How do I encrypt a string?

[Chris]

Has anyone got a function (or class) that will take a string and encrypt it
into printable characters, then a similar function that will decrypt it
again, without the need to call external programs (eg: pgp, etc)?

Ideally the number of characters in the encrypted strng should not be the
same as the decrypted version either.

Thanks,
Chris

[ZeldorBlat]

Re: How do I encrypt a string?

Try the mcrypt library or the rot13() function.

[BKDotCom]

Re: How do I encrypt a string?

what kind of key do you need?
a simple encrypt/decrypt key, or a public/private key?

here's blowfish encryption using the mcrypt library

// returns base64_encoded string
function encrypt_blowfis h($key,$data)
{
$mode = MCRYPT_MODE_CBC ;
$iv_size = mcrypt_get_iv_s ize(MCRYPT_BLOW FISH, $mode);
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);
$encrypted = $iv.mcrypt_encr ypt(MCRYPT_BLOW FISH, $key, $data,
$mode, $iv);
$encrypted = base64_encode($ encrypted);
return $encrypted;
}

// encrypted should be base64_encoded
function decrypt_blowfis h($key,$encrypt ed)
{
$mode = MCRYPT_MODE_CBC ;
$iv_size = mcrypt_get_iv_s ize(MCRYPT_BLOW FISH, $mode);
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);
$encrypted = base64_decode($ encrypted);
$decrypted = substr(trim(mcr ypt_decrypt(MCR YPT_BLOWFISH, $key,
$encrypted, $mode, $iv),"\0"),$iv_ size);
return $decrypted;
}