User-directed transcript-based RAM checking. (#176)

* user-directed transcript-based RAM checking when the `transcript` type qualifier is used. * fix ram tests * fmt & lint * rm incomplete test
circify · Nov 3, 2023 · 68b0b45 · 68b0b45
1 parent c035529
commit 68b0b45
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Showing 18 changed files with 251 additions and 95 deletions.
diff --git a/examples/ZoKrates/pf/mem/ann_transcript_const.zok b/examples/ZoKrates/pf/mem/ann_transcript_const.zok
@@ -0,0 +1,10 @@
+const u32 N = 100
+const u32 A = 100
+const field[N] TABLE = [4, ...[5; N-1]]
+
+def main(field[A] is) -> field:
+    field sum = 0
+    for u32 i in 0..A do
+        sum = sum + TABLE[is[i]]
+    endfor
+    return sum
diff --git a/examples/ZoKrates/pf/mem/arr_of_str.zok b/examples/ZoKrates/pf/mem/arr_of_str.zok
@@ -6,7 +6,7 @@ struct Pt {
     field y
     field z
 }
-const Pt [LEN] array = [Pt {x: 4, y: 5, z: 6}, ...[Pt {x: 0, y: 1, z: 2}; LEN - 1]]
+const transcript Pt [LEN] array = [Pt {x: 4, y: 5, z: 6}, ...[Pt {x: 0, y: 1, z: 2}; LEN - 1]]
 
 def main(private field[ACCESSES] idx) -> field:
     field prod = 1

diff --git a/examples/ZoKrates/pf/mem/two_level_ptr.zok b/examples/ZoKrates/pf/mem/two_level_ptr.zok
@@ -1,7 +1,7 @@
 const u32 LEN = 4
 const u32 ACCESSES = 2
 
-const field[LEN] array = [0, ...[100; LEN-1]]
+const transcript field[LEN] array = [0, ...[100; LEN-1]]
 
 def main(private field[ACCESSES] y) -> field:
     field result = 0

diff --git a/examples/ZoKrates/pf/mem/volatile.zok b/examples/ZoKrates/pf/mem/volatile.zok
@@ -3,7 +3,7 @@ const u32 LEN = 8196
 const field ACC = 10
 
 def main(private field x, private field y, private bool b) -> field:
-    field[LEN] array = [0; LEN]
+    transcript field[LEN] array = [0; LEN]
     for field i in 0..ACC do
         cond_store(array, x+i, 1f, b)
     endfor

diff --git a/examples/ZoKrates/pf/mem/volatile_struct.zok b/examples/ZoKrates/pf/mem/volatile_struct.zok
@@ -8,7 +8,7 @@ struct Pt {
 }
 
 def main(private field x, private field y, private bool b) -> field:
-    Pt [LEN] array = [Pt {x: 0, y: 0} ; LEN]
+    transcript Pt [LEN] array = [Pt {x: 0, y: 0} ; LEN]
     for field i in 0..ACCESSES do
         array[x+i] = if b then Pt{x : 1, y: i} else array[x+i] fi
     endfor

diff --git a/examples/circ.rs b/examples/circ.rs
@@ -270,18 +270,12 @@ fn main() {
             opts.push(Opt::ConstantFold(Box::new([])));
             opts.push(Opt::Obliv);
             // The obliv elim pass produces more tuples, that must be eliminated
-            if options.circ.ram.enabled {
-                // Waksman can only route scalars, so tuple first!
-                if options.circ.ram.permutation == circ_opt::PermutationStrategy::Waksman {
-                    opts.push(Opt::Tuple);
-                }
-                opts.push(Opt::PersistentRam);
-                opts.push(Opt::VolatileRam);
-                opts.push(Opt::SkolemizeChallenges);
-                opts.push(Opt::ScalarizeVars);
-                opts.push(Opt::ConstantFold(Box::new([])));
-                opts.push(Opt::Obliv);
-            }
+            opts.push(Opt::PersistentRam);
+            opts.push(Opt::VolatileRam);
+            opts.push(Opt::SkolemizeChallenges);
+            opts.push(Opt::ScalarizeVars);
+            opts.push(Opt::ConstantFold(Box::new([])));
+            opts.push(Opt::Obliv);
             opts.push(Opt::LinearScan);
             // The linear scan pass produces more tuples, that must be eliminated
             opts.push(Opt::Tuple);

