diff --git a/.env.example b/.env.example
index 95ca9e9..76f1d2a 100644
--- a/.env.example
+++ b/.env.example
@@ -55,6 +55,7 @@ FILESYSTEM_DISK=local
 QUEUE_CONNECTION=database
 
 CACHE_STORE=database
+ARCADIA_CACHE_STORE=redis
 # CACHE_PREFIX=
 
 MEMCACHED_HOST=127.0.0.1
@@ -83,3 +84,5 @@ VITE_APP_NAME="${APP_NAME}"
 
 THROTTLE_WEB=120
 THROTTLE_API_V1=60
+
+ARCADIA_AUTH_DEV_BYPASS=false
diff --git a/.env.testing b/.env.testing
index 86eff9b..807a73a 100644
--- a/.env.testing
+++ b/.env.testing
@@ -29,10 +29,13 @@ BROADCAST_CONNECTION=null
 FILESYSTEM_DISK=local
 QUEUE_CONNECTION=sync
 CACHE_STORE=array
-MAIL_MAILER=array
+MAIL_MAILER=
+
+ARCADIA_CACHE_STORE=array
 
 SPEC_PATH=documentation/OpenApi
 
 PULSE_ENABLED=false
 TELESCOPE_ENABLED=false
 NIGHTWATCH_ENABLED=false
+ARCADIA_AUTH_DEV_BYPASS=true
diff --git a/bootstrap/providers.php b/bootstrap/providers.php
index e8feb77..8b714a0 100644
--- a/bootstrap/providers.php
+++ b/bootstrap/providers.php
@@ -4,8 +4,10 @@ declare(strict_types=1);
 
 use Infra\Providers\AppServiceProvider;
 use Infra\Providers\DomainServiceProvider;
+use Infra\Providers\SecurityServiceProvider;
 
 return [
-    DomainServiceProvider::class,
     AppServiceProvider::class,
+    DomainServiceProvider::class,
+    SecurityServiceProvider::class,
 ];
diff --git a/config/auth.php b/config/auth.php
index 5710a70..18290dc 100644
--- a/config/auth.php
+++ b/config/auth.php
@@ -116,4 +116,24 @@ return [
 
     'password_timeout' => env('AUTH_PASSWORD_TIMEOUT', 10800),
 
+    /*
+    |--------------------------------------------------------------------------
+    | HMAC Authentication Options
+    |--------------------------------------------------------------------------
+    |
+    | allow_dev_bypass: When enabled in local or testing environments, allows
+    | requests without HMAC signatures to proceed using a default dev client.
+    |
+     */
+
+    'hmac' => [
+        'allow_dev_bypass' => (bool) env('ARCADIA_AUTH_DEV_BYPASS', false),
+        'dev_client'       => [
+            'id'         => env('ARCADIA_DEV_CLIENT_ID', '01915ec0-0000-7000-8000-000000000001'),
+            'name'       => env('ARCADIA_DEV_CLIENT_NAME', 'Arcadia Dev Test Client'),
+            'identifier' => env('ARCADIA_DEV_CLIENT_IDENTIFIER', 'arcadia_id_00000000000000000000000000000001'),
+            'secret'     => env('ARCADIA_DEV_CLIENT_SECRET', 'arcadia_sec_00000000000000000000000000000000000000000000000000000000000000000000000000000000000001'),
+        ],
+    ],
+
 ];
diff --git a/config/cache.php b/config/cache.php
index a28f5fa..c201d1b 100644
--- a/config/cache.php
+++ b/config/cache.php
@@ -19,6 +19,8 @@ return [
 
     'default' => env('CACHE_STORE', 'database'),
 
+    'arcadia_store' => env('ARCADIA_CACHE_STORE', env('CACHE_STORE', 'database')),
+
     /*
     |--------------------------------------------------------------------------
     | Cache Stores
diff --git a/database/factories/ApiClientFactory.php b/database/factories/ApiClientFactory.php
new file mode 100644
index 0000000..d9559ab
--- /dev/null
+++ b/database/factories/ApiClientFactory.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Database\Factories;
+
+use Application\Security\Ports\Services\ClientCredentialGenerator;
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Infra\Database\Models\ApiClient;
+use Ramsey\Uuid\Uuid;
+
+/**
+ * @extends Factory<ApiClient>
+ */
+final class ApiClientFactory extends Factory
+{
+    protected $model = ApiClient::class;
+
+    /**
+     * @return array<string, mixed>
+     */
+    #[\Override]
+    public function definition(): array
+    {
+        $clientIdentifierGenerator = resolve(ClientCredentialGenerator::class);
+
+        return [
+            'id'         => Uuid::uuid7()->toString(),
+            'name'       => fake()->company(),
+            'identifier' => $clientIdentifierGenerator->generateIdentifier()->value,
+            'secret'     => $clientIdentifierGenerator->generateSecret()->value,
+            'is_active'  => true,
+            'created_at' => now(),
+            'updated_at' => now(),
+        ];
+    }
+}
diff --git a/database/factories/EmployeeFactory.php b/database/factories/EmployeeFactory.php
index c29b27b..db46758 100644
--- a/database/factories/EmployeeFactory.php
+++ b/database/factories/EmployeeFactory.php
@@ -30,6 +30,8 @@ final class EmployeeFactory extends Factory
             'establishment'          => '01',
             'site'                   => 'LDCSER',
             'service'                => '097',
+            'created_at'             => now()->toDateTimeString(),
+            'updated_at'             => now()->toDateTimeString(),
         ];
     }
 }
diff --git a/database/migrations/2026_08_10_145347_create_api_clients_table.php b/database/migrations/2026_08_10_145347_create_api_clients_table.php
index fe0d6a1..c29e463 100644
--- a/database/migrations/2026_08_10_145347_create_api_clients_table.php
+++ b/database/migrations/2026_08_10_145347_create_api_clients_table.php
@@ -18,10 +18,11 @@ return new class () extends Migration
 
             $table->string('name');
             $table->string('identifier')->unique();
-            $table->string('secret');
+            $table->text('secret');
             $table->boolean('is_active');
 
-            $table->timestamps();
+            $table->timestamp('created_at');
+            $table->timestamp('updated_at');
         });
     }
 
