快速，简单易用的对称密码，用于Java中的整数加密 [英] Fast, simple to use symmetric cipher for integer encryption in Java

问题描述

Java中有什么用于具有这些属性的整数加密的密码函数？：

What is in Java a cipher function for integer encryption having these properties?:

• 快速


• 对称密钥算法


• 使用简单（即使用几行代码而不包括外部库）


• < s>可以指定输出长度（例如20个字符）

• Fast
• Symmetric-key algorithm
• Simple to use (i.e. a couple of lines of code to use it and no external library to include)
• It is possible to specify the output length (e.g. 20 characters)

我只需要使用它来加密/ decrypt integers。

I need to use it only to encrypt/decrypt integers.

推荐答案

没有外部库的要求会将列表减少为DES，3DES和AES。 DES和3DES的块大小为64位，而AES的块大小为128位。有不同的方面，可以检查这个。

The requirement for no external library reduces the list to DES, 3DES and AES. DES and 3DES have a block size of 64 bits whereas AES has a block size of 128 bits. There are different aspects, one can examine this for.

DES和3DES最适合用于最多为56位宽（非全长）的整数，因为填充的结果将是8字节的单个块。如果加密一个完整的long值，那么将添加一个额外的填充块。

DES and 3DES are best used for integers that are at most 56-bit wide (non-full long), because the result will be a single block of 8 byte, because of padding. If you encrypt a full long value, then an additional padding block will be added.

AES将始终为任何长值的int生成一个16字节的密文。

AES will always produce a 16 byte ciphertext for any int of long value.

根据此分析 AES（Rijndael-128）的速度是DES / 3DES的两倍多，密钥大小更大（更安全）。当CPU支持AES-NI时，AES甚至可以比DES或3DES快得多。所有当前的CPU都支持这一点。这是我从 openssl speed 命令获取的当前结果。

According to this analysis AES (Rijndael-128) is more than twice as fast as DES/3DES with a bigger key size (more secure). AES can be even much faster than DES or 3DES when the CPU supports AES-NI. All current CPUs support this. This is my current result for taken from the openssl speed command.

AES为16字节有效负载达到127MB / s而3DES只能达到27MB / s。 这里是要搜索的数据。

AES achieves 127MB/s for 16 byte payloads whereas 3DES only achieves 27MB/s. Here's the data to poke around.

不要将DES用于任何严重的事情，因为它只有56位密钥（带有奇偶校验的64位密钥）。暴力迫使成本为2 ⁵⁶ 。 3DES也不是那么好，因为Brute强制成本是 2 ¹¹² 。 AES的强制成本是2 ¹²⁸ ，2 ¹⁹² ，2 ²⁵⁶ ，具体取决于使用的密钥大小。

Don't use DES for anything serious, because it only has a 56-bit key (64-bit with parity). Brute forcing cost is 2⁵⁶. 3DES is also not that good, because Brute forcing cost is 2¹¹². Brute forcing cost for AES is 2¹²⁸, 2¹⁹², 2²⁵⁶ depending on the used key size.

可能使用AES：

private final String CIPHER_NAME = "AES/ECB/PKCS5Padding";
private final String ALGORITHM_NAME = "AES"; // keySizes 128, 192, 256
// private final String CIPHER_NAME = "DES/ECB/PKCS5Padding";
// private final String ALGORITHM_NAME = "DES"; // keySize 56
// private final String CIPHER_NAME = "DESede/ECB/PKCS5Padding";
// private final String ALGORITHM_NAME = "DESede"; // keySize 168

byte[] encrypt(SecretKey key, long num) {
    BigInteger bignum = BigInteger.valueOf(num);
    Cipher cipher = Cipher.getInstance(CIPHER_NAME);
    cipher.init(Cipher.ENCRYPT_MODE, key);
    return cipher.doFinal(bignum.toByteArray());
}

long decrypt(SecretKey key, byte[] ct) {
    Cipher cipher = Cipher.getInstance(CIPHER_NAME);
    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] pt = cipher.doFinal(ct);
    BigInteger bignum = new BigInteger(pt);
    return bignum.longValue();
}

SecretKey keyGen(String algorithm, int keySize) {
    KeyGenerator keygen = KeyGenerator.getInstance(algorithm);
    keygen.init(keySize);
    return keygen.generateKey();
}

运作模式

这里我使用ECB模式。使用它通常不是一个好主意。它存在一个问题，即使用相同的密钥加密相同的明文会产生相同的密文。这可能不是可接受的财产。如果不可接受，那么您需要使用例如带有新随机IV的CBC模式。随着将通过一个额外的块炸掉密文。

Mode of operation

Here I use ECB mode. It is generally not a good idea to use it. It has a problem that encrypting the same plaintext with the same key results in the same ciphertext. This may not be a property that is acceptable. If it is not acceptable, then you need to use for example CBC mode with a new random IV. With will blow up the ciphertext by an additional block.

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