diff --git a/ethereum/Cargo.lock b/ethereum/Cargo.lock
index e177aba8..fe090fe0 100644
--- a/ethereum/Cargo.lock
+++ b/ethereum/Cargo.lock
@@ -17,12 +17,43 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.86"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"
+
 [[package]]
 name = "autocfg"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
 
+[[package]]
+name = "bitvec"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bc2832c24239b0141d5674bb9174f9d68a8b5b3f2753311927c172ca46f7e9c"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
+[[package]]
+name = "bls12_381"
+version = "0.8.0"
+source = "git+https://github.com/lurk-lab/bls12_381.git?branch=zkvm#0d57d6ac0af6a464c4764809b5bf994d15920762"
+dependencies = [
+ "cfg-if",
+ "ff",
+ "group",
+ "pairing",
+ "rand_core",
+ "subtle",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.16.0"
@@ -97,11 +128,18 @@ version = "0.1.0"
 dependencies = [
  "ethereum-lc-core",
  "ethereum-programs",
+ "getset",
 ]
 
 [[package]]
 name = "ethereum-lc-core"
 version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "bls12_381",
+ "getset",
+ "thiserror",
+]
 
 [[package]]
 name = "ethereum-programs"
@@ -111,12 +149,52 @@ dependencies = [
  "sphinx-helper",
 ]
 
+[[package]]
+name = "ff"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ded41244b729663b1e574f1b4fb731469f69f79c17667b5d776b16cda0479449"
+dependencies = [
+ "bitvec",
+ "rand_core",
+ "subtle",
+]
+
+[[package]]
+name = "funty"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
+
+[[package]]
+name = "getset"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e45727250e75cc04ff2846a66397da8ef2b3db8e40e0cef4df67950a07621eb9"
+dependencies = [
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "glob"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
+[[package]]
+name = "group"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0f9ef7462f7c099f518d754361858f86d8a07af53ba9af0fe635bbccb151a63"
+dependencies = [
+ "ff",
+ "rand_core",
+ "subtle",
+]
+
 [[package]]
 name = "iana-time-zone"
 version = "0.1.60"
@@ -182,6 +260,39 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "pairing"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81fec4625e73cf41ef4bb6846cafa6d44736525f442ba45e407c4a000a13996f"
+dependencies = [
+ "group",
+]
+
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.86"
@@ -200,6 +311,18 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "radium"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+
 [[package]]
 name = "ryu"
 version = "1.0.18"
@@ -232,7 +355,7 @@ checksum = "500cbc0ebeb6f46627f50f3f5811ccf6bf00643be300b4c3eabc0ef55dc5b5ba"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.68",
 ]
 
 [[package]]
@@ -255,6 +378,23 @@ dependencies = [
  "chrono",
 ]
 
+[[package]]
+name = "subtle"
+version = "2.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
+
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.68"
@@ -266,6 +406,12 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
 [[package]]
 name = "thiserror"
 version = "1.0.61"
@@ -283,7 +429,7 @@ checksum = "46c3384250002a6d5af4d114f2845d37b57521033f30d5c3f46c4d70e1197533"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.68",
 ]
 
 [[package]]
@@ -292,6 +438,12 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
 
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.92"
@@ -313,7 +465,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.68",
  "wasm-bindgen-shared",
 ]
 
@@ -335,7 +487,7 @@ checksum = "e94f17b526d0a461a191c78ea52bbce64071ed5c04c9ffe424dcb38f74171bb7"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.68",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
@@ -419,6 +571,15 @@ version = "0.52.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bec47e5bfd1bff0eeaf6d8b485cc1074891a197ab4225d504cb7a1ab88b02bf0"
 
+[[package]]
+name = "wyz"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05f360fc0b24296329c78fda852a1e9ae82de9cf7b27dae4b7f62f118f77b9ed"
+dependencies = [
+ "tap",
+]
+
 [[patch.unused]]
 name = "sha2"
 version = "0.10.8"
diff --git a/ethereum/Cargo.toml b/ethereum/Cargo.toml
index 9b44a3f0..a7fd1863 100644
--- a/ethereum/Cargo.toml
+++ b/ethereum/Cargo.toml
@@ -4,7 +4,10 @@ resolver = "2"
 members = ["core", "ethereum-programs", "light-client"]
 