diff --git a/database/seeders/ApiClientSeeder.php b/database/seeders/ApiClientSeeder.php
new file mode 100644
index 0000000..4a7bcda
--- /dev/null
+++ b/database/seeders/ApiClientSeeder.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Database\Seeders;
+
+use Illuminate\Database\Seeder;
+use Illuminate\Support\Facades\Config;
+use Infra\Database\Models\ApiClient;
+
+final class ApiClientSeeder extends Seeder
+{
+    public function run(): void
+    {
+        /** @var array{id: string, name: string, identifier: string, secret: string} $devClient */
+        $devClient = Config::array('auth.hmac.dev_client');
+
+        ApiClient::query()->updateOrCreate(
+            ['identifier' => $devClient['identifier']],
+            [
+                'id'        => $devClient['id'],
+                'name'      => $devClient['name'],
+                'secret'    => $devClient['secret'],
+                'is_active' => true,
+            ]
+        );
+
+        $this->command?->info('API client seeded successfully.');
+        $this->command?->info('Client ID: ' . $devClient['id']);
+        $this->command?->info('Client Identifier: ' . $devClient['identifier']);
+        $this->command?->info('Client Secret: ' . $devClient['secret']);
+    }
+}
diff --git a/database/seeders/DatabaseSeeder.php b/database/seeders/DatabaseSeeder.php
index 08417dd..f00efe6 100644
--- a/database/seeders/DatabaseSeeder.php
+++ b/database/seeders/DatabaseSeeder.php
@@ -16,6 +16,7 @@ final class DatabaseSeeder extends Seeder
         $this->call([
             EmployeeSeeder::class,
             IncoSheetSeeder::class,
+            ApiClientSeeder::class,
         ]);
     }
 }
diff --git a/src/Infra/Adapters/Repositories/ApiClientRepository.php b/src/Infra/Adapters/Repositories/ApiClientRepository.php
new file mode 100644
index 0000000..df3159d
--- /dev/null
+++ b/src/Infra/Adapters/Repositories/ApiClientRepository.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Repositories;
+
+use Application\Security\Models\Entities\Client;
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\Entities\ClientId;
+use Application\Security\Ports\Repositories\ClientRepository;
+use Infra\Database\Models\ApiClient;
+use Shared\Paginated;
+use Shared\Pagination;
+
+final class ApiClientRepository implements ClientRepository
+{
+    #[\Override]
+    public function persist(Client $client): void
+    {
+        ApiClient::query()->updateOrCreate(
+            ['id' => $client->id->value],
+            [
+                'name'       => $client->name,
+                'identifier' => $client->identifier,
+                'secret'     => $client->secret,
+                'is_active'  => $client->isActive,
+            ]
+        );
+    }
+
+    #[\Override]
+    public function findByIdentifier(ClientIdentifier $identifier): ?Client
+    {
+        return transform(
+            ApiClient::query()
+                ->where('identifier', $identifier->value)
+                ->first(),
+            fn (ApiClient $apiClient) => $this->toDomain($apiClient)
+        );
+    }
+
+    #[\Override]
+    public function find(ClientId $id): ?Client
+    {
+        return transform(
+            ApiClient::query()->where('id', $id->value)->first(),
+            fn (ApiClient $apiClient) => $this->toDomain($apiClient)
+        );
+    }
+
+    #[\Override]
+    public function findAll(Pagination $pagination): Paginated
+    {
+        $query = ApiClient::query();
+        $total = $query->count();
+        $items = $query->forPage(
+            $pagination->pageNumber(),
+            $pagination->pageSize()
+        )->get();
+
+        return new Paginated(
+            pagination: $pagination,
+            items: $items->map(fn (ApiClient $apiClient) => $this->toDomain($apiClient))->all(),
+            total: $total,
+        );
+    }
+
+    #[\Override]
+    public function delete(Client $client): void
+    {
+        $deleted = ApiClient::query()->where('id', $client->id->value)->delete();
+        if ($deleted === 0) {
+            throw new \LogicException('Client not found');
+        }
+    }
+
+    private function toDomain(ApiClient $apiClient): Client
+    {
+        return Client::hydrate(
+            id: new ClientId($apiClient->id),
+            name: $apiClient->name,
+            identifier: $apiClient->identifier,
+            secret: $apiClient->secret,
+            isActive: $apiClient->is_active,
+            createdAt: $apiClient->created_at,
+            updatedAt: $apiClient->updated_at,
+        );
+    }
+}
diff --git a/src/Infra/Adapters/Services/CachedNonceValidator.php b/src/Infra/Adapters/Services/CachedNonceValidator.php
new file mode 100644
index 0000000..4300a7a
--- /dev/null
+++ b/src/Infra/Adapters/Services/CachedNonceValidator.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\Request\Nonce;
+use Application\Security\Ports\Services\NonceValidator;
+use Application\Security\Ports\Services\TimestampValidator;
+use Psr\Log\LoggerInterface;
+use Psr\SimpleCache\CacheInterface;
+
+final readonly class CachedNonceValidator implements NonceValidator
+{
+    private const string CACHE_KEY_PREFIX = 'nonce:';
+
+    private const int CACHE_TTL_SECONDS = TimestampValidator::ALLOWED_TIMESTAMP_SKEW_SECONDS;
+
+    public function __construct(
+        private readonly LoggerInterface $logger,
+        private readonly CacheInterface $cacheStore,
+    ) {
+    }
+
+    #[\Override]
+    public function validateAndConsume(Nonce $nonce, ClientIdentifier $forClientIdentifier): bool
+    {
+        $key = $this->getCacheKey($forClientIdentifier, $nonce);
+
+        if ($this->isKeyConsumed($key)) {
+            $this->logger->debug(
+                'Nonce already used for client: {clientIdentifier}, nonce: {nonce}',
+                [
+                    'clientIdentifier' => $forClientIdentifier->value,
+                    'nonce'            => $nonce->value,
+                ]
+            );
+
+            return false;
+        }
+
+        $this->consumeKey($key);
+
+        return true;
+    }
+
+    private function isKeyConsumed(string $key): bool
+    {
+        return $this->cacheStore->has($key);
+    }
+
+    private function consumeKey(string $key): void
+    {
+        $this->cacheStore->set(
+            $key,
+            'used',
+            self::CACHE_TTL_SECONDS
+        );
+
+        $this->logger->debug(
+            'Nonce consumed for key: {key}',
+            ['key' => $key]
+        );
+    }
+
+    private function getCacheKey(ClientIdentifier $forClientIdentifier, Nonce $nonce): string
+    {
+        return sprintf(
+            self::CACHE_KEY_PREFIX . '%s:%s',
+            $forClientIdentifier->value,
+            $nonce->value
+        );
+    }
+}
diff --git a/src/Infra/Adapters/Services/ClientCredentialGeneratorImpl.php b/src/Infra/Adapters/Services/ClientCredentialGeneratorImpl.php
new file mode 100644
index 0000000..966764a
--- /dev/null
+++ b/src/Infra/Adapters/Services/ClientCredentialGeneratorImpl.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Application\Security\Ports\Services\ClientCredentialGenerator;
+
+final readonly class ClientCredentialGeneratorImpl implements ClientCredentialGenerator
+{
+    private const string IDENTIFIER_PREFIX = 'arcadia_id_';
+
+    private const string SECRET_PREFIX     = 'arcadia_sec_';
+
+    #[\Override]
+    public function generateIdentifier(): ClientIdentifier
+    {
+        $random = bin2hex(random_bytes(16));
+
+        return new ClientIdentifier(self::IDENTIFIER_PREFIX . $random);
+    }
+
+    #[\Override]
+    public function generateSecret(): ClientSecret
+    {
+        $random = bin2hex(random_bytes(32));
+        $random = base64_encode($random);
+        $random = strtr($random, '+/', '');
+        $random = rtrim($random, '=');
+
+        return new ClientSecret(self::SECRET_PREFIX . $random);
+    }
+}
diff --git a/src/Infra/Adapters/Services/HmacSignatureValidatorImpl.php b/src/Infra/Adapters/Services/HmacSignatureValidatorImpl.php
new file mode 100644
index 0000000..d76b490
--- /dev/null
+++ b/src/Infra/Adapters/Services/HmacSignatureValidatorImpl.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Application\Security\Models\ValueObjects\Request\Request;
+use Application\Security\Models\ValueObjects\Request\RequestSignature;
+use Application\Security\Ports\Services\HmacSignatureValidator;
+use Uri\Rfc3986\Uri;
+
+final readonly class HmacSignatureValidatorImpl implements HmacSignatureValidator
+{
+    private const string SHA256_EMPTY_STRING_HASH = 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855';
+
+    #[\Override]
+    public function validate(Request $request, ClientSecret $withSecret): bool
+    {
+        $payloadToSign = $this->compileDataToSign($request);
+
+        $expectedSignature = $this->calculateSignature(
+            $payloadToSign,
+            $withSecret
+        );
+
+        return $this->compareSignatures(
+            $expectedSignature,
+            $request->signature
+        );
+    }
+
+    private function compareSignatures(string $expectedSignature, RequestSignature $providedSignature): bool
+    {
+        // NOTE: Use hash_equals to prevent timing attacks when comparing signatures.
