MbedTLS AES 128在Java中加密和解密

我试图在运行FreeRTOS和mbedTLS的微处理器上加密一些文本。我正在使用AES 128 CBC和PKCS7填充。如果我尝试在文本长度小于16个字符时用mbedTLS加密并用Java解密，它就可以工作。我可以用Java解密它，文本匹配。如果它更长，那么它就不再工作。我做错了什么

mbedTLS代码：

unsigned char key[17] = "asdfghjklqwertzu";
unsigned char iv[17] = "qwertzuiopasdfgh";
unsigned char output[1024];
size_t olen;
size_t total_len = 0;

mbedtls_cipher_context_t ctx;
mbedtls_cipher_init(&ctx);
mbedtls_cipher_set_padding_mode(&ctx, MBEDTLS_PADDING_PKCS7);
mbedtls_cipher_setup(&ctx,
        mbedtls_cipher_info_from_values(MBEDTLS_CIPHER_ID_AES, 128,
                MBEDTLS_MODE_CBC));
mbedtls_cipher_setkey(&ctx, key, 128, MBEDTLS_ENCRYPT);
mbedtls_cipher_set_iv(&ctx, iv, 16);
mbedtls_cipher_reset(&ctx);

char aa[] = "hello world! test long padd";
for( int offset = 0; offset < strlen(aa); offset += mbedtls_cipher_get_block_size( &ctx ) ) {
    int ilen = ( (unsigned int) strlen(aa) - offset > mbedtls_cipher_get_block_size( &ctx ) ) ?
            mbedtls_cipher_get_block_size( &ctx ) : (unsigned int) ( strlen(aa) - offset );

      char sub[100];

      strncpy ( sub, aa+offset, ilen );
      unsigned char* sub2 = reinterpret_cast<unsigned char *>(sub);
      mbedtls_cipher_update(&ctx, sub2, ilen, output, &olen);
      total_len += olen;
}
// After the loop
mbedtls_cipher_finish(&ctx, output, &olen);
total_len += olen;
mbedtls_cipher_free(&ctx);

Java抛出javax.crypto.BadPaddingException:填充块已损坏

谢谢

//编辑：

尝试了一种更新方法，但仍然没有成功，相同的例外：

unsigned char key[17] = "asdfghjklqwertzu";
unsigned char iv[17] = "qwertzuiopasdfgh";
//unsigned char buffer[1024];
unsigned char output[1024];
size_t olen;

unsigned char text[] = "abc abc abc abc abc abc abc abc abc abc abc abc abc abc abc";

mbedtls_cipher_context_t ctx;
mbedtls_cipher_init(&ctx);
mbedtls_cipher_set_padding_mode(&ctx, MBEDTLS_PADDING_PKCS7);
mbedtls_cipher_setup(&ctx,
        mbedtls_cipher_info_from_values(MBEDTLS_CIPHER_ID_AES, 128,
                MBEDTLS_MODE_CBC));
mbedtls_cipher_setkey(&ctx, key, 128, MBEDTLS_ENCRYPT);
mbedtls_cipher_set_iv(&ctx, iv, 16);
mbedtls_cipher_reset(&ctx);
mbedtls_cipher_update(&ctx, text, strlen((char*) text), output, &olen); // Olen is 48
mbedtls_cipher_finish(&ctx, output, &olen); // Olen is 16
mbedtls_cipher_free(&ctx);

// 48 + 16 = 64 which is according to https://www.devglan.com/online-tools/aes-encryption-decryption correct

Java获得64字节的数据，但仍然抛出相同的异常

---

Topaco能否提供更新和完成功能使用的简短示例？谢谢

，因为它是在评论中写的，现在仍然不起作用。下面是您的代码以及@Topaco在注释中建议的更改：

#include <stdio.h>
#include <string.h>
#include <mbedtls/cipher.h>

int main() {
    unsigned char key[17] = "asdfghjklqwertzu";
    unsigned char iv[17] = "qwertzuiopasdfgh";
    unsigned char output[1024];
    size_t olen;
    size_t total_len = 0;

    mbedtls_cipher_context_t ctx;
    mbedtls_cipher_init(&ctx);
    mbedtls_cipher_set_padding_mode(&ctx, MBEDTLS_PADDING_PKCS7);
    mbedtls_cipher_setup(&ctx,
                         mbedtls_cipher_info_from_values(MBEDTLS_CIPHER_ID_AES, 128,
                                                         MBEDTLS_MODE_CBC));
    mbedtls_cipher_setkey(&ctx, key, 128, MBEDTLS_ENCRYPT);
    mbedtls_cipher_set_iv(&ctx, iv, 16);
    mbedtls_cipher_reset(&ctx);

    char aa[] = "hello world! test long padd";
    for (int offset = 0; offset < strlen(aa); offset += mbedtls_cipher_get_block_size(&ctx)) {
        int ilen = ((unsigned int) strlen(aa) - offset > mbedtls_cipher_get_block_size(&ctx)) ?
                   mbedtls_cipher_get_block_size(&ctx) : (unsigned int) (strlen(aa) - offset);

        char sub[100];

        strncpy (sub, aa + offset, ilen);
        unsigned char *sub2 = (unsigned char *) (sub);
        mbedtls_cipher_update(&ctx, sub2, ilen, output + total_len, &olen);
        total_len += olen;
    }
    mbedtls_cipher_finish(&ctx, output + total_len, &olen);
    total_len += olen;
    for (int i = 0; i < total_len; i++)
        printf("%02X", output[i]);
    mbedtls_cipher_free(&ctx);
    return 0;
}

