Getting an error in PHP with function mcrypt_cbc()

I am using this function I made to encrypt data:

function encryptCredentia开发者_StackOverflow社区l($data) {
$key = '9cqkTFHOfOmKn8kt&NSlIK*XMRWWx*tNY$azRdEvm2to*AQOll%8tP18g35H!zNg9l85pgnww$&q6y@1WrWZhKhx&23acq^*FWf*xdnmI%7aWwM6JQLm%tzYG^*8PIh1zD@D5QKa98Gg';
$encryptedData = mcrypt_cbc(MCRYPT_TripleDES, substr($key,0,32), pad($data), MCRYPT_ENCRYPT, substr($key,32,16));
return base64_encode($encryptedData);
}

PHP then gives me this warning:

PHP Warning:  mcrypt_cbc() [<a href='function.mcrypt-cbc'>function.mcrypt-cbc</a>]: The IV parameter must be as long as the blocksize in /home/xxxxx/public_html/libraries/global.inc.php on line xx

Is my key too long? How many characters should it be?

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You should heed deprecation warnings when you find them.

That said, the block size of TripleDES is 8 bytes, but you're supplying 16 bytes for the IV. Change your substr($key,32,16) to substr($key,32,8) and it ought to work.

But I'd still recommend moving to the new API.

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The block size, and so the IV size, is 8 bytes. The key size 24 bytes.

You can get this information with mcrypt_get_iv_size and mcrypt_get_key_size.

In CBC mode the IV must be unique and unpredictable for each encrypted message. Use mcrypt_create_iv(8) to create a suitable one. It needn't be secret, so it can be stored with the encrypted message.

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The function you are using seems to be depricated, see http://se2.php.net/manual/en/function.mcrypt-cbc.php

This function should not be used anymore, see mcrypt_generic() and mdecrypt_generic() for replacements.

Try those functions instead and see if you still get the error

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Thanks for all the help. I will fix the IV later but here are my new functions for anyone seeing this page and needing them:

`//start encryptCredential function function encryptCredential($data) { $key = '9cqkTFHOfOmKn8kt&NSlIK*XMRWWx*tNY$azRdEvm2to*AQOll%8tP18g35H!zNg9l85pgnww$&q6y@1WrWZhKhx&23acq^*FWf*xdnmI%7aWwM6JQLm%tzYG^*8PIh1zD@D5QKa98Gg'; $cipher = mcrypt_module_open(MCRYPT_blowfish, '', 'cbc', ''); mcrypt_generic_init($cipher, substr($key,8,56), substr($key,32,8)); $encrypted = mcrypt_generic($cipher, pad($data)); mcrypt_generic_deinit($cipher); return base64_encode($encrypted); } //end encryptCredential function

//start decryptCredential function function decryptCredential($data) { $encryptedData = base64_decode($data); $key = '9cqkTFHOfOmKn8kt&NSlIK*XMRWWx*tNY$azRdEvm2to*AQOll%8tP18g35H!zNg9l85pgnww$&q6y@1WrWZhKhx&23acq^*FWf*xdnmI%7aWwM6JQLm%tzYG^*8PIh1zD@D5QKa98Gg'; $cipher = mcrypt_module_open(MCRYPT_blowfish, '', 'cbc', ''); mcrypt_generic_init($cipher, substr($key,8,56), substr($key,32,8)); $decrypted = unpad(mdecrypt_generic($cipher, $encryptedData)); mcrypt_generic_deinit($cipher); return $decrypted; } //end decryptCredential function`