feat: add Casper Network support (kobe-casper)

.github/workflows/ci.yml

@@ -87,6 +87,8 @@ jobs:
         run: cargo check -p kobe-nostr --target thumbv7m-none-eabi --no-default-features --features alloc
       - name: kobe-xrpl (no_std)
         run: cargo check -p kobe-xrpl --target thumbv7m-none-eabi --no-default-features --features alloc
+      - name: kobe-casper (no_std)
+        run: cargo check -p kobe-casper --target thumbv7m-none-eabi --no-default-features --features alloc
       - name: kobe (no_std)
         run: cargo check -p kobe --target thumbv7m-none-eabi --no-default-features --features alloc
       - name: kobe (no_std + all chains)

.github/workflows/publish.yml

@@ -8,6 +8,6 @@ jobs:
   publish:
     uses: qntx/workflows/.github/workflows/publish-crates.yml@main
     with:
-      packages: "kobe-primitives kobe-aptos kobe-btc kobe-evm kobe-svm kobe-cosmos kobe-tron kobe-spark kobe-fil kobe-ton kobe-sui kobe-xrpl kobe-nostr kobe kobe-cli"
+      packages: "kobe-primitives kobe-aptos kobe-btc kobe-evm kobe-svm kobe-cosmos kobe-tron kobe-spark kobe-fil kobe-ton kobe-sui kobe-xrpl kobe-nostr kobe-casper kobe kobe-cli"
     secrets:
       CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}

CHANGELOG.md

@@ -4,6 +4,18 @@ All notable changes to this workspace are documented in this file. The format is
 
 ## [Unreleased]
 
+### Added
+
+- **Casper Network (`kobe-casper`)** — offline HD derivation for CSPR
+  (SLIP-44 coin type `506`):
+  - Default algorithm **secp256k1** at Ledger path `m/44'/506'/0'/0/{i}`
+  - Alternate **Ed25519** (SLIP-10) at `m/44'/506'/0'/0'/{i}'` via `--algo ed25519`
+  - Primary address: Casper **AccountHash** (`account-hash-` + 64 hex);
+    preimage matches `casper-types` (`algorithm_name || 0x00 || raw_pubkey`)
+  - Library `CasperAccount` also exposes tagged public-key hex (`01…` / `02…`)
+  - CLI: `kobe casper` / `kobe cspr` (`new` / `import`)
+  - Umbrella feature: `casper` (included in `all-chains`)
+
 ## [3.1.1] - 2026-08-08
 
 ### Security

Cargo.toml

@@ -33,6 +33,7 @@ kobe-tron       = { version = "3.1", path = "crates/kobe-tron",       default-fe
 kobe-aptos      = { version = "3.1", path = "crates/kobe-aptos",      default-features = false }
 kobe-nostr      = { version = "3.1", path = "crates/kobe-nostr",      default-features = false }
 kobe-xrpl       = { version = "3.1", path = "crates/kobe-xrpl",       default-features = false }
+kobe-casper     = { version = "3.1", path = "crates/kobe-casper",     default-features = false }
 
 alloy-primitives = { version = "1.6.1",  default-features = false, features = ["k256"] }
 base64           = { version = "0.23.1", default-features = false, features = ["alloc"] }

Justfile

@@ -38,6 +38,7 @@ check-no-std:
     cargo check -p kobe-sui --no-default-features --features alloc
     cargo check -p kobe-nostr --no-default-features --features alloc
     cargo check -p kobe-xrpl --no-default-features --features alloc
+    cargo check -p kobe-casper --no-default-features --features alloc
     cargo check -p kobe --no-default-features --features alloc
     cargo check -p kobe --no-default-features --features "alloc,all-chains"
 

Makefile

@@ -36,6 +36,7 @@ check-no-std:
 	cargo check -p kobe-sui --no-default-features --features alloc
 	cargo check -p kobe-nostr --no-default-features --features alloc
 	cargo check -p kobe-xrpl --no-default-features --features alloc
+	cargo check -p kobe-casper --no-default-features --features alloc
 	cargo check -p kobe --no-default-features --features alloc
 	cargo check -p kobe --no-default-features --features "alloc,all-chains"
 

README.md

@@ -17,9 +17,9 @@
 [rust-badge]: https://img.shields.io/badge/rust-edition%202024-orange.svg
 [rust-url]: https://doc.rust-lang.org/edition-guide/
 
