PHP openssl_encrypt的错误原因是什么？

Question

PHP Warning: openssl_encrypt(): IV passed is 16 bytes long which is longer than the 0 expected by selected cipher

Answer 1

不同的加密算法需要不同的初始化向量（IV），也就是 openssl_encrypt 的第 5 个参数 $iv:

openssl_encrypt ( string $data , string $method , string $key , int $options = 0 , string $iv = "" , string &$tag = NULL , string $aad = "" , int $tag_length = 16 ) : string

看错误信息，你用的加密算法是不需要初始化向量的（多半是不安全的 ECB 模式），不传 $iv 就可以了。

不同算法需要的IV长度可以通过 openssl_cipher_iv_length 获取：

foreach (openssl_get_cipher_methods(true) as $m) {
    echo $m . ' => ' . openssl_cipher_iv_length($m) . PHP_EOL;
}

结果：

aes-128-cbc => 16
aes-128-cbc-hmac-sha1 => 16
aes-128-cbc-hmac-sha256 => 16
aes-128-ccm => 12
aes-128-cfb => 16
aes-128-cfb1 => 16
aes-128-cfb8 => 16
aes-128-ctr => 16
aes-128-ecb => 0
aes-128-gcm => 12
aes-128-ocb => 12
aes-128-ofb => 16
aes-128-xts => 16
aes-192-cbc => 16
aes-192-ccm => 12
aes-192-cfb => 16
aes-192-cfb1 => 16
aes-192-cfb8 => 16
aes-192-ctr => 16
aes-192-ecb => 0
aes-192-gcm => 12
aes-192-ocb => 12
aes-192-ofb => 16
aes-256-cbc => 16
aes-256-cbc-hmac-sha1 => 16
aes-256-cbc-hmac-sha256 => 16
aes-256-ccm => 12
aes-256-cfb => 16
aes-256-cfb1 => 16
aes-256-cfb8 => 16
aes-256-ctr => 16
aes-256-ecb => 0
aes-256-gcm => 12
aes-256-ocb => 12
aes-256-ofb => 16
aes-256-xts => 16
aes128 => 16
aes128-wrap => 8
aes192 => 16
aes192-wrap => 8
aes256 => 16
aes256-wrap => 8
aria-128-cbc => 16
aria-128-ccm => 12
aria-128-cfb => 16
aria-128-cfb1 => 16
aria-128-cfb8 => 16
aria-128-ctr => 16
aria-128-ecb => 0
aria-128-gcm => 12
aria-128-ofb => 16
aria-192-cbc => 16
aria-192-ccm => 12
aria-192-cfb => 16
aria-192-cfb1 => 16
aria-192-cfb8 => 16
aria-192-ctr => 16
aria-192-ecb => 0
aria-192-gcm => 12
aria-192-ofb => 16
aria-256-cbc => 16
aria-256-ccm => 12
aria-256-cfb => 16
aria-256-cfb1 => 16
aria-256-cfb8 => 16
aria-256-ctr => 16
aria-256-ecb => 0
aria-256-gcm => 12
aria-256-ofb => 16
aria128 => 16
aria192 => 16
aria256 => 16
bf => 8
bf-cbc => 8
bf-cfb => 8
bf-ecb => 0
bf-ofb => 8
blowfish => 8
camellia-128-cbc => 16
camellia-128-cfb => 16
camellia-128-cfb1 => 16
camellia-128-cfb8 => 16
camellia-128-ctr => 16
camellia-128-ecb => 0
camellia-128-ofb => 16
camellia-192-cbc => 16
camellia-192-cfb => 16
camellia-192-cfb1 => 16
camellia-192-cfb8 => 16
camellia-192-ctr => 16
camellia-192-ecb => 0
camellia-192-ofb => 16
camellia-256-cbc => 16
camellia-256-cfb => 16
camellia-256-cfb1 => 16
camellia-256-cfb8 => 16
camellia-256-ctr => 16
camellia-256-ecb => 0
camellia-256-ofb => 16
camellia128 => 16
camellia192 => 16
camellia256 => 16
cast => 8
cast-cbc => 8
cast5-cbc => 8
cast5-cfb => 8
cast5-ecb => 0
cast5-ofb => 8
chacha20 => 16
chacha20-poly1305 => 12
des => 8
des-cbc => 8
des-cfb => 8
des-cfb1 => 8
des-cfb8 => 8
des-ecb => 0
des-ede => 0
des-ede-cbc => 8
des-ede-cfb => 8
des-ede-ecb => 0
des-ede-ofb => 8
des-ede3 => 0
des-ede3-cbc => 8
des-ede3-cfb => 8
des-ede3-cfb1 => 8
des-ede3-cfb8 => 8
des-ede3-ecb => 0
des-ede3-ofb => 8
des-ofb => 8
des3 => 8
des3-wrap => 0
desx => 8
desx-cbc => 8
id-aes128-CCM => 12
id-aes128-GCM => 12
id-aes128-wrap => 8
id-aes128-wrap-pad => 4
id-aes192-CCM => 12
id-aes192-GCM => 12
id-aes192-wrap => 8
id-aes192-wrap-pad => 4
id-aes256-CCM => 12
id-aes256-GCM => 12
id-aes256-wrap => 8
id-aes256-wrap-pad => 4
id-smime-alg-CMS3DESwrap => 0
idea => 8
idea-cbc => 8
idea-cfb => 8
idea-ecb => 0
idea-ofb => 8
rc2 => 8
rc2-128 => 8
rc2-40 => 8
rc2-40-cbc => 8
rc2-64 => 8
rc2-64-cbc => 8
rc2-cbc => 8
rc2-cfb => 8
rc2-ecb => 0
rc2-ofb => 8
rc4 => 0
rc4-40 => 0
rc4-hmac-md5 => 0
seed => 16
seed-cbc => 16
seed-cfb => 16
seed-ecb => 0
seed-ofb => 16
sm4 => 16
sm4-cbc => 16
sm4-cfb => 16
sm4-ctr => 16
sm4-ecb => 0
sm4-ofb => 16

知道长度之后用 random_bytes 对应生成长度的 iv 就可以了。（有些算法对 iv 还有特殊的要求，例如 AES-GCM 需要保证唯一，但不要求随机）

Answer 2

传的加密向量值有问题，长度是2的次方

随便打16个字符传进去