-
-  enum Kind {
-    INT = 0;
-    STRING = 1;
-    DATE = 2;
-    SYMBOL = 3;
-    BYTES = 4;
-  }
-
-  required Kind kind = 2;
-
-  optional IntConstraintV0 int = 3;
-  optional StringConstraintV0 str = 4;
-  optional DateConstraintV0 date = 5;
-  optional SymbolConstraintV0 symbol = 6;
-  optional BytesConstraintV0 bytes = 7;
+  repeated IDV2 ids = 2;
 }
 
-message IntConstraintV0 {
-  enum Kind {
-    LOWER = 0;
-    LARGER = 1;
-    LOWER_OR_EQUAL = 2;
-    LARGER_OR_EQUAL = 3;
-    EQUAL = 4;
-    IN = 5;
-    NOT_IN = 6;
-  }
-
-  required Kind kind = 1;
-
-  optional int64 lower = 2;
-  optional int64 larger = 3;
-  optional int64 lower_or_equal = 4;
-  optional int64 larger_or_equal = 5;
-  optional int64 equal = 6;
-  repeated int64 in_set = 7 [packed=true];
-  repeated int64 not_in_set = 8 [packed=true];
-}
-
-message StringConstraintV0 {
-  enum Kind {
-    PREFIX = 0;
-    SUFFIX = 1;
-    EQUAL = 2;
-    IN = 3;
-    NOT_IN = 4;
-    REGEX = 5;
-  }
-
-  required Kind kind = 1;
-
-  optional string prefix = 2;
-  optional string suffix = 3;
-  optional string equal = 4;
-  repeated string in_set = 5;
-  repeated string not_in_set = 6;
-  optional string regex = 7;
-}
-
-message DateConstraintV0 {
-  enum Kind {
-    BEFORE = 0;
-    AFTER = 1;
-  }
-
-  required Kind kind = 1;
-
-  optional uint64 before = 2;
-  optional uint64 after = 3;
-}
-
-message SymbolConstraintV0 {
-  enum Kind {
-    IN = 0;
-    NOT_IN = 1;
-  }
-
-  required Kind kind = 1;
-
-  repeated uint64 in_set = 2;
-  repeated uint64 not_in_set = 3;
-}
-
-message BytesConstraintV0 {
-  enum Kind {
-    EQUAL = 0;
-    IN = 1;
-    NOT_IN = 2;
-  }
-
-  required Kind kind = 1;
-
-  optional bytes equal = 2;
-  repeated bytes in_set = 3;
-  repeated bytes not_in_set = 4;
-}
-
-message FactV1 {
-  required PredicateV1 predicate = 1;
-}
-
-message RuleV1 {
-  required PredicateV1 head = 1;
-  repeated PredicateV1 body = 2;
-  repeated ExpressionV1 expressions = 3;
-}
-
-message CheckV1 {
-  repeated RuleV1 queries = 1;
-}
-
-message PredicateV1 {
-  required uint64 name = 1;
-  repeated IDV1 ids = 2;
-}
-
-message IDV1 {
+message IDV2 {
   oneof Content {
     uint64 symbol = 1;
     uint32 variable = 2;
@@ -204,22 +66,22 @@
 }
 
 message IDSet {
-  repeated IDV1 set = 1;
+  repeated IDV2 set = 1;
 }
 
-message ConstraintV1 {
+message ConstraintV2 {
   required uint32 id = 1;
 
   oneof Constraint {
-    IntConstraintV1 int = 2;
-    StringConstraintV1 string = 3;
-    DateConstraintV1 date = 4;
-    SymbolConstraintV1 symbol = 5;
-    BytesConstraintV1 bytes = 6;
+    IntConstraintV2 int = 2;
+    StringConstraintV2 string = 3;
+    DateConstraintV2 date = 4;
+    SymbolConstraintV2 symbol = 5;
+    BytesConstraintV2 bytes = 6;
   }
 }
 
-message IntConstraintV1 {
+message IntConstraintV2 {
   oneof Constraint {
     int64 less_than = 1;
     int64 greater_than = 2;
@@ -235,7 +97,7 @@
   repeated int64 set = 7 [packed=true];
 }
 
-message StringConstraintV1 {
+message StringConstraintV2 {
   oneof Constraint {
     string prefix = 1;
     string suffix = 2;
@@ -250,14 +112,14 @@
   repeated string set = 1;
 }
 
-message DateConstraintV1 {
+message DateConstraintV2 {
   oneof Constraint {
     uint64 before = 1;
     uint64 after = 2;
   }
 }
 
-message SymbolConstraintV1 {
+message SymbolConstraintV2 {
   oneof Constraint {
     SymbolSet in_set = 1;
     SymbolSet not_in_set = 2;
@@ -268,7 +130,7 @@
   repeated uint64 set = 1 [packed=true];
 }
 
-message BytesConstraintV1 {
+message BytesConstraintV2 {
   oneof Constraint {
     bytes equal = 1;
     BytesSet in_set = 2;
@@ -280,15 +142,16 @@
   repeated bytes set = 1;
 }
 
-message ExpressionV1 {
+message ExpressionV2 {
   repeated Op ops = 1;
 }
 
 message Op {
   oneof Content {
-    IDV1 value = 1;
+    IDV2 value = 1;
     OpUnary unary = 2;
     OpBinary Binary = 3;
+    OpTernary Ternary = 4;
   }
 }
 
@@ -321,6 +184,15 @@
     Or = 14;
     Intersection = 15;
     Union = 16;
+    SignEd25519 = 17;
+  }
+
+  required Kind kind = 1;
+}
+
+message OpTernary {
+  enum Kind {
+    VerifyEd25519Signature = 0;
   }
 
   required Kind kind = 1;
@@ -332,15 +204,15 @@
     Deny = 1;
   }
 
-  repeated RuleV1 queries = 1;
+  repeated RuleV2 queries = 1;
   required Kind kind = 2;
 }
 
 message VerifierPolicies {
   repeated string symbols = 1;
   optional uint32 version = 2;
-  repeated FactV1 facts = 3;
-  repeated RuleV1 rules = 4;
-  repeated CheckV1 checks = 5;
+  repeated FactV2 facts = 3;
+  repeated RuleV2 rules = 4;
+  repeated CheckV2 checks = 5;
   repeated Policy policies = 6;
 }

[divarvel]

it seems redundant with the block index in the list. What should be done if there is a discrepancy between explicit indices and the position in the list?

[Geal]

the field can be removed, since now the signatures guarantee the order

[divarvel]

👌

[divarvel]

there was talk of n-ary operations, but with a stack model, I think it's better to have the arity explicit. In any case, adding new operations will be backwards-compatible wrt to the wire format

[divarvel]

there was agreement on supporting signature operations. there was no clear decision on the API. Here i think supporting the same alg that's used for the token itself is a good choice, and making it explicit in the tokens is also a good choice, while we decide if and how we'd want to have configurable signature algorithms.

[divarvel]

The 2.0 changes have been integrated in the relevant branch. The ed25519 operations can be done later, as they're completely unrelated to the rest.