Common encryption and decryption errors encountered in PHP language development and their solutions

PHP language is often used for web development. During data transmission and storage, encryption and decryption algorithms are often needed to ensure data security. However, some common encryption and decryption errors will be encountered during development. This article will introduce the causes of these errors and provide solutions.

1. Error: The encrypted string is garbled

Cause: When using the encryption algorithm, PHP uses the ASCII character set for conversion by default. However, if the plain text contains characters from other languages, such as Chinese, Japanese, etc., garbled characters will appear.

Solution: You can use the mb_convert_encoding() function to perform encoding conversion, for example:

$encrypted_str = base64_encode(openssl_encrypt(mb_convert_encoding($str, 'UTF-8', 'auto'), $method, $key, $options, $iv));

2. Error: The decrypted string does not match the original string

Cause: The encrypted string may be URL-encoded during encryption, but forgotten to be decoded during decryption.

Solution: Use the urlencode() function to decode the encrypted string before decryption, for example:

$decrypted_str = openssl_decrypt(base64_decode(urldecode($encrypted_str)), $method, $key, $options, $iv);

3. Error: After using MD5() to encrypt, the encrypted string returned Inconsistent string length

Cause: The MD5() function always returns the 32-bit string length after encryption, so if the plaintext length is different, the encrypted length will also be different.

Solution: You can use other encryption methods in the hash() function, such as sha1(), sha256(), sha512(), etc., which are all fixed length. For example:

$encrypted_str = hash('sha256', $str);

4. Error: "data too large for key size" appears during decryption

Cause: When using the RSA encryption algorithm, if the key length is not enough, then Plain text cannot be encrypted.

Solution: When generating a key pair, you need to specify the key length. For example:

$config = array(
    "digest_alg" => "sha512",
    "private_key_bits" => 2048,
    "private_key_type" => OPENSSL_KEYTYPE_RSA,
);

$resource = openssl_pkey_new($config);

The above is an introduction to common encryption and decryption errors and solutions in PHP development. When using encryption algorithms, you need to pay attention to factors such as encoding issues, URL encoding, encryption methods, and key lengths to ensure data security and the normal operation of the program.

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