diff --git a/androscalpel_serializer/src/items/hiddenapi.rs b/androscalpel_serializer/src/items/hiddenapi.rs
new file mode 100644
index 0000000..a918a5a
--- /dev/null
+++ b/androscalpel_serializer/src/items/hiddenapi.rs
@@ -0,0 +1,141 @@
+//! Hidden api items.
+
+use crate as androscalpel_serializer;
+use crate::{Error, ReadSeek, Result, Serializable, Uleb128};
+use std::io::{Cursor, Write};
+
+/// https://source.android.com/docs/core/runtime/dex-format#hiddenapi-class-data-item
+/// Hard to serialize/deserialize without additional data like the number of classes
+/// or the method/field of the classes.
+#[derive(Clone, PartialEq, Eq)]
+pub struct HiddenapiClassDataItem {
+    //pub size: u32,
+    pub data: Vec<u8>,
+}
+
+impl HiddenapiClassDataItem {
+    pub fn size_field(&self) -> u32 {
+        self.data.len() as u32
+    }
+
+    /// Return `hiddenapi_class_data_item.offsets[class_idx]`.
+    ///
+    /// If `0`: Either no data for this class or all API flags are zero.
+    /// Else: offset from the begining of the [`HiddenapiClassDataItem`]
+    /// (including the size /!\).
+    ///
+    /// # Warning
+    ///
+    /// They are no check weither the `class_idx` is valid one or not.
+    /// Giving an invalid idx (like an idx >= nb class) is UB.
+    pub fn get_offset(&self, class_idx: u32) -> Result<u32> {
+        let index = (class_idx as usize) * 4;
+        if self.data.len() < index - 4 {
+            Err(Error::InconsistantStruct(format!(
+                "class index 0x{class_idx:x} out of bound of HiddenapiClassDataItem data"
+            )))
+        } else {
+            u32::deserialize_from_slice(&self.data[index..])
+        }
+    }
+
+    /// Return `hiddenapi_class_data_item.offsets`.
+    ///
+    /// # Warning
+    ///
+    /// They are no check weither the `nb_class` is valid one or not.
+    /// Giving an invalid `nb_class`.
+    pub fn get_offsets(&self, nb_class: u32) -> Result<Vec<u32>> {
+        let mut offsets = vec![];
+        let mut buffer = Cursor::new(self.data.as_slice());
+        for _ in 0..nb_class {
+            offsets.push(u32::deserialize(&mut buffer)?);
+        }
+        Ok(offsets)
+    }
+
+    /// Get a list of `nb_flags` flags from the `offset`.
+    /// `nb_flags` should be the number of field + the number of method
+    /// of the class associated to `offset`.
+    ///
+    /// # Warning
+    ///
+    /// They are no check weither the `nb_flags` or `offset`
+    /// are valid. Providing invalid values is UB.
+    pub fn get_flags(&self, nb_flags: usize, offset: u32) -> Result<Vec<Uleb128>> {
+        if offset == 0 {
+            Ok(vec![Uleb128(0); nb_flags])
+        } else if offset < 4 {
+            // < 8 is almost certainly false
+            panic!()
+        } else {
+            let mut buffer = Cursor::new(self.data.as_slice());
+            let mut flags = vec![];
+            for _ in 0..nb_flags {
+                flags.push(Uleb128::deserialize(&mut buffer)?);
+            }
+            Ok(flags)
+        }
+    }
+}
+
+impl Serializable for HiddenapiClassDataItem {
+    fn serialize(&self, output: &mut dyn Write) -> Result<()> {
+        self.size_field().serialize(output)?;
+        for byte in &self.data {
+            byte.serialize(output)?;
+        }
+        Ok(())
+    }
+
+    fn deserialize(input: &mut dyn ReadSeek) -> Result<Self> {
+        let size = u32::deserialize(input)?;
+        let mut data = vec![];
+        for _ in 0..size {
+            data.push(u8::deserialize(input)?);
+        }
+        Ok(Self { data })
+    }
+
+    fn size(&self) -> usize {
+        self.size_field().size() + self.data.iter().map(|val| val.size()).sum::<usize>()
+    }
+}
+
+/// Flags for hidden api
+#[derive(Serializable, Debug, PartialEq, Eq, Copy, Clone)]
+#[prefix_type(Uleb128)]
+pub enum HiddenApiFlag {
+    /// Interfaces that can be freely used and are supported as
+    /// part of the officially documented Android framework Package Index
+    #[prefix(Uleb128(0x00))]
+    Whitelist,
+    /// Non-SDK interfaces that can be used regardless of the
+    /// application's target API level
+    #[prefix(Uleb128(0x01))]
+    Greylist,
+    /// Non-SDK interfaces that cannot be used regardless of the
+    /// application's target API level. Accessing one of these
+    /// interfaces causes a runtime error.
+    #[prefix(Uleb128(0x02))]
+    Blacklist,
+    /// Non-SDK interfaces that can be used for Android 8.x and
+    /// below unless they are restricted.
+    #[prefix(Uleb128(0x03))]
+    GreylistMaxO,
+    /// Non-SDK interfaces that can be used for Android 9.x unless
+    /// they are restricted.
+    #[prefix(Uleb128(0x04))]
+    GreylistMaxP,
+    /// Non-SDK interfaces that can be used for Android 10.x unless
+    /// they are restricted.
+    #[prefix(Uleb128(0x05))]
+    GreylistMaxQ,
+    /// Non-SDK interfaces that can be used for Android 11.x unless
+    /// they are restricted.
+    #[prefix(Uleb128(0x06))]
+    GreylistMaxR,
+    /// Unknown flag, either an error or this crate is out of date.
+    #[default_variant]
+    Unknwon(Uleb128),
+}
diff --git a/androscalpel_serializer/src/items/mod.rs b/androscalpel_serializer/src/items/mod.rs
index c870b28..99abac7 100644
--- a/androscalpel_serializer/src/items/mod.rs
+++ b/androscalpel_serializer/src/items/mod.rs
@@ -6,11 +6,13 @@ use crate::{EncodedArray, Serializable};
 pub mod class;
 pub mod code;
 pub mod header;
+pub mod hiddenapi;
 pub mod map;
 
 pub use class::*;
 pub use code::*;
 pub use header::*;
+pub use hiddenapi::*;
 pub use map::*;
 
 /// https://source.android.com/docs/core/runtime/dex-format#string-item