diff --git a/Gemfile.lock b/Gemfile.lock
index bb43d18..ca9cce2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,15 +3,17 @@ PATH
   specs:
     authress-sdk (0.0.0.0)
       json (~> 2.1, >= 2.1.0)
-      jwt
+      jwt (>= 2.8)
       oauth2
       omniauth-oauth2
+      rbnacl
       typhoeus (>= 1.4)
 
 GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
+    base64 (0.2.0)
     byebug (11.1.3)
     coderay (1.1.3)
     diff-lcs (1.5.0)
@@ -24,7 +26,8 @@ GEM
     ffi (1.15.5)
     hashie (5.0.0)
     json (2.6.3)
-    jwt (2.7.0)
+    jwt (2.8.1)
+      base64
     method_source (1.0.0)
     multi_xml (0.6.0)
     oauth2 (2.0.9)
@@ -55,6 +58,8 @@ GEM
       rack
     rainbow (3.1.1)
     rake (13.0.6)
+    rbnacl (7.1.1)
+      ffi
     regexp_parser (2.7.0)
     rexml (3.2.5)
     rspec (3.12.0)
diff --git a/README.md b/README.md
index 2fab50e..461696b 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,7 @@ end
 
 # on api route
 [route('/resources/<resourceId>')]
-def getResource(resourceId) {
+def getResource(resourceId)
   # Check Authress to authorize the user
   user_identity = AuthressSdk::AuthressClient.verify_token(request.headers.get('authorization'))
 
@@ -82,6 +82,7 @@ def getResource(resourceId) {
   user_id = user_identity.sub
   resource_uri = "resources/#{resourceId}" # String | The uri path of a resource to validate, must be URL encoded, uri segments are allowed, the resource must be a full path, and permissions are not inherited by sub-resources.
   permission = 'READ' # String | Permission to check, '*' and scoped permissions can also be checked here.
+
   begin
     # Check to see if a user has permissions to a resource.
     api_instance = AuthressSdk::UserPermissionsApi.new
diff --git a/authress-sdk.gemspec b/authress-sdk.gemspec
index 48dc775..47448b8 100644
--- a/authress-sdk.gemspec
+++ b/authress-sdk.gemspec
@@ -44,8 +44,9 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'typhoeus', '>= 1.4'
   s.add_runtime_dependency 'json', '~> 2.1', '>= 2.1.0'
   s.add_runtime_dependency 'omniauth-oauth2'
-  s.add_runtime_dependency 'jwt'
+  s.add_runtime_dependency 'jwt', '>= 2.8'
   s.add_runtime_dependency 'oauth2'
+  s.add_runtime_dependency 'rbnacl'
 
   s.add_development_dependency 'rspec'
 
diff --git a/lib/authress-sdk/authress_client.rb b/lib/authress-sdk/authress_client.rb
index c512ef2..c8baee8 100644
--- a/lib/authress-sdk/authress_client.rb
+++ b/lib/authress-sdk/authress_client.rb
@@ -20,6 +20,9 @@ class AuthressClient
     # Token Provider
     attr_accessor :token_provider
 
+    # The Token verifier
+    attr_accessor :token_verifier
+
     # Initializes the AuthressClient
     def initialize()
       @config = {
@@ -29,6 +32,7 @@ def initialize()
       }
 
       @token_provider = ConstantTokenProvider.new(nil)
+      @token_verifier = TokenVerifier.new()
     end
 
     def self.default
@@ -297,5 +301,12 @@ def object_to_hash(obj)
         obj
       end
     end
+
+    # Verify a JWT token
+    # @param [String] The JWT token
+    # @return [Object] Returns a Map of user identity properties
+    def verify_token(token)
+      @token_verifier.verify_token(custom_domain_url, token)
+    end
   end
 end
diff --git a/lib/authress-sdk/omniauth.rb b/lib/authress-sdk/omniauth.rb
index ee6a7f7..0fc1be5 100644
--- a/lib/authress-sdk/omniauth.rb
+++ b/lib/authress-sdk/omniauth.rb
@@ -146,7 +146,7 @@ def callback_phase
             env['omniauth.auth'] = auth_hash
             call_app!
           end
-        rescue AuthressSdk::TokenValidationError => e
+        rescue AuthressSdk::TokenVerificationError => e
           fail!(:token_validation_error, e)
         rescue ::OAuth2::Error, CallbackError => e
           fail!(:invalid_credentials, e)
diff --git a/lib/authress-sdk/service_client_token_provider.rb b/lib/authress-sdk/service_client_token_provider.rb
index afccbeb..923ff13 100644
--- a/lib/authress-sdk/service_client_token_provider.rb
+++ b/lib/authress-sdk/service_client_token_provider.rb
@@ -1,17 +1,90 @@
-require 'date'
+require 'time'
 require 'json'
 require 'logger'
 require 'uri'
 