如果我稍微修改Java端并使用以下命令传输消息：

byte[] message = hexStringToByteArray("2FE64A72125E30B15C376FD2142D36FA778142DC4FD4A1F36EECDBCDA19BFAA0");

其中hexStringToByteArray取自此答案：

我在Java端得到以下代码：

public Optional<ByteString> test() {
    String encryptionKey = "asdfghjklqwertzu";
    String iv = "qwertzuiopasdfgh";
    byte[] message = hexStringToByteArray("2FE64A72125E30B15C376FD2142D36FA778142DC4FD4A1F36EECDBCDA19BFAA0");
    Security.addProvider(new BouncyCastleProvider());

    try {
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv.getBytes());
        SecretKeySpec skey = new SecretKeySpec(encryptionKey.getBytes(), "AES");
        Cipher cipherDecrypt = Cipher.getInstance("AES/CBC/PKCS7Padding");
        cipherDecrypt.init(Cipher.DECRYPT_MODE, skey, ivParameterSpec);
        return Optional.ofNullable(ByteString.copyFrom(cipherDecrypt.doFinal(message)));
    } catch (BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException | InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException e) {
        System.out.println("Error during message decryption: " + e);
    }
    return null;
}

公共可选测试（）{
字符串encryptionKey=“asdfghjklqwerzi”；
字符串iv=“qwertzuiopasdfgh”；
字节[]消息=hexStringToByteArray（“2FE64A72125E30B15C376FD2142D36FA778142DC4FD4A1F36EECDBCDA19BFAA0”）；
addProvider（新的BouncyCastleProvider（））；
试一试{
IvParameterSpec IvParameterSpec=新的IvParameterSpec（iv.getBytes（））；
SecretKeySpec skey=新的SecretKeySpec（encryptionKey.getBytes（），“AES”）；
Cipher cipherDecrypt=Cipher.getInstance（“AES/CBC/PKCS7Padding”）；
cipherDecrypt.init（Cipher.DECRYPT_模式，skey，ivParameterSpec）；
返回可选的.ofNullable（ByteString.copyFrom（cipherDecrypt.doFinal（message））；
}捕获（BadPaddingException | IllegalBlockSizeException | InvalidGorithmParameterException | InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException e）{
System.out.println（“消息解密期间出错：+e”）；
}
返回null；
}

它最终在调试控制台上提供以下输出：

Optional[<ByteString@1e127982 size=27 contents="hello world! test long padd">]

可选[]

---

这是原始消息-因此它是这样工作的。

代码中仍然存在一个问题。 在设置填充模式之前，您需要设置密码信息。否则功能

---

mbedtls_cipher_set_padding_mode将返回错误

total_len+=olen

是错误的，尽管您没有在代码中使用它。如果我正确阅读了文档，则总长度为

olen

。我怀疑在代码的另一部分中，您正在编写或发送

总长度

字节以供java解密。由于未设置当前位置，因此

输出

中的内容会被每次

mbedtls\u密码更新

或

mbedtls\u密码完成

覆盖。在这两种情况下，

mbedtls\u cipher\u update

和

mbedtls\u cipher\u finish

，

输出必须替换为
output+total\u len
。顺便说一句，一个
mbedtls\u cipher\u update
和
mbedtls\u cipher\u finish
调用就足够了（但这个实现可能更适合探索）。我尝试了你们两位写的东西，但仍然不起作用。你能检查一下代码编辑吗？谢谢。
\u update
从
输出开始，给出一个长度，称为len1<代码>\u final
应该从
output+len1
开始，然后给你另一个长度，比如len2；总密文为
len1+len2
。注意@Topaco说“更新和完成都必须是…”
output+total\u len
“谢谢@Topaco和dave\u thompson\u 085的帮助。
byte[] message = hexStringToByteArray("2FE64A72125E30B15C376FD2142D36FA778142DC4FD4A1F36EECDBCDA19BFAA0");

public Optional<ByteString> test() {
    String encryptionKey = "asdfghjklqwertzu";
    String iv = "qwertzuiopasdfgh";
    byte[] message = hexStringToByteArray("2FE64A72125E30B15C376FD2142D36FA778142DC4FD4A1F36EECDBCDA19BFAA0");
    Security.addProvider(new BouncyCastleProvider());

    try {
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv.getBytes());
        SecretKeySpec skey = new SecretKeySpec(encryptionKey.getBytes(), "AES");
        Cipher cipherDecrypt = Cipher.getInstance("AES/CBC/PKCS7Padding");
        cipherDecrypt.init(Cipher.DECRYPT_MODE, skey, ivParameterSpec);
        return Optional.ofNullable(ByteString.copyFrom(cipherDecrypt.doFinal(message)));
    } catch (BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException | InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException e) {
        System.out.println("Error during message decryption: " + e);
    }
    return null;
}

Optional[<ByteString@1e127982 size=27 contents="hello world! test long padd">]