diff --git a/Cargo.lock b/Cargo.lock
index 6fab48aa..982faef3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -66,6 +66,15 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
 
+[[package]]
+name = "arbitrary"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d5a26814d8dcb93b0e5a0ff3c6d80a8843bafb21b39e8e18a6f05471870e110"
+dependencies = [
+ "derive_arbitrary",
+]
+
 [[package]]
 name = "arrayref"
 version = "0.3.7"
@@ -233,6 +242,17 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d7bc6d6292be3a19e6379786dac800f551e5865a5bb51ebbe3064ab80433f403"
 dependencies = [
+ "ff",
+ "rand_core",
+ "subtle",
+]
+
+[[package]]
+name = "bls12_381"
+version = "0.8.0"
+source = "git+https://github.com/heliaxdev/bls12_381.git?rev=d3ebe9dd6488fac1923db120a7498079e55dd838#d3ebe9dd6488fac1923db120a7498079e55dd838"
+dependencies = [
+ "arbitrary",
  "ff",
  "group",
  "pairing",
@@ -518,6 +538,17 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "derive_arbitrary"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67e77553c4162a157adbf834ebae5b415acbecbeafc7a74b0e886657506a7611"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -826,7 +857,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8499f7a74008aafbecb2a2e608a3e13e4dd3e84df198b604451efe93f2de6e61"
 dependencies = [
  "bitvec",
- "bls12_381",
+ "bls12_381 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ff",
+ "group",
+ "rand_core",
+ "subtle",
+]
+
+[[package]]
+name = "jubjub"
+version = "0.10.0"
+source = "git+https://github.com/heliaxdev/jubjub.git?rev=e887d6964985f267a1085d480756f20d9eaceb19#e887d6964985f267a1085d480756f20d9eaceb19"
+dependencies = [
+ "arbitrary",
+ "bitvec",
+ "bls12_381 0.8.0 (git+https://github.com/heliaxdev/bls12_381.git?rev=d3ebe9dd6488fac1923db120a7498079e55dd838)",
  "ff",
  "group",
  "rand_core",
@@ -887,6 +932,7 @@ checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
 name = "masp_note_encryption"
 version = "1.0.0"
 dependencies = [
+ "arbitrary",
  "borsh",
  "chacha20",
  "chacha20poly1305",
@@ -900,12 +946,13 @@ name = "masp_primitives"
 version = "1.0.0"
 dependencies = [
  "aes",
+ "arbitrary",
  "assert_matches",
  "bip0039",
  "bitvec",
  "blake2b_simd",
  "blake2s_simd",
- "bls12_381",
+ "bls12_381 0.8.0 (git+https://github.com/heliaxdev/bls12_381.git?rev=d3ebe9dd6488fac1923db120a7498079e55dd838)",
  "borsh",
  "byteorder",
  "chacha20poly1305",
@@ -915,7 +962,7 @@ dependencies = [
  "group",
  "hex",
  "incrementalmerkletree",
- "jubjub",
+ "jubjub 0.10.0 (git+https://github.com/heliaxdev/jubjub.git?rev=e887d6964985f267a1085d480756f20d9eaceb19)",
  "lazy_static",
  "masp_note_encryption",
  "memuse",
@@ -936,14 +983,14 @@ version = "1.0.0"
 dependencies = [
  "bellman",
  "blake2b_simd",
- "bls12_381",
+ "bls12_381 0.8.0 (git+https://github.com/heliaxdev/bls12_381.git?rev=d3ebe9dd6488fac1923db120a7498079e55dd838)",
  "byteorder",
  "criterion",
  "directories",
  "getrandom",
  "group",
  "itertools 0.11.0",
- "jubjub",
+ "jubjub 0.10.0 (git+https://github.com/heliaxdev/jubjub.git?rev=e887d6964985f267a1085d480756f20d9eaceb19)",
  "lazy_static",
  "masp_primitives",
  "minreq",
@@ -1403,7 +1450,7 @@ dependencies = [
  "byteorder",
  "group",
  "hex",
- "jubjub",
+ "jubjub 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pasta_curves",
  "rand_core",
  "serde",
diff --git a/masp_note_encryption/Cargo.toml b/masp_note_encryption/Cargo.toml
index 4d790ffe..8bd27006 100644
--- a/masp_note_encryption/Cargo.toml
+++ b/masp_note_encryption/Cargo.toml
@@ -25,11 +25,13 @@ chacha20poly1305 = { version = "0.10", default-features = false }
 rand_core = { version = "0.6", default-features = false }
 subtle = { version = "2.3", default-features = false }
 borsh = {version = "1.2.0", features = ["unstable__schema", "derive"]}
+arbitrary = {version = "1.3", features = ["derive"], optional = true }
 
