v0.0.14: Ethereum-compatible identity (secp256k1 + Keccak-256)

Protocol (ethereum.rs):
- derive_eth_identity(): HKDF from seed (info="warzone-secp256k1")
- secp256k1 signing key (k256 crate)
- Ethereum address: Keccak-256(uncompressed_pubkey[1..])[-20:]
- EIP-55 checksum address formatting
- eth_sign() / eth_verify() for secp256k1 ECDSA
- EthAddress type with Display, hex parsing, checksum
- 5 tests: deterministic, format, checksum, sign/verify, uniqueness

CLI:
- `warzone eth` — show Ethereum address alongside Warzone fingerprint
- Same seed produces both identities (dual-curve)

Dual identity model:
- Ed25519 + X25519 for Warzone messaging (fast, small signatures)
- secp256k1 for Ethereum compatibility (MetaMask, ENS, Ledger/Trezor)
- Both derived from the same BIP39 seed via different HKDF paths

28/28 protocol tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/Cargo.lock

@@ -191,6 +191,12 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "base16ct"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c7f02d4ea65f2c1853089ffd8d2787bdbc63de2f0d29dedbcf8ccdfa0ccd4cf"
+
 [[package]]
 name = "base64"
 version = "0.22.1"
@@ -510,6 +516,24 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "crunchy"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "460fbee9c2c2f33933d720630a6a0bac33ba7053db5344fac858d4b8952d77d5"
+
+[[package]]
+name = "crypto-bigint"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0dc92fb57ca44df6db8059111ab3af99a63d5d0f8375d9972e319a379c6bab76"
+dependencies = [
+ "generic-array",
+ "rand_core",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "crypto-common"
 version = "0.1.7"
@@ -606,6 +630,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
  "block-buffer",
+ "const-oid",
  "crypto-common",
  "subtle",
 ]
@@ -621,6 +646,21 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "ecdsa"
+version = "0.16.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee27f32b5c5292967d2d4a9d7f1e0b0aed2c15daded5a60300e4abb9d8020bca"
+dependencies = [
+ "der",
+ "digest",
+ "elliptic-curve",
+ "rfc6979",
+ "serdect",
+ "signature",
+ "spki",
+]
+
 [[package]]
 name = "ed25519"
 version = "2.2.3"
@@ -653,6 +693,26 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
+[[package]]
+name = "elliptic-curve"
+version = "0.13.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5e6043086bf7973472e0c7dff2142ea0b680d30e18d9cc40f267efbf222bd47"
+dependencies = [
+ "base16ct",
+ "crypto-bigint",
+ "digest",
+ "ff",
+ "generic-array",
+ "group",
+ "pkcs8",
+ "rand_core",
+ "sec1",
+ "serdect",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -684,6 +744,16 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
+[[package]]
+name = "ff"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0b50bfb653653f9ca9095b427bed08ab8d75a137839d9ad64eb11810d5b6393"
+dependencies = [
+ "rand_core",
+ "subtle",
+]
+
 [[package]]
 name = "fiat-crypto"
 version = "0.2.9"
@@ -811,6 +881,7 @@ checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
 dependencies = [
  "typenum",
  "version_check",
+ "zeroize",
 ]
 
 [[package]]
@@ -839,6 +910,17 @@ dependencies = [
  "wasip3",
 ]
 
+[[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 = "h2"
 version = "0.4.13"
@@ -1276,6 +1358,21 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "k256"
+version = "0.13.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f6e3919bbaa2945715f0bb6d3934a173d1e9a59ac23767fbaaef277265a7411b"
+dependencies = [
+ "cfg-if",
+ "ecdsa",
+ "elliptic-curve",
+ "once_cell",
+ "serdect",
+ "sha2",
+ "signature",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -1760,6 +1857,16 @@ dependencies = [
  "web-sys",
 ]
 
+[[package]]
+name = "rfc6979"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8dd2a808d456c4a54e300a23e9f5a67e122c3024119acbfd73e3bf664491cb2"
+dependencies = [
+ "hmac",
+ "subtle",
+]
+
 [[package]]
 name = "ring"
 version = "0.17.14"
@@ -1869,6 +1976,21 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "sec1"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3e97a565f76233a6003f9f5c54be1d9c5bdfa3eccfb189469f11ec4901c47dc"
+dependencies = [
+ "base16ct",
+ "der",
+ "generic-array",
+ "pkcs8",
+ "serdect",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "security-framework"
 version = "3.7.0"
@@ -1964,6 +2086,16 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serdect"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a84f14a19e9a014bb9f4512488d9829a68e04ecabffb0f9904cd1ace94598177"
+dependencies = [
+ "base16ct",
+ "serde",
+]
+
 [[package]]
 name = "sha1"
 version = "0.10.6"
@@ -2038,6 +2170,7 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77549399552de45a898a580c1b41d445bf730df867cc44e6c0233bbc4b8329de"
 dependencies = [
+ "digest",
  "rand_core",
 ]
 
@@ -2249,6 +2382,15 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "tiny-keccak"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c9d3793400a45f954c52e73d068316d76b6f4e36977e3fcebb13a2721e80237"
+dependencies = [
+ "crunchy",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.2"
@@ -2647,7 +2789,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-client"
-version = "0.0.12"
+version = "0.0.13"
 dependencies = [
  "anyhow",
  "argon2",
@@ -2680,7 +2822,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-mule"
-version = "0.0.12"
+version = "0.0.13"
 dependencies = [
  "anyhow",
  "clap",
@@ -2689,7 +2831,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-protocol"
-version = "0.0.12"
+version = "0.0.13"
 dependencies = [
  "base64",
  "bincode",
@@ -2700,11 +2842,13 @@ dependencies = [
  "ed25519-dalek",
  "hex",
  "hkdf",
+ "k256",
  "rand",
  "serde",
  "serde_json",
  "sha2",
  "thiserror 2.0.18",
+ "tiny-keccak",
  "uuid",
  "x25519-dalek",
  "zeroize",
@@ -2712,7 +2856,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-server"
-version = "0.0.12"
+version = "0.0.13"
 dependencies = [
  "anyhow",
  "axum",
@@ -2739,7 +2883,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-wasm"
-version = "0.0.12"
+version = "0.0.13"
 dependencies = [
  "base64",
  "bincode",