diff --git a/.gitignore b/.gitignore
index 19f34be..25e7cd5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 */target/**
+/target
+/target/**
diff --git a/Cargo.lock b/Cargo.lock
index 6f879da..c2f19ca 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -37,6 +37,15 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "atomic-polyfill"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cf2bce30dfe09ef0bfaef228b9d414faaf7e563035494d7fe092dba54b300f4"
+dependencies = [
+ "critical-section",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -94,13 +103,23 @@ dependencies = [
  "common",
  "ed25519-dalek",
  "hkdf",
+ "postcard",
  "rand 0.9.1",
  "rsa",
+ "serde",
+ "serde-big-array",
  "sha2",
+ "socket2",
  "x25519-dalek",
  "zeroize",
 ]
 
+[[package]]
+name = "cobs"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67ba02a97a2bd10f4b59b25c7973101c79642302776489e030cd13cdab09ed15"
+
 [[package]]
 name = "common"
 version = "0.1.0"
@@ -108,9 +127,13 @@ dependencies = [
  "aes-gcm",
  "ed25519-dalek",
  "hkdf",
+ "postcard",
  "rand 0.9.1",
  "rsa",
+ "serde",
+ "serde-big-array",
  "sha2",
+ "socket2",
  "x25519-dalek",
  "zeroize",
 ]
@@ -137,13 +160,23 @@ dependencies = [
  "aes-gcm",
  "ed25519-dalek",
  "hkdf",
+ "postcard",
  "rand 0.9.1",
  "rsa",
+ "serde",
+ "serde-big-array",
  "sha2",
+ "socket2",
  "x25519-dalek",
  "zeroize",
 ]
 
+[[package]]
+name = "critical-section"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
+
 [[package]]
 name = "crypto-common"
 version = "0.1.6"
@@ -289,6 +322,29 @@ dependencies = [
  "polyval",
 ]
 
+[[package]]
+name = "hash32"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+dependencies = [
+ "byteorder",
+]
+
+[[package]]
+name = "heapless"
+version = "0.7.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdc6457c0eb62c71aac4bc17216026d8410337c4126773b9c5daba343f17964f"
+dependencies = [
+ "atomic-polyfill",
+ "hash32",
+ "rustc_version",
+ "serde",
+ "spin",
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "hkdf"
 version = "0.12.4"
@@ -337,6 +393,16 @@ version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8355be11b20d696c8f18f6cc018c4e372165b1fa8126cef092399c9951984ffa"
 
+[[package]]
+name = "lock_api"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07af8b9cdd281b7915f413fa73f29ebd5d55d0d3f0155584dade1ff18cea1b17"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
 [[package]]
 name = "num-bigint-dig"
 version = "0.8.4"
@@ -432,6 +498,17 @@ dependencies = [
  "universal-hash",
 ]
 
+[[package]]
+name = "postcard"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "170a2601f67cc9dba8edd8c4870b15f71a6a2dc196daec8c83f72b59dff628a8"
+dependencies = [
+ "cobs",
+ "heapless",
+ "serde",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.21"
@@ -552,6 +629,12 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
 [[package]]
 name = "semver"
 version = "1.0.26"
@@ -567,6 +650,15 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-big-array"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11fc7cc2c76d73e0f27ee52abbd64eec84d46f370c88371120433196934e4b7f"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_derive"
 version = "1.0.219"
@@ -586,9 +678,13 @@ dependencies = [
  "common",
  "ed25519-dalek",
  "hkdf",
+ "postcard",
  "rand 0.9.1",
  "rsa",
+ "serde",
+ "serde-big-array",
  "sha2",
+ "socket2",
  "x25519-dalek",
  "zeroize",
 ]
@@ -620,11 +716,24 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8917285742e9f3e1683f0a9c4e6b57960b7314d0b08d30d1ecd426713ee2eee9"
 
