---
name: "xcrypt"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/xcrypt"
---

# xcrypt(3)

RFS password encryption

## NAME

xencrypt, xdecrypt, passwd2des - RFS password encryption

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <rpc/des_crypt.h>
```

**void passwd2des(char** *\*passwd***, char \****key***);**

**int xencrypt(char \****secret***, char \****passwd***);** **int xdecrypt(char \****secret***, char \****passwd***);**

## DESCRIPTION

**WARNING**: Do not use these functions in new code. They do not achieve any type of acceptable cryptographic security guarantees.

The function **passwd2des**() takes a character string *passwd* of arbitrary length and fills a character array *key* of length 8. The array *key* is suitable for use as DES key. It has odd parity set in bit 0 of each byte. Both other functions described here use this function to turn their argument *passwd* into a DES key.

The **xencrypt**() function takes the ASCII character string *secret* given in hex, which must have a length that is a multiple of 16, encrypts it using the DES key derived from *passwd* by **passwd2des**(), and outputs the result again in *secret* as a hex string of the same length.

The **xdecrypt**() function performs the converse operation.

## RETURN VALUE

The functions **xencrypt**() and **xdecrypt**() return 1 on success and 0 on error.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **passwd2des**(), **xencrypt**(), **xdecrypt**() | Thread safety | MT-Safe |

## VERSIONS

These functions are available since glibc 2.1.

## BUGS

The prototypes are missing from the abovementioned include file.

## SEE ALSO

[**cbc\_crypt**(3)](/cbc_crypt/3.md)