=pod

=head1 NAME

PKCS12_newpass - change the password of a PKCS12 structure

=head1 SYNOPSIS

 #include <openssl/pkcs12.h>

 int PKCS12_newpass(PKCS12 *p12, const char *oldpass, const char *newpass);

=head1 DESCRIPTION

PKCS12_newpass() changes the password of a PKCS12 structure.

B<p12> is a pointer to a PKCS12 structure. B<oldpass> is the existing password
and B<newpass> is the new password.

=head1 NOTES

Each of B<oldpass> and B<newpass> is independently interpreted as a string in
the UTF-8 encoding. If it is not valid UTF-8, it is assumed to be ISO8859-1
instead.

In particular, this means that passwords in the locale character set
(or code page on Windows) must potentially be converted to UTF-8 before
use. This may include passwords from local text files, or input from
the terminal or command line. Refer to the documentation of
L<UI_OpenSSL(3)>, for example.

=head1 RETURN VALUES

PKCS12_newpass() returns 1 on success or 0 on failure. Applications can
retrieve the most recent error from PKCS12_newpass() with ERR_get_error().

=head1 EXAMPLE

This example loads a PKCS#12 file, changes its password and writes out
the result to a new file.

 #include <stdio.h>
 #include <stdlib.h>
 #include <openssl/pem.h>
 #include <openssl/err.h>
 #include <openssl/pkcs12.h>

 int main(int argc, char **argv)
 {
     FILE *fp;
     PKCS12 *p12;

     if (argc != 5) {
         fprintf(stderr, "Usage: pkread p12file password newpass opfile\n");
         return 1;
     }
     if ((fp = fopen(argv[1], "rb")) == NULL) {
         fprintf(stderr, "Error opening file %s\n", argv[1]);
         return 1;
     }
     p12 = d2i_PKCS12_fp(fp, NULL);
     fclose(fp);
     if (p12 == NULL) {
         fprintf(stderr, "Error reading PKCS#12 file\n");
         ERR_print_errors_fp(stderr);
         return 1;
     }
     if (PKCS12_newpass(p12, argv[2], argv[3]) == 0) {
         fprintf(stderr, "Error changing password\n");
         ERR_print_errors_fp(stderr);
         PKCS12_free(p12);
         return 1;
     }
     if ((fp = fopen(argv[4], "wb")) == NULL) {
         fprintf(stderr, "Error opening file %s\n", argv[4]);
         PKCS12_free(p12);
         return 1;
     }
     i2d_PKCS12_fp(fp, p12);
     PKCS12_free(p12);
     fclose(fp);
     return 0;
 }


=head1 NOTES

If the PKCS#12 structure does not have a password, then you must use the empty
string "" for B<oldpass>. Using NULL for B<oldpass> will result in a
PKCS12_newpass() failure.

If the wrong password is used for B<oldpass> then the function will fail,
with a MAC verification error. In rare cases the PKCS12 structure does not
contain a MAC: in this case it will usually fail with a decryption padding
error.

=head1 BUGS

The password format is a NULL terminated ASCII string which is converted to
Unicode form internally. As a result some passwords cannot be supplied to
this function.

=head1 SEE ALSO

L<PKCS12_create(3)>, L<ERR_get_error(3)>,
L<passphrase-encoding(7)>

=head1 COPYRIGHT

Copyright 2016-2018 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