ciphers=

static VALUE
ossl_sslctx_set_ciphers(VALUE self, VALUE v)
{
    SSL_CTX *ctx;
    VALUE str, elem;
    int i;

    rb_check_frozen(self);
    if (NIL_P(v))
        return v;
    else if (TYPE(v) == T_ARRAY) {
        str = rb_str_new(0, 0);
        for (i = 0; i < RARRAY_LEN(v); i++) {
            elem = rb_ary_entry(v, i);
            if (TYPE(elem) == T_ARRAY) elem = rb_ary_entry(elem, 0);
            elem = rb_String(elem);
            rb_str_append(str, elem);
            if (i < RARRAY_LEN(v)-1) rb_str_cat2(str, ":");
        }
    } else {
        str = v;
        StringValue(str);
    }

    Data_Get_Struct(self, SSL_CTX, ctx);
    if(!ctx){
        ossl_raise(eSSLError, "SSL_CTX is not initialized.");
        return Qnil;
    }
    if (!SSL_CTX_set_cipher_list(ctx, RSTRING_PTR(str))) {
        ossl_raise(eSSLError, "SSL_CTX_set_cipher_list:");
    }

    return v;
}