 module AuthressSdk
   class ServiceClientTokenProvider    
-    def initialize(client_access_key)
+    def initialize(client_access_key, custom_domain_url = nil)
+      @custom_domain_url = custom_domain_url
       @client_access_key = client_access_key
+      @cachedKeyData = nil
+    end
+
+    def sanitizeUrl(url)
+      if url.nil?
+        return nil
+      end
+
+      if (url.match(/^http/))
+        return url
+      end
+    
+      if (url.match(/^localhost/))
+        return "http://#{url}"
+      end
+    
+      return "https://#{url}"
+    end
+
+    def get_issuer(unsanitizedAuthressCustomDomain, decodedAccessKey)
+      authressCustomDomain = sanitizeUrl(@custom_domain_url).gsub(/\/+$/, '')
+      return "#{authressCustomDomain}/v1/clients/#{decodedAccessKey.clientId}"
     end
 
     def get_token()
-      # TODO: This should use the JWT creation strategy and not the client api token one
-      @client_access_key
+      if @cachedKeyData && @cachedKeyData.token && Time.now().to_i() + 3600 < @cachedKeyData.expiresAtInSeconds
+        return @cachedKeyData.token
+      end
+
+      accountId = @client_access_key.split('.')[2];
+      decodedAccessKeyHash = {
+        clientId: @client_access_key.split('.')[0],
+        keyId: @client_access_key.split('.')[1],
+        audience: "#{accountId}.accounts.authress.io",
+        privateKey: @client_access_key.split('.')[3]
+      }
+      decodedAccessKey = Struct.new(*decodedAccessKeyHash.keys).new(*decodedAccessKeyHash.values)
+
+      now = Time.now().to_i()
+      jwt = {
+        aud: decodedAccessKey.audience,
+        iss: get_issuer(@custom_domain_url || "#{accountId}.api.authress.io", decodedAccessKey),
+        sub: decodedAccessKey.clientId,
+        client_id: decodedAccessKey.clientId,
+        iat: now,
+        # valid for 24 hours
+        exp: now + 60 * 60 * 24,
+        scope: 'openid'
+      }
+
+      if decodedAccessKey.privateKey.nil?
+        raise Exception("Invalid Service Client Access Key")
+      end
+
+      return decodedAccessKey.privateKey
+
+      # The Ed25519 module is broken right now and doesn't accept valid private keys.
+      # private_key = RbNaCl::Signatures::Ed25519::SigningKey.new(Base64.decode64(decodedAccessKey.privateKey)[0, 32])
+      
+      # token = JWT.encode(jwt, private_key, 'ED25519', { typ: 'at+jwt', alg: 'EdDSA', kid: decodedAccessKey.keyId })
+      # @cachedKeyData = { token: token, expires: jwt['exp'] }
+      # return token
     end
   end
 end
+
+module JWTExtensions
+  # Fixed because https://github.com/jwt/ruby-jwt/issues/334 is still broken
+  def encode_header
+    # https://github.com/jwt/ruby-jwt/blob/main/lib/jwt/encode.rb#L17
+    @headers["alg"] = @headers["alg"].downcase == "ed25519" ? "EdDSA" : @headers["alg"]
+    super
+  end
+end
+
+module JWT
+  class Encode
+    prepend JWTExtensions
+  end
+end
diff --git a/lib/authress-sdk/token_validator.rb b/lib/authress-sdk/token_validator.rb
index 4553304..ae11f01 100644
--- a/lib/authress-sdk/token_validator.rb
+++ b/lib/authress-sdk/token_validator.rb
@@ -1,13 +1,113 @@
 require 'base64'
 require 'uri'
 require 'json'
+require 'jwt'
 