+        return hash_equals($expectedSignature, $providedSignature->value);
+    }
+
+    /** @param list<string> $signaturePayload */
+    private function calculateSignature(array $signaturePayload, ClientSecret $withSecret): string
+    {
+        $payloadString = implode('|', $signaturePayload);
+
+        return hash_hmac('sha256', $payloadString, $withSecret->value);
+    }
+
+    /** @return list<string> */
+    private function compileDataToSign(Request $request): array
+    {
+        return [
+            $request->method->name,
+            $this->getOrdonatedPathAndQuery($request->uri),
+            $request->timestamp->value->format(\DateTimeInterface::ATOM),
+            $request->nonce->value->toString(),
+            $request->bodyHash->value ?? self::SHA256_EMPTY_STRING_HASH,
+        ];
+    }
+
+    private function getOrdonatedPathAndQuery(Uri $fromUri): string
+    {
+        $path  = $fromUri->getPath();
+        $query = $fromUri->getQuery();
+
+        if ($query === null || $query === '') {
+            return $path;
+        }
+
+        // NOTE: Sort query parameters to ensure consistent signature generation
+        parse_str($query, $queryParams);
+        ksort($queryParams);
+        $sortedQuery = http_build_query($queryParams);
+
+        return $path . '?' . $sortedQuery;
+    }
+}
diff --git a/src/Infra/Adapters/Services/RequestValidatorImpl.php b/src/Infra/Adapters/Services/RequestValidatorImpl.php
new file mode 100644
index 0000000..ad79d40
--- /dev/null
+++ b/src/Infra/Adapters/Services/RequestValidatorImpl.php
@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Services;
+
+use Application\Security\Models\Entities\Client;
+use Application\Security\Models\ValueObjects\Request\Request;
+use Application\Security\Ports\Repositories\ClientRepository;
+use Application\Security\Ports\Services\HmacSignatureValidator;
+use Application\Security\Ports\Services\NonceValidator;
+use Application\Security\Ports\Services\RequestValidation\RequestValidationResult;
+use Application\Security\Ports\Services\RequestValidation\RequestValidationStatus;
+use Application\Security\Ports\Services\RequestValidator;
+use Application\Security\Ports\Services\TimestampValidator;
+use Psr\Log\LoggerInterface;
+
+final readonly class RequestValidatorImpl implements RequestValidator
+{
+    public function __construct(
+        private readonly LoggerInterface $logger,
+        private readonly HmacSignatureValidator $signatureValidator,
+        private readonly NonceValidator $nonceValidator,
+        private readonly TimestampValidator $timestampValidator,
+        private readonly ClientRepository $clientRepository,
+    ) {
+    }
+
+    #[\Override]
+    public function validate(Request $request): RequestValidationResult
+    {
+        $client       = $this->findClientFrom($request);
+        $firstFailure = null;
+
+        if ($client === null) {
+            $this->logger->debug(
+                'Client not found for identifier: {identifier}',
+                ['identifier' => $request->identifier]
+            );
+            $firstFailure = RequestValidationStatus::CLIENT_NOT_FOUND;
+        }
+
+        if ($client !== null && ! $client->isActive) {
+            $this->logger->debug(
+                'Client is disabled for identifier: {identifier}',
+                ['identifier' => $request->identifier]
+            );
+            $firstFailure ??= RequestValidationStatus::CLIENT_NOT_AUTHORIZED;
+        }
+
+        if (! $this->validateTimestampFrom($request)) {
+            $this->logger->debug(
+                'Invalid timestamp: {timestamp}',
+                ['timestamp' => $request->timestamp->value->format(\DateTimeInterface::ATOM)]
+            );
+            $firstFailure ??= RequestValidationStatus::INVALID_TIMESTAMP;
+        }
+
+        if ($client !== null && ! $this->validateSignatureFrom($request, $client)) {
+            $this->logger->debug(
+                'Invalid signature for client: {clientId}',
+                ['clientId' => $request->identifier]
+            );
+            $firstFailure ??= RequestValidationStatus::INVALID_SIGNATURE;
+        }
+
+        if ($firstFailure === null && ! $this->validateNonceFrom($request)) {
+            $this->logger->debug(
+                'Invalid nonce: {nonce}',
+                ['nonce' => $request->nonce]
+            );
+
+            return RequestValidationResult::failed(RequestValidationStatus::INVALID_NONCE);
+        }
+
+        if ($firstFailure !== null) {
+            return RequestValidationResult::failed($firstFailure);
+        }
+
+        /** @var Client $client */
+        return RequestValidationResult::valid($client);
+    }
+
+    private function findClientFrom(Request $request): ?Client
+    {
+        return $this->clientRepository->findByIdentifier(
+            identifier: $request->identifier
+        );
+    }
+
+    private function validateNonceFrom(Request $request): bool
+    {
+        return $this->nonceValidator->validateAndConsume(
+            nonce: $request->nonce,
+            forClientIdentifier: $request->identifier
+        );
+    }
+
+    private function validateTimestampFrom(Request $request): bool
+    {
+        return $this->timestampValidator->validate(
+            timestamp: $request->timestamp->value
+        );
+    }
+
+    private function validateSignatureFrom(Request $request, Client $forClient): bool
+    {
+        return $this->signatureValidator->validate(
+            request: $request,
+            withSecret: $forClient->secret
+        );
+    }
+}
diff --git a/src/Infra/Adapters/Services/TimestampValidatorImpl.php b/src/Infra/Adapters/Services/TimestampValidatorImpl.php
new file mode 100644
index 0000000..4983ccd
--- /dev/null
+++ b/src/Infra/Adapters/Services/TimestampValidatorImpl.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Adapters\Services;
+
+use Application\Security\Ports\Services\TimestampValidator;
+
+final readonly class TimestampValidatorImpl implements TimestampValidator
+{
+    public function __construct(
+        private \DateTimeZone $timezone
+    ) {
+    }
+
+    #[\Override]
+    public function validate(\DateTimeInterface $timestamp): bool
+    {
+        $allowedSkew = $this->getAllowedSkew();
+
+        return $this->isTimestampInSkew($timestamp, $allowedSkew);
+    }
+
+    private function isTimestampInSkew(\DateTimeInterface $timestamp, \DateInterval $allowedSkew): bool
+    {
+        $now = $this->getCurrentTime();
+
+        return ($timestamp >= $now->sub($allowedSkew)) && ($timestamp <= $now->add($allowedSkew));
+    }
+
+    private function getCurrentTime(): \DateTimeImmutable
+    {
+        return new \DateTimeImmutable('now', $this->timezone);
+    }
+
+    private function getAllowedSkew(): \DateInterval
+    {
+        return new \DateInterval('PT' . TimestampValidator::ALLOWED_TIMESTAMP_SKEW_SECONDS . 'S');
+    }
+}
diff --git a/src/Infra/Casts/ClientIdentifierCast.php b/src/Infra/Casts/ClientIdentifierCast.php
new file mode 100644
index 0000000..f21f699
--- /dev/null
+++ b/src/Infra/Casts/ClientIdentifierCast.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Casts;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+use Illuminate\Database\Eloquent\Model;
+
+/** @implements CastsAttributes<ClientIdentifier, string|ClientIdentifier> */
+final class ClientIdentifierCast implements CastsAttributes
+{
+    public function get(Model $model, string $key, mixed $value, array $attributes): ClientIdentifier
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientIdentifier value cannot be null');
+        }
+
+        if (! is_string($value)) {
+            throw new \InvalidArgumentException('Value must be a string');
+        }
+
+        return new ClientIdentifier($value);
+    }
+
+    public function set(Model $model, string $key, mixed $value, array $attributes): string
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientIdentifier value cannot be null');
+        }
+
+        if ($value instanceof ClientIdentifier) {
+            return $value->value;
+        }
+
+        if (is_string($value)) {
+            return (new ClientIdentifier($value))->value;
+        }
+
+        throw new \InvalidArgumentException('Value must be a string or instance of ClientIdentifier');
+    }
+}
diff --git a/src/Infra/Casts/ClientNameCast.php b/src/Infra/Casts/ClientNameCast.php
new file mode 100644
index 0000000..2a04c03
--- /dev/null
+++ b/src/Infra/Casts/ClientNameCast.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Casts;
+
+use Application\Security\Models\ValueObjects\ClientName;
+use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+use Illuminate\Database\Eloquent\Model;
+
+/** @implements CastsAttributes<ClientName, string|ClientName> */
+final class ClientNameCast implements CastsAttributes
+{
+    public function get(Model $model, string $key, mixed $value, array $attributes): ClientName
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientName value cannot be null');
+        }
+
+        if (! is_string($value)) {
+            throw new \InvalidArgumentException('Value must be a string');
+        }
+
+        return new ClientName($value);
+    }
+
+    public function set(Model $model, string $key, mixed $value, array $attributes): string
