Asymmetric Ciphers

Cipher

Cipher cipher(Key key, String algorithm, Mode mode);

�Returns an asymmetric cipher.

Usage Example

KeyStore aliceKeystore = keystore("classpath:/keystore-alice.p12", "password", "PKCS12");
KeyStore bobKeystore = keystore("classpath:/keystore-bob.p12", "password", "PKCS12");
Key alicePrivateKey = privateKey(aliceKeystore, "alice", "password");
Key bobPrivateKey = privateKey(bobKeystore, "bob", "password");
Key alicePublicKey = publicKey(aliceKeystore, "alice");
Key bobPublicKey = publicKey(bobKeystore, "bob");

Cipher encryptForAlice = cipher(alicePublicKey, "RSA", ENCRYPT);
Cipher decryptForAlice = cipher(alicePrivateKey, "RSA", DECRYPT);
Cipher encryptForBob = cipher(bobPublicKey, "RSA", ENCRYPT);
Cipher decryptForBob = cipher(bobPrivateKey, "RSA", DECRYPT);

// Alice writes to Bob
byte[] aliceMsg01 = "Hello".getBytes(UTF_8);
byte[] aliceMsg01Encrypted = encryptForBob.encrypt(aliceMsg01);

// Bob decrypts Alice's message
byte[] aliceMsg01Decrypted = decryptForBob.encrypt(aliceMsg01Encrypted);

// Bob responds to Alice's message
byte[] bobMsg01 = "Hey Alice, nice to hear from you.".getBytes(UTF_8);
byte[] bobMsg01Encrypted = encryptForAlice.encrypt(bobMsg01);

// Alice decrypts Bob's message
byte[] bobMsg01Decrypted = decryptForAlice.encrypt(bobMsg01Encrypted);

Builder Pattern Alternative

For complex asymmetric cipher configurations, use the fluent builder API:

Basic Asymmetric Cipher Builder

EncodingCipher cipher = cipherBuilder()
    .key(publicKey)
    .algorithm("RSA")
    .mode(ENCRYPT)
    .buildAsymmetric();

String encrypted = cipher.encrypt("Hello Bob");

Advanced Asymmetric Cipher Builder

EncodingCipher encrypter = cipherBuilder()
    .key(bobPublicKey)
    .algorithm("RSA")
    .provider("BC")
    .mode(ENCRYPT)
    .charset(UTF_8)
    .encoding(BASE64)
    .buildAsymmetric();

EncodingCipher decrypter = cipherBuilder()
    .key(bobPrivateKey)
    .algorithm("RSA")
    .provider("BC")
    .mode(DECRYPT)
    .charset(UTF_8)
    .encoding(BASE64)
    .buildAsymmetric();

String message = "Hello Bob";
String encrypted = encrypter.encrypt(message);
String decrypted = decrypter.encrypt(encrypted);
assertEquals(message, decrypted);

�Cipher By Key

CipherByKey cipher(Map<String, Key> keys, String algorithm);

�Returns a cipher interface for working with a map of preconfigured keys.

Usage Example

KeyStore aliceKeystore = keystore("classpath:/keystore-alice.p12", "password", "PKCS12");
KeyStore bobKeystore = keystore("classpath:/keystore-bob.p12", "password", "PKCS12");
Key alicePrivateKey = privateKey(aliceKeystore, "alice", "password");
Key bobPrivateKey = privateKey(bobKeystore, "bob", "password");
Key alicePublicKey = publicKey(aliceKeystore, "alice");
Key bobPublicKey = publicKey(bobKeystore, "bob");

Map<String, Key> keys = Map.of(
        "alice-public", alicePublicKey,
        "alice-private", alicePrivateKey,
        "bob-public", bobPublicKey,
        "bob-private", bobPrivateKey
);

CipherByKey cipher = cipher(keys, "RSA");

// Alice writes to Bob
byte[] aliceMsg01 = "Hello".getBytes(UTF_8);
byte[] aliceMsg01Encrypted = cipher.encrypt("bob-public", ENCRYPT, aliceMsg01);

// Bob decrypts Alice's message
byte[] aliceMsg01Decrypted = cipher.encrypt("bob-private", DECRYPT, aliceMsg01Encrypted);
assertArrayEquals(aliceMsg01, aliceMsg01Decrypted);

