diff --git a/server/src/crypto/cipher.hpp b/server/src/crypto/cipher.hpp
index a05674f..dc2ec9a 100644
--- a/server/src/crypto/cipher.hpp
+++ b/server/src/crypto/cipher.hpp
@@ -1,13 +1,19 @@
 #ifndef SOSC_CRYPTO_CIPHER_H
 #define SOSC_CRYPTO_CIPHER_H
 
+#include "../utils/bigint.hpp"
+
 namespace sosc {
 namespace cgc {
 class Cipher {
 public:
     
 private:
+    const std::string sigma = "expand 32-byte k";
+    const std::string tau = "expand 16-byte k";
     
+    std::string key;
+    std::string state;
 };
 }}
 
diff --git a/server/src/crypto/keyex.cpp b/server/src/crypto/keyex.cpp
index 8cc2d17..64bf911 100644
--- a/server/src/crypto/keyex.cpp
+++ b/server/src/crypto/keyex.cpp
@@ -1,2 +1,52 @@
 #include "keyex.hpp"
 
+sosc::cgc::KeyExchange::KeyExchange() {
+    if(KeyExchange::secret.IsZero())
+        KeyExchange::secret = 
+            BigUInt::GenerateRandomPrime(this->key_size_bytes);
+            
+    this->modulus = BigUInt::GenerateRandomPrime(this->key_size_bytes);
+}
+
+sosc::Packet sosc::cgc::KeyExchange::GenerateRequest() const {
+    return Packet(1, {
+        this->generator.ToString(),
+        this->modulus.ToString(),
+        BigUInt::ModPow(this->generator, this->secret, this->modulus);
+    });
+}
+
+bool sosc::cgc::KeyExchange::ParseRequest
+    (const Packet& request, Packet* response) 
+{
+    if(request.GetId() != 1 || request.RegionCount() != 3)
+        return false;
+    
+    BigUInt generator, modulus, public_key;
+    bool check = generator.Parse(request[0]);
+    check = check || modulus.Parse(request[1]);
+    check = check || public_key.Parse(request[2]);
+    
+    if(!check)
+        return false;
+    
+    this->private_key = BigUInt::ModPow(public_key, this->secret, modulus);
+    public_key = BigUInt::ModPow(generator, this->secret, modulus);
+    *response = Packet(1, { public_key.ToString() });
+    
+    return true;
+}
+
+bool sosc::cgc::KeyExchange::ParseResponse(const Packet& response) {
+    if(response.GetId() != 1 || response.RegionCount() != 1)
+        return false;
+    
+    BigUInt public_key;
+    if(!public_key.Parse(response[0]))
+        return false;
+    
+    this->private_key = 
+        BigUInt::ModPow(public_key, this->secret, this->modulus);
+        
+    return true;
+}
diff --git a/server/src/crypto/keyex.hpp b/server/src/crypto/keyex.hpp
index c76a8c7..b4708eb 100644
--- a/server/src/crypto/keyex.hpp
+++ b/server/src/crypto/keyex.hpp
@@ -1,15 +1,35 @@
 #ifndef SOSC_CRYPTO_KEYEX_H
 #define SOSC_CRYPTO_KEYEX_H
 
+#include "../utils/bigint.hpp"
+#include "../sock/packet.hpp"
+
 namespace sosc {
 namespace cgc {
 class KeyExchange {
 public:
-    const int key_size = 512;
-    const int key_size_bytes = key_size / 8;
-    const int generator = 2;
-private:
+    KeyExchange();
     
+    Packet GenerateRequest() const;
+    bool ParseRequest(const Packet& request, Packet* response);
+    bool ParseResponse(const Packet& response);
+    
+    inline bool Succeeded() {
+        return !this->private_key.IsZero();
+    }
+    
+    inline const BigUInt& GetPrivateKey() {
+        return this->private_key;
+    }
+private:
+    const int key_size = 256;
+    const int key_size_bytes = key_size / 8;
+    
+    const BigUInt generator = BigUInt(2u);
+    static BigUInt secret;
+    BigUInt modulus;
+    
+    BigUInt private_key;
 };
 }}
 
diff --git a/server/src/sock/packet.cpp b/server/src/sock/packet.cpp
index 1fceb3c..e6b4ac6 100644
--- a/server/src/sock/packet.cpp
+++ b/server/src/sock/packet.cpp
@@ -1,5 +1,14 @@
 #include "packet.hpp"
 
+sosc::Packet::Packet() {
+    this->id = 0;
+}
+
+sosc::Packet::Packet(uint8_t id, std::vector<std::string> data) {
+    this->SetId(id);
+    this->regions = data;
+}
+
 bool sosc::Packet::AddRegion(std::string data) {
     if(this->regions.size() >= 256)
         return false;
diff --git a/server/src/sock/packet.hpp b/server/src/sock/packet.hpp
index 75d4ab5..87bc587 100644
--- a/server/src/sock/packet.hpp
+++ b/server/src/sock/packet.hpp
@@ -18,6 +18,9 @@
 namespace sosc {
 class Packet {
 public:
+    Packet();
+    Packet(uint8_t id, std::vector<std::string> data);
+    
     bool AddRegion(std::string data);
     bool AddRegions(std::vector<std::string> data);
     
diff --git a/server/src/utils/bigint.cpp b/server/src/utils/bigint.cpp
index 74d7419..cc7eac2 100644
--- a/server/src/utils/bigint.cpp
+++ b/server/src/utils/bigint.cpp
@@ -437,6 +437,11 @@ sosc::BigUInt sosc::BigUInt::operator << (const uint64_t& rhs) const {
     return shifted;
 }
 
+std::string sosc::BigUInt::ToRawString(uint64_t byte_count) const {
+    std::string raw(byte_count == 0 ? this->UsedByteCount() : byte_count, 0);
+    
+}
+
 std::string sosc::BigUInt::ToString() const {
     std::stringstream stream;
     for(size_t i = this->WordCount() - 1;; --i) {
diff --git a/server/src/utils/bigint.hpp b/server/src/utils/bigint.hpp
index 8c01171..013766a 100644
--- a/server/src/utils/bigint.hpp
+++ b/server/src/utils/bigint.hpp
@@ -82,6 +82,7 @@ public:
     BigUInt operator >> (const uint64_t& rhs) const;
     BigUInt operator << (const uint64_t& rhs) const;
     
+    std::string ToRawString(uint64_t byte_count = 0) const;
     std::string ToString() const;
     inline operator std::string () const {
         return this->ToString();