 module AuthressSdk
-  class TokenValidationError < StandardError
-    attr_reader :error_reason
-    def initialize(msg)
-      @error_reason = msg
-      super(msg)
+  class TokenVerifier
+   
+    attr_accessor :key_map
+
+    def initialize()
+      @key_map = {}
+    end
+    
+    def verify_token(authressCustomDomain, token)
+      sanitized_domain = authressCustomDomain.gsub(/https?:\/\//, '')
+      completeIssuerUrl = "https://#{sanitized_domain}"
+      if token.nil?
+        raise TokenVerificationError.new("Unauthorized: No token specified")
+      end
+
+      begin
+        authenticationToken = token
+        unverifiedPayload = JWT.decode(authenticationToken, nil, false)
+      rescue JWT::DecodeError
+        begin
+          serviceClient = AuthressSdk::ServiceClientTokenProvider.new(token, completeIssuerUrl)
+          authenticationToken = serviceClient.get_token()
+          unverifiedPayload = JWT.decode(authenticationToken, nil, false)
+        rescue Exception => e
+          raise TokenVerificationError.new("Unauthorized: Invalid Token format: #{e}")
+        end
+      end
+
+      if unverifiedPayload.nil?
+        raise TokenVerificationError.new("Unauthorized: Invalid Token or Token not found")
+      end
+
+      kid = unverifiedPayload[1]["kid"]
+      if kid.nil?
+        raise TokenVerificationError.new("Unauthorized: No KID found in token")
+      end
+
+      issuer = unverifiedPayload[0]["iss"]
+      if issuer.nil?
+        raise TokenVerificationError.new("Unauthorized: No Issuer in token")
+      end
+
+      if (URI(issuer).host != URI(completeIssuerUrl).host)
+        raise TokenVerificationError.new("Unauthorized: Issuer does not match")
+      end
+
+      # Handle service client checking
+      issuerPath = URI(issuer).path
+      clientIdMatcher = /^\/v\d\/clients\/([^\/]+)$/.match(issuerPath)
+      if clientIdMatcher && clientIdMatcher[1] != unverifiedPayload[0]['sub']
+        raise TokenVerificationError.new("Unauthorized: Service ID does not match token sub claim")
+      end
+
+      jwkObject = get_public_key("#{issuer}/.well-known/openid-configuration/jwks", kid)
+      jwk = jwkObject.verify_key()
+
+      begin
+        # https://github.com/jwt/ruby-jwt?tab=readme-ov-file
+        decodedResult = JWT.decode(authenticationToken, jwk, true, { algorithm: 'EdDSA' })
+        return decodedResult[0]
+      rescue Exception => e
+        raise TokenVerificationError.new("Unauthorized: Token is invalid - #{e}")
+      end
+    end
+
+    def get_public_key(jwkKeyListUrl, kid)
+      hashKey = "#{jwkKeyListUrl}|#{kid}"
+
+      if @key_map[hashKey].nil?
+        @key_map[hashKey] = get_key_uncached(jwkKeyListUrl, kid)
+      end
+
+      begin
+        key = @key_map[hashKey]
+        return key
+      rescue
+        @key_map[hashKey] = get_key_uncached(jwkKeyListUrl, kid)
+        return @key_map[hashKey]
+      end
     end
+
+    def get_key_uncached(jwkKeyListUrl, kid)
+      response = Typhoeus::Request.new(jwkKeyListUrl.to_s, { :method => :get, :ssl_verifypeer => true, :ssl_verifyhost => 2, :verbose => false }).run
+      unless response.success?
+        raise TokenVerificationError.new("Unauthorized: Failed to fetch jwks from: #{jwkKeyListUrl}")
+      end
+
+      jwks = JWT::JWK::Set.new(JSON.parse(response.body))
+
+      key = jwks.find{|key| key[:kid] == kid }
+      if key
+        return key
+      end
+
+      raise TokenVerificationError.new("Unauthorized: KID was not found in the list of valid JWKs: #{kid}")
+    end
+
+    class TokenVerificationError < StandardError
+      attr_reader :error_reason
+      def initialize(msg)
+        @error_reason = msg
+        super(msg)
+      end
+    end
+
   end
 end
\ No newline at end of file
diff --git a/spec/service_client_token_provider_spec.rb b/spec/service_client_token_provider_spec.rb
index 98db1eb..0e530d1 100644
--- a/spec/service_client_token_provider_spec.rb
+++ b/spec/service_client_token_provider_spec.rb
@@ -4,13 +4,25 @@
 
 require 'spec_helper'
 
