1 cfa37a7b 2004-04-10 devnull .TH ELGAMAL 3
  2 cfa37a7b 2004-04-10 devnull .SH NAME
  3 cfa37a7b 2004-04-10 devnull eggen, egencrypt, egdecrypt, egsign, egverify, egpuballoc, egpubfree, egprivalloc, egprivfree, egsigalloc, egsigfree, egprivtopub - elgamal encryption
  4 cfa37a7b 2004-04-10 devnull .SH SYNOPSIS
  5 cfa37a7b 2004-04-10 devnull .B #include <u.h>
  6 cfa37a7b 2004-04-10 devnull .br
  7 cfa37a7b 2004-04-10 devnull .B #include <libc.h>
  8 cfa37a7b 2004-04-10 devnull .br
  9 cfa37a7b 2004-04-10 devnull .B #include <mp.h>
 10 cfa37a7b 2004-04-10 devnull .br
 11 cfa37a7b 2004-04-10 devnull .B #include <libsec.h>
 12 cfa37a7b 2004-04-10 devnull .PP
 13 cfa37a7b 2004-04-10 devnull .B
 14 cfa37a7b 2004-04-10 devnull EGpriv*	eggen(int nlen, int nrep)
 15 cfa37a7b 2004-04-10 devnull .PP
 16 cfa37a7b 2004-04-10 devnull .B
 17 cfa37a7b 2004-04-10 devnull mpint*	egencrypt(EGpub *k, mpint *in, mpint *out)
 18 cfa37a7b 2004-04-10 devnull .PP
 19 cfa37a7b 2004-04-10 devnull .B
 20 cfa37a7b 2004-04-10 devnull mpint*	egdecrypt(EGpriv *k, mpint *in, mpint *out)
 21 cfa37a7b 2004-04-10 devnull .PP
 22 cfa37a7b 2004-04-10 devnull .B
 23 cfa37a7b 2004-04-10 devnull EGsig*	egsign(EGpriv *k, mpint *m)
 24 cfa37a7b 2004-04-10 devnull .PP
 25 cfa37a7b 2004-04-10 devnull .B
 26 cfa37a7b 2004-04-10 devnull int		egverify(EGpub *k, EGsig *sig, mpint *m)
 27 cfa37a7b 2004-04-10 devnull .PP
 28 cfa37a7b 2004-04-10 devnull .B
 29 cfa37a7b 2004-04-10 devnull EGpub*	egpuballoc(void)
 30 cfa37a7b 2004-04-10 devnull .PP
 31 cfa37a7b 2004-04-10 devnull .B
 32 cfa37a7b 2004-04-10 devnull void		egpubfree(EGpub*)
 33 cfa37a7b 2004-04-10 devnull .PP
 34 cfa37a7b 2004-04-10 devnull .B
 35 cfa37a7b 2004-04-10 devnull EGpriv*	egprivalloc(void)
 36 cfa37a7b 2004-04-10 devnull .PP
 37 cfa37a7b 2004-04-10 devnull .B
 38 cfa37a7b 2004-04-10 devnull void		egprivfree(EGpriv*)
 39 cfa37a7b 2004-04-10 devnull .PP
 40 cfa37a7b 2004-04-10 devnull .B
 41 cfa37a7b 2004-04-10 devnull EGsig*	egsigalloc(void)
 42 cfa37a7b 2004-04-10 devnull .PP
 43 cfa37a7b 2004-04-10 devnull .B
 44 cfa37a7b 2004-04-10 devnull void		egsigfree(EGsig*)
 45 cfa37a7b 2004-04-10 devnull .PP
 46 cfa37a7b 2004-04-10 devnull .B
 47 cfa37a7b 2004-04-10 devnull EGpub*	egprivtopub(EGpriv*)
 48 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
 49 cfa37a7b 2004-04-10 devnull .PP
 50 cfa37a7b 2004-04-10 devnull Elgamal is a public key encryption and signature algorithm.  The owner of a key publishes
 51 cfa37a7b 2004-04-10 devnull the public part of the key:
 52 cfa37a7b 2004-04-10 devnull .EX
 53 cfa37a7b 2004-04-10 devnull 	struct EGpub
 54 cfa37a7b 2004-04-10 devnull 	{
 55 cfa37a7b 2004-04-10 devnull 		mpint	*p;	// modulus
 56 cfa37a7b 2004-04-10 devnull 		mpint	*alpha;	// generator
 57 cfa37a7b 2004-04-10 devnull 		mpint	*key;	// (encryption key) alpha**secret mod p
 58 cfa37a7b 2004-04-10 devnull 	};
 59 cfa37a7b 2004-04-10 devnull .EE
 60 cfa37a7b 2004-04-10 devnull This part can be used for encrypting data (with
 61 cfa37a7b 2004-04-10 devnull .IR egencrypt )
 62 cfa37a7b 2004-04-10 devnull to be sent to the owner.
 63 cfa37a7b 2004-04-10 devnull The owner decrypts (with
 64 cfa37a7b 2004-04-10 devnull .IR egdecrypt )
 65 cfa37a7b 2004-04-10 devnull using his private key:
 66 cfa37a7b 2004-04-10 devnull .EX
 67 cfa37a7b 2004-04-10 devnull 	struct EGpriv
 68 cfa37a7b 2004-04-10 devnull 	{
 69 cfa37a7b 2004-04-10 devnull 		EGpub	pub;
 70 cfa37a7b 2004-04-10 devnull 		mpint	*secret; // (decryption key)
 71 cfa37a7b 2004-04-10 devnull 	};
 72 cfa37a7b 2004-04-10 devnull .EE
 73 cfa37a7b 2004-04-10 devnull .PP
 74 cfa37a7b 2004-04-10 devnull Keys are generated using
 75 cfa37a7b 2004-04-10 devnull .IR eggen .
 76 cfa37a7b 2004-04-10 devnull .I Eggen
 77 cfa37a7b 2004-04-10 devnull takes both bit length of the modulus
 78 cfa37a7b 2004-04-10 devnull and the number of repetitions of the Miller-Rabin
 79 cfa37a7b 2004-04-10 devnull primality test to run.  If the latter is 0, it does the default number
 80 cfa37a7b 2004-04-10 devnull of rounds.
 81 cfa37a7b 2004-04-