 [features]
 default = ["alloc"]
 alloc = []
 pre-zip-212 = []
+arbitrary = ["dep:arbitrary"]
 
 [lib]
 bench = false
diff --git a/masp_note_encryption/src/lib.rs b/masp_note_encryption/src/lib.rs
index 24d9f4bb..135b2c52 100644
--- a/masp_note_encryption/src/lib.rs
+++ b/masp_note_encryption/src/lib.rs
@@ -11,7 +11,7 @@
 //! [in-band secret distribution scheme]: https://zips.z.cash/protocol/protocol.pdf#saplingandorchardinband
 //! [`masp_primitives`]: https://github.com/anoma/masp
 
-#![no_std]
+#![cfg_attr(not(feature = "arbitrary"), no_std)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
 // Catch documentation errors caused by code changes.
 #![deny(rustdoc::broken_intra_doc_links)]
@@ -75,10 +75,10 @@ impl AsRef<[u8]> for OutgoingCipherKey {
         &self.0
     }
 }
-
 /// Newtype representing the byte encoding of an [`EphemeralPublicKey`].
 ///
 /// [`EphemeralPublicKey`]: Domain::EphemeralPublicKey
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     BorshSerialize,
     BorshDeserialize,
diff --git a/masp_primitives/Cargo.toml b/masp_primitives/Cargo.toml
index 1c696803..6ee5c051 100644
--- a/masp_primitives/Cargo.toml
+++ b/masp_primitives/Cargo.toml
@@ -43,11 +43,13 @@ num-traits = { version = "0.2.19", git = "https://github.com/heliaxdev/num-trait
 subtle = "2.2.3"
 
 # - Shielded protocols
-bls12_381 = "0.8"
+# branch "tomas/arbitrary"
+bls12_381 = { git = "https://github.com/heliaxdev/bls12_381.git", rev = "d3ebe9dd6488fac1923db120a7498079e55dd838" }
 ff = "0.13"
 group = { version = "0.13", features = ["wnaf-memuse"] }
 incrementalmerkletree = "0.3"
-jubjub = "0.10"
+# branch "tomas/arbitrary"
+jubjub = { git = "https://github.com/heliaxdev/jubjub.git", rev = "a373686962f4e9d0edb3b4716f86ff6bbd9aa86c" }
 nonempty = "0.7"
 
 # - Static constants
@@ -74,6 +76,8 @@ aes = "0.8"
 fpe = "0.6"
 
 borsh = {version = "1.2.0", features = ["unstable__schema", "derive"]}
+arbitrary = {version = "1.3", features = ["derive"], optional = true }
+
 [dependencies.masp_note_encryption]
 version = "1.0.0"
 path = "../masp_note_encryption"
@@ -90,6 +94,7 @@ rand_xorshift = "0.3"
 transparent-inputs = []
 test-dependencies = ["proptest"]
 default = ["transparent-inputs"]
+arbitrary = ["dep:arbitrary", "masp_note_encryption/arbitrary", "bls12_381/arbitrary", "jubjub/arbitrary"]
 
