Copyright (c) 2009,2010 The NetBSD Foundation, Inc.
All rights reserved.
This manual page is derived from software contributed to The
NetBSD Foundation by Alistair Crooks (agc@NetBSD.org)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
.Dd May 10, 2018 .Dt LIBNETPGP 3 .Os .Sh NAME .Nm libnetpgp .Nd digital signing and verification, encryption and decryption .Sh LIBRARY .Lb libnetpgp .Sh SYNOPSIS n netpgp.h
p The following functions relate to initialisations and finalisations: .Ft int .Fo netpgp_init .Fa "netpgp_t *netpgp" .Fc .Ft int .Fo netpgp_end .Fa "netpgp_t *netpgp" .Fc
p The following functions are for debugging, reflection and information: .Ft int .Fo netpgp_set_debug .Fa "const char *filename" .Fc .Ft int .Fo netpgp_get_debug .Fa "const char *filename" .Fc .Ft int .Fo netpgp_get_info .Fa "const char *type" .Fc .Ft int .Fo netpgp_list_packets .Fa "netpgp_t *netpgp" "char *filename" "int armour" "char *pubringname" .Fc
p The following functions are for variable management: .Ft int .Fo netpgp_setvar .Fa "netpgp_t *netpgp" "const char *name" "const char *value" .Fc .Ft char * .Fo netpgp_getvar .Fa "netpgp_t *netpgp" "const char *name" .Fc .Ft int .Fo netpgp_incvar .Fa "netpgp_t *netpgp" "const char *name" "const int delta" .Fc .Ft int .Fo netpgp_unsetvar .Fa "netpgp_t *netpgp" "const char *name" .Fc
p The following function sets the home directory: .Ft int .Fo netpgp_set_homedir .Fa "netpgp_t *netpgp" "char *homedir" "char *subdir" "const int quiet" .Fc
p The following functions are used for key management: .Ft int .Fo netpgp_list_keys .Fa "netpgp_t *netpgp" "const int printsigs" .Fc .Ft int .Fo netpgp_list_keys_json .Fa "netpgp_t *netpgp" "char **json" "const int psigs" .Fc .Ft int .Fo netpgp_match_keys .Fa "netpgp_t *netpgp" "char *name" "const char *fmt" "void *vp" "const int psigs" .Fc .Ft int .Fo netpgp_match_keys_json .Fa "netpgp_t *netpgp" "char **json" "char *name" "const char *fmt" "const int psigs" .Fc .Ft int .Fo netpgp_match_pubkeys .Fa "netpgp_t *netpgp" "char *name" "void *vp" .Fc .Ft int .Fo netpgp_find_key .Fa "netpgp_t *netpgp" "char *userid" .Fc .Ft char * .Fo netpgp_get_key .Fa "netpgp_t *netpgp" "const char *name" "const char *fmt" .Fc .Ft int .Fo netpgp_export_key .Fa "netpgp_t *netpgp" "char *userid" .Fc .Ft int .Fo netpgp_import_key .Fa "netpgp_t *netpgp" "char *file" .Fc .Ft int .Fo netpgp_generate_key .Fa "netpgp_t *netpgp" "char *userid" "int numbits" .Fc .Ft int .Fo netpgp_validate_sigs .Fa "netpgp_t *netpgp" .Fc .Ft int .Fo netpgp_format_json .Fa "void *vp" "const char *json" "const int psigs" .Fc
p The following functions are used for file management: .Ft int .Fo netpgp_encrypt_file .Fa "netpgp_t *netpgp" "const char *userid" "const char *filename" "char *out" .Fa "int armored" .Fc .Ft int .Fo netpgp_decrypt_file .Fa "netpgp_t *netpgp" "const char *filename" "char *out" "int armored" .Fc .Ft int .Fo netpgp_sign_file .Fa "netpgp_t *netpgp" "const char *userid" "const char *filename" "char *out" .Fa "int armored" "int cleartext" "int detached" .Fc .Ft int .Fo netpgp_verify_file .Fa "netpgp_t *netpgp" "const char *in" "const char *out" "int armored" .Fc
p The following functions are used for memory signing and encryption: .Ft int .Fo netpgp_encrypt_memory .Fa "netpgp_t *netpgp" "const char *userid" "void *in" "const size_t insize" .Fa "char *out" "size_t outsize" "int armored" .Fc .Ft int .Fo netpgp_decrypt_memory .Fa "netpgp_t *netpgp" "const void *input" "const size_t insize" .Fa "char *out" "size_t outsize" "const int armored" .Fc .Ft int .Fo netpgp_sign_memory .Fa "netpgp_t *netpgp" "const char *userid" "char *mem" .Fa "size_t size" "char *out" "size_t outsize" .Fa "const unsigned armored" "const unsigned cleartext" .Fc .Ft int .Fo netpgp_verify_memory .Fa "netpgp_t *netpgp" "const void *in" "const size_t insize" .Fa "void *out" "size_t outsize" "const int armored" .Fc .Sh DESCRIPTION .Nm is a library interface to enable digital signatures to be created and verified, and also for files and memory to be encrypted and decrypted. Functions are also provided for management of user keys.
