I needed using sha1 encryptation
and mirc doesnt support this. =\

Exactly how do you need to use it? To encrypt what you're saying in a channel? To encrypt files?

It's not an encryption method. It's just a cryptographic hash function, like MD5. It's also been cracked, like MD5. Ideally if mIRC implements another hash function it should be something that has no known flaws (eg. from the SHA-2 or RIPEMD families).

i need use it to send password to server with socket

yeah pitty mirc cant let you do /socklisten and make it ssl..
also pitty that mirc doesnt do a handful of hash functions..
$crc()
$md5()
$sha1()
$sha2()
$ripemd()
etc..
perhaps a number of hash functions listed at:
http://en.wikipedia.org/wiki/Cryptographic_hash_function
altho im sure there's dll's out there that can do it all anyway.