@@ -1,8 +1,14 @@
-@c This node must have no pointers.
-@node Cryptographic Functions
-@c @node Cryptographic Functions, Debugging Support, System Configuration, Top
-@chapter DES Encryption and Password Handling
-@c %MENU% DES encryption and password handling
+@node Cryptographic Functions, Debugging Support, System Configuration, Top
+@chapter Cryptographic Functions
+@c %MENU% Password storage and strongly unpredictable bytes
+
+@menu
+* crypt:: A one-way function for passwords.
+* Unpredictable Bytes:: Randomness for cryptography purposes.
+@end menu
+
+@node crypt
+@section Encrypting Passwords
On many systems, it is unnecessary to have any kind of user
authentication; for instance, a workstation which is not connected to a
@@ -30,103 +36,6 @@ message-digest algorithm that is compatible with modern BSD systems,
and the other based on the Data Encryption Standard (DES) that is
compatible with Unix systems.
-@menu
-* Legal Problems:: This software can get you locked up, or worse.
-* getpass:: Prompting the user for a password.
-* crypt:: A one-way function for passwords.
-* Unpredictable Bytes:: Randomness for cryptography purposes.
-@end menu
-
-@node Legal Problems
-@section Legal Problems
-
-Because of the continuously changing state of the law, it's not possible
-to provide a definitive survey of the laws affecting cryptography.
-Instead, this section warns you of some of the known trouble spots; this
-may help you when you try to find out what the laws of your country are.
-
-Some countries require that you have a license to use, possess, or import
-cryptography. These countries are believed to include Byelorussia,
-Burma, India, Indonesia, Israel, Kazakhstan, Pakistan, Russia, and Saudi
-Arabia.
-
-Some countries restrict the transmission of encrypted messages by radio;
-some telecommunications carriers restrict the transmission of encrypted
-messages over their network.
-
-Many countries have some form of export control for encryption software.
-The Wassenaar Arrangement is a multilateral agreement between 33
-countries (Argentina, Australia, Austria, Belgium, Bulgaria, Canada, the
-Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary,
-Ireland, Italy, Japan, Luxembourg, the Netherlands, New Zealand, Norway,
-Poland, Portugal, the Republic of Korea, Romania, the Russian
-Federation, the Slovak Republic, Spain, Sweden, Switzerland, Turkey,
-Ukraine, the United Kingdom and the United States) which restricts some
-kinds of encryption exports. Different countries apply the arrangement
-in different ways; some do not allow the exception for certain kinds of
-``public domain'' software (which would include this library), some
-only restrict the export of software in tangible form, and others impose
-significant additional restrictions.
-
-The United States has additional rules. This software would generally
-be exportable under 15 CFR 740.13(e), which permits exports of
-``encryption source code'' which is ``publicly available'' and which is
-``not subject to an express agreement for the payment of a licensing fee or
-royalty for commercial production or sale of any product developed with
-the source code'' to most countries.
-
-The rules in this area are continuously changing. If you know of any
-information in this manual that is out-of-date, please report it to
-the bug database. @xref{Reporting Bugs}.
-
-@node getpass
-@section Reading Passwords
-
-When reading in a password, it is desirable to avoid displaying it on
-the screen, to help keep it secret. The following function handles this
-in a convenient way.
-
-@deftypefun {char *} getpass (const char *@var{prompt})
-@standards{BSD, unistd.h}
-@safety{@prelim{}@mtunsafe{@mtasuterm{}}@asunsafe{@ascuheap{} @asulock{} @asucorrupt{}}@acunsafe{@acuterm{} @aculock{} @acucorrupt{}}}
-@c This function will attempt to create a stream for terminal I/O, but
-@c will fallback to stdio/stderr. It attempts to change the terminal
-@c mode in a thread-unsafe way, write out the prompt, read the password,
-@c then restore the terminal mode. It has a cleanup to close the stream
-@c in case of (synchronous) cancellation, but not to restore the
-@c terminal mode.
-
-@code{getpass} outputs @var{prompt}, then reads a string in from the
-terminal without echoing it. It tries to connect to the real terminal,
-@file{/dev/tty}, if possible, to encourage users not to put plaintext
-passwords in files; otherwise, it uses @code{stdin} and @code{stderr}.
-@code{getpass} also disables the INTR, QUIT, and SUSP characters on the
-terminal using the @code{ISIG} terminal attribute (@pxref{Local Modes}).
-The terminal is flushed before and after @code{getpass}, so that
-characters of a mistyped password are not accidentally visible.
-
-In other C libraries, @code{getpass} may only return the first
-@code{PASS_MAX} bytes of a password. @Theglibc{} has no limit, so
-@code{PASS_MAX} is undefined.
-
-The prototype for this function is in @file{unistd.h}. @code{PASS_MAX}
-would be defined in @file{limits.h}.