diff --git a/scripts/ram_test.zsh b/scripts/ram_test.zsh
@@ -16,16 +16,18 @@ function ram_test {
     proof_impl=$2
     ex_name=$1
     rm -rf P V pi
-    $BIN --ram true $=3 $ex_name r1cs --action setup --proof-impl $proof_impl
+    $BIN $=3 $ex_name r1cs --action setup --proof-impl $proof_impl
     $ZK_BIN --inputs $ex_name.pin --action prove --proof-impl $proof_impl
     $ZK_BIN --inputs $ex_name.vin --action verify --proof-impl $proof_impl
     rm -rf P V pi
 }
 
 ram_test ./examples/ZoKrates/pf/mem/two_level_ptr.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
 ram_test ./examples/ZoKrates/pf/mem/volatile.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
-ram_test ./examples/ZoKrates/pf/mem/volatile_struct.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
-ram_test ./examples/ZoKrates/pf/mem/arr_of_str.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
+# waksman is broken for non-scalar array values
+# ram_test ./examples/ZoKrates/pf/mem/volatile_struct.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
+# waksman is broken for non-scalar array values
+# ram_test ./examples/ZoKrates/pf/mem/arr_of_str.zok groth16 "--ram-permutation waksman --ram-index sort --ram-range bit-split"
 ram_test ./examples/ZoKrates/pf/mem/two_level_ptr.zok mirage ""
 ram_test ./examples/ZoKrates/pf/mem/volatile.zok mirage ""
 ram_test ./examples/ZoKrates/pf/mem/volatile_struct.zok mirage ""

diff --git a/src/front/zsharp/mod.rs b/src/front/zsharp/mod.rs
@@ -11,7 +11,7 @@ use crate::front::proof::PROVER_ID;
 use crate::ir::proof::ConstraintMetadata;
 use crate::ir::term::*;
 
-use log::{debug, trace, warn};
+use log::{debug, info, trace, warn};
 use rug::Integer;
 use std::cell::{Cell, RefCell};
 use std::collections::HashMap;
@@ -141,7 +141,11 @@ fn loc_store(struct_: T, loc: &[ZAccess], val: T) -> Result<T, String> {
 enum ZVis {
     Public,
     Private(u8),
+}
+
+enum ArrayParamMetadata {
     Committed,
+    Transcript,
 }
 