-**`no_std`-compatible Rust toolkit for multi-chain HD wallet derivation — one BIP-39 seed, twelve networks, zero hand-written cryptography, cross-implementation KATs.**
+**`no_std`-compatible Rust toolkit for multi-chain HD wallet derivation — one BIP-39 seed, thirteen networks, zero hand-written cryptography, cross-implementation KATs.**
 
-Kobe derives standards-compliant accounts and addresses for Aptos, Bitcoin, Ethereum, Solana, Cosmos, Tron, Sui, TON, Filecoin, Spark, XRP Ledger, and Nostr (NIP-06 / NIP-19) from a single BIP-39 mnemonic. It layers thin wrappers around [`bip39`](https://docs.rs/bip39), [`bip32`](https://docs.rs/bip32), [`k256`](https://docs.rs/k256), and [`ed25519-dalek`](https://docs.rs/ed25519-dalek) on top of a unified `Wallet` + `Derive` trait surface (Bitcoin address/WIF encoding is local in `kobe-btc`, not the full `bitcoin` crate); every library crate builds under `no_std + alloc`, mnemonics and private keys wrap in `Zeroizing<T>` and wipe on drop, and every chain's pipeline is pinned against independent reference implementations (bitcoinjs-lib, @ton/core, @noble/hashes, NIP-06 official vectors, ethanmarcuss/spark-address, …).
+Kobe derives standards-compliant accounts and addresses for Aptos, Bitcoin, Ethereum, Solana, Cosmos, Tron, Sui, TON, Filecoin, Spark, XRP Ledger, Nostr (NIP-06 / NIP-19), and Casper from a single BIP-39 mnemonic. It layers thin wrappers around [`bip39`](https://docs.rs/bip39), [`bip32`](https://docs.rs/bip32), [`k256`](https://docs.rs/k256), and [`ed25519-dalek`](https://docs.rs/ed25519-dalek) on top of a unified `Wallet` + `Derive` trait surface (Bitcoin address/WIF encoding is local in `kobe-btc`, not the full `bitcoin` crate); every library crate builds under `no_std + alloc`, mnemonics and private keys wrap in `Zeroizing<T>` and wipe on drop, and every chain's pipeline is pinned against independent reference implementations (bitcoinjs-lib, @ton/core, @noble/hashes, NIP-06 official vectors, ethanmarcuss/spark-address, casper-types AccountHash preimage, …).
 
 > **See also** [`signer`](https://github.com/qntx/signer) — the companion transaction-signing toolkit that consumes kobe's derived accounts via `Signer::from_derived`.
 