 [badges]
 maintenance = { status = "actively-developed" }
diff --git a/masp_primitives/src/asset_type.rs b/masp_primitives/src/asset_type.rs
index 91de6458..4043361d 100644
--- a/masp_primitives/src/asset_type.rs
+++ b/masp_primitives/src/asset_type.rs
@@ -15,6 +15,7 @@ use std::{
     hash::{Hash, Hasher},
 };
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, BorshSerialize, BorshDeserialize, Clone, Copy, Eq, BorshSchema)]
 pub struct AssetType {
     identifier: [u8; ASSET_IDENTIFIER_LENGTH], //32 byte asset type preimage
diff --git a/masp_primitives/src/consensus.rs b/masp_primitives/src/consensus.rs
index bea5de0e..00edcc81 100644
--- a/masp_primitives/src/consensus.rs
+++ b/masp_primitives/src/consensus.rs
@@ -13,6 +13,7 @@ use std::ops::{Add, Bound, RangeBounds, Sub};
 
 /// A wrapper type representing blockchain heights. Safe conversion from
 /// various integer types, as well as addition and subtraction, are provided.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[repr(transparent)]
 #[derive(
     Clone, Copy, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
@@ -244,6 +245,7 @@ pub const ZIP212_GRACE_PERIOD: u32 = 0;
 /// See [ZIP 200](https://zips.z.cash/zip-0200) for more details.
 ///
 /// [`signature_hash`]: crate::transaction::sighash::signature_hash
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum BranchId {
     /// The consensus rules deployed by [`NetworkUpgrade::MASP`].
diff --git a/masp_primitives/src/merkle_tree.rs b/masp_primitives/src/merkle_tree.rs
index 87e7fd25..75cd3d8f 100644
--- a/masp_primitives/src/merkle_tree.rs
+++ b/masp_primitives/src/merkle_tree.rs
@@ -716,6 +716,7 @@ impl<Node: Hashable> BorshDeserialize for IncrementalWitness<Node> {
 }
 
 /// A path from a position in a particular commitment tree to the root of that tree.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct MerklePath<Node> {
     pub auth_path: Vec<(Node, bool)>,
diff --git a/masp_primitives/src/sapling.rs b/masp_primitives/src/sapling.rs
index 53c4fce8..1b5ee1ee 100644
--- a/masp_primitives/src/sapling.rs
+++ b/masp_primitives/src/sapling.rs
@@ -85,6 +85,7 @@ pub fn merkle_hash(depth: usize, lhs: &[u8; 32], rhs: &[u8; 32]) -> [u8; 32] {
 }
 
 /// A node within the Sapling commitment tree.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, BorshSerialize, BorshDeserialize, Default)]
 pub struct Node {
     repr: [u8; 32],
@@ -450,6 +451,7 @@ impl SaplingIvk {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Copy, Clone, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
@@ -624,6 +626,7 @@ impl BorshSchema for PaymentAddress {
 /// Before ZIP 212, the note commitment trapdoor `rcm` must be a scalar value.
 /// After ZIP 212, the note randomness `rseed` is a 32-byte sequence, used to derive
 /// both the note commitment trapdoor `rcm` and the ephemeral private key `esk`.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Copy, Clone, Debug)]
 pub enum Rseed {
     BeforeZip212(jubjub::Fr),
@@ -686,6 +689,7 @@ impl BorshDeserialize for Rseed {
 }
 
 /// Typesafe wrapper for nullifier values.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Copy,
     Clone,
@@ -743,6 +747,7 @@ impl From<NoteValue> for u64 {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Debug, Copy)]
 pub struct Note<R = Rseed> {
     /// The asset type that the note represents
diff --git a/masp_primitives/src/sapling/keys.rs b/masp_primitives/src/sapling/keys.rs
index 0cfe59d1..c7ff4243 100644
--- a/masp_primitives/src/sapling/keys.rs
+++ b/masp_primitives/src/sapling/keys.rs
@@ -38,12 +38,14 @@ pub enum DecodingError {
 }
 
 /// An outgoing viewing key
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone, Copy, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
 pub struct OutgoingViewingKey(pub [u8; 32]);
 
