JOSE Implementation

/**
 * JWS token input and parsing utilities
 */
public class JWSInput {
    /**
     * Create JWS input from token string
     * @param token JWS token string
     */
    public JWSInput(String token) throws JWSInputException;
    
    /**
     * Get the JWS header
     * @return JWS header object
     */
    public JWSHeader getHeader();
    
    /**
     * Get the raw payload content
     * @return Payload bytes
     */
    public byte[] getContent();
    
    /**
     * Read JSON payload content as specified type
     * @param type Target class type
     * @return Deserialized object
     * @throws IOException if JSON parsing fails
     */
    public <T> T readJsonContent(Class<T> type) throws IOException;
    
    /**
     * Get the encoded signature input (header + payload)
     * @return Base64URL encoded signature input
     */
    public String getEncodedSignatureInput();
    
    /**
     * Get the signature bytes
     * @return Signature bytes
     */
    public byte[] getSignature();
    
    /**
     * Get the raw token string
     * @return Original token string
     */
    public String getWireString();
}

/**
 * JWS header representation
 */
public class JWSHeader extends JOSEHeader {
    /**
     * Get the signature algorithm
     * @return Algorithm identifier (e.g., "RS256", "ES256")
     */
    public String getAlgorithm();
    
    /**
     * Get the key ID
     * @return Key identifier
     */
    public String getKeyId();
    
    /**
     * Get the token type
     * @return Type value (usually "JWT")
     */
    public String getType();
    
    /**
     * Get the content type
     * @return Content type value
     */
    public String getContentType();
    
    /**
     * Get critical header parameters
     * @return Set of critical parameter names
     */
    public Set<String> getCritical();
    
    /**
     * Get custom header parameter
     * @param name Parameter name
     * @return Parameter value
     */
    public Object getOtherHeaderParameter(String name);
}

/**
 * JWS token builder for creating signed tokens
 */
public class JWSBuilder {
    /**
     * Set JSON content as payload
     * @param content Object to serialize as JSON
     * @return JWSBuilder for chaining
     */
    public JWSBuilder jsonContent(Object content);
    
    /**
     * Set raw content as payload
     * @param content Raw payload bytes
     * @return JWSBuilder for chaining
     */
    public JWSBuilder content(byte[] content);
    
    /**
     * Set content type header
     * @param contentType Content type value
     * @return JWSBuilder for chaining
     */
    public JWSBuilder contentType(String contentType);
    
    /**
     * Set token type header
     * @param type Type value
     * @return JWSBuilder for chaining
     */
    public JWSBuilder type(String type);
    
    /**
     * Set key ID header
     * @param kid Key identifier
     * @return JWSBuilder for chaining
     */
    public JWSBuilder kid(String kid);
    
    /**
     * Sign the token with the provided signer context
     * @param signer Signature signer context
     * @return Signed JWS token string
     */
    public String sign(SignatureSignerContext signer);
}

/**
 * JWE token representation and utilities
 */
public class JWE {
    /**
     * Create JWE from encrypted token string
     * @param token JWE token string
     */
    public JWE(String token) throws JWEException;
    
    /**
     * Get the JWE header
     * @return JWE header object
     */
    public JWEHeader getHeader();
    
    /**
     * Get the encrypted key
     * @return Encrypted key bytes
     */
    public byte[] getEncryptedKey();
    
    /**
     * Get the initialization vector
     * @return IV bytes
     */
    public byte[] getIv();
    
    /**
     * Get the encrypted content
     * @return Encrypted content bytes
     */
    public byte[] getEncryptedContent();
    
    /**
     * Get the authentication tag
     * @return Authentication tag bytes
     */
    public byte[] getTag();
}

/**
 * JWE header representation
 */
public class JWEHeader extends JOSEHeader {
    /**
     * Get the key management algorithm
     * @return Algorithm identifier (e.g., "RSA-OAEP", "A256KW")
     */
    public String getAlgorithm();
    
