package com.nimbusds.jose.crypto;
import java.security.SecureRandom;
import java.security.interfaces.RSAPublicKey;
import javax.crypto.SecretKey;
import com.nimbusds.jose.EncryptionMethod;
import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.JWEAlgorithm;
import com.nimbusds.jose.JWECryptoParts;
import com.nimbusds.jose.JWEEncrypter;
import com.nimbusds.jose.ReadOnlyJWEHeader;
import com.nimbusds.jose.util.Base64URL;
import com.nimbusds.jose.util.StringUtils;
/**
* RSA encrypter of {@link com.nimbusds.jose.JWEObject JWE objects}. This class
* is thread-safe.
*
* <p>Supports the following JWE algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA1_5}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA_OAEP}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#RSA_OAEP_256}
* </ul>
*
* <p>Supports the following encryption methods:
*
* <ul>
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192CBC_HS384}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256_DEPRECATED}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512_DEPRECATED}
* </ul>
*
* @author David Ortiz
* @author Vladimir Dzhuvinov
* @version $version$ (2014-05-23)
*/
public class RSAEncrypter extends RSACryptoProvider implements JWEEncrypter {
/**
* The public RSA key.
*/
private final RSAPublicKey publicKey;
/**
* Creates a new RSA encrypter.
*
* @param publicKey The public RSA key. Must not be {@code null}.
*
* @throws JOSEException If the underlying secure random generator
* couldn't be instantiated.
*/
public RSAEncrypter(final RSAPublicKey publicKey)
throws JOSEException {
if (publicKey == null) {
throw new IllegalArgumentException("The public RSA key must not be null");
}
this.publicKey = publicKey;
}
/**
* Gets the public RSA key.
*
* @return The public RSA key.
*/
public RSAPublicKey getPublicKey() {
return publicKey;
}
@Override
public JWECryptoParts encrypt(final ReadOnlyJWEHeader header, final byte[] bytes)
throws JOSEException {
final JWEAlgorithm alg = header.getAlgorithm();
final EncryptionMethod enc = header.getEncryptionMethod();
// Generate and encrypt the CEK according to the enc method
final SecureRandom randomGen = getSecureRandom();
final SecretKey cek = AES.generateKey(enc.cekBitLength(), randomGen);
Base64URL encryptedKey; // The second JWE part
if (alg.equals(JWEAlgorithm.RSA1_5)) {
encryptedKey = Base64URL.encode(RSA1_5.encryptCEK(publicKey, cek, keyEncryptionProvider));
} else if (alg.equals(JWEAlgorithm.RSA_OAEP)) {
encryptedKey = Base64URL.encode(RSA_OAEP.encryptCEK(publicKey, cek, keyEncryptionProvider));
} else if (alg.equals(JWEAlgorithm.RSA_OAEP_256)) {
encryptedKey = Base64URL.encode(RSA_OAEP_256.encryptCEK(publicKey, cek, keyEncryptionProvider));
} else {
throw new JOSEException("Unsupported JWE algorithm, must be RSA1_5, RSA-OAEP, or RSA-OAEP-256");
}
// Apply compression if instructed
byte[] plainText = DeflateHelper.applyCompression(header, bytes);
// Compose the AAD
byte[] aad = StringUtils.toByteArray(header.toBase64URL().toString());
// Encrypt the plain text according to the JWE enc
byte[] iv;
AuthenticatedCipherText authCipherText;
if (enc.equals(EncryptionMethod.A128CBC_HS256) ||
enc.equals(EncryptionMethod.A192CBC_HS384) ||
enc.equals(EncryptionMethod.A256CBC_HS512) ) {
iv = AESCBC.generateIV(randomGen);
authCipherText = AESCBC.encryptAuthenticated(
cek, iv, plainText, aad,
contentEncryptionProvider, macProvider);
} else if (enc.equals(EncryptionMethod.A128GCM) ||
enc.equals(EncryptionMethod.A192GCM) ||
enc.equals(EncryptionMethod.A256GCM) ) {
iv = AESGCM.generateIV(randomGen);
authCipherText = AESGCM.encrypt(
cek, iv, plainText, aad,
contentEncryptionProvider);
} else if (enc.equals(EncryptionMethod.A128CBC_HS256_DEPRECATED) ||
enc.equals(EncryptionMethod.A256CBC_HS512_DEPRECATED) ) {
iv = AESCBC.generateIV(randomGen);
authCipherText = AESCBC.encryptWithConcatKDF(
header, cek, encryptedKey, iv, plainText,
contentEncryptionProvider, macProvider);
} else {
throw new JOSEException("Unsupported encryption method, must be A128CBC_HS256, A192CBC_HS384, A256CBC_HS512, A128GCM, A192GCM or A256GCM");
}
return new JWECryptoParts(encryptedKey,
Base64URL.encode(iv),
Base64URL.encode(authCipherText.getCipherText()),
Base64URL.encode(authCipherText.getAuthenticationTag()));
}
}