@@ -61,6 +61,8 @@ kobe svm    new                              # Solana (Phantom / Backpack / Solf
 kobe cosmos new                              # Cosmos Hub (`cosmos1…`)
 kobe aptos  new                              # Aptos
 kobe sui    new                              # Sui
+kobe casper new                              # Casper (CSPR)
+kobe casper new --algo ed25519               # Casper Ed25519 path
 kobe ton    new                              # TON wallet v5r1 (UQ… non-bounceable)
 kobe ton    new --bounceable                 # TON bounceable (EQ…), smart-contract style
 kobe ton    new --testnet --workchain -1     # TON testnet masterchain
@@ -91,7 +93,7 @@ kobe upgrade --force                     # reinstall even when up to date
 echo "abandon abandon ... about" | kobe -r evm import -m -
 ```
 
-Every chain subcommand accepts the shared flags `-w/--words`, `-c/--count`, `-p/--passphrase`, and `--qr` through a flattened `SimpleArgs` group, so ergonomics stay consistent across the 12 networks. Global `-r` / `--reveal` opts into printing mnemonics and private keys (default: hidden).
+Every chain subcommand accepts the shared flags `-w/--words`, `-c/--count`, `-p/--passphrase`, and `--qr` through a flattened `SimpleArgs` group, so ergonomics stay consistent across the 13 networks. Global `-r` / `--reveal` opts into printing mnemonics and private keys (default: hidden).
 
 ### Library Usage
 
@@ -169,13 +171,15 @@ println!("Mnemonic: {}", wallet.mnemonic());
 | Sui        | `kobe-sui`     | Ed25519 (SLIP-10)     | 784         | `m/44'/784'/{i}'/0'/0'`     | `0x` + hex(`BLAKE2b-256(0x00 ‖ pubkey)`) |
 | TON        | `kobe-ton`     | Ed25519 (SLIP-10)     | 607         | `m/44'/607'/{i}'`           | wallet v5r1 (`UQ…` / `EQ…` / `0Q…` / …)  |
 | Aptos      | `kobe-aptos`   | Ed25519 (SLIP-10)     | 637         | `m/44'/637'/{i}'/0'/0'`     | `0x` + hex(`SHA3-256(pubkey ‖ 0x00)`)    |
+| Casper     | `kobe-casper`  | secp256k1 / Ed25519   | 506         | `m/44'/506'/0'/0/{i}` ‡     | `account-hash-` + BLAKE2b-256            |
 
 \* Cosmos coin type defaults to `118`; Terra (`330`), Secret (`529`), Kava (`459`), and custom chains are selectable via `ChainConfig`.
 † Spark purpose `8797555` is Spark-specific (`SHA-256("spark")` truncated), not a BIP-44 assignment.
+‡ Casper default is secp256k1 (Ledger); Ed25519 uses `m/44'/506'/0'/0'/{i}'`. AccountHash preimage is `algorithm_name || 0x00 || raw_pubkey` per `casper-types`.
 
 ## Design
 
-- **12 chains** — Aptos, Bitcoin, Ethereum, Solana, Cosmos, Tron, Sui, TON, Filecoin, Spark, XRP Ledger, Nostr — one BIP-39 seed
+- **13 chains** — Aptos, Bitcoin, Ethereum, Solana, Cosmos, Tron, Sui, TON, Filecoin, Spark, XRP Ledger, Nostr, Casper — one BIP-39 seed
 - **Mature crypto dependencies** — `bip39` for mnemonic ↔ entropy, `bip32` + `k256` for BIP-32 secp256k1 (via `kobe-primitives`), `ed25519-dalek` for SLIP-10 Ed25519; hashing via `sha2` / `sha3` / `blake2` / `ripemd`; encoding via `bech32` / `bs58` (Bitcoin addresses/WIF implemented in-tree and KAT-pinned)
 - **Unified derivation contract** — shared `Derive` trait with an associated `Account` type + shared `DerivationStyle` trait; every chain has typed public keys via `DerivedPublicKey`, one shared `DeriveError`, and one shared `ParseDerivationStyleError`
 - **Consistent entry points** — `derive` / `derive_with` / `derive_at` / `derive_at_with` across every chain (Bitcoin's structured path also available as `derive_structured`)

crates/README.md

@@ -16,6 +16,7 @@
 | **[`kobe-spark`](kobe-spark/)** | [![crates.io][kobe-spark-crate]][kobe-spark-crate-url] [![docs.rs][kobe-spark-doc]][kobe-spark-doc-url] | Spark (Bitcoin L2) — identity keys + Bech32m `spark1…` addresses |
 | **[`kobe-xrpl`](kobe-xrpl/)** | [![crates.io][kobe-xrpl-crate]][kobe-xrpl-crate-url] [![docs.rs][kobe-xrpl-doc]][kobe-xrpl-doc-url] | XRP Ledger — classic `r`-addresses, secp256k1 |
 | **[`kobe-nostr`](kobe-nostr/)** | [![crates.io][kobe-nostr-crate]][kobe-nostr-crate-url] [![docs.rs][kobe-nostr-doc]][kobe-nostr-doc-url] | Nostr — NIP-06 key derivation, NIP-19 bech32 `nsec`/`npub` |
+| **[`kobe-casper`](kobe-casper/)** | [![crates.io][kobe-casper-crate]][kobe-casper-crate-url] [![docs.rs][kobe-casper-doc]][kobe-casper-doc-url] | Casper — secp256k1 / Ed25519 HD + AccountHash |
 | **[`kobe-cli`](kobe-cli/)** | [![crates.io][kobe-cli-crate]][kobe-cli-crate-url] | CLI — generate, import, derive; `upgrade` via sh.qntx.fun |
 
 ## Dependency Graph
@@ -35,7 +36,8 @@ kobe-cli
         ├── kobe-svm    ── kobe-primitives/slip10
         ├── kobe-ton    ── kobe-primitives/slip10
         ├── kobe-tron   ── kobe-primitives/bip32
-        └── kobe-xrpl   ── kobe-primitives/bip32
+        ├── kobe-xrpl   ── kobe-primitives/bip32
+        └── kobe-casper ── kobe-primitives/bip32 + slip10
 ```
 
 All chain crates consume key derivation through the wallet-level shortcuts
@@ -65,6 +67,7 @@ The umbrella `kobe` crate provides fine-grained feature control:
 | `aptos` | | Aptos chain support (enables `slip10`) |
 | `xrpl` | | XRP Ledger chain support (enables `bip32`) |
 | `nostr` | | Nostr chain support (enables `bip32`) |
+| `casper` | | Casper Network support (enables `bip32` + `slip10`) |
 | `all-chains` | | Enable all chain crates |
 
