diff --git a/Cargo.toml b/Cargo.toml
index 9c19eb44..4fa34aef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,8 +19,10 @@ publish = false
 rustdoc-args = [ "--html-in-header", "katex-header.html" ]
 
 [dependencies]
+aes = "0.6"
 blake2b_simd = "0.5"
 ff = "0.9"
+fpe = "0.4"
 group = "0.9"
 halo2 = { git = "https://github.com/zcash/halo2.git", branch = "main" }
 nonempty = "0.6"
diff --git a/src/keys.rs b/src/keys.rs
index 2049da28..e66f5c17 100644
--- a/src/keys.rs
+++ b/src/keys.rs
@@ -3,6 +3,8 @@
 use std::convert::TryInto;
 use std::mem;
 
+use aes::Aes256;
+use fpe::ff1::{BinaryNumeralString, FF1};
 use group::GroupEncoding;
 use halo2::{arithmetic::FieldExt, pasta::pallas};
 use subtle::CtOption;
@@ -176,8 +178,12 @@ impl DiversifierKey {
     }
 
     /// Returns the diversifier at the given index.
-    pub fn get(&self, _: impl Into<DiversifierIndex>) -> Diversifier {
-        todo!()
+    pub fn get(&self, j: impl Into<DiversifierIndex>) -> Diversifier {
+        let ff = FF1::<Aes256>::new(&self.0, 2).expect("valid radix");
+        let enc = ff
+            .encrypt(&[], &BinaryNumeralString::from_bytes_le(&j.into().0[..]))
+            .unwrap();
+        Diversifier(enc.to_bytes_le().try_into().unwrap())
     }
 }