 /// A Sapling expanded spending key
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, PartialEq, Eq, Copy)]
 pub struct ExpandedSpendingKey {
     pub ask: jubjub::Fr,
diff --git a/masp_primitives/src/sapling/redjubjub.rs b/masp_primitives/src/sapling/redjubjub.rs
index 856a12c7..a528b687 100644
--- a/masp_primitives/src/sapling/redjubjub.rs
+++ b/masp_primitives/src/sapling/redjubjub.rs
@@ -38,6 +38,7 @@ fn h_star(a: &[u8], b: &[u8]) -> jubjub::Fr {
     hash_to_scalar(b"MASP__RedJubjubH", a, b)
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Copy, Clone, Debug, PartialOrd, PartialEq, Ord, Eq, Hash, BorshSchema)]
 pub struct Signature {
     rbar: [u8; 32],
@@ -46,6 +47,7 @@ pub struct Signature {
 
 pub struct PrivateKey(pub jubjub::Fr);
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone, PartialEq, Eq, Copy)]
 pub struct PublicKey(pub ExtendedPoint);
 
diff --git a/masp_primitives/src/transaction.rs b/masp_primitives/src/transaction.rs
index a4cd3f70..948ca62d 100644
--- a/masp_primitives/src/transaction.rs
+++ b/masp_primitives/src/transaction.rs
@@ -39,6 +39,7 @@ use borsh::schema::Fields;
 use borsh::schema::{Declaration, Definition};
 use std::ops::RangeInclusive;
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone,
     Copy,
@@ -60,6 +61,7 @@ pub type GrothProofBytes = [u8; GROTH_PROOF_SIZE];
 const MASPV5_TX_VERSION: u32 = 2;
 const MASPV5_VERSION_GROUP_ID: u32 = 0x26A7270A;
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
@@ -114,6 +116,7 @@ impl TxId {
 /// transaction fields. Note that this is not dependent on epoch, only on transaction encoding.
 /// For example, if a particular epoch defines a new transaction version but also allows the
 /// previous version, then only the new version would be added to this enum.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum TxVersion {
     MASPv5,
@@ -192,11 +195,27 @@ impl BorshSchema for TxVersion {
 
 /// Authorization state for a bundle of transaction data.
 pub trait Authorization {
+    #[cfg(not(feature = "arbitrary"))]
     type TransparentAuth: transparent::Authorization + PartialEq + BorshDeserialize + BorshSerialize;
+    #[cfg(not(feature = "arbitrary"))]
     type SaplingAuth: sapling::Authorization + PartialEq + BorshDeserialize + BorshSerialize;
+
+    #[cfg(feature = "arbitrary")]
+    type TransparentAuth: transparent::Authorization
+        + PartialEq
+        + BorshDeserialize
+        + BorshSerialize
+        + for<'a> arbitrary::Arbitrary<'a>;
+    #[cfg(feature = "arbitrary")]
+    type SaplingAuth: sapling::Authorization
+        + PartialEq
+        + BorshDeserialize
+        + BorshSerialize
+        + for<'a> arbitrary::Arbitrary<'a>;
 }
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub struct Unproven;
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub struct Authorized;
 
@@ -213,6 +232,7 @@ impl Authorization for Unauthorized {
 }
 
 /// A MASP transaction.
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone)]
 pub struct Transaction {
     txid: TxId,
@@ -233,6 +253,7 @@ impl PartialEq for Transaction {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, PartialEq, Clone)]
 pub struct TransactionData<A: Authorization> {
     version: TxVersion,
diff --git a/masp_primitives/src/transaction/components/amount.rs b/masp_primitives/src/transaction/components/amount.rs
index 3ed1141d..f27e4fe4 100644
--- a/masp_primitives/src/transaction/components/amount.rs
+++ b/masp_primitives/src/transaction/components/amount.rs
@@ -50,6 +50,7 @@ pub type I128Sum = ValueSum<AssetType, i128>;
 
 pub type U128Sum = ValueSum<AssetType, u128>;
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Default, Debug, PartialEq, Eq, Hash)]
 pub struct ValueSum<
     Unit: Hash + Ord + BorshSerialize + BorshDeserialize,
diff --git a/masp_primitives/src/transaction/components/sapling.rs b/masp_primitives/src/transaction/components/sapling.rs
index 61d87c2c..e1c716e7 100644
--- a/masp_primitives/src/transaction/components/sapling.rs
+++ b/masp_primitives/src/transaction/components/sapling.rs
@@ -35,8 +35,15 @@ pub mod builder;
 pub mod fees;
 