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientName value cannot be null');
+        }
+
+        if ($value instanceof ClientName) {
+            return $value->value;
+        }
+
+        if (is_string($value)) {
+            return (new ClientName($value))->value;
+        }
+
+        throw new \InvalidArgumentException('Value must be a string or instance of ClientName');
+    }
+}
diff --git a/src/Infra/Casts/ClientSecretCast.php b/src/Infra/Casts/ClientSecretCast.php
new file mode 100644
index 0000000..4563446
--- /dev/null
+++ b/src/Infra/Casts/ClientSecretCast.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Casts;
+
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+use Illuminate\Contracts\Encryption\DecryptException;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Facades\Crypt;
+
+/** @implements CastsAttributes<ClientSecret, string|ClientSecret> */
+final class ClientSecretCast implements CastsAttributes
+{
+    /**
+     * @param  array<string, mixed>  $attributes
+     */
+    #[\Override]
+    public function get(Model $model, string $key, mixed $value, array $attributes): ClientSecret
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientSecret value cannot be null');
+        }
+
+        if (! is_string($value)) {
+            throw new \InvalidArgumentException('Value must be a string');
+        }
+
+        try {
+            $decrypted = Crypt::decryptString($value);
+        } catch (DecryptException) {
+            $decrypted = $value;
+        }
+
+        return new ClientSecret($decrypted);
+    }
+
+    /**
+     * @param  array<string, mixed>  $attributes
+     */
+    #[\Override]
+    public function set(Model $model, string $key, mixed $value, array $attributes): string
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('ClientSecret value cannot be null');
+        }
+
+        $plainSecret = match (true) {
+            $value instanceof ClientSecret => $value->value,
+            is_string($value)              => (new ClientSecret($value))->value,
+            default                        => throw new \InvalidArgumentException('Value must be a string or instance of ClientSecret'),
+        };
+
+        return Crypt::encryptString($plainSecret);
+    }
+}
diff --git a/src/Infra/Casts/UuidCast.php b/src/Infra/Casts/UuidCast.php
new file mode 100644
index 0000000..9627292
--- /dev/null
+++ b/src/Infra/Casts/UuidCast.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Casts;
+
+use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
+use Illuminate\Database\Eloquent\Model;
+use Ramsey\Uuid\Uuid;
+use Ramsey\Uuid\UuidInterface;
+use Shared\Helpers\UuidHelper;
+
+/** @implements CastsAttributes<\Ramsey\Uuid\UuidInterface, string> */
+final class UuidCast implements CastsAttributes
+{
+    public function get(Model $model, string $key, mixed $value, array $attributes): UuidInterface
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('UUID value cannot be null');
+        }
+
+        if (! is_string($value)) {
+            throw new \InvalidArgumentException('Value must be a string');
+        }
+
+        return Uuid::fromString($value);
+    }
+
+    public function set(Model $model, string $key, mixed $value, array $attributes): string
+    {
+        if ($value === null) {
+            throw new \InvalidArgumentException('UUID value cannot be null');
+        }
+
+        if (is_string($value)) {
+            $value = Uuid::fromString($value);
+        }
+
+        if (! $value instanceof UuidInterface) {
+            throw new \InvalidArgumentException('Value must be a string or instance of UuidInterface');
+        }
+
+        UuidHelper::validateUuid($value);
+
+        return (string) $value;
+    }
+}
diff --git a/src/Infra/Database/Models/ApiClient.php b/src/Infra/Database/Models/ApiClient.php
new file mode 100644
index 0000000..2d55bf8
--- /dev/null
+++ b/src/Infra/Database/Models/ApiClient.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Database\Models;
+
+use Database\Factories\ApiClientFactory;
+use Illuminate\Database\Eloquent\Concerns\HasUuids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Foundation\Auth\User as Authenticatable;
+use Illuminate\Notifications\Notifiable;
+use Infra\Casts\ClientIdentifierCast;
+use Infra\Casts\ClientNameCast;
+use Infra\Casts\ClientSecretCast;
+use Infra\Casts\UuidCast;
+
+/**
+ * @property \Ramsey\Uuid\UuidInterface $id
+ * @property \Application\Security\Models\ValueObjects\ClientName $name
+ * @property \Application\Security\Models\ValueObjects\ClientIdentifier $identifier
+ * @property \Application\Security\Models\ValueObjects\ClientSecret $secret
+ * @property bool $is_active
+ * @property \Illuminate\Support\Carbon $created_at
+ * @property \Illuminate\Support\Carbon $updated_at
+ * @property-read \Illuminate\Notifications\DatabaseNotificationCollection<int, \Illuminate\Notifications\DatabaseNotification> $notifications
+ *
+ * @method static \Database\Factories\ApiClientFactory factory($count = null, $state = [])
+ *
+ * @mixin \Eloquent
+ */
+final class ApiClient extends Authenticatable
+{
+    /** @use HasFactory<ApiClientFactory> */
+    use HasFactory;
+
+    use HasUuids;
+    use Notifiable;
+
+    protected static function newFactory(): ApiClientFactory
+    {
+        return ApiClientFactory::new();
+    }
+
+    protected $table = 'api_clients';
+
+    public $timestamps = true;
+
+    /** @var list<string> */
+    protected $fillable = [
+        'id',
+        'name',
+        'identifier',
+        'secret',
+        'is_active',
+        'created_at',
+        'updated_at',
+    ];
+
+    /** @var list<string> */
+    protected $hidden = [
+        'secret',
+    ];
+
+    /** @return array<string, string> */
+    #[\Override]
+    protected function casts(): array
+    {
+        return [
+            'id'         => UuidCast::class,
+            'name'       => ClientNameCast::class,
+            'identifier' => ClientIdentifierCast::class,
+            'secret'     => ClientSecretCast::class,
+            'is_active'  => 'boolean',
+            'created_at' => 'datetime',
+            'updated_at' => 'datetime',
+        ];
+    }
+}
diff --git a/src/Infra/Providers/SecurityServiceProvider.php b/src/Infra/Providers/SecurityServiceProvider.php
new file mode 100644
index 0000000..85a1337
--- /dev/null
+++ b/src/Infra/Providers/SecurityServiceProvider.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Infra\Providers;
+
+use Application\Security\Ports\Repositories\ClientRepository;
+use Application\Security\Ports\Services\ClientCredentialGenerator;
+use Application\Security\Ports\Services\HmacSignatureValidator;
+use Application\Security\Ports\Services\NonceValidator;
+use Application\Security\Ports\Services\RequestValidator;
+use Application\Security\Ports\Services\TimestampValidator;
+use Illuminate\Contracts\Foundation\Application;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\Config;
+use Illuminate\Support\ServiceProvider;
+use Infra\Adapters\Repositories\ApiClientRepository;
+use Infra\Adapters\Services\CachedNonceValidator;
+use Infra\Adapters\Services\ClientCredentialGeneratorImpl;
+use Infra\Adapters\Services\HmacSignatureValidatorImpl;
+use Infra\Adapters\Services\RequestValidatorImpl;
+use Infra\Adapters\Services\TimestampValidatorImpl;
+use Presentation\Api\V1\Security\ApiUserDetailsProvider;
+use Presentation\Console\Security\ConsoleUserDetailsProvider;
+use Psr\Log\LoggerInterface;
+use Shared\DDD\Security\UserDetailsProvider;
+
+final class SecurityServiceProvider extends ServiceProvider
+{
+    #[\Override]
+    public function register(): void
+    {
+        $this->app->bind(ClientCredentialGenerator::class, ClientCredentialGeneratorImpl::class);
+        $this->app->bind(ClientRepository::class, ApiClientRepository::class);
+        $this->app->bind(HmacSignatureValidator::class, HmacSignatureValidatorImpl::class);
+
+        $this->app->bind(NonceValidator::class, function (Application $app): CachedNonceValidator {
+            $storeName = Config::string('cache.arcadia_store');
+            /** @var \Psr\SimpleCache\CacheInterface $cache */
+            $cache = Cache::store($storeName);
+
+            return new CachedNonceValidator(
+                logger: $app->make(LoggerInterface::class),
+                cacheStore: $cache,
+            );
+        });
+
+        $this->app->bind(TimestampValidator::class, function () {
+            $timezone = new \DateTimeZone(Config::string('app.timezone'));
+
+            return new TimestampValidatorImpl($timezone);
+        });
+        $this->app->bind(RequestValidator::class, RequestValidatorImpl::class);
+
+        if ($this->app->runningInConsole()) {
+            $this->app->bind(UserDetailsProvider::class, ConsoleUserDetailsProvider::class);
+        } else {
+            $this->app->scoped(ApiUserDetailsProvider::class);
+            $this->app->bind(UserDetailsProvider::class, ApiUserDetailsProvider::class);
+        }
+    }
+}
diff --git a/src/Infra/Usecase/LaravelExecutor.php b/src/Infra/Usecase/LaravelExecutor.php
index 78625bf..2d262f1 100644
--- a/src/Infra/Usecase/LaravelExecutor.php
+++ b/src/Infra/Usecase/LaravelExecutor.php
@@ -6,55 +6,70 @@ namespace Infra\Usecase;
 