 [workspace.dependencies]
+anyhow = "1.0.86"
 glob = "0.3.1"
+getset = "0.1.2"
+thiserror = "1.0.61"
 # Crypto dependencies
 bls12_381 = { git = "https://github.com/lurk-lab/bls12_381.git", branch = "zkvm" }
 # Sphinx dependencies
diff --git a/ethereum/core/Cargo.toml b/ethereum/core/Cargo.toml
index ac494a99..d0808bef 100644
--- a/ethereum/core/Cargo.toml
+++ b/ethereum/core/Cargo.toml
@@ -4,4 +4,10 @@ version = "0.1.0"
 edition = "2021"
 license = "Apache-2.0"
 homepage = "https://github.com/wormhole-foundation/example-zk-light-clients"
-repository = "https://github.com/wormhole-foundation/example-zk-light-clients"
\ No newline at end of file
+repository = "https://github.com/wormhole-foundation/example-zk-light-clients"
+
+[dependencies]
+anyhow = { workspace = true }
+bls12_381 = { workspace = true }
+getset = { workspace = true }
+thiserror = { workspace = true }
\ No newline at end of file
diff --git a/ethereum/core/src/crypto/error.rs b/ethereum/core/src/crypto/error.rs
new file mode 100644
index 00000000..e94e2b50
--- /dev/null
+++ b/ethereum/core/src/crypto/error.rs
@@ -0,0 +1,14 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+use thiserror::Error;
+
+/// The error type for the `crypto` module.
+#[derive(Debug, Error)]
+pub enum CryptoError {
+    #[error("Internal error occurred: {source}")]
+    Internal {
+        #[source]
+        source: Box<dyn std::error::Error + Sync + Send>,
+    },
+}
diff --git a/ethereum/core/src/crypto/mod.rs b/ethereum/core/src/crypto/mod.rs
new file mode 100644
index 00000000..9788ed0d
--- /dev/null
+++ b/ethereum/core/src/crypto/mod.rs
@@ -0,0 +1,17 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+//! # Cryptographic Utilities for the Aptos Light Client
+//!
+//! This module contains cryptographic utilities used by the light client.
+//! It is divided into several sub-modules, each with its own specific functionality.
+//!
+//! ## Sub-modules
+//!
+//! - `sig`: This sub-module contains the `Signature` and `PublicKey` structures and their associated methods.
+//! - `error`: This sub-module contains the ``CryptoError` error type used throughout the `crypto` module.
+//!
+//! For more detailed information, users should refer to the specific documentation for each sub-module.
+
+pub mod error;
+pub mod sig;
diff --git a/ethereum/core/src/crypto/sig.rs b/ethereum/core/src/crypto/sig.rs
new file mode 100644
index 00000000..419b401d
--- /dev/null
+++ b/ethereum/core/src/crypto/sig.rs
@@ -0,0 +1,75 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+use crate::crypto::error::CryptoError;
+use anyhow::Result;
+use bls12_381::G1Affine;
+use std::cell::OnceCell;
+
+/// Length of a public key in bytes.
+pub const PUB_KEY_LEN: usize = 48;
+
+/// A structure representing a public key.
+///
+/// The public key is represented as a compressed byte array and an optional `G1Affine` point.
+/// The `G1Affine` point is computed from the compressed byte array when needed.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct PublicKey {
+    compressed_pubkey: [u8; PUB_KEY_LEN],
+    pubkey: OnceCell<G1Affine>,
+}
+
+impl Default for PublicKey {
+    fn default() -> Self {
+        Self {
+            compressed_pubkey: [0u8; PUB_KEY_LEN],
+            pubkey: OnceCell::new(),
+        }
+    }
+}
+
+impl PublicKey {
+    /// Returns the `G1Affine` point representing the public key.
+    ///
+    /// If the `G1Affine` point has not been computed yet, it is computed from the compressed byte array and stored.
+    ///
+    /// # Returns
+    ///
+    /// A `G1Affine` point representing the public key.
+    ///
+    /// # Note
+    ///
+    // All public key data we receive are in a message signed by validators of a (prior) epoch.
+    // We assume those signers check against rogue key attacks before signing those keys.
+    #[inline]
+    fn pubkey(&self) -> &G1Affine {
+        self.pubkey
+            .get_or_init(|| G1Affine::from_compressed_unchecked(&self.compressed_pubkey).unwrap())
+    }
+
+    /// Aggregates a vector of public keys into a single public key.
+    ///
+    /// # Arguments
+    ///
+    /// * `pubkeys` - A slice of references to `PublicKey` instances to be aggregated.
+    ///
+    /// # Returns
+    ///
+    /// A `Result` which is `Ok` if the public keys could be aggregated successfully. If the aggregation fails,
+    /// the `Result` is `Err` with an error message.