 pub trait Authorization: Debug {
+    #[cfg(not(feature = "arbitrary"))]
     type Proof: Clone + Debug + PartialEq + Hash;
+    #[cfg(not(feature = "arbitrary"))]
     type AuthSig: Clone + Debug + PartialEq;
+
+    #[cfg(feature = "arbitrary")]
+    type Proof: Clone + Debug + PartialEq + Hash + for<'a> arbitrary::Arbitrary<'a>;
+    #[cfg(feature = "arbitrary")]
+    type AuthSig: Clone + Debug + PartialEq + for<'a> arbitrary::Arbitrary<'a>;
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -47,6 +54,7 @@ impl Authorization for Unproven {
     type AuthSig = ();
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize, BorshSchema)]
 pub struct Authorized {
     pub binding_sig: redjubjub::Signature,
@@ -89,6 +97,7 @@ impl MapAuth<Authorized, Authorized> for () {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Debug, PartialEq)]
 pub struct Bundle<A: Authorization + PartialEq + BorshSerialize + BorshDeserialize> {
     pub shielded_spends: Vec<SpendDescription<A>>,
@@ -146,6 +155,7 @@ impl<A: Authorization + PartialEq + BorshSerialize + BorshDeserialize> Bundle<A>
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, PartialEq, Eq)]
 pub struct SpendDescription<A: Authorization + PartialEq> {
     pub cv: jubjub::ExtendedPoint,
@@ -299,6 +309,7 @@ impl BorshSchema for SpendDescriptionV5 {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, PartialEq, Eq)]
 pub struct OutputDescription<Proof: Clone> {
     pub cv: jubjub::ExtendedPoint,
@@ -507,6 +518,8 @@ impl<Proof: Clone + Hash> Hash for OutputDescription<Proof> {
         self.zkproof.hash(state);
     }
 }
+
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, PartialEq, Eq)]
 pub struct ConvertDescription<Proof: PartialEq> {
     pub cv: jubjub::ExtendedPoint,
diff --git a/masp_primitives/src/transaction/components/sapling/builder.rs b/masp_primitives/src/transaction/components/sapling/builder.rs
index 55dfc50a..d46f58bf 100644
--- a/masp_primitives/src/transaction/components/sapling/builder.rs
+++ b/masp_primitives/src/transaction/components/sapling/builder.rs
@@ -425,6 +425,7 @@ impl fmt::Display for Error {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone, PartialEq)]
 pub struct SpendDescriptionInfo<Key = ExtendedSpendingKey> {
     extsk: Key,
@@ -599,6 +600,7 @@ impl fees::OutputView for SaplingOutputInfo {
 }
 
 /// Metadata about a transaction created by a [`SaplingBuilder`].
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize, BorshSchema)]
 pub struct SaplingMetadata {
     spend_indices: Vec<usize>,
@@ -745,6 +747,7 @@ impl<P: BorshDeserialize, Key: BorshDeserialize> BorshDeserialize for SaplingBui
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
 pub struct Unauthorized {
     tx_metadata: SaplingMetadata,
diff --git a/masp_primitives/src/transaction/components/transparent.rs b/masp_primitives/src/transaction/components/transparent.rs
index ef4758fd..bb2a2e24 100644
--- a/masp_primitives/src/transaction/components/transparent.rs
+++ b/masp_primitives/src/transaction/components/transparent.rs
@@ -18,9 +18,14 @@ pub mod builder;
 pub mod fees;
 
 pub trait Authorization: fmt::Debug {
+    #[cfg(not(feature = "arbitrary"))]
     type TransparentSig: fmt::Debug + Clone + PartialEq;
+
+    #[cfg(feature = "arbitrary")]
+    type TransparentSig: fmt::Debug + Clone + PartialEq + for<'a> arbitrary::Arbitrary<'a>;
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
 pub struct Authorized;
 
