10564b1175
groff 1.23.0 added .MR to its -man macro package. The NEWS file states
that the inclusion of the macro "was prompted by its introduction to
Plan 9 from User Space's troff in August 2020." From d32deab it seems
that the name for Plan 9 from User Space's implementation was suggested
by groff maintainer G. Brandon Robinson.
Not sure if the intention was to make these definitions compatible, but
it would be nice if they were.
Currently, Plan 9 from User Space's .MR expects its second argument to
be parenthesized. groff's .MR does not. This results in extra
parentheses appearing in manual references when viewing Plan 9 from User
Space's manual pages on a system using groff.
126 lines
2.1 KiB
Groff
126 lines
2.1 KiB
Groff
.TH ELGAMAL 3
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.SH NAME
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eggen, egencrypt, egdecrypt, egsign, egverify, egpuballoc, egpubfree, egprivalloc, egprivfree, egsigalloc, egsigfree, egprivtopub - elgamal encryption
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.br
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.B #include <mp.h>
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.br
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.B #include <libsec.h>
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.PP
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.B
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EGpriv* eggen(int nlen, int nrep)
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.PP
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.B
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mpint* egencrypt(EGpub *k, mpint *in, mpint *out)
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.PP
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.B
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mpint* egdecrypt(EGpriv *k, mpint *in, mpint *out)
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.PP
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.B
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EGsig* egsign(EGpriv *k, mpint *m)
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.PP
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.B
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int egverify(EGpub *k, EGsig *sig, mpint *m)
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.PP
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.B
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EGpub* egpuballoc(void)
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.PP
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.B
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void egpubfree(EGpub*)
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.PP
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.B
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EGpriv* egprivalloc(void)
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.PP
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.B
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void egprivfree(EGpriv*)
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.PP
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.B
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EGsig* egsigalloc(void)
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.PP
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.B
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void egsigfree(EGsig*)
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.PP
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.B
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EGpub* egprivtopub(EGpriv*)
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.SH DESCRIPTION
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.PP
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Elgamal is a public key encryption and signature algorithm. The owner of a key publishes
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the public part of the key:
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.EX
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struct EGpub
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{
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mpint *p; // modulus
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mpint *alpha; // generator
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mpint *key; // (encryption key) alpha**secret mod p
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};
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.EE
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This part can be used for encrypting data (with
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.IR egencrypt )
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to be sent to the owner.
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The owner decrypts (with
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.IR egdecrypt )
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using his private key:
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.EX
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struct EGpriv
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{
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EGpub pub;
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mpint *secret; // (decryption key)
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};
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.EE
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.PP
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Keys are generated using
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.IR eggen .
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.I Eggen
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takes both bit length of the modulus
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and the number of repetitions of the Miller-Rabin
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primality test to run. If the latter is 0, it does the default number
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of rounds.
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.I Egprivtopub
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returns a newly allocated copy of the public key
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corresponding to the private key.
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.PP
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The routines
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.IR egpuballoc ,
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.IR egpubfree ,
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.IR egprivalloc ,
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and
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.I egprivfree
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are provided to manage key storage.
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.PP
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.I Egsign
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signs message
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.I m
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using a private key
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.I k
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yielding a
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.EX
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struct EGsig
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{
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mpint *r, *s;
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};
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.EE
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.I Egverify
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returns 0 if the signature is valid and \-1 if not.
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.PP
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The routines
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.I egsigalloc
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and
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.I egsigfree
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are provided to manage signature storage.
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.SH SOURCE
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.B \*9/src/libsec
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.SH SEE ALSO
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.MR mp 3 ,
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.MR aes 3 ,
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.MR blowfish 3 ,
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.MR des 3 ,
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.MR dsa 3 ,
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.MR rc4 3 ,
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.MR rsa 3 ,
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.MR sechash 3 ,
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.MR prime 3 ,
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.MR rand 3
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