// Bob responds to Alice's message
byte[] bobMsg01 = "Hey Alice, nice to hear from you.".getBytes(UTF_8);
byte[] bobMsg01Encrypted = cipher.encrypt("alice-public", ENCRYPT, bobMsg01);

// Alice decrypts Bob's message
byte[] bobMsg01Decrypted = cipher.encrypt("alice-private", DECRYPT, bobMsg01Encrypted);
assertArrayEquals(bobMsg01, bobMsg01Decrypted);

�Encoding Cipher

EncodingCipher cipher(
    Key key, 
    String algorithm, 
    Mode mode, 
    Encoding encoding, 
    Charset charset
);

�Returns an encoding cipher. The character set refers to the plain text message string encoding.

Usage Example

KeyStore aliceKeystore = keystore("classpath:/keystore-alice.p12", "password", "PKCS12");
KeyStore bobKeystore = keystore("classpath:/keystore-bob.p12", "password", "PKCS12");
Key alicePrivateKey = privateKey(aliceKeystore, "alice", "password");
Key bobPrivateKey = privateKey(bobKeystore, "bob", "password");
Key alicePublicKey = publicKey(aliceKeystore, "alice");
Key bobPublicKey = publicKey(bobKeystore, "bob");

EncodingCipher encryptForAlice = cipher(alicePublicKey, "RSA", ENCRYPT, BASE64, UTF_8);
EncodingCipher decryptForAlice = cipher(alicePrivateKey, "RSA", DECRYPT, BASE64, UTF_8);
EncodingCipher encryptForBob = cipher(bobPublicKey, "RSA", ENCRYPT, BASE64, UTF_8);
EncodingCipher decryptForBob = cipher(bobPrivateKey, "RSA", DECRYPT, BASE64, UTF_8);

// Alice writes to Bob
String aliceMsg01 = "Hello";
String aliceMsg01Encrypted = encryptForBob.encrypt(aliceMsg01);

// Bob decrypts Alice's message
String aliceMsg01Decrypted = decryptForBob.encrypt(aliceMsg01Encrypted);
assertEquals(aliceMsg01, aliceMsg01Decrypted);

// Bob responds to Alice's message
String bobMsg01 = "Hey Alice, nice to hear from you.";
String bobMsg01Encrypted = encryptForAlice.encrypt(bobMsg01);

// Alice decrypts Bob's message
String bobMsg01Decrypted = decryptForAlice.encrypt(bobMsg01Encrypted);
assertEquals(bobMsg01, bobMsg01Decrypted);

�Encoding Cipher By Key

EncodingCipherByKey cipher(
    Map<String, Key> keys, 
    String algorithm, 
    Encoding encoding, 
    Charset charset
);

�Returns an encoding cipher with a set of preconfigured keys.

Usage Example

KeyStore aliceKeystore = keystore("classpath:/keystore-alice.p12", "password", "PKCS12");
KeyStore bobKeystore = keystore("classpath:/keystore-bob.p12", "password", "PKCS12");
Key alicePrivateKey = privateKey(aliceKeystore, "alice", "password");
Key bobPrivateKey = privateKey(bobKeystore, "bob", "password");
Key alicePublicKey = publicKey(aliceKeystore, "alice");
Key bobPublicKey = publicKey(bobKeystore, "bob");

Map<String, Key> keys = Map.of(
    "alice-public", alicePublicKey,
    "alice-private", alicePrivateKey,
    "bob-public", bobPublicKey,
    "bob-private", bobPrivateKey
);

EncodingCipherByKey cipher = cipher(keys, "RSA", BASE64, UTF_8);

// Alice writes to Bob
String aliceMsg01 = "Hello";
String aliceMsg01Encrypted = cipher.encrypt("bob-public", ENCRYPT, aliceMsg01);

// Bob decrypts Alice's message
String aliceMsg01Decrypted = cipher.encrypt("bob-private", DECRYPT, aliceMsg01Encrypted);
assertEquals(aliceMsg01, aliceMsg01Decrypted);

// Bob responds to Alice's message
String bobMsg01 = "Hey Alice, nice to hear from you.";
String bobMsg01Encrypted = cipher.encrypt("alice-public", ENCRYPT, bobMsg01);

// Alice decrypts Bob's message
String bobMsg01Decrypted = cipher.encrypt("alice-private", DECRYPT, bobMsg01Encrypted);
assertEquals(bobMsg01, bobMsg01Decrypted);