 use Illuminate\Database\DatabaseManager;
 use Psr\Log\LoggerInterface;
+use Shared\DDD\Security\UserDetailsProvider;
 use Shared\DDD\Usecase\Builder\UsecaseExecutor;
 use Shared\DDD\Usecase\Input;
 use Shared\DDD\Usecase\Presenter;
 use Shared\DDD\Usecase\Usecase;
 
-/** @implements UsecaseExecutor<Input, \Shared\DDD\Usecase\Output> */
 final readonly class LaravelExecutor implements UsecaseExecutor
 {
     public function __construct(
         private DatabaseManager $database,
         private LoggerInterface $logger,
+        private ?UserDetailsProvider $userDetailsProvider = null,
     ) {
     }
 
     /**
+     * @template TInput of Input
+     * @template TOutput of \Shared\DDD\Usecase\Output
      * @template TView of object
      *
-     * @param  Usecase<Input, \Shared\DDD\Usecase\Output>  $usecase
-     * @param  Presenter<\Shared\DDD\Usecase\Output, TView>  $presenter
+     * @param  Usecase<TInput, TOutput>  $usecase
+     * @param  TInput  $input
+     * @param  Presenter<TOutput, TView>  $presenter
      * @return TView
      */
     #[\Override]
     public function execute(Usecase $usecase, Input $input, Presenter $presenter): object
     {
+        $currentUser = $this->userDetailsProvider?->currentUser();
+
         $context = [
             'usecase'   => $usecase::class,
             'input'     => $input::class,
             'presenter' => $presenter::class,
+            'user'      => $currentUser ? [
+                'id'         => $currentUser->id(),
+                'name'       => $currentUser->name(),
+                'type'       => $currentUser->type()->type(),
+                'identifier' => $currentUser->identifier(),
+            ] : null,
         ];
 
-        $this->logger->debug('Usecase execution started', $context);
+        $this->logger->debug('Starting usecase execution', $context);
 
         try {
-            /** @var TView $result */
             $result = $this->database->transaction(function () use ($usecase, $input, $presenter): object {
                 $output = $usecase->execute($input);
 
                 return $presenter->present($output);
             });
 
-            $this->logger->info('Usecase execution succeeded', $context);
+            $this->logger->info('Usecase executed successfully', $context);
 
+            /** @var TView */
             return $result;
-        } catch (\Throwable $exception) {
-            $this->logger->error('Usecase execution failed', $context + [
-                'exception' => $exception,
+        } catch (\Throwable $e) {
+            $this->logger->error('Usecase execution failed: ' . $e->getMessage(), [
+                ...$context,
+                'exception' => $e::class,
+                'file'      => $e->getFile(),
+                'line'      => $e->getLine(),
             ]);
 
