54 lines
980 B
Markdown
54 lines
980 B
Markdown
# SM4
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SM4 is a block cipher. CFB mode, OFB mode, CTR mode and CBC mode are implemented in libsm.
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Here are their definitions:
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```rust
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pub enum CipherMode {
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Cfb,
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Ofb,
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Ctr,
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Cbc,
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}
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```
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## Create Cipher
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Choose a mode when creating a cipher. Then call the creating function.
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Sample:
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```rust
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use libsm::sm4::{Mode, Cipher};
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use rand::RngCore;
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fn rand_block() -> [u8; 16] {
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let mut rng = rand::thread_rng();;
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let mut block: [u8; 16] = [0; 16];
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rng.fill_bytes(&mut block[..]);
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block
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}
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let key = rand_block();
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let cipher = Cipher::new(&key, Mode::Cfb);
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```
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## Encryption and Decryption
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Initialize a random IV(Initial Vector), which can be generated using the `rand_block()` function above.
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Sample:
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```rust
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let iv = rand_block();
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let plain_text = String::from("plain text");
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// Encryption
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let cipher_text: Vec<u8> = cipher.encrypt(plain_text.to_bytes(), &iv);
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// Decryption
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let plain_text: Vec<u8> = cipher.decrypt(&cipher_text[..], &iv);
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```
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