=pod

=head1 NAME

EVP_rc4,
EVP_rc4_40,
EVP_rc4_hmac_md5
- EVP RC4 stream cipher

=head1 SYNOPSIS

 #include <openssl/evp.h>

 const EVP_CIPHER *EVP_rc4(void);
 const EVP_CIPHER *EVP_rc4_40(void);
 const EVP_CIPHER *EVP_rc4_hmac_md5(void);

=head1 DESCRIPTION

The RC4 stream cipher for EVP.

=over 4

=item EVP_rc4()

RC4 stream cipher. This is a variable key length cipher with a default key
length of 128 bits.

=item EVP_rc4_40()

RC4 stream cipher with 40 bit key length.

WARNING: this function is obsolete. Its usage should be replaced with the
EVP_rc4() and the EVP_CIPHER_CTX_set_key_length() functions.

=item EVP_rc4_hmac_md5()

Authenticated encryption with the RC4 stream cipher with MD5 as HMAC.

WARNING: this is not intended for usage outside of TLS and requires calling of
some undocumented ctrl functions. These ciphers do not conform to the EVP AEAD
interface.

=back

=head1 NOTES

Developers should be aware of the negative performance implications of
calling these functions multiple times and should consider using
L<EVP_CIPHER_fetch(3)> with L<EVP_CIPHER-RC4(7)> instead.
See L<crypto(7)/Performance> for further information.

=head1 RETURN VALUES

These functions return an B<EVP_CIPHER> structure that contains the
implementation of the symmetric cipher.

=head1 SEE ALSO

L<evp(7)>,
L<EVP_EncryptInit(3)>

=head1 COPYRIGHT

Copyright 2017-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