-            throw $exception;
+            throw $e;
         }
     }
 }
diff --git a/tests/Integration/Database/Seeders/ApiClientSeederTest.php b/tests/Integration/Database/Seeders/ApiClientSeederTest.php
new file mode 100644
index 0000000..9210cfd
--- /dev/null
+++ b/tests/Integration/Database/Seeders/ApiClientSeederTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Database\Seeders;
+
+use Database\Seeders\ApiClientSeeder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Infra\Database\Models\ApiClient;
+use Tests\TestCase;
+
+covers(ApiClient::class);
+
+uses(TestCase::class, RefreshDatabase::class);
+
+describe('ApiClientSeeder Integration Test', function (): void {
+    it('seeds default api client records successfully', function (): void {
+        // GIVEN
+        $seeder = new ApiClientSeeder();
+
+        // WHEN
+        $seeder->run();
+
+        // THEN
+        $client = ApiClient::query()
+            ->where('name', 'Arcadia Dev Test Client')
+            ->first();
+        expect($client)->not->toBeNull()
+            ->and($client?->is_active)->toBeTrue();
+    });
+});
diff --git a/tests/Integration/Infra/Adapters/Repositories/ApiClientRepositoryTest.php b/tests/Integration/Infra/Adapters/Repositories/ApiClientRepositoryTest.php
new file mode 100644
index 0000000..de9280b
--- /dev/null
+++ b/tests/Integration/Infra/Adapters/Repositories/ApiClientRepositoryTest.php
@@ -0,0 +1,208 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Infra\Adapters\Repositories;
+
+use Application\Security\Models\Entities\Client;
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\ClientName;
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Application\Security\Models\ValueObjects\Entities\ClientId;
+use DateTimeImmutable;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Infra\Adapters\Repositories\ApiClientRepository;
+use Infra\Database\Models\ApiClient;
+use Ramsey\Uuid\Uuid;
+use Shared\Pagination;
+use Tests\TestCase;
+
+uses(TestCase::class, RefreshDatabase::class);
+covers(ApiClientRepository::class);
+
+beforeEach(function (): void {
+    ApiClient::query()->delete();
+});
+
+describe('ApiClientRepository Integration Tests', function (): void {
+    it('persists a new client into database', function (): void {
+        // GIVEN
+        $repository = new ApiClientRepository();
+        $clientId   = new ClientId(Uuid::uuid7());
+        $identifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $secret     = new ClientSecret('arcadia_sec_' . str_repeat('b', 86));
+
+        $client = Client::hydrate(
+            id: $clientId,
+            name: new ClientName('New API Client'),
+            identifier: $identifier,
+            secret: $secret,
+            isActive: true,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: new DateTimeImmutable(),
+        );
+
+        // WHEN
+        $repository->persist($client);
+
+        // THEN
+        $found = $repository->find($clientId);
+        expect($found)->not->toBeNull()
+            ->and($found->id->value)->toBe($clientId->value)
+            ->and($found->name->value)->toBe('New API Client')
+            ->and($found->identifier->value)->toBe($identifier->value)
+            ->and($found->secret->value)->toBe($secret->value)
+            ->and($found->isActive)->toBeTrue();
+    });
+
+    it('updates an existing client in database on persist', function (): void {
+        // GIVEN
+        $repository = new ApiClientRepository();
+        $rawId      = Uuid::uuid7()->toString();
+        $identifier = 'arcadia_id_' . str_repeat('a', 32);
+        $oldSecret  = 'arcadia_sec_' . str_repeat('1', 86);
+        $newSecret  = 'arcadia_sec_' . str_repeat('2', 86);
+
+        ApiClient::query()->create([
+            'id'         => $rawId,
+            'name'       => 'Initial Client',
+            'identifier' => $identifier,
+            'secret'     => $oldSecret,
+            'is_active'  => true,
+        ]);
+
+        $clientId = new ClientId(Uuid::fromString($rawId));
+        $client   = Client::hydrate(
+            id: $clientId,
+            name: new ClientName('Initial Client'),
+            identifier: new ClientIdentifier($identifier),
+            secret: new ClientSecret($oldSecret),
+            isActive: true,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: new DateTimeImmutable(),
+        );
+
+        $client->regenerateSecret(new ClientSecret($newSecret));
+
+        // WHEN
+        $repository->persist($client);
+
+        // THEN
+        $found = $repository->find($clientId);
+        expect($found)->not->toBeNull()
+            ->and($found->secret->value)->toBe($newSecret);
+    });
+
+    it('finds a client by its ClientId', function (): void {
+        // GIVEN
+        $repository = new ApiClientRepository();
+        $rawId      = Uuid::uuid7()->toString();
+        $identifier = 'arcadia_id_' . str_repeat('a', 32);
+        $secret     = 'arcadia_sec_' . str_repeat('b', 86);
+
+        ApiClient::query()->create([
+            'id'         => $rawId,
+            'name'       => 'Existing Client',
+            'identifier' => $identifier,
+            'secret'     => $secret,
+            'is_active'  => true,
+        ]);
+
+        $clientId = new ClientId(Uuid::fromString($rawId));
+
+        // WHEN
+        $client = $repository->find($clientId);
+
+        // THEN
+        expect($client)->not->toBeNull()
+            ->and($client->id->value)->toBe($rawId)
+            ->and($client->name->value)->toBe('Existing Client')
+            ->and($client->identifier->value)->toBe($identifier);
+    });
+
+    it('finds a client by its ClientIdentifier', function (): void {
+        // GIVEN
+        $repository = new ApiClientRepository();
+        $rawId      = Uuid::uuid7()->toString();
+        $identifier = 'arcadia_id_' . str_repeat('a', 32);
+        $secret     = 'arcadia_sec_' . str_repeat('b', 86);
+
+        ApiClient::query()->create([
+            'id'         => $rawId,
+            'name'       => 'Searchable Client',
+            'identifier' => $identifier,
+            'secret'     => $secret,
+            'is_active'  => true,
+        ]);
+
+        $clientIdentifier = new ClientIdentifier($identifier);
+
+        // WHEN
+        $client = $repository->findByIdentifier($clientIdentifier);
+
+        // THEN
+        expect($client)->not->toBeNull()
+            ->and($client->identifier->value)->toBe($identifier)
+            ->and($client->name->value)->toBe('Searchable Client');
+    });
+
+    it('deletes an existing client from database', function (): void {
+        // GIVEN
+        /** @var \Tests\TestCase $this */
+        $repository = new ApiClientRepository();
+        $rawId      = Uuid::uuid7()->toString();
+        $identifier = 'arcadia_id_' . str_repeat('a', 32);
+        $secret     = 'arcadia_sec_' . str_repeat('b', 86);
+
+        ApiClient::query()->create([
+            'id'         => $rawId,
+            'name'       => 'Client to Delete',
+            'identifier' => $identifier,
+            'secret'     => $secret,
+            'is_active'  => true,
+        ]);
+
+        $client = Client::hydrate(
+            id: new ClientId(Uuid::fromString($rawId)),
+            name: new ClientName('Client to Delete'),
+            identifier: new ClientIdentifier($identifier),
+            secret: new ClientSecret($secret),
+            isActive: true,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: new DateTimeImmutable(),
+        );
+
+        // WHEN
+        $repository->delete($client);
+
+        // THEN
+        $this->assertDatabaseMissing('api_clients', [
+            'id' => $rawId,
+        ]);
+    });
+
+    it('finds all clients with pagination', function (): void {
+        // GIVEN
+        $repository = new ApiClientRepository();
+
+        for ($i = 1; $i <= 5; $i++) {
+            ApiClient::query()->create([
+                'id'         => Uuid::uuid7()->toString(),
+                'name'       => "Client $i",
+                'identifier' => 'arcadia_id_' . str_pad((string) $i, 32, '0', STR_PAD_LEFT),
+                'secret'     => 'arcadia_sec_' . str_pad((string) $i, 86, '0', STR_PAD_LEFT),
+                'is_active'  => true,
+            ]);
+        }
