license-key

一个用于生成和验证许可证密钥的库，无需互联网连接。当然，您也可以通过互联网验证许可证密钥以获得进一步的保护。

功能

• 无需互联网连接。
• 在软件更新中轻松撤销特定的许可证密钥。
• 由于验证过程不检查整个许可证密钥，因此无法通过反汇编应用程序来了解如何生成100%有效的密钥。

有关更多信息，请阅读在 Delphi 中实现部分序列号验证系统，本库基于该系统。

许可证密钥的结构

每个许可证密钥由一个种子、一个有效载荷和一个校验和组成。有效载荷中的每个字节都是种子和初始化向量的操作。16位校验和用于快速检查密钥是否有效，而种子是用于标识许可证密钥所有者（如电子邮件地址或类似）的某物的64位哈希值。

有效载荷的大小取决于初始化向量的大小。在下面的示例中，我们使用了一个5字节的初始化向量，因此有效载荷为5字节。

┌───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┐
│0x0│0x1│0x2│0x3│0x4│0x5│0x6│0x7│0x8│0x9│0xa│0xb│0xc│0xd│0xe│0xf│
├───┴───┴───┴───┴───┴───┴───┴───┴───┼───┴───┴───┴───┴───┼───┴───┤
│ SEED                              │ PAYLOAD           │ CHECK │
│                                   │                   │  SUM  │
└───────────────────────────────────┴───────────────────┴───────┘

生成许可证密钥

use license_key::*;

// Define a hasher that will hash the seed and a initialization vector.
// DON'T USE THIS ONE. It's only for demonstrational purposes.
struct DummyHasher { }
impl KeyHasher for DummyHasher {
    fn hash(&self, seed: u64, a: u64, b: u64, c: u64) -> u8 {
        ((seed ^ a ^ b ^ c) & 0xFF) as u8
    }
}

// Create a license generator
// We use only four triplets in our initialization vector,
// but in a real world scenario you would want to use a lot more.
let generator = Generator::new(
    DummyHasher { },
    vec![
        // DON'T USE THIS ONE.
        // Generate your own.
        (114, 83, 170),
        (60, 208, 27),
        (69, 14, 202),
        (61, 232, 54)
     ],
);

// Generate a license key using a seed.
// A seed is unique per license key, and could be a hash of an e-mail address or similar.
// You can later block individual seeds during verification.
let key = generator.generate(1234567891011121314_u64);

// Write the key in hex format to the console.
// This will output something like: 112210F4B2D230A229552341B2E723
println!("{}", key.serialize::<HexFormat>());

验证许可证密钥

use license_key::*;

// Use the exact same hasher that we used when generating the key
struct DummyHasher { }
impl KeyHasher for DummyHasher {
    fn hash(&self, seed: u64, a: u64, b: u64, c: u64) -> u8 {
        ((seed ^ a ^ b ^ c) & 0xFF) as u8
    }
}

// Create the license key verifier
let mut verifier = Verifier::new(
    DummyHasher { },
    vec![
        // Use the first byte (zero indexed) from the initialization vector.
        // If a third-party key generator is created for the app, simply change this
        // to another byte and any forged keys won't work anymore.
        ByteCheck::new(0, (114, 83, 170)),
    ],
);

// Block a specific seed.
// You might want to do this if a key was leaked or the the 
// license key owner requested a refund.
verifier.block(11111111_u64);

// Parse a key in hex format
let key = LicenseKey::parse::<HexFormat>("112210F4B2D230A229552341E723");

// Verify the license key
match verifier.verify(&key) {
    Status::Valid => println!("Key is valid!"),
    Status::Invalid => println!("Key is invalid!"),
    Status::Blocked => println!("Key has been blocked!"),
    Status::Forged => println!("Key has been forged!"),
}