    /**
     * Get the content encryption algorithm
     * @return Encryption algorithm (e.g., "A256GCM", "A128CBC-HS256")
     */
    public String getEncryptionAlgorithm();
    
    /**
     * Get the compression algorithm
     * @return Compression algorithm or null
     */
    public String getCompressionAlgorithm();
    
    /**
     * Get the key ID
     * @return Key identifier
     */
    public String getKeyId();
}

/**
 * JWE constants for algorithms and parameters
 */
public interface JWEConstants {
    // Key management algorithms
    String RSA1_5 = "RSA1_5";
    String RSA_OAEP = "RSA-OAEP";
    String RSA_OAEP_256 = "RSA-OAEP-256";
    String A128KW = "A128KW";
    String A192KW = "A192KW";
    String A256KW = "A256KW";
    String DIR = "dir";
    String A128GCMKW = "A128GCMKW";
    String A192GCMKW = "A192GCMKW";
    String A256GCMKW = "A256GCMKW";
    
    // Content encryption algorithms
    String A128CBC_HS256 = "A128CBC-HS256";
    String A192CBC_HS384 = "A192CBC-HS384";
    String A256CBC_HS512 = "A256CBC-HS512";
    String A128GCM = "A128GCM";
    String A192GCM = "A192GCM";
    String A256GCM = "A256GCM";
    
    // Compression algorithms
    String DEF = "DEF";
}

/**
 * JWE utilities for encryption and decryption operations
 */
public class JWEUtils {
    /**
     * Encrypt content using direct encryption with shared key
     * @param content Content to encrypt
     * @param encryptionAlg Content encryption algorithm
     * @param encryptionKey Symmetric encryption key
     * @return JWE token string
     * @throws JWEException if encryption fails
     */
    public static String encryptDirect(byte[] content, String encryptionAlg, SecretKey encryptionKey) 
        throws JWEException;
    
    /**
     * Decrypt JWE token using direct decryption with shared key
     * @param jweString JWE token string
     * @param encryptionKey Symmetric encryption key
     * @return Decrypted content bytes
     * @throws JWEException if decryption fails
     */
    public static byte[] decryptDirect(String jweString, SecretKey encryptionKey) 
        throws JWEException;
    
    /**
     * Encrypt content using RSA key encryption
     * @param content Content to encrypt
     * @param keyAlg Key management algorithm
     * @param encryptionAlg Content encryption algorithm
     * @param publicKey RSA public key for key encryption
     * @return JWE token string
     * @throws JWEException if encryption fails
     */
    public static String encryptRSA(byte[] content, String keyAlg, String encryptionAlg, PublicKey publicKey) 
        throws JWEException;
    
    /**
     * Decrypt JWE token using RSA key decryption
     * @param jweString JWE token string
     * @param privateKey RSA private key for key decryption
     * @return Decrypted content bytes
     * @throws JWEException if decryption fails
     */
    public static byte[] decryptRSA(String jweString, PrivateKey privateKey) 
        throws JWEException;
}

/**
 * JSON Web Key representation
 */
public class JWK {
    /**
     * Get the key type
     * @return Key type (e.g., "RSA", "EC", "oct")
     */
    public String getKeyType();
    
    /**
     * Get the key ID
     * @return Key identifier
     */
    public String getKeyId();
    
    /**
     * Get the algorithm
     * @return Algorithm identifier
     */
    public String getAlgorithm();
    
    /**
     * Get the key usage
     * @return Key use (e.g., "sig", "enc")
     */
    public String getKeyUse();
    
    /**
     * Get key operations
     * @return List of key operations
     */
    public List<String> getKeyOps();
    
    /**
     * Convert to PublicKey instance
     * @return PublicKey object
     */
    public PublicKey toPublicKey();
    
    /**
     * Check if key ID is present
     * @return true if key has an ID
     */
    public boolean hasKeyId();
    
