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LIBNETPGP(3)               Library Functions Manual               LIBNETPGP(3)

NAME
     libnetpgp -- digital signing and verification, encryption and decryption

LIBRARY
     Netpgp signing, verification, encryption and decryption (libnetpgp,
     -lnetpgp)

SYNOPSIS
     #include <&lt;netpgp.h>&gt;

     The following functions relate to initialisations and finalisations:
     int
     netpgp_init(netpgp_t *netpgp);

     int
     netpgp_end(netpgp_t *netpgp);

     The following functions are for debugging, reflection and information:
     int
     netpgp_set_debug(const char *filename);

     int
     netpgp_get_debug(const char *filename);

     int
     netpgp_get_info(const char *type);

     int
     netpgp_list_packets(netpgp_t *netpgp, char *filename, int armour, char
     *pubringname);

     The following functions are for variable management:
     int
     netpgp_setvar(netpgp_t *netpgp, const char *name, const char *value);

     char *
     netpgp_getvar(netpgp_t *netpgp, const char *name);

     int
     netpgp_incvar(netpgp_t *netpgp, const char *name, const int delta);

     The following function sets the home directory:
     int
     netpgp_set_homedir(netpgp_t *netpgp, char *homedir, char *subdir, const
     int quiet);

     The following functions are used for key management:
     int
     netpgp_list_keys(netpgp_t *netpgp, const int printsigs);

     int
     netpgp_match_list_keys(netpgp_t *netpgp, char *pattern);

     int
     netpgp_find_key(netpgp_t *netpgp, char *userid);

     char *
     netpgp_get_key(netpgp_t *netpgp, const char *id);

     int
     netpgp_export_key(netpgp_t *netpgp, char *userid);

     int
     netpgp_import_key(netpgp_t *netpgp, char *file);

     int
     netpgp_generate_key(netpgp_t *netpgp, char *userid, int numbits);

     The following functions are used for file management:
     int
     netpgp_encrypt_file(netpgp_t *netpgp, char *userid, char *filename, char
     *out, int armored);

     int
     netpgp_decrypt_file(netpgp_t *netpgp, char *filename, char *out, int
     armored);

     int
     netpgp_sign_file(netpgp_t *netpgp, char *userid, char *filename, char
     *out, int armored, int cleartext, int detached);

     int
     netpgp_verify_file(netpgp_t *netpgp, char *f, int armored);

     The following functions are used for memory signing and encryption:
     int
     netpgp_encrypt_memory(netpgp_t *netpgp, char *userid, void *in, const
     size_t insize, char *out, size_t outsize, int armored);

     int
     netpgp_decrypt_memory(netpgp_t *netpgp, const void *input, const size_t
     insize, char *out, size_t outsize, const int armored);

     int
     netpgp_sign_memory(netpgp_t *netpgp, const char *userid, char *mem,
     size_t size, char *out, size_t outsize, const unsigned armored, const
     unsigned cleartext);

     int
     netpgp_verify_memory(netpgp_t *netpgp, const void *in, const size_t
     insize, void *out, size_t outsize, const int armored);

DESCRIPTION
     libnetpgp 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.

     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.

     Normal operation sees the libnetpgp process be initialised using the
     netpgp_init() function, which will set up the public and private
     keyrings, and set the user identity to the userid argument passed stored
     in the netpgp_t structure, and set using the netpgp_setvar() function.
     If no public key ring file is set, initial values will be taken from
     those in the .gnupg/pubring.gpg file in the user's home directory.
     Similarily, if no secret key ring file is set, initial values will be
     taken from those in the .gnupg/secring.gpg file in the user's home
     directory.  The netpgp_init() returns 1 on sucess, 0 on failure.

     To list all the keys in a keyring, the netpgp_list_keys() function is
     used.  The signature subkey fields can also be displayed using this
     function.  The netpgp_match_list_keys() function is used to match (via
     regular expression) a subset of the keys in the keyring.  If the
     expression to match is NULL, the search will degenerate into a listing of
     all keys in the keyring.

     The home directory is specified as an internal variable, and its
     existence is checked using the 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.

     To export a key, the netpgp_export_key() is used.  Output is sent to the
     standard output.

     To import a key onto the public keyring, the netpgp_import_key() is used.
     The name of the file containing the key to be imported is provided as the
     filename argument.

     To generate a key, the netpgp_generate_key() 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.

     Encryption, decryption, signing and verification of files are the
     lifeblood of the libnetpgp library.  To encrypt a file, the
     netpgp_encrypt_file() and the netpgp_decrypt_file() is used to decrypt
     the results of the encryption.  To sign a file, the netpgp_sign_file() is
     used, and the resulting signed file can be verified using the
     netpgp_verify_file() function.

     netpgp_sign_memory() is a function which can sign an area of memory, and
     netpgp_verify_memory() verifies the digital signature produced.

     Internally, an encrypted or signed file is made up of ``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 netpgp_list_packets() function.

     The netpgp_setvar() and 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
     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.

     In libnetpgp 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.

     Some utility functions are also provided for debugging, and for finding
     out version and maintainer information from calling programs.  These are
     the netpgp_set_debug() and the netpgp_get_debug() functions (for getting
     verbose debugging information on a per-source file basis).

     The netpgp_get_info() returns the version or maintainer information
     depending upon the type argument.  At the present time, two types are
     defined: ``version'' and ``maintainer''.  A failure to present a known
     type argument to netpgp_get_info() will result in the string
     ``[unknown]'' being returned.

SEE ALSO
     netpgp(1), ssl(3)

HISTORY
     The libnetpgp library first appeared in NetBSD 6.0.

AUTHORS
     Ben Laurie,
     Rachel Willmer.
     Alistair Crooks <agcATNetBSD.org> wrote this high-level interface.

     This manual page was written by
     Alistair Crooks.

NetBSD 6.1.5                     June 17, 2010                    NetBSD 6.1.5