 [kobe-crate]: https://img.shields.io/crates/v/kobe.svg
@@ -125,3 +128,7 @@ The umbrella `kobe` crate provides fine-grained feature control:
 [kobe-nostr-crate-url]: https://crates.io/crates/kobe-nostr
 [kobe-nostr-doc]: https://img.shields.io/docsrs/kobe-nostr.svg
 [kobe-nostr-doc-url]: https://docs.rs/kobe-nostr
+[kobe-casper-crate]: https://img.shields.io/crates/v/kobe-casper.svg
+[kobe-casper-crate-url]: https://crates.io/crates/kobe-casper
+[kobe-casper-doc]: https://img.shields.io/docsrs/kobe-casper.svg
+[kobe-casper-doc-url]: https://docs.rs/kobe-casper

crates/kobe-casper/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name                   = "kobe-casper"
+version.workspace      = true
+edition.workspace      = true
+rust-version.workspace = true
+license.workspace      = true
+repository.workspace   = true
+readme                 = "../../README.md"
+description            = "Casper Network wallet for Kobe"
+keywords               = ["casper", "cspr", "wallet", "crypto", "no_std"]
+categories             = ["cryptography", "no-std"]
+
+[features]
+default = ["std"]
+std     = ["alloc", "kobe-primitives/std", "hex/std"]
+alloc   = ["kobe-primitives/alloc", "hex/alloc"]
+
+[dependencies]
+# Casper uses both secp256k1 (Ledger default path) and Ed25519 (casper-client default).
+# Secrets zeroize via `kobe-primitives::DerivedAccount` / key types.
+kobe-primitives  = { workspace = true, features = ["bip32", "slip10"] }
+blake2.workspace = true
+hex.workspace    = true
+
+[lints]
+workspace = true

