diff --git a/src/circuit.rs b/src/circuit.rs
index 1730e008..6cf6fb9a 100644
--- a/src/circuit.rs
+++ b/src/circuit.rs
@@ -42,11 +42,13 @@ use gadget::{
         StateWord, Word,
     },
     sinsemilla::{
-        chip::{SinsemillaChip, SinsemillaConfig, SinsemillaHashDomains},
+        chip::{SinsemillaChip, SinsemillaCommitDomains, SinsemillaConfig, SinsemillaHashDomains},
+        commit_ivk::CommitIvkConfig,
         merkle::{
             chip::{MerkleChip, MerkleConfig},
             MerklePath,
         },
+        CommitDomain,
     },
     utilities::{
         copy,
@@ -78,6 +80,7 @@ pub struct Config {
     merkle_config_2: MerkleConfig,
     sinsemilla_config_1: SinsemillaConfig,
     sinsemilla_config_2: SinsemillaConfig,
+    commit_ivk_config: CommitIvkConfig,
 }
 
 /// The Orchard Action circuit.
@@ -233,6 +236,11 @@ impl plonk::Circuit<pallas::Base> for Circuit {
             (sinsemilla_config_2, merkle_config_2)
         };
 
+        // Configuration to handle decomposition and canonicity checking
+        // for CommitIvk.
+        let commit_ivk_config =
+            CommitIvkConfig::configure(meta, advices, sinsemilla_config_1.clone());
+
         // TODO: Infrastructure to handle public inputs.
         let q_primary = meta.selector();
         let primary = meta.instance_column();
@@ -263,6 +271,7 @@ impl plonk::Circuit<pallas::Base> for Circuit {
             merkle_config_2,
             sinsemilla_config_1,
             sinsemilla_config_2,
+            commit_ivk_config,
         }
     }
 
@@ -543,6 +552,27 @@ impl plonk::Circuit<pallas::Base> for Circuit {
             alpha_commitment.add(layouter.namespace(|| "rk"), &ak)?
         };
 
+        // Diversified address integrity.
+        let _pk_d_old = {
+            let commit_ivk_config = config.commit_ivk_config.clone();
+
+            let ivk = {
+                let rivk = self.rivk.map(|rivk| *rivk);
+
+                commit_ivk_config.assign_region(
+                    config.sinsemilla_chip_1(),
+                    ecc_chip.clone(),
+                    layouter.namespace(|| "CommitIvk"),
+                    *ak.extract_p().inner(),
+                    nk,
+                    rivk,
+                )?
+            };
+
+            // [ivk] g_d_old
+            g_d_old.mul(layouter.namespace(|| "[ivk] g_d_old"), ivk.inner())?
+        };
+
         Ok(())
     }
 }
diff --git a/src/circuit/gadget.rs b/src/circuit/gadget.rs
index dbcf8450..866e44dd 100644
--- a/src/circuit/gadget.rs
+++ b/src/circuit/gadget.rs
@@ -2,7 +2,7 @@ use pasta_curves::pallas;
 
 use ecc::chip::EccChip;
 use poseidon::Pow5T3Chip as PoseidonChip;
-use sinsemilla::merkle::chip::MerkleChip;
+use sinsemilla::{chip::SinsemillaChip, merkle::chip::MerkleChip};
 use utilities::plonk::PLONKChip;
 
 pub(crate) mod ecc;
@@ -19,6 +19,14 @@ impl super::Config {
         EccChip::construct(self.ecc_config.clone())
     }
 
+    pub(super) fn sinsemilla_chip_1(&self) -> SinsemillaChip {
+        SinsemillaChip::construct(self.sinsemilla_config_1.clone())
+    }
+
+    pub(super) fn sinsemilla_chip_2(&self) -> SinsemillaChip {
+        SinsemillaChip::construct(self.sinsemilla_config_2.clone())
+    }
+
     pub(super) fn merkle_chip_1(&self) -> MerkleChip {
         MerkleChip::construct(self.merkle_config_1.clone())
     }
diff --git a/src/constants.rs b/src/constants.rs
index 50a26277..062ec384 100644
--- a/src/constants.rs
+++ b/src/constants.rs
@@ -43,6 +43,11 @@ pub(crate) const L_ORCHARD_SCALAR: usize = 255;
 /// $\ell_\mathsf{value}$
 pub(crate) const L_VALUE: usize = 64;
 
+/// T_PRIME_BITS is the smallest multiple of 10 such that 2^T_PRIME_BITS
+/// is larger than t_P. t_P is defined in q_P = 2^254 + t_P for the
+/// Pallas base field.
+pub(crate) const PALLAS_T_PRIME_BITS: usize = 130;
+
 /// SWU hash-to-curve personalization for the spending key base point and
 /// the nullifier base point K^Orchard
 pub const ORCHARD_PERSONALIZATION: &str = "z.cash:Orchard";