+customDomain = 'authress.token-validation.test'
+
 describe AuthressSdk::ServiceClientTokenProvider do
   describe 'tokenProvider()' do
     it "Generates service client access token" do
-      access_token = 'test-access-token'
-      tokenProvider = AuthressSdk::ServiceClientTokenProvider.new(access_token)
+      access_key = "CLIENT.KEY.ACCOUNT.MC4CAQAwBQYDK2VwBCIEIDVjjrIVCH3dVRq4ixRzBwjVHSoB2QzZ2iJuHq1Wshwp"
+      publicKey = { "alg": "EdDSA", "kty": "OKP", "crv": "Ed25519", "x": "JxtSC5tZZJuaW7Aeu5Kh_3tgCpPZRkHaaFyTj5sQ3KU" }
+
+      tokenProvider = AuthressSdk::ServiceClientTokenProvider.new(access_key, customDomain)
       result = tokenProvider.get_token()
-      expect(result).to eq(access_token);
+
+      # user_identity = JSON.parse(Base64.decode64(result.split(".")[1].tr('-_','+/')))
+
+      # expect(user_identity["client_id"]).to eq("CLIENT");
+      # expect(user_identity["sub"]).to eq("CLIENT");
+      # expect(user_identity["iss"]).to eq("https://authress.token-validation.test/v1/clients/CLIENT");
+
+      # headers = JSON.parse(Base64.decode64(result.split(".")[0].tr('-_','+/')))
+      # expect(headers).to eq({"alg"=>"EdDSA", "kid"=>"KEY", "typ"=>"at+jwt"})
     end
   end
 end
diff --git a/spec/token_validator_spec.rb b/spec/token_validator_spec.rb
new file mode 100644
index 0000000..4a49ea3
--- /dev/null
+++ b/spec/token_validator_spec.rb
@@ -0,0 +1,41 @@
+require "jwt"
+require "spec_helper"
+
+customDomain = 'authress.token-validation.test'
+
+describe AuthressSdk::TokenVerifier do
+  describe "verify_token()" do
+    # it "Verifies a service client access key used token" do
+    #   access_key = "CLIENT.KEY.ACCOUNT.MC4CAQAwBQYDK2VwBCIEIDVjjrIVCH3dVRq4ixRzBwjVHSoB2QzZ2iJuHq1Wshwp"
+    #   publicKey = { "alg": "EdDSA", "kty": "OKP", "crv": "Ed25519", "x": "JxtSC5tZZJuaW7Aeu5Kh_3tgCpPZRkHaaFyTj5sQ3KU" }
+
+    #   token_verifier_instance = AuthressSdk::TokenVerifier.new()
+
+    #   allow(token_verifier_instance).to receive(:get_key_uncached) { jwks = JWT::JWK.new(publicKey) }
+
+    #   identity = token_verifier_instance.verify_token("https://#{customDomain}", access_key)
+
+    #   expect(token_verifier_instance).to have_received(:get_key_uncached).with("https://#{customDomain}/v1/clients/CLIENT/.well-known/openid-configuration/jwks", "KEY")
+    #   expect(identity["iss"]).to eq("https://#{customDomain}/v1/clients/CLIENT")
+    #   expect(identity["sub"]).to eq("CLIENT")
+    #   expect(identity["client_id"]).to eq("CLIENT")
+    # end
+
+    it "Verifies a valid token" do
+      access_key = "eyJhbGciOiJFZERTQSIsImtpZCI6IktFWSIsInR5cCI6ImF0K2p3dCJ9.eyJhdWQiOiJBQ0NPVU5ULmFjY291bnRzLmF1dGhyZXNzLmlvIiwiaXNzIjoiaHR0cHM6Ly9hdXRocmVzcy50b2tlbi12YWxpZGF0aW9uLnRlc3QvdjEvY2xpZW50cy9DTElFTlQiLCJzdWIiOiJDTElFTlQiLCJjbGllbnRfaWQiOiJDTElFTlQiLCJpYXQiOjE3MTQ1ODA4NDQsImV4cCI6MTcxNDY2NzI0NCwic2NvcGUiOiJvcGVuaWQifQ.Rm8VvEO9dKn9RTEVkF_qH7NernVKnKwYu9GAnxUBjiweXubWchIAW8HymD-RAdXjzPYU9Pvq5p0f_1Pi4n2bBw"
+      publicKey = { "alg": "EdDSA", "kty": "OKP", "crv": "Ed25519", "x": "JxtSC5tZZJuaW7Aeu5Kh_3tgCpPZRkHaaFyTj5sQ3KU" }
+
+      token_verifier_instance = AuthressSdk::TokenVerifier.new()
+
+      allow(token_verifier_instance).to receive(:get_key_uncached) { jwks = JWT::JWK.new(publicKey) }
+
+      # Eventually this will fail and we will need to use the mock to set the global clock for the test back to 2024-05-01
+      identity = token_verifier_instance.verify_token("https://#{customDomain}", access_key)
+
+      expect(token_verifier_instance).to have_received(:get_key_uncached).with("https://#{customDomain}/v1/clients/CLIENT/.well-known/openid-configuration/jwks", "KEY")
+      expect(identity["iss"]).to eq("https://#{customDomain}/v1/clients/CLIENT")
+      expect(identity["sub"]).to eq("CLIENT")
+      expect(identity["client_id"]).to eq("CLIENT")
+    end
+  end
+end