crates/kobe-casper/src/address.rs

@@ -0,0 +1,155 @@
+//! Casper `PublicKey` tagging and `AccountHash` encoding.
+//!
+//! Encoding matches `casper-types` (`casper-node` `types` crate):
+//!
+//! - **Tagged public key** (serialization / display hex): tag byte + raw key.
+//! - **`AccountHash`** preimage: `algorithm_name || 0x00 || raw_key` (no tag).
+
+#[cfg(feature = "alloc")]
+use alloc::{format, string::String, vec::Vec};
+
+use blake2::Blake2bVar;
+use blake2::digest::{Update, VariableOutput};
+use kobe_primitives::DeriveError;
+
+/// Prefix applied to the hex-encoded `AccountHash` for display.
+pub const ACCOUNT_HASH_PREFIX: &str = "account-hash-";
+
+/// Casper serialization tag for Ed25519 public keys (`PublicKey::Ed25519`).
+pub const ED25519_TAG: u8 = 0x01;
+
+/// Casper serialization tag for secp256k1 public keys (`PublicKey::Secp256k1`).
+pub const SECP256K1_TAG: u8 = 0x02;
+
+/// Lowercase algorithm name used in the `AccountHash` preimage (Ed25519).
+const ED25519_NAME: &[u8] = b"ed25519";
+
+/// Lowercase algorithm name used in the `AccountHash` preimage (secp256k1).
+const SECP256K1_NAME: &[u8] = b"secp256k1";
+
+/// Format a 32-byte `AccountHash` digest as `account-hash-` + lowercase hex.
+#[inline]
+#[must_use]
+pub fn format_account_hash(digest: &[u8; 32]) -> String {
+    format!("{ACCOUNT_HASH_PREFIX}{}", hex::encode(digest))
+}
+
+/// Tagged public-key hex (no `0x` prefix): `01 ‖ ed25519` or `02 ‖ secp`.
+///
+/// `raw_key` must be the 32-byte Ed25519 key or 33-byte compressed secp256k1
+/// key (without the Casper algorithm tag).
+#[inline]
+#[must_use]
+pub fn tagged_public_key_hex(tag: u8, raw_key: &[u8]) -> String {
+    let mut buf = Vec::with_capacity(1 + raw_key.len());
+    buf.push(tag);
+    buf.extend_from_slice(raw_key);
+    hex::encode(buf)
+}
+
+/// Compute the Casper `AccountHash` for an Ed25519 public key.
+///
+/// Preimage: `b"ed25519" || 0x00 || pubkey` (32-byte raw key).
+///
+/// # Errors
+///
+/// Returns [`DeriveError::Crypto`] if `BLAKE2b` initialization or finalization
+/// fails (should not occur for a fixed 32-byte output size).
+pub fn account_hash_ed25519(pubkey: &[u8; 32]) -> Result<[u8; 32], DeriveError> {
+    account_hash_from_parts(ED25519_NAME, pubkey)
+}
+
+/// Compute the Casper `AccountHash` for a compressed secp256k1 public key.
+///
+/// Preimage: `b"secp256k1" || 0x00 || compressed_pubkey` (33-byte `SEC1`).
+///
+/// # Errors
+///
+/// Returns [`DeriveError::Crypto`] if `BLAKE2b` initialization or finalization
+/// fails.
+pub fn account_hash_secp256k1(compressed_pubkey: &[u8; 33]) -> Result<[u8; 32], DeriveError> {
+    account_hash_from_parts(SECP256K1_NAME, compressed_pubkey)
+}
+
+/// Shared `AccountHash` construction: `name || 0x00 || raw_key` → `BLAKE2b`-256.
+fn account_hash_from_parts(algorithm_name: &[u8], raw_key: &[u8]) -> Result<[u8; 32], DeriveError> {
+    let mut preimage = Vec::with_capacity(algorithm_name.len() + 1 + raw_key.len());
+    preimage.extend_from_slice(algorithm_name);
+    preimage.push(0);
+    preimage.extend_from_slice(raw_key);
+    blake2b_256(&preimage)
+}
+
+/// `BLAKE2b`-256 (empty key), matching Casper's `crypto::blake2b`.
+fn blake2b_256(data: &[u8]) -> Result<[u8; 32], DeriveError> {
+    let mut hasher =
+        Blake2bVar::new(32).map_err(|e| DeriveError::Crypto(format!("blake2b init: {e}")))?;
+    hasher.update(data);
+    let mut out = [0u8; 32];
+    hasher
+        .finalize_variable(&mut out)
+        .map_err(|e| DeriveError::Crypto(format!("blake2b finalize: {e}")))?;
+    Ok(out)
+}
+
+#[cfg(test)]
+#[allow(
+    clippy::unwrap_used,
+    clippy::expect_used,
+    reason = "unit tests panic on assertion failure"
+)]
+mod tests {
+    use super::*;
+
+    /// Independent stdlib-equivalent vectors: preimage is `name||0x00||key`,
+    /// digest is `BLAKE2b`-256. Cross-checked with Python `hashlib.blake2b`.
+    #[test]
+    fn kat_account_hash_ed25519_fixed_key() {
+        let pk = hex::decode("0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef")
+            .unwrap();
+        let pk: [u8; 32] = pk.try_into().unwrap();
+        let digest = account_hash_ed25519(&pk).unwrap();
+        assert_eq!(
+            hex::encode(digest),
+            "5b1c945c6e0923bf4f8da320444804791eb60d70983c7c5756d8ef236c1fdece"
+        );
+        assert_eq!(
+            format_account_hash(&digest),
+            "account-hash-5b1c945c6e0923bf4f8da320444804791eb60d70983c7c5756d8ef236c1fdece"
+        );
+        assert_eq!(
+            tagged_public_key_hex(ED25519_TAG, &pk),
+            "010123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+        );
+    }
+
+    /// secp256k1 generator point (compressed) — independent `BLAKE2b` KAT.
+    #[test]
+    fn kat_account_hash_secp256k1_generator() {
+        let pk = hex::decode("0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798")
+            .unwrap();
+        let pk: [u8; 33] = pk.try_into().unwrap();
+        let digest = account_hash_secp256k1(&pk).unwrap();
+        assert_eq!(
+            hex::encode(digest),
+            "86937931937ee0281e50806b94f8d4993e8869b0689dfa0a21d2946ab677183c"
+        );
+        assert_eq!(
+            tagged_public_key_hex(SECP256K1_TAG, &pk),
+            "020279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798"
+        );
+    }
+
+    /// Preimage must include the null separator; wrong layout must not match.
+    #[test]
+    fn preimage_includes_null_separator() {
+        let pk = [0xab_u8; 32];
+        let good = account_hash_ed25519(&pk).unwrap();
+        // Tag-only layout (incorrect for AccountHash) must differ.
+        let mut wrong = Vec::with_capacity(33);
+        wrong.push(ED25519_TAG);
+        wrong.extend_from_slice(&pk);
+        let wrong_hash = blake2b_256(&wrong).unwrap();
+        assert_ne!(good, wrong_hash);
+    }
+}