3des-encryption-decryption-in-java のようなコードを使用していますが、復号化を使用すると、このようなエラーが発生しました
javax.crypto.IllegalBlockSizeException: last block incomplete in decryption
07-17 11:27:27.580: WARN/System.err(22432): at com.android.org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(BaseBlockCipher.java:705)
07-17 11:27:27.580: WARN/System.err(22432): at javax.crypto.Cipher.doFinal(Cipher.java:1111)
しかし、に変更final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");するfinal Cipher decipher = Cipher.getInstance("DESede/CFB/NoPadding");と、メソッドは実行できますが、間違った結果が得られます (モードはサーバーとは異なります)。なので、その理由が知りたいです。
復号化方法:
public static String decrypt(byte[] message) throws Exception {
final MessageDigest md = MessageDigest.getInstance("SHA-1");
final byte[] digestOfPassword = md.digest(token.getBytes("utf-8"));
final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
for (int j = 0, k = 16; j < 8;) {
keyBytes[k++] = keyBytes[j++];
}
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
// final Cipher decipher = Cipher.getInstance("DESede/CFB/NoPadding");
decipher.init(Cipher.DECRYPT_MODE, key, iv);
final byte[] plainText = decipher.doFinal(message);
return new String(plainText, "UTF-8");
}
暗号化方法:
public static byte[] encrypt(String message) throws Exception {
final MessageDigest md = MessageDigest.getInstance("SHA-1");
final byte[] digestOfPassword = md.digest(token
.getBytes("utf-8"));
final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
for (int j = 0, k = 16; j < 8; ) {
keyBytes[k++] = keyBytes[j++];
}
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, iv, new SecureRandom(new byte[5]));
cipher.init(Cipher.ENCRYPT_MODE, key, iv);
final byte[] plainTextBytes = message.getBytes("utf-8");
final byte[] cipherText = cipher.doFinal(plainTextBytes);
return cipherText;
}