org.jboss.resteasy.jose.jwe.crypto.RSADecrypter Maven / Gradle / Ivy
package org.jboss.resteasy.jose.jwe.crypto;
import java.nio.charset.StandardCharsets;
import java.security.interfaces.RSAPrivateKey;
import java.util.Base64;
import javax.crypto.SecretKey;
import org.jboss.resteasy.jose.i18n.Messages;
import org.jboss.resteasy.jose.jwe.Algorithm;
import org.jboss.resteasy.jose.jwe.EncryptionMethod;
import org.jboss.resteasy.jose.jwe.JWEHeader;
/**
* RSA decrypter. This class
* is thread-safe.
*
* Supports the following JWE algorithms:
*
*
* - RSA1_5
*
- RSA_OAEP
*
*
* Supports the following encryption methods:
*
*
* - A128CBC_HS256
*
- A256CBC_HS512
*
- A128GCM
*
- A256GCM
*
*
* @author David Ortiz
* @author Vladimir Dzhuvinov
* @version $version$ (2013-05-29)
*/
public class RSADecrypter {
public static byte[] decrypt(final JWEHeader readOnlyJWEHeader,
final String encodedHeader,
final String encodedEncryptedKey,
final String encodedIv,
final String encodedCipherText,
final String encodedAuthTag,
final RSAPrivateKey privateKey) {
// Validate required JWE parts
if (encodedEncryptedKey == null) {
throw new RuntimeException(Messages.MESSAGES.encryptedKeyMustNotBeNull());
}
if (encodedIv == null) {
throw new RuntimeException(Messages.MESSAGES.initializationVectorMustNotBeNull());
}
if (encodedAuthTag == null) {
throw new RuntimeException(Messages.MESSAGES.authenticationTagMustNotBeNull());
}
// Derive the content encryption key
Algorithm alg = readOnlyJWEHeader.getAlgorithm();
SecretKey cek = null;
byte[] encryptedKey = Base64.getUrlDecoder().decode(encodedEncryptedKey);
byte[] aad = encodedHeader.getBytes(StandardCharsets.UTF_8);
byte[] iv = Base64.getUrlDecoder().decode(encodedIv);
byte[] cipherText = Base64.getUrlDecoder().decode(encodedCipherText);
byte[] authTag = Base64.getUrlDecoder().decode(encodedAuthTag);
if (alg.equals(Algorithm.RSA1_5)) {
int keyLength = readOnlyJWEHeader.getEncryptionMethod().getCekBitLength();
SecretKey randomCEK = AES.generateKey(keyLength);
try {
cek = RSA1_5.decryptCEK(privateKey, encryptedKey, keyLength);
} catch (Exception e) {
// Protect against MMA attack by generating random CEK on failure,
// see http://www.ietf.org/mail-archive/web/jose/current/msg01832.html
cek = randomCEK;
}
} else if (alg.equals(Algorithm.RSA_OAEP)) {
cek = RSA_OAEP.decryptCEK(privateKey, encryptedKey);
} else {
throw new RuntimeException(Messages.MESSAGES.unsupportedJWEalgorithm());
}
// Decrypt the cipher text according to the JWE enc
EncryptionMethod enc = readOnlyJWEHeader.getEncryptionMethod();
byte[] plainText;
if (enc.equals(EncryptionMethod.A128CBC_HS256) || enc.equals(EncryptionMethod.A256CBC_HS512)) {
plainText = AESCBC.decryptAuthenticated(cek, iv, cipherText, aad, authTag);
} else if (enc.equals(EncryptionMethod.A128GCM) || enc.equals(EncryptionMethod.A256GCM)) {
plainText = AESGCM.decrypt(cek, iv, cipherText, aad, authTag);
} else {
throw new RuntimeException(Messages.MESSAGES.unsupportedEncryptionMethod());
}
// Apply decompression if requested
return DeflateHelper.applyDecompression(readOnlyJWEHeader.getCompressionAlgorithm(), plainText);
}
}