+[[package]]
+name = "socket2"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f5fd57c80058a56cf5c777ab8a126398ece8e442983605d280a44ce79d0edef"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
+
 [[package]]
 name = "spin"
 version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+dependencies = [
+ "lock_api",
+]
 
 [[package]]
 name = "spki"
@@ -636,6 +745,12 @@ dependencies = [
  "der",
 ]
 
+[[package]]
+name = "stable_deref_trait"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -696,6 +811,79 @@ dependencies = [
  "wit-bindgen-rt",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
 [[package]]
 name = "wit-bindgen-rt"
 version = "0.39.0"
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 03eec15..74144a6 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -14,3 +14,7 @@ rsa = "0.9.8"
 x25519-dalek = "2.0.1"
 ed25519-dalek = {version="2.1.1", features=["rand_core", "serde", "pkcs8", "alloc" , "pem", "std"]}
 rand = "0.9.1"
+socket2 = "0.5.9"
+serde = { version = "1.0", features = ["derive"] }
+serde-big-array = "0.5"
+postcard = "1.0.0"
diff --git a/common/Cargo.toml b/common/Cargo.toml
index 2365cd1..b6c1942 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -12,3 +12,7 @@ rsa = "0.9.8"
 x25519-dalek = "2.0.1"
 ed25519-dalek = {version="2.1.1", features=["rand_core", "serde", "pkcs8", "alloc", "pem", "std"]}
 rand = "0.9.1"
+socket2 = "0.5.9"
+serde = { version = "1.0", features = ["derive"] }
+serde-big-array = "0.5"
+postcard = "1.0.0"
diff --git a/common/src/lib.rs b/common/src/lib.rs
index 5bdca67..c48597c 100644
--- a/common/src/lib.rs
+++ b/common/src/lib.rs
@@ -1,14 +1,20 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
+// always use the following derive flags: #[derive(Deserialize, Serialize, Type, PartialEq, Debug)]
+
+use serde::{Deserialize, Serialize};
+use serde_big_array::BigArray;
+const CHALLENGE_DIFF: usize = 40;
+const SHA_LENGTH: usize = 512;
+const BITS_IN_BYTE: usize = 8;
+#[derive(Deserialize, Serialize, PartialEq, Debug)]
+pub struct PowChallengeQuery{
+    #[serde(with = "BigArray")]
+    hash: [u8;SHA_LENGTH/BITS_IN_BYTE],
 }
+#[derive(Deserialize, Serialize, PartialEq, Debug)]
+pub struct PowChallengeResponse{
+    #[serde(with = "BigArray")]
+    hash: [u8; SHA_LENGTH/BITS_IN_BYTE],
+    #[serde(with = "BigArray")]
+    secret: [u8; CHALLENGE_DIFF/BITS_IN_BYTE],
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
 }
diff --git a/cred-helper/Cargo.toml b/cred-helper/Cargo.toml
index 5ad5489..2327438 100644
--- a/cred-helper/Cargo.toml
+++ b/cred-helper/Cargo.toml
@@ -12,4 +12,7 @@ rsa = "0.9.8"
 x25519-dalek = "2.0.1"
 ed25519-dalek = {version="2.1.1", features=["rand_core", "serde", "pkcs8", "alloc", "pem", "std"]}
 rand = "0.9.1"
-
+socket2 = "0.5.9"
+serde = { version = "1.0", features = ["derive"] }
+serde-big-array = "0.5"
+postcard = "1.0.0"
diff --git a/server/Cargo.toml b/server/Cargo.toml
index c5cac56..b43014a 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -14,3 +14,7 @@ rsa = "0.9.8"
 x25519-dalek = "2.0.1"
 ed25519-dalek = {version="2.1.1", features=["rand_core", "serde", "pkcs8", "alloc" , "pem", "std"]}
 rand = "0.9.1"
+socket2 = "0.5.9"
+serde = { version = "1.0", features = ["derive"] }
+serde-big-array = "0.5"
+postcard = "1.0.0"