-@end deftypefun
-
-This precise set of operations may not suit all possible situations. In
-this case, it is recommended that users write their own @code{getpass}
-substitute. For instance, a very simple substitute is as follows:
-
-@smallexample
-@include mygetpass.c.texi
-@end smallexample
-
-The substitute takes the same parameters as @code{getline}
-(@pxref{Line Input}); the user must print any prompt desired.
-
-@node crypt
-@section Encrypting Passwords
-
@deftypefun {char *} crypt (const char *@var{key}, const char *@var{salt})
@standards{BSD, crypt.h}
@standards{SVID, crypt.h}
@@ -177,24 +86,6 @@ password against the result of a previous call to @code{crypt}, pass
the result of the previous call as the @var{salt}.
@end deftypefun
-The following short program is an example of how to use @code{crypt} the
-first time a password is entered. Note that the @var{salt} generation
-is just barely acceptable; in particular, it is not unique between
-machines, and in many applications it would not be acceptable to let an
-attacker know what time the user's password was last set.
-
-@smallexample
-@include genpass.c.texi
-@end smallexample
-
-The next program shows how to verify a password. It prompts the user
-for a password and prints ``Access granted.'' if the user types
-@code{GNU libc manual}.
-
-@smallexample
-@include testpass.c.texi
-@end smallexample
-
@deftypefun {char *} crypt_r (const char *@var{key}, const char *@var{salt}, {struct crypt_data *} @var{data})
@standards{GNU, crypt.h}
@safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{} @asulock{} @ascuheap{} @ascudlopen{}}@acunsafe{@aculock{} @acsmem{}}}
@@ -212,6 +103,24 @@ The @code{crypt_r} function is a GNU extension.
The @code{crypt} and @code{crypt_r} functions are prototyped in the
header @file{crypt.h}.
+The following short program is an example of how to use @code{crypt} the
+first time a password is entered. Note that the @var{salt} generation
+is just barely acceptable; in particular, it is not unique between
+machines, and in many applications it would not be acceptable to let an
+attacker know what time the user's password was last set.
+
+@smallexample
+@include genpass.c.texi
+@end smallexample
+
+The next program shows how to verify a password. It prompts the user
+for a password and prints ``Access granted.'' if the user types
+@code{GNU libc manual}.
+
+@smallexample
+@include testpass.c.texi
+@end smallexample
+
@node Unpredictable Bytes
@section Generating Unpredictable Bytes
@@ -24,6 +24,7 @@ descriptor is and how to open a file descriptor for a terminal device.
* Line Control:: Sending break sequences, clearing
terminal buffers @dots{}
* Noncanon Example:: How to read single characters without echo.
+* getpass:: Prompting the user for a password.
* Pseudo-Terminals:: How to open a pseudo-terminal.
@end menu
@@ -1871,6 +1872,50 @@ existing shells do not actually do this, so you may wish to establish
handlers for job control signals that reset terminal modes. The above
example does so.
+@node getpass
+@section Reading Passwords
+
+When reading in a password, it is desirable to avoid displaying it on
+the screen, to help keep it secret. The following function handles this
+in a convenient way.
+
+@deftypefun {char *} getpass (const char *@var{prompt})
+@standards{BSD, unistd.h}
+@safety{@prelim{}@mtunsafe{@mtasuterm{}}@asunsafe{@ascuheap{} @asulock{} @asucorrupt{}}@acunsafe{@acuterm{} @aculock{} @acucorrupt{}}}
+@c This function will attempt to create a stream for terminal I/O, but
+@c will fallback to stdio/stderr. It attempts to change the terminal
+@c mode in a thread-unsafe way, write out the prompt, read the password,
+@c then restore the terminal mode. It has a cleanup to close the stream
+@c in case of (synchronous) cancellation, but not to restore the
+@c terminal mode.
+
+@code{getpass} outputs @var{prompt}, then reads a string in from the
+terminal without echoing it. It tries to connect to the real terminal,
+@file{/dev/tty}, if possible, to encourage users not to put plaintext
+passwords in files; otherwise, it uses @code{stdin} and @code{stderr}.
+@code{getpass} also disables the INTR, QUIT, and SUSP characters on the
+terminal using the @code{ISIG} terminal attribute (@pxref{Local Modes}).
+The terminal is flushed before and after @code{getpass}, so that
+characters of a mistyped password are not accidentally visible.
+
+In other C libraries, @code{getpass} may only return the first
+@code{PASS_MAX} bytes of a password. @Theglibc{} has no limit, so
+@code{PASS_MAX} is undefined.
+
+The prototype for this function is in @file{unistd.h}. @code{PASS_MAX}
+would be defined in @file{limits.h}.
+@end deftypefun
+
+This precise set of operations may not suit all possible situations. In
+this case, it is recommended that users write their own @code{getpass}
+substitute. For instance, a very simple substitute is as follows:
+
+@smallexample
+@include mygetpass.c.texi
+@end smallexample
+
+The substitute takes the same parameters as @code{getline}
+(@pxref{Line Input}); the user must print any prompt desired.
@node Pseudo-Terminals
@section Pseudo-Terminals