+    pub fn aggregate(pubkeys: &[&Self]) -> Result<PublicKey, CryptoError> {
+        let aggregate = pubkeys
+            .iter()
+            .fold(G1Affine::identity(), |acc, pk| acc.add_affine(pk.pubkey()));
+
+        let pubkey = OnceCell::new();
+        pubkey.set(aggregate).map_err(|_| CryptoError::Internal {
+            source: "Failed to set the aggregate public key value in the cell.".into(),
+        })?;
+
+        Ok(PublicKey {
+            compressed_pubkey: [0u8; PUB_KEY_LEN],
+            pubkey,
+        })
+    }
+}
diff --git a/ethereum/core/src/lib.rs b/ethereum/core/src/lib.rs
index d839d793..29e5dec9 100644
--- a/ethereum/core/src/lib.rs
+++ b/ethereum/core/src/lib.rs
@@ -1,2 +1,5 @@
 // Copyright (c) Yatima, Inc.
 // SPDX-License-Identifier: APACHE-2.0
+
+pub mod crypto;
+pub mod types;
diff --git a/ethereum/core/src/types/block.rs b/ethereum/core/src/types/block.rs
new file mode 100644
index 00000000..a5ed9927
--- /dev/null
+++ b/ethereum/core/src/types/block.rs
@@ -0,0 +1,49 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+use crate::types::Bytes32;
+use getset::Getters;
+
+/// `BeaconBlockHeader` represents the header of a beacon block.
+///
+/// From [the CL specifications](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/beacon-chain.md#beaconblockheader).
+#[derive(Debug, Default, Clone, Getters)]
+#[getset(get = "pub")]
+pub struct BeaconBlockHeader {
+    slot: u64,
+    proposer_index: u64,
+    parent_root: Bytes32,
+    state_root: Bytes32,
+    body_root: Bytes32,
+}
+
+impl BeaconBlockHeader {
+    /// Create a new `BeaconBlockHeader`.
+    ///
+    /// # Arguments
+    ///
+    /// * `slot` - The slot number of the block.
+    /// * `proposer_index` - The validator registry index of the validator who proposed the block.
+    /// * `parent_root` - The hash of the parent block's header.
+    /// * `state_root` - The hash of the beacon state at the start of the block.
+    /// * `body_root` - The hash representing the block body.
+    ///
+    /// # Returns
+    ///
+    /// A new `BeaconBlockHeader`.
+    pub const fn new(
+        slot: u64,
+        proposer_index: u64,
+        parent_root: Bytes32,
+        state_root: Bytes32,
+        body_root: Bytes32,
+    ) -> Self {
+        Self {
+            slot,
+            proposer_index,
+            parent_root,
+            state_root,
+            body_root,
+        }
+    }
+}
diff --git a/ethereum/core/src/types/committee.rs b/ethereum/core/src/types/committee.rs
new file mode 100644
index 00000000..a2460807
--- /dev/null
+++ b/ethereum/core/src/types/committee.rs
@@ -0,0 +1,17 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+use crate::crypto::sig::PublicKey;
+use crate::types::SYNC_COMMITTEE_SIZE;
+use getset::Getters;
+
+/// `SyncCommittee` is a committee of validators that are responsible for attesting to the latest
+/// block. The sync committee is a subset of the full validator set.
+///
+/// From [the Altair upgrade specifications](https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/altair/beacon-chain.md#synccommittee).
+#[derive(Debug, Clone, Getters)]
+#[getset(get = "pub")]
+pub struct SyncCommittee {
+    pubkeys: [PublicKey; SYNC_COMMITTEE_SIZE],
+    aggregate_pubkey: PublicKey,
+}
diff --git a/ethereum/core/src/types/mod.rs b/ethereum/core/src/types/mod.rs
new file mode 100644
index 00000000..43d9e009
--- /dev/null
+++ b/ethereum/core/src/types/mod.rs
@@ -0,0 +1,23 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+//! # Types Module
+//!
+//! This module provides the core data structures and types used in the Ethereum Light Client.
+//!
+//! ## Sub-modules
+//!
+//! - `block`: This sub-module contains all the structures related to block data on the Beacon chain.
+//! - `committee`: This sub-module contains all the structures related to committees on the Beacon chain.
+//!
+//! For more detailed information, users should refer to the specific
+//! documentation for each sub-module.
+
+pub mod block;
+pub mod committee;
+
+/// Constant number of validators in the sync committee.
+pub const SYNC_COMMITTEE_SIZE: usize = 512;
+
+/// A 32-byte array.
+pub type Bytes32 = [u8; 32];
diff --git a/ethereum/ethereum-programs/src/lib.rs b/ethereum/ethereum-programs/src/lib.rs
index 859d1a99..9b097b3a 100644
--- a/ethereum/ethereum-programs/src/lib.rs
+++ b/ethereum/ethereum-programs/src/lib.rs
@@ -3,4 +3,4 @@
 