p The library uses functions from the openssl library for multi-precision integer arithmetic, and for RSA and DSA key signing and verification, encryption and decryption.
p Normal operation sees the .Nm process be initialised using the .Fn netpgp_init function, which will set up the public and private keyrings, as well as set the user identity in the .Ar userid member of the .Dv netpgp_t structure. These are set using the .Fn netpgp_setvar function and unset using the .Fn netpgp_unsetvar function. If no public key ring file is set, initial values will be taken from those in the
a .gnupg/pubring.gpg file in the user's home directory. Similarly, if no secret key ring file is set, initial values will be taken from those in the
a .gnupg/secring.gpg file in the user's home directory. The user identity is obtained from the .Ev userid environment variable, or failing that, the value of the .Dq default-key setting from
a .gnupg/gpg.conf file in the user's home directory is used. The .Fn netpgp_init function returns 1 on success, 0 on failure.
p To list all the keys in a keyring, the .Fn netpgp_list_keys function is used. To list all the keys in a keyring as a JSON encoded string, the .Fn netpgp_list_keys_json function is used. To find and list keys in a keyring, the .Fn netpgp_match_keys function is used. To find and list keys in a keyring, output as a JSON encoded string, the .Fn netpgp_match_keys_json function is used. To find and list keys in a better suited machine-readble format, such as for redirection to other parsing engines, the .Fn netpgp_match_pubkeys function is used. The signature subkey fields can also be displayed using this function.
p The home directory is specified as an internal variable, and its existence is checked using the .Fn netpgp_set_homedir function. This function can operate in a verbose or quiet manner, depending on the value of the argument provided. If the subdirectory argument is provided, this subdirectory is appended to the home directory in order to search for the keyrings.
p To print key information from a JSON encoded string, stored in a file, the .Fn netpgp_format_json function is used.
p To validate the signature of keys in a public key keyring, the .Fn netpgp_validate_sigs function is used.
p To export a key, the .Fn netpgp_export_key function is used. Output is sent to the standard output.
p To import a key onto the public keyring, the .Fn netpgp_import_key function is used. The name of the file containing the key to be imported is provided as the filename argument.
p To generate a key, the .Fn netpgp_generate_key function is used. It takes an argument of the number of bits to use in the key. At the time that this manual page was created (April 2009), the recommendations are that the bare minimum key size of at least 2048 bits is used, and it would be much better to use at least 4096 or 8192 bits. This situation should be monitored to ensure that it does not go out of date.
p Encryption, decryption, signing and verification of files are the lifeblood of the .Nm library. To encrypt a file, the .Fn netpgp_encrypt_file function is used, and the .Fn netpgp_decrypt_file function is used to decrypt the results of the encryption. To sign a file, the .Fn netpgp_sign_file function is used, and the resulting signed file can be verified using the .Fn netpgp_verify_file function.
p .Fn netpgp_sign_memory is a function which can sign an area of memory, and .Fn netpgp_verify_memory verifies the digital signature produced.
p Internally, an encrypted or signed file is made up of .Dq packets which hold information pertaining to the signature, encryption method, and the data which is being protected. This information can be displayed in a verbose manner using the .Fn netpgp_list_packets function.
p The .Fn netpgp_setvar and .Fn netpgp_getvar functions are used to manage the hash algorithm that is used with RSA signatures. These functions are general purpose functions, and are used to set and retrieve values for internal variables. For example, they can be used to set and to retrieve the value of the user id which has been set, the home directory from which to find the keyrings, the verbosity settings, and many more. The .Fn netpgp_incvar function is used to add a numeric increment to the internal variable. This incremental value can be negative. It is primarily used to increase the verbosity settings.
p In .Nm files are encrypted using the public key of the userid. The secret key is used to decrypt the results of that encryption. Files are signed using the secret key of the userid. The public key is used to verify that the file was signed, who signed the file, and the date and time at which it was signed.
p Some utility functions are also provided for debugging, and for finding out version and maintainer information from calling programs. These are the .Fn netpgp_set_debug and the .Fn netpgp_get_debug functions (for getting verbose debugging information on a per-source file basis).
p The .Fn netpgp_get_info function returns the version or maintainer information depending upon the .Ar type argument. At the present time, two types are defined: .Dq version and .Dq maintainer . The maintainer information returned contains the name, email address, and PGP short key id. A failure to present a known .Ar type argument to .Fn netpgp_get_info will result in the string .Dq [unknown] being returned. .Sh SEE ALSO .Xr netpgp 1 , .Xr ssl 3 .Sh HISTORY The .Nm library first appeared in .Nx 6.0 . .Sh AUTHORS .An -nosplit .An Ben Laurie , .An Rachel Willmer . .An Alistair Crooks Aq Mt agc@NetBSD.org wrote this high-level interface.
p This manual page was written by .An Alistair Crooks .