    /**
     * Get custom JWK parameter
     * @param name Parameter name
     * @return Parameter value
     */
    public Object getOtherKeyParameter(String name);
}

/**
 * JSON Web Key Set representation
 */
public class JSONWebKeySet {
    /**
     * Get all keys in the set
     * @return List of JWK objects
     */
    public List<JWK> getKeys();
    
    /**
     * Get a key by its key ID
     * @param kid Key identifier
     * @return JWK object or null if not found
     */
    public JWK getKeyByKid(String kid);
    
    /**
     * Get keys by algorithm
     * @param algorithm Algorithm identifier
     * @return List of matching JWK objects
     */
    public List<JWK> getKeysByAlg(String algorithm);
    
    /**
     * Get keys by key use
     * @param use Key use identifier
     * @return List of matching JWK objects
     */
    public List<JWK> getKeysByUse(String use);
}

/**
 * RSA public key JWK representation
 */
public class RSAPublicJWK extends JWK {
    /**
     * Get the RSA modulus (n parameter)
     * @return Base64URL encoded modulus
     */
    public String getModulus();
    
    /**
     * Get the RSA public exponent (e parameter)
     * @return Base64URL encoded exponent
     */
    public String getPublicExponent();
    
    /**
     * Convert to RSA PublicKey
     * @return RSAPublicKey instance
     */
    public RSAPublicKey toRSAPublicKey();
}

/**
 * Elliptic Curve public key JWK representation
 */
public class ECPublicJWK extends JWK {
    /**
     * Get the curve name (crv parameter)
     * @return Curve identifier (e.g., "P-256", "P-384", "P-521")
     */
    public String getCrv();
    
    /**
     * Get the x coordinate (x parameter)
     * @return Base64URL encoded x coordinate
     */
    public String getX();
    
    /**
     * Get the y coordinate (y parameter)
     * @return Base64URL encoded y coordinate
     */
    public String getY();
    
    /**
     * Convert to EC PublicKey
     * @return ECPublicKey instance
     */
    public ECPublicKey toECPublicKey();
}

/**
 * Octet Key Pair (EdDSA) JWK representation
 */
public class OKPPublicJWK extends JWK {
    /**
     * Get the curve name (crv parameter)
     * @return Curve identifier (e.g., "Ed25519", "Ed448")
     */
    public String getCrv();
    
    /**
     * Get the public key value (x parameter)
     * @return Base64URL encoded public key
     */
    public String getX();
}

/**
 * JWK builder for creating JWK objects from keys
 */
public class JWKBuilder {
    /**
     * Create JWK from RSA public key
     * @param publicKey RSA public key
     * @return RSAPublicJWK instance
     */
    public static RSAPublicJWK createRSAJWK(RSAPublicKey publicKey);
    
    /**
     * Create JWK from EC public key
     * @param publicKey EC public key
     * @return ECPublicJWK instance
     */
    public static ECPublicJWK createECJWK(ECPublicKey publicKey);
    
    /**
     * Create JWK from secret key
     * @param secretKey Symmetric secret key
     * @return JWK instance
     */
    public static JWK createSecretJWK(SecretKey secretKey);
}

/**
 * JWK parsing utilities
 */
public class JWKParser {
    /**
     * Parse JWK from JSON string
     * @param json JWK JSON representation
     * @return JWK instance
     * @throws IOException if parsing fails
     */
    public static JWK parseJWK(String json) throws IOException;
    
    /**
     * Parse JWK Set from JSON string
     * @param json JWK Set JSON representation
     * @return JSONWebKeySet instance
     * @throws IOException if parsing fails
     */
    public static JSONWebKeySet parseJWKSet(String json) throws IOException;
}

/**
 * JWK utilities for key operations
 */
public class JWKUtil {
    /**
     * Convert JWK to KeyWrapper
     * @param jwk JWK instance
     * @return KeyWrapper instance
     */
    public static KeyWrapper toKeyWrapper(JWK jwk);
    