 pub const INCLUSION_PROGRAM: &[u8] = include_bytes!("../artifacts/inclusion-program");
 
-pub const EPOCH_CHANGE_PROGRAM: &[u8] = include_bytes!("../artifacts/epoch-change-program");
+pub const COMMITTEE_CHANGE_PROGRAM: &[u8] = include_bytes!("../artifacts/committee-change-program");
diff --git a/ethereum/light-client/Cargo.toml b/ethereum/light-client/Cargo.toml
index fb6b9d01..1d47f7c5 100644
--- a/ethereum/light-client/Cargo.toml
+++ b/ethereum/light-client/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+getset = { workspace = true }
 # LC crates
 ethereum-lc-core = { path = "../core" }
 ethereum-programs = { path = "../ethereum-programs" }
diff --git a/ethereum/light-client/src/lib.rs b/ethereum/light-client/src/lib.rs
index 4bcb7464..8fe61d1d 100644
--- a/ethereum/light-client/src/lib.rs
+++ b/ethereum/light-client/src/lib.rs
@@ -1,2 +1,4 @@
 // Copyright (c) Yatima, Inc.
 // SPDX-License-Identifier: Apache-2.0
+
+pub mod types;
diff --git a/ethereum/light-client/src/types/mod.rs b/ethereum/light-client/src/types/mod.rs
new file mode 100644
index 00000000..55a5d4dd
--- /dev/null
+++ b/ethereum/light-client/src/types/mod.rs
@@ -0,0 +1,3 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+pub mod snapshot;
diff --git a/ethereum/light-client/src/types/snapshot.rs b/ethereum/light-client/src/types/snapshot.rs
new file mode 100644
index 00000000..a82bafc7
--- /dev/null
+++ b/ethereum/light-client/src/types/snapshot.rs
@@ -0,0 +1,21 @@
+// Copyright (c) Yatima, Inc.
+// SPDX-License-Identifier: APACHE-2.0
+
+use ethereum_lc_core::types::block::BeaconBlockHeader;
+use ethereum_lc_core::types::committee::SyncCommittee;
+use getset::Getters;
+
+/// `LightClientSnapshot` represents the light client's view of the most recent block header that
+/// the light client is convinced is securely part of the chain.
+///
+/// From [the sync protocol specifications](https://github.com/ethereum/annotated-spec/blob/master/altair/sync-protocol.md#lightclientsnapshot).
+#[derive(Debug, Clone, Getters)]
+#[getset(get = "pub")]
+pub struct LightClientSnapshot {
+    /// Beacon block header
+    header: BeaconBlockHeader,
+    /// Latest validated sync committee
+    current_sync_committee: SyncCommittee,
+    /// Next sync committee
+    next_sync_committee: SyncCommittee,
+}