Use u32 for TaskProv's histogram

cloudflare · Jul 14, 2023 · bce9e8a · bce9e8a
1 parent dbd506d
commit bce9e8a
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Showing 7 changed files with 15 additions and 11 deletions.
diff --git a/daphne/src/lib.rs b/daphne/src/lib.rs
@@ -662,8 +662,8 @@ pub enum Prio3Config {
  /// equal to `0` or `1`.
  Count,
 
- /// A histogram for estimating the distribution of 64-bit, unsigned integers using pre-defined
- /// bucket boundaries.
+ /// A histogram for estimating the distribution of 64-bit, unsigned integers where each
+ /// measurement is a bucket index in range `[0, len)`.
  Histogram { len: usize },
 
  /// The sum of 64-bit, unsigned integers. Each measurement is an integer in range `[0,

diff --git a/daphne/src/messages/mod_test.rs b/daphne/src/messages/mod_test.rs
@@ -325,7 +325,7 @@ fn read_unsupported_hpke_config() {
  );
 }
 
-// NOTE: these test vectors are no longer valid, TaskProv doesn't match the VDAF-06
+// NOTE: these test vectors are no longer valid, TaskProv doesn't match the VDAF-06 spec.
 // Tracking the issue here: https://github.com/wangshan/draft-wang-ppm-dap-taskprov/issues/33.
 // #[test]
 // fn read_vdaf_config() {

diff --git a/daphne/src/messages/taskprov.rs b/daphne/src/messages/taskprov.rs
@@ -54,7 +54,9 @@ impl KeyType for VdafType {
 pub enum VdafTypeVar {
  Prio3Aes128Count,
  Prio3Aes128Sum { bit_length: u8 },
- Prio3Aes128Histogram { len_length: u8 },
+ // NOTE: this doesn't comply with the TaskProv spec, which doesn't match the VDAF-06 spec.
+ // Tracking the issue here: https://github.com/wangshan/draft-wang-ppm-dap-taskprov/issues/33.
+ Prio3Aes128Histogram { len: u32 },
  Poplar1Aes128 { bit_length: u16 },
  NotImplemented(u32),
 }
@@ -67,9 +69,9 @@ impl Encode for VdafTypeVar {
  VDAF_TYPE_PRIO3_AES128_SUM.encode(bytes);
  bit_length.encode(bytes);
  }
- VdafTypeVar::Prio3Aes128Histogram { len_length } => {
+ VdafTypeVar::Prio3Aes128Histogram { len } => {
  VDAF_TYPE_PRIO3_AES128_HISTOGRAM.encode(bytes);
- len_length.encode(bytes);
+ len.encode(bytes);
  }
  VdafTypeVar::Poplar1Aes128 { bit_length } => {
  VDAF_TYPE_POPLAR1_AES128.encode(bytes);
@@ -91,7 +93,7 @@ impl Decode for VdafTypeVar {
  bit_length: u8::decode(bytes)?,
  }),
  VDAF_TYPE_PRIO3_AES128_HISTOGRAM => Ok(Self::Prio3Aes128Histogram {
- len_length: u8::decode(bytes)?,
+ len: u32::decode(bytes)?,
  }),
  VDAF_TYPE_POPLAR1_AES128 => Ok(Self::Poplar1Aes128 {
  bit_length: u16::decode(bytes)?,

diff --git a/daphne/src/taskprov.rs b/daphne/src/taskprov.rs
@@ -242,9 +242,9 @@ impl From<VdafTypeVar> for VdafConfig {
  fn from(var: VdafTypeVar) -> Self {
  match var {
  VdafTypeVar::Prio3Aes128Count => VdafConfig::Prio3(Prio3Config::Count),
- VdafTypeVar::Prio3Aes128Histogram { len_length } => {
+ VdafTypeVar::Prio3Aes128Histogram { len } => {
  VdafConfig::Prio3(Prio3Config::Histogram {
- len: len_length.into(),
+ len: len.try_into().unwrap(),
  })
  }
  VdafTypeVar::Prio3Aes128Sum { bit_length } => VdafConfig::Prio3(Prio3Config::Sum {

diff --git a/daphne/src/taskprov_test.rs b/daphne/src/taskprov_test.rs
@@ -69,7 +69,7 @@ fn test_resolve_advertised_task_config() {
  task_expiration: 0x6352f9a5,
  vdaf_config: VdafConfig {
  dp_config: DpConfig::None,
- var: VdafTypeVar::Prio3Aes128Histogram { len_length: 1 },
+ var: VdafTypeVar::Prio3Aes128Histogram { len: 3 },
  },
  };
 

diff --git a/daphne/src/vdaf/prio3.rs b/daphne/src/vdaf/prio3.rs
@@ -54,7 +54,8 @@ pub(crate) fn prio3_shard(
  }
  (Prio3Config::Histogram { len }, DapMeasurement::U64(measurement)) => {
  let vdaf = Prio3::new_histogram(2, *len)?;
- Ok(shard!(vdaf, &(measurement as usize), nonce))
+ let m: usize = measurement.try_into().unwrap();
+ Ok(shard!(vdaf, &m, nonce))
  }
  (Prio3Config::Sum { bits }, DapMeasurement::U64(measurement)) => {
  let vdaf = Prio3::new_sum(2, *bits)?;

diff --git a/daphne_worker/src/config.rs b/daphne_worker/src/config.rs
@@ -926,6 +926,7 @@ impl<'srv> DaphneWorker<'srv> {
  }
  // NOTE: the VDAF-06 format is not supported yet
  // https://datatracker.ietf.org/doc/html/draft-dcook-ppm-dap-interop-test-design-04#name-internal-test-add_task
+ // Issue tracked here: https://github.com/divergentdave/draft-dcook-ppm-dap-interop-test-design/issues/40
  ("Prio3Histogram", Some(len), None) => {
  let len = len.parse().map_err(int_err)?;
  VdafConfig::Prio3(Prio3Config::Histogram { len })