如何使openssl_encrypt将输入填充到所需的块大小? [英] How do I make openssl_encrypt pad the input to the required block size?

问题描述

如果我手动将字符串填充到32的长度，我的代码将起作用.
我的问题是:有没有办法使openSSL填充数据，还是我总是必须为此做?

My code works if I manually pad my string to the length of 32.
My question is: Is there a way to make the openSSL pad the data, or do I always have to do it for it?

工作:

 openssl_encrypt ("my baba is over the ocean1111111", 'AES-256-CBC', $MY_SECRET_KEY,OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING,$MY_IV);

不起作用:

openssl_encrypt ("my baba is over the ocean", 'AES-256-CBC', $MY_SECRET_KEY,OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING,$MY_IV);

我目前通过自我填充解决了这个问题:

I solve this currently by self padding:

$pad = 32 - (strlen("my baba is over the ocean") % 32);
$clear = "my baba is over the ocean" . str_repeat(chr($pad), $pad); //encrypt this string

推荐答案

正如卢克·帕克(Luke Park)所说，与其明确告诉openssl_encrypt使用OPENSSL_ZERO_PADDING，不如从参数中删除该选项，它将默认为 PKCS#7填充方案(用0x0n填充块的其余部分，其中 n 是必需的字节数；如果该块已经完成，则为+ 16 0x00. 注意:在这种情况下，Luke和PKCS#7引用的PKCS#5实际上是相同的.

As Luke Park said, instead of explicitly telling openssl_encrypt to use OPENSSL_ZERO_PADDING, simply remove that option from the parameter and it will default to the PKCS #7 padding scheme (fills the rest of the block with 0x0n where n is the number of bytes necessary; + 16 0x00 if the block is already complete). Note: PKCS #5 as referenced by Luke and PKCS #7 are effectively identical in this scenario.

来自 PHP文档:

不使用OPENSSL_ZERO_PADDING，您将自动获得PKCS#7填充.

Without using OPENSSL_ZERO_PADDING, you will automatically get PKCS#7 padding.

所以您应该打电话给

openssl_encrypt("my baba is over the ocean", 'AES-256-CBC', $MY_SECRET_KEY, OPENSSL_RAW_DATA, $MY_IV);

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