    /**
     * Convert KeyWrapper to JWK
     * @param keyWrapper KeyWrapper instance
     * @return JWK instance
     */
    public static JWK fromKeyWrapper(KeyWrapper keyWrapper);
    
    /**
     * Validate JWK structure and parameters
     * @param jwk JWK to validate
     * @return true if valid
     */
    public static boolean isValid(JWK jwk);
}

/**
 * Generic JOSE parser for JWS and JWE tokens
 */
public class JOSEParser {
    /**
     * Parse JOSE token (JWS or JWE)
     * @param token JOSE token string
     * @return JOSE object
     * @throws JOSEException if parsing fails
     */
    public static JOSE parse(String token) throws JOSEException;
    
    /**
     * Parse JOSE header only
     * @param token JOSE token string
     * @return JOSEHeader object
     * @throws JOSEException if parsing fails
     */
    public static JOSEHeader parseHeader(String token) throws JOSEException;
    
    /**
     * Check if token is JWS format
     * @param token Token string
     * @return true if JWS format
     */
    public static boolean isJWS(String token);
    
    /**
     * Check if token is JWE format
     * @param token Token string
     * @return true if JWE format
     */
    public static boolean isJWE(String token);
}

/**
 * Base JOSE header representation
 */
public class JOSEHeader {
    /**
     * Get the algorithm header parameter
     * @return Algorithm identifier
     */
    public String getAlgorithm();
    
    /**
     * Get the type header parameter
     * @return Type value
     */
    public String getType();
    
    /**
     * Get the key ID header parameter
     * @return Key identifier
     */
    public String getKeyId();
    
    /**
     * Get the content type header parameter
     * @return Content type value
     */
    public String getContentType();
    
    /**
     * Get custom header parameter
     * @param name Parameter name
     * @return Parameter value
     */
    public Object getHeaderParameter(String name);
}

/**
 * Base JOSE token representation
 */
public class JOSE {
    /**
     * Get the JOSE header
     * @return JOSEHeader object
     */
    public JOSEHeader getHeader();
    
    /**
     * Get the raw token string
     * @return Original token string
     */
    public String serialize();
}

/**
 * Exception thrown during JWS input parsing
 */
public class JWSInputException extends Exception {
    public JWSInputException(String message);
    public JWSInputException(String message, Throwable cause);
}

/**
 * Exception thrown during JWE operations
 */
public class JWEException extends Exception {
    public JWEException(String message);
    public JWEException(String message, Throwable cause);
}

/**
 * General JOSE exception
 */
public class JOSEException extends Exception {
    public JOSEException(String message);
    public JOSEException(String message, Throwable cause);
}

import org.keycloak.jose.jws.*;
import org.keycloak.jose.jwk.*;
import org.keycloak.jose.jwe.*;
import org.keycloak.crypto.*;

// Create and sign a JWS token
JWSBuilder builder = new JWSBuilder();
String jws = builder
    .jsonContent(Map.of("sub", "user123", "name", "John Doe"))
    .type("JWT")
    .kid("key-1")
    .sign(signerContext);

// Parse and verify JWS token
JWSInput jwsInput = new JWSInput(jws);
JWSHeader header = jwsInput.getHeader();
Map<String, Object> payload = jwsInput.readJsonContent(Map.class);

// Work with JWK Set
String jwksJson = "{ \"keys\": [...] }";
JSONWebKeySet jwks = JWKParser.parseJWKSet(jwksJson);
JWK signingKey = jwks.getKeyByKid("key-1");
PublicKey publicKey = signingKey.toPublicKey();

// JWE encryption/decryption
byte[] content = "sensitive data".getBytes();
String jweToken = JWEUtils.encryptDirect(content, JWEConstants.A256GCM, secretKey);
byte[] decrypted = JWEUtils.decryptDirect(jweToken, secretKey);