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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | LINKING | SEE ALSO | COLOPHON |
KEYCTL_DH_COMPUTE(3) Linux Key Management Calls KEYCTL_DH_COMPUTE(3)
keyctl_dh_compute - Compute a Diffie-Hellman shared secret or public
key
#include <keyutils.h>
long keyctl_dh_compute(key_serial_t private, key_serial_t prime,
key_serial_t base, char *buffer, size_t buflen);
long keyctl_dh_compute_alloc(key_serial_t private,
key_serial_t prime, key_serial_t base, void **_buffer);
keyctl_dh_compute() computes a Diffie-Hellman public key or shared
secret. That computation is:
base ^ private ( mod prime )
When base is a key containing the shared generator value, the remote
public key is computed. When base is a key containing the remote
public key, the shared secret is computed.
base, private, and prime must all refer to user-type keys containing
the parameters for the computation. Each of these keys must grant
the caller read permission in order for them to be used.
buffer and buflen specify the buffer into which the computed result
will be placed. buflen may be zero, in which case the buffer is not
used and the minimum buffer length is fetched.
keyctl_dh_compute_alloc() is similar to keyctl_dh_compute() except
that it allocates a buffer big enough to hold the payload data and
places the data in it. If successful, a pointer to the buffer is
placed in *_buffer. The caller must free the buffer.
On success keyctl_dh_compute() returns the amount of data placed into
the buffer when buflen is non-zero. When buflen is zero, the minimum
buffer length to hold the data is returned.
On success keyctl_dh_compute_alloc() returns the amount of data in
the buffer.
On error, both functions set errno to an appropriate code and return
the value -1.
ENOKEY One of the keys specified is invalid or not readable.
EINVAL The buffer pointer is invalid or buflen is too small.
EOPNOTSUPP
One of the keys was not a valid user key.
This is a library function that can be found in libkeyutils. When
linking, -lkeyutils should be specified to the linker.
keyctl(1),
keyctl(2),
keyctl(3),
keyutils(7)
This page is part of the keyutils (key management utilities) project.
Information about the project can be found at [unknown -- if you
know, please contact man-pages@man7.org] If you have a bug report for
this manual page, send it to keyrings@linux-nfs.org. This page was
obtained from the project's upstream Git repository
⟨http://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git⟩
on 2017-07-05. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-to-
date source for the page, or you have corrections or improvements to
the information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
Linux 07 Apr 2016 KEYCTL_DH_COMPUTE(3)
Pages that refer to this page: keyctl(3)