 impl<'ast> ZGen<'ast> {
@@ -685,12 +689,25 @@ impl<'ast> ZGen<'ast> {
         for p in f.parameters.iter() {
             let ty = self.type_(&p.ty);
             debug!("Entry param: {}: {}", p.id.value, ty);
+            let md = self.interpret_array_md(&p.array_metadata);
             let vis = self.interpret_visibility(&p.visibility);
-            if let ZVis::Committed = &vis {
-                persistent_arrays.push(p.id.value.clone());
+            let r = self.circ_declare_input(p.id.value.clone(), &ty, vis, None, false, &md);
+            let unwrapped = self.unwrap(r, &p.span);
+            if let Some(md_some) = md {
+                match md_some {
+                    ArrayParamMetadata::Committed => {
+                        info!(
+                            "Input committed array of type {} in {:?}",
+                            ty,
+                            self.file_stack.borrow().last().unwrap()
+                        );
+                        persistent_arrays.push(p.id.value.clone());
+                    }
+                    ArrayParamMetadata::Transcript => {
+                        self.mark_array_as_transcript(&p.id.value, unwrapped);
+                    }
+                }
             }
-            let r = self.circ_declare_input(p.id.value.clone(), &ty, vis, None, false);
-            self.unwrap(r, &p.span);
         }
         for s in &f.statements {
             self.unwrap(self.stmt_impl_::<false>(s), s.span());
@@ -722,7 +739,14 @@ impl<'ast> ZGen<'ast> {
                     let name = "return".to_owned();
                     let ret_val = r.unwrap_term();
                     let ret_var_val = self
-                        .circ_declare_input(name, ty, ZVis::Public, Some(ret_val.clone()), false)
+                        .circ_declare_input(
+                            name,
+                            ty,
+                            ZVis::Public,
+                            Some(ret_val.clone()),
+                            false,
+                            &None,
+                        )
                         .expect("circ_declare return");
                     let ret_eq = eq(ret_val, ret_var_val).unwrap().term;
                     let mut assertions = std::mem::take(&mut *self.assertions.borrow_mut());
@@ -772,13 +796,20 @@ impl<'ast> ZGen<'ast> {
             }
         }
     }
+    fn interpret_array_md(
+        &self,
+        md: &Option<ast::ArrayParamMetadata<'ast>>,
+    ) -> Option<ArrayParamMetadata> {
+        match md {
+            Some(ast::ArrayParamMetadata::Committed(_)) => Some(ArrayParamMetadata::Committed),
+            Some(ast::ArrayParamMetadata::Transcript(_)) => Some(ArrayParamMetadata::Transcript),
+            None => None,
+        }
+    }
+
     fn interpret_visibility(&self, visibility: &Option<ast::Visibility<'ast>>) -> ZVis {
         match visibility {
             None | Some(ast::Visibility::Public(_)) => ZVis::Public,
-            Some(ast::Visibility::Committed(_)) => match self.mode {
-                Mode::Proof => ZVis::Committed,
-                _ => unimplemented!(),
-            },
             Some(ast::Visibility::Private(private)) => match self.mode {
                 Mode::Proof | Mode::Opt | Mode::ProofOfHighValue(_) => {
                     if private.number.is_some() {
@@ -1230,7 +1261,16 @@ impl<'ast> ZGen<'ast> {
                                 l.identifier.value.clone(),
                                 decl_ty,
                                 e,
-                            )
+                            )?;
+                            let md = self.interpret_array_md(&l.array_metadata);
+                            if let Some(ArrayParamMetadata::Transcript) = md {
+                                let value = self
+                                    .circ_get_value(Loc::local(l.identifier.value.clone()))
+                                    .map_err(|e| format!("{e}"))?
+                                    .unwrap_term();
+                                self.mark_array_as_transcript(&l.identifier.value, value);
+                            }
+                            Ok(())
                         }
                     }
                 } else {
@@ -1465,6 +1505,13 @@ impl<'ast> ZGen<'ast> {
             );
         }
 
+        if let Some(ast::ArrayParamMetadata::Transcript(_)) = &c.array_metadata {
+            if !value.type_().is_array() {
+                self.err(format!("Non-array transcript {}", &c.id.value), &c.span);
+            }
+            self.mark_array_as_transcript(&c.id.value, value.clone());
+        }
+
         // insert into constant map
         if self
             .constants
@@ -1849,6 +1896,22 @@ impl<'ast> ZGen<'ast> {
         }
     }
 
+    fn mark_array_as_transcript(&self, name: &str, array: T) {
+        info!(
+            "Transcript array {} of type {} in {:?}",
+            name,
+            array.ty,
+            self.file_stack.borrow().last().unwrap()
+        );
+        self.circ
+            .borrow()
+            .cir_ctx()
+            .cs
+            .borrow_mut()
+            .ram_arrays
+            .insert(array.term);
+    }
+
     /*** circify wrapper functions (hides RefCell) ***/
 