+
+        $pagination = Pagination::ofPage(pageNumber: 1, pageSize: 2);
+
+        // WHEN
+        $paginated = $repository->findAll($pagination);
+
+        // THEN
+        expect($paginated->getTotal())->toBe(5)
+            ->and(count($paginated->getItems()))->toBe(2)
+            ->and($paginated->getPagination()->pageNumber())->toBe(1);
+    });
+});
diff --git a/tests/Unit/Infra/Adapters/Services/CachedNonceValidatorTest.php b/tests/Unit/Infra/Adapters/Services/CachedNonceValidatorTest.php
new file mode 100644
index 0000000..51e42e3
--- /dev/null
+++ b/tests/Unit/Infra/Adapters/Services/CachedNonceValidatorTest.php
@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\Request\Nonce;
+use Infra\Adapters\Services\CachedNonceValidator;
+use Mockery;
+use Psr\Log\NullLogger;
+use Psr\SimpleCache\CacheInterface;
+use Ramsey\Uuid\Uuid;
+
+covers(CachedNonceValidator::class);
+
+describe('CachedNonceValidator Unit Tests', function (): void {
+    it('validates and consumes a new nonce', function (): void {
+        // GIVEN
+        $cacheStore = Mockery::mock(CacheInterface::class);
+        $logger     = new NullLogger();
+        $validator  = new CachedNonceValidator($logger, $cacheStore);
+
+        $clientIdentifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $nonce            = new Nonce(Uuid::uuid7());
+
+        $expectedKey = 'nonce:' . $clientIdentifier->value . ':' . $nonce->value->toString();
+
+        $cacheStore->expects('has')
+            ->once()
+            ->with($expectedKey)
+            ->andReturn(false);
+
+        $cacheStore->expects('set')
+            ->once()
+            ->with($expectedKey, 'used', 300)
+            ->andReturn(true);
+
+        // WHEN
+        $isValid = $validator->validateAndConsume($nonce, $clientIdentifier);
+
+        // THEN
+        expect($isValid)->toBeTrue();
+    });
+
+    it('rejects an already consumed nonce', function (): void {
+        // GIVEN
+        $cacheStore = Mockery::mock(CacheInterface::class);
+        $logger     = new NullLogger();
+        $validator  = new CachedNonceValidator($logger, $cacheStore);
+
+        $clientIdentifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $nonce            = new Nonce(Uuid::uuid7());
+
+        $expectedKey = 'nonce:' . $clientIdentifier->value . ':' . $nonce->value->toString();
+
+        $cacheStore->expects('has')
+            ->once()
+            ->with($expectedKey)
+            ->andReturn(true);
+
+        $cacheStore->shouldNotReceive('set');
+
+        // WHEN
+        $isValid = $validator->validateAndConsume($nonce, $clientIdentifier);
+
+        // THEN
+        expect($isValid)->toBeFalse();
+    });
+});
diff --git a/tests/Unit/Infra/Adapters/Services/ClientCredentialGeneratorImplTest.php b/tests/Unit/Infra/Adapters/Services/ClientCredentialGeneratorImplTest.php
new file mode 100644
index 0000000..69066a7
--- /dev/null
+++ b/tests/Unit/Infra/Adapters/Services/ClientCredentialGeneratorImplTest.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Infra\Adapters\Services\ClientCredentialGeneratorImpl;
+
+covers(ClientCredentialGeneratorImpl::class);
+
+describe('ClientCredentialGeneratorImpl Unit Tests', function (): void {
+    it('generates a valid client identifier', function (): void {
+        // GIVEN
+        $generator = new ClientCredentialGeneratorImpl();
+
+        // WHEN
+        $identifier = $generator->generateIdentifier();
+
+        // THEN
+        expect($identifier)->toBeInstanceOf(ClientIdentifier::class)
+            ->and($identifier->value)->toStartWith('arcadia_id_')
+            ->and(strlen($identifier->value))->toBe(43);
+    });
+
+    it('generates a valid client secret', function (): void {
+        // GIVEN
+        $generator = new ClientCredentialGeneratorImpl();
+
+        // WHEN
+        $secret = $generator->generateSecret();
+
+        // THEN
+        expect($secret)->toBeInstanceOf(ClientSecret::class)
+            ->and($secret->value)->toStartWith('arcadia_sec_')
+            ->and(strlen($secret->value))->toBeGreaterThanOrEqual(86)
+            ->and(strlen($secret->value))->toBeLessThanOrEqual(120);
+    });
+
+    it('generates unique credentials on subsequent calls', function (): void {
+        // GIVEN
+        $generator = new ClientCredentialGeneratorImpl();
+
+        // WHEN
+        $id1  = $generator->generateIdentifier();
+        $id2  = $generator->generateIdentifier();
+        $sec1 = $generator->generateSecret();
+        $sec2 = $generator->generateSecret();
+
+        // THEN
+        expect($id1->value)->not->toBe($id2->value)
+            ->and($sec1->value)->not->toBe($sec2->value);
+    });
+});
diff --git a/tests/Unit/Infra/Adapters/Services/HmacSignatureValidatorImplTest.php b/tests/Unit/Infra/Adapters/Services/HmacSignatureValidatorImplTest.php
new file mode 100644
index 0000000..8a25a5b
--- /dev/null
+++ b/tests/Unit/Infra/Adapters/Services/HmacSignatureValidatorImplTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Infra\Adapters\Services;
+
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Application\Security\Models\ValueObjects\Request\HttpMethod;
+use Application\Security\Models\ValueObjects\Request\Nonce;
+use Application\Security\Models\ValueObjects\Request\Request;
+use Application\Security\Models\ValueObjects\Request\RequestSignature;
+use Application\Security\Models\ValueObjects\Request\RequestTimestamp;
+use DateTimeImmutable;
+use DateTimeInterface;
+use Infra\Adapters\Services\HmacSignatureValidatorImpl;
+use Ramsey\Uuid\Uuid;
+use Uri\Rfc3986\Uri;
+
+covers(HmacSignatureValidatorImpl::class);
+
+describe('HmacSignatureValidatorImpl Unit Tests', function (): void {
+    it('validates a matching HMAC signature', function (): void {
+        // GIVEN
+        $validator  = new HmacSignatureValidatorImpl();
+        $secret     = new ClientSecret(str_repeat('s', 98));
+        $identifier = new ClientIdentifier(str_repeat('c', 43));
+        $timestamp  = new DateTimeImmutable('2026-08-17T12:00:00+00:00');
+        $nonce      = new Nonce(Uuid::uuid7());
+        $uri        = new Uri('http://localhost/api/v1/test?b=2&a=1');
+
+        $expectedPayload = implode('|', [
+            'GET',
+            '/api/v1/test?a=1&b=2',
+            $timestamp->format(DateTimeInterface::ATOM),
+            $nonce->value->toString(),
+            'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855',
+        ]);
+
+        $signatureHash = hash_hmac('sha256', $expectedPayload, $secret->value);
+        $signature     = new RequestSignature($signatureHash);
+
+        $request = new Request(
+            uri: $uri,
+            method: HttpMethod::GET,
+            bodyHash: null,
+            signature: $signature,
+            nonce: $nonce,
+            identifier: $identifier,
+            timestamp: new RequestTimestamp($timestamp),
+        );
+
+        // WHEN
+        $isValid = $validator->validate($request, $secret);
+
+        // THEN
+        expect($isValid)->toBeTrue();
+    });
+});
diff --git a/tests/Unit/Infra/Adapters/Services/RequestValidatorImplTest.php b/tests/Unit/Infra/Adapters/Services/RequestValidatorImplTest.php
new file mode 100644
index 0000000..3c059b7
--- /dev/null
+++ b/tests/Unit/Infra/Adapters/Services/RequestValidatorImplTest.php
@@ -0,0 +1,199 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Infra\Adapters\Services;
+
+use Application\Security\Models\Entities\Client;
+use Application\Security\Models\ValueObjects\ClientIdentifier;
+use Application\Security\Models\ValueObjects\ClientName;
+use Application\Security\Models\ValueObjects\ClientSecret;
+use Application\Security\Models\ValueObjects\Entities\ClientId;
+use Application\Security\Models\ValueObjects\Request\HttpMethod;
+use Application\Security\Models\ValueObjects\Request\Nonce;
+use Application\Security\Models\ValueObjects\Request\Request;
+use Application\Security\Models\ValueObjects\Request\RequestSignature;
+use Application\Security\Models\ValueObjects\Request\RequestTimestamp;
+use Application\Security\Ports\Repositories\ClientRepository;
+use Application\Security\Ports\Services\HmacSignatureValidator;
+use Application\Security\Ports\Services\NonceValidator;
+use Application\Security\Ports\Services\RequestValidation\RequestValidationStatus;
