> For the complete documentation index, see [llms.txt](https://aptofl.gitbook.io/aptofl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://aptofl.gitbook.io/aptofl/deep-dive/technical-deep-dive-1.md).

# Technical Deep dive

## Detailed Explanation of Aptos Smart Contracts

### Overview

The Aptos smart contracts consist of three main modules: **User Registration**, **Random Number Generation**, and **Aggregation**. Each module is designed to support different functionalities in the federated learning architecture.

#### 1. **User Registration Module**

**Structure**

```rust
module registry::user_registration {
    use std::signer;
    use std::string;
    use std::error;
    use aptos_framework::event;
    #[test_only]
    use std::debug;
```

* The module imports necessary libraries and defines dependencies like signer management and string handling.

**User Registry Resource**

```rust
struct UserRegistry has key {
    user_id: string::String,
}
```

* **UserRegistry**: A struct that holds user registration information, specifically a user ID, and is stored as a resource with a unique key.

**Events**

```rust
#[event]
struct UserRegistrationEvent has drop, store {
    account: address,
    old_user_id: string::String,
    new_user_id: string::String,
}
```

* **UserRegistrationEvent**: An event that is emitted when a user registers or updates their information, containing the account address and the old and new user IDs.

**Entry Functions**

```rust
public entry fun register_user(account: signer, new_user_id: string::String) acquires UserRegistry {
    ...
}
```

* **register\_user**: The primary function for user registration. It checks if a user is already registered and either creates a new entry or updates an existing one. It also emits a registration event upon updates.

**View Functions**

```rust
rustCopy code#[view]
public fun get_user_id(addr: address): string::String acquires UserRegistry {
    ...
}
```

* **get\_user\_id**: Allows querying of a registered user ID by address, asserting that a user is registered.

#### 2. **Random Number Generation Module**

**Structure**

```rust
rustCopy codemodule generator::RandomNumberGenerator {
    use aptos_framework::randomness;
    use aptos_framework::event;
    use std::signer;
    use std::error;
```

* This module imports the randomness framework and other standard libraries.

**Random Value Resource**

```rust
rustCopy codestruct RandomValueStore has key {
    owner: address,
    generated_value: GeneratedRandomValue,
}
```

* **RandomValueStore**: Holds the generated random value for each user, linking it to the user's address.

**Events**

```rust
#[event]
struct RandomValueGenerated has drop, store {
    account: address,
    r: vector<u8>,
}
```

* **RandomValueGenerated**: An event emitted when a new random value is generated, capturing the associated account and value.

**Entry Functions**

```rust
public entry fun generate_random_value(account: &signer) acquires RandomValueStore {
    ...
}
```

* **generate\_random\_value**: Generates a random byte vector for a user, emits an event, and stores the value in a user-specific resource.

**View Functions**

```rust
public fun get_random_value(addr: address): vector<u8> acquires RandomValueStore {
    ...
}
```

* **get\_random\_value**: Retrieves the random value generated for a user, ensuring that it exists in the store.

#### 3. **Aggregation Module**

**Structure**

```rust
module aggregator::aggregator {
    use std::vector;
    use aptos_std::type_info::{Self, TypeInfo};
```

* The module focuses on handling encrypted data and performing aggregation functions.

**Parameter Initialization**

```rust
struct Params has key {
    p: vector<u8>,
    q: vector<u8>,
    g: vector<u8>,
    h: vector<u8>,
}
```

* **Params**: Stores the parameters needed for the aggregation and commitment process.

**Encrypted Data Storage**

```rust
struct EncryptedValueStore has key {
    account: address,
    encrypted_value: vector<u8>,
}
```

* **EncryptedValueStore**: Stores encrypted values submitted by users for aggregation.

**Entry Functions**

```rust
public entry fun initialize(p: vector<u8>, q: vector<u8>, g: vector<u8>, h: vector<u8>) {
    ...
}
```

* **initialize**: Sets up the necessary parameters for the aggregation process, enabling contract configuration.

```rust
public entry fun add_encrypted_value(account: signer, encrypted_value: vector<u8>) acquires EncryptedValueStore {
    ...
}
```

* **add\_encrypted\_value**: Accepts an encrypted value from a user, storing it in the `EncryptedValueStore`.

```rust
public entry fun multiply_encrypted_values(values: vector<vector<u8>>) acquires EncryptedValueStore {
    ...
}
```

* **multiply\_encrypted\_values**: Placeholder for multiplying encrypted values (specific implementation details need further development).

```rust
rpublic entry fun decrypt(values: vector<vector<u8>>) {
    ...
}
```

* **decrypt**: Placeholder for the decryption process of aggregated encrypted values, requiring implementation of the decryption logic.