     fn circ_enter_condition(&self, cond: Term) {
@@ -1894,32 +1957,30 @@ impl<'ast> ZGen<'ast> {
         vis: ZVis,
         precomputed_value: Option<T>,
         mangle_name: bool,
+        md: &Option<ArrayParamMetadata>,
     ) -> Result<T, CircError> {
-        match vis {
-            ZVis::Public => {
-                self.circ
-                    .borrow_mut()
-                    .declare_input(name, ty, None, precomputed_value, mangle_name)
-            }
-            ZVis::Private(i) => self.circ.borrow_mut().declare_input(
+        if let Some(ArrayParamMetadata::Committed) = md {
+            let size = match ty {
+                Ty::Array(size, _) => *size,
+                _ => panic!(),
+            };
+            Ok(self.circ.borrow_mut().start_persistent_array(
+                &name,
+                size,
+                default_field(),
+                crate::front::proof::PROVER_ID,
+            ))
+        } else {
+            self.circ.borrow_mut().declare_input(
                 name,
                 ty,
-                Some(i),
+                match vis {
+                    ZVis::Public => None,
+                    ZVis::Private(i) => Some(i),
+                },
                 precomputed_value,
                 mangle_name,
-            ),
-            ZVis::Committed => {
-                let size = match ty {
-                    Ty::Array(size, _) => *size,
-                    _ => panic!(),
-                };
-                Ok(self.circ.borrow_mut().start_persistent_array(
-                    &name,
-                    size,
-                    default_field(),
-                    crate::front::proof::PROVER_ID,
-                ))
-            }
+            )
         }
     }
 

diff --git a/src/front/zsharp/term.rs b/src/front/zsharp/term.rs
@@ -102,6 +102,10 @@ impl Ty {
             _ => panic!("Not an array type: {:?}", self),
         }
     }
+    /// Is this an array?
+    pub fn is_array(&self) -> bool {
+        matches!(self, Self::Array(_, _) | Self::MutArray(_))
+    }
 }
 
 #[derive(Clone, Debug)]

diff --git a/src/front/zsharp/zvisit/walkfns.rs b/src/front/zsharp/zvisit/walkfns.rs
@@ -189,14 +189,24 @@ pub fn walk_parameter<'ast, Z: ZVisitorMut<'ast>>(
     visitor.visit_span(&mut param.span)
 }
 
+pub fn walk_array_param_metadata<'ast, Z: ZVisitorMut<'ast>>(
+    visitor: &mut Z,
+    vis: &mut ast::ArrayParamMetadata<'ast>,
+) -> ZVisitorResult {
+    use ast::ArrayParamMetadata::*;
+    match vis {
+        Committed(x) => visitor.visit_array_committed(x),
+        Transcript(x) => visitor.visit_array_transcript(x),
+    }
+}
+
 pub fn walk_visibility<'ast, Z: ZVisitorMut<'ast>>(
     visitor: &mut Z,
     vis: &mut ast::Visibility<'ast>,
 ) -> ZVisitorResult {
     use ast::Visibility::*;
     match vis {
         Public(pu) => visitor.visit_public_visibility(pu),
-        Committed(c) => visitor.visit_commited_visibility(c),
         Private(pr) => visitor.visit_private_visibility(pr),
     }
 }

diff --git a/src/front/zsharp/zvisit/zvmut.rs b/src/front/zsharp/zvisit/zvmut.rs
@@ -113,7 +113,18 @@ pub trait ZVisitorMut<'ast>: Sized {
         Ok(())
     }
 
-    fn visit_commited_visibility(&mut self, _c: &mut ast::CommittedVisibility) -> ZVisitorResult {
+    fn visit_array_param_metadata(
+        &mut self,
+        vis: &mut ast::ArrayParamMetadata<'ast>,
+    ) -> ZVisitorResult {
+        walk_array_param_metadata(self, vis)
+    }
+
+    fn visit_array_committed(&mut self, _c: &mut ast::ArrayCommitted<'ast>) -> ZVisitorResult {
+        Ok(())
+    }
+
+    fn visit_array_transcript(&mut self, _c: &mut ast::ArrayTranscript<'ast>) -> ZVisitorResult {
         Ok(())
     }