@@ -33,6 +38,7 @@ pub trait MapAuth<A: Authorization, B: Authorization> {
     fn map_authorization(&self, s: A) -> B;
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone, PartialEq)]
 pub struct Bundle<A: Authorization> {
     pub vin: Vec<TxIn<A>>,
@@ -85,6 +91,7 @@ impl<A: Authorization> Bundle<A> {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct TxIn<A: Authorization> {
     pub asset_type: AssetType,
     pub value: u64,
@@ -162,6 +169,7 @@ impl BorshSchema for TxIn<Authorized> {
 }
 
 #[derive(Clone, Debug, Hash, PartialOrd, PartialEq, Ord, Eq)]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct TxOut {
     pub asset_type: AssetType,
     pub value: u64,
diff --git a/masp_primitives/src/transaction/components/transparent/builder.rs b/masp_primitives/src/transaction/components/transparent/builder.rs
index 5cb1fa35..fbbddeb9 100644
--- a/masp_primitives/src/transaction/components/transparent/builder.rs
+++ b/masp_primitives/src/transaction/components/transparent/builder.rs
@@ -45,6 +45,7 @@ impl fees::InputView for InvalidTransparentInput {
     }
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg(feature = "transparent-inputs")]
 #[derive(Debug, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize, BorshSchema)]
 struct TransparentInputInfo {
@@ -65,6 +66,7 @@ pub struct TransparentBuilder {
     vout: Vec<TxOut>,
 }
 
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Debug, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
 pub struct Unauthorized {
     #[cfg(feature = "transparent-inputs")]
diff --git a/masp_primitives/src/zip32.rs b/masp_primitives/src/zip32.rs
index c21e0961..870acb75 100644
--- a/masp_primitives/src/zip32.rs
+++ b/masp_primitives/src/zip32.rs
@@ -28,6 +28,7 @@ use std::io::{Read, Write};
 // ZIP 32 structures
 
 /// A child index for a derived key
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum ChildIndex {
     NonHardened(u32),
@@ -81,6 +82,7 @@ impl BorshSchema for ChildIndex {
 }
 
 /// A BIP-32 chain code
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone, Copy, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
diff --git a/masp_primitives/src/zip32/sapling.rs b/masp_primitives/src/zip32/sapling.rs
index 83b122e7..cf2b70f8 100644
--- a/masp_primitives/src/zip32/sapling.rs
+++ b/masp_primitives/src/zip32/sapling.rs
@@ -143,6 +143,7 @@ impl FvkFingerprint {
 }
 
 /// A Sapling full viewing key tag
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone, Copy, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
@@ -159,6 +160,7 @@ impl FvkTag {
 }
 
 /// A key used to derive diversifiers for a particular child key
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(
     Clone, Copy, Debug, PartialEq, Eq, Hash, BorshSerialize, BorshDeserialize, BorshSchema,
 )]
@@ -245,6 +247,7 @@ impl DiversifierKey {
 }
 
 /// A Sapling extended spending key
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Eq, Hash, Copy)]
 pub struct ExtendedSpendingKey {
     depth: u8,
diff --git a/masp_proofs/Cargo.toml b/masp_proofs/Cargo.toml
index deaa55c3..1ac3538f 100644
--- a/masp_proofs/Cargo.toml
+++ b/masp_proofs/Cargo.toml
@@ -20,9 +20,11 @@ masp_primitives = { version = "1.0.0", path = "../masp_primitives" }
 # Dependencies exposed in a public API:
 # (Breaking upgrades to these require a breaking upgrade to this crate.)
 bellman = { version = "0.14", default-features = false, features = ["groth16"] }
-bls12_381 = "0.8"
+# branch "tomas/arbitrary"
+bls12_381 = { git = "https://github.com/heliaxdev/bls12_381.git", rev = "d3ebe9dd6488fac1923db120a7498079e55dd838" }
 group = "0.13"
-jubjub = "0.10"
+# branch "tomas/arbitrary"
+jubjub = { git = "https://github.com/heliaxdev/jubjub.git", rev = "a373686962f4e9d0edb3b4716f86ff6bbd9aa86c" }
 lazy_static = "1"
 minreq = { version = "2.11.0", features = ["https"], optional = true }
 rand_core = "0.6"