+use Application\Security\Ports\Services\TimestampValidator;
+use DateTimeImmutable;
+use Infra\Adapters\Services\RequestValidatorImpl;
+use Mockery;
+use Psr\Log\NullLogger;
+use Ramsey\Uuid\Uuid;
+use Uri\Rfc3986\Uri;
+
+covers(RequestValidatorImpl::class);
+
+describe('RequestValidatorImpl Unit Tests', function (): void {
+    it('returns valid result when all security checks pass', function (): void {
+        // GIVEN
+        $logger             = new NullLogger();
+        $signatureValidator = Mockery::mock(HmacSignatureValidator::class);
+        $nonceValidator     = Mockery::mock(NonceValidator::class);
+        $timestampValidator = Mockery::mock(TimestampValidator::class);
+        $clientRepository   = Mockery::mock(ClientRepository::class);
+
+        $validator = new RequestValidatorImpl(
+            $logger,
+            $signatureValidator,
+            $nonceValidator,
+            $timestampValidator,
+            $clientRepository
+        );
+
+        $clientIdentifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $clientSecret     = new ClientSecret('arcadia_sec_' . str_repeat('b', 86));
+        $client           = Client::hydrate(
+            id: new ClientId(Uuid::uuid7()),
+            name: new ClientName('Test Client'),
+            identifier: $clientIdentifier,
+            secret: $clientSecret,
+            isActive: true,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: new DateTimeImmutable(),
+        );
+
+        $request = new Request(
+            uri: new Uri('http://localhost/api/v1/test'),
+            method: HttpMethod::GET,
+            bodyHash: null,
+            signature: new RequestSignature(str_repeat('a', 64)),
+            nonce: new Nonce(Uuid::uuid7()),
+            identifier: $clientIdentifier,
+            timestamp: new RequestTimestamp(new DateTimeImmutable()),
+        );
+
+        $clientRepository->expects('findByIdentifier')
+            ->with($clientIdentifier)
+            ->andReturn($client);
+
+        $timestampValidator->expects('validate')
+            ->once()
+            ->andReturn(true);
+
+        $signatureValidator->expects('validate')
+            ->once()
+            ->with($request, $clientSecret)
+            ->andReturn(true);
+
+        $nonceValidator->expects('validateAndConsume')
+            ->once()
+            ->with($request->nonce, $clientIdentifier)
+            ->andReturn(true);
+
+        // WHEN
+        $result = $validator->validate($request);
+
+        // THEN
+        expect($result->isValid())->toBeTrue()
+            ->and($result->status)->toBe(RequestValidationStatus::VALID)
+            ->and($result->client)->toBe($client);
+    });
+
+    it('returns client not found when client does not exist', function (): void {
+        // GIVEN
+        $logger             = new NullLogger();
+        $signatureValidator = Mockery::mock(HmacSignatureValidator::class);
+        $nonceValidator     = Mockery::mock(NonceValidator::class);
+        $timestampValidator = Mockery::mock(TimestampValidator::class);
+        $clientRepository   = Mockery::mock(ClientRepository::class);
+
+        $validator = new RequestValidatorImpl(
+            $logger,
+            $signatureValidator,
+            $nonceValidator,
+            $timestampValidator,
+            $clientRepository
+        );
+
+        $clientIdentifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $request          = new Request(
+            uri: new Uri('http://localhost/api/v1/test'),
+            method: HttpMethod::GET,
+            bodyHash: null,
+            signature: new RequestSignature(str_repeat('a', 64)),
+            nonce: new Nonce(Uuid::uuid7()),
+            identifier: $clientIdentifier,
+            timestamp: new RequestTimestamp(new DateTimeImmutable()),
+        );
+
+        $clientRepository->expects('findByIdentifier')
+            ->with($clientIdentifier)
+            ->andReturn(null);
+
+        $timestampValidator->expects('validate')
+            ->once()
+            ->andReturn(true);
+
+        // WHEN
+        $result = $validator->validate($request);
+
+        // THEN
+        expect($result->isValid())->toBeFalse()
+            ->and($result->status)->toBe(RequestValidationStatus::CLIENT_NOT_FOUND)
+            ->and($result->client)->toBeNull();
+    });
+
+    it('returns client not authorized when client is inactive', function (): void {
+        // GIVEN
+        $logger             = new NullLogger();
+        $signatureValidator = Mockery::mock(HmacSignatureValidator::class);
+        $nonceValidator     = Mockery::mock(NonceValidator::class);
+        $timestampValidator = Mockery::mock(TimestampValidator::class);
+        $clientRepository   = Mockery::mock(ClientRepository::class);
+
+        $validator = new RequestValidatorImpl(
+            $logger,
+            $signatureValidator,
+            $nonceValidator,
+            $timestampValidator,
+            $clientRepository
+        );
+
+        $clientIdentifier = new ClientIdentifier('arcadia_id_' . str_repeat('a', 32));
+        $clientSecret     = new ClientSecret('arcadia_sec_' . str_repeat('b', 86));
+        $client           = Client::hydrate(
+            id: new ClientId(Uuid::uuid7()),
+            name: new ClientName('Inactive Client'),
+            identifier: $clientIdentifier,
+            secret: $clientSecret,
+            isActive: false,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: new DateTimeImmutable(),
+        );
+
+        $request = new Request(
+            uri: new Uri('http://localhost/api/v1/test'),
+            method: HttpMethod::GET,
+            bodyHash: null,
+            signature: new RequestSignature(str_repeat('a', 64)),
+            nonce: new Nonce(Uuid::uuid7()),
+            identifier: $clientIdentifier,
+            timestamp: new RequestTimestamp(new DateTimeImmutable()),
+        );
+
+        $clientRepository->expects('findByIdentifier')
+            ->with($clientIdentifier)
+            ->andReturn($client);
+
+        $timestampValidator->expects('validate')
+            ->once()
+            ->andReturn(true);
+
+        $signatureValidator->expects('validate')
+            ->once()
+            ->with($request, $clientSecret)
+            ->andReturn(true);
+
+        // WHEN
+        $result = $validator->validate($request);
+
+        // THEN
+        expect($result->isValid())->toBeFalse()
+            ->and($result->status)->toBe(RequestValidationStatus::CLIENT_NOT_AUTHORIZED);
+    });
+});
diff --git a/tests/Unit/Infra/Adapters/Services/TimestampValidatorImplTest.php b/tests/Unit/Infra/Adapters/Services/TimestampValidatorImplTest.php
new file mode 100644
index 0000000..138c148
--- /dev/null
+++ b/tests/Unit/Infra/Adapters/Services/TimestampValidatorImplTest.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Infra\Adapters\Services;
+
+use DateTimeImmutable;
+use DateTimeZone;
+use Infra\Adapters\Services\TimestampValidatorImpl;
+
+covers(TimestampValidatorImpl::class);
+
+describe('TimestampValidatorImpl Unit Tests', function (): void {
+    it('accepts timestamps within the 300 seconds skew window', function (string $modifier): void {
+        // GIVEN
+        $timezone  = new DateTimeZone('UTC');
+        $validator = new TimestampValidatorImpl($timezone);
+        $timestamp = new DateTimeImmutable($modifier, $timezone);
+
+        // WHEN
+        $isValid = $validator->validate($timestamp);
+
+        // THEN
+        expect($isValid)->toBeTrue();
+    })->with([
+        'now',
+        '-2 minutes',
+        '+2 minutes',
+        '-299 seconds',
+        '+299 seconds',
+    ]);
+
+    it('rejects timestamps outside the 300 seconds skew window', function (string $modifier): void {
+        // GIVEN
+        $timezone  = new DateTimeZone('UTC');
+        $validator = new TimestampValidatorImpl($timezone);
+        $timestamp = new DateTimeImmutable($modifier, $timezone);
+
+        // WHEN
+        $isValid = $validator->validate($timestamp);
+
+        // THEN
+        expect($isValid)->toBeFalse();
+    })->with([
+        '-6 minutes',
+        '+6 minutes',
+        '-301 seconds',
+        '+301 seconds',
+        '-1 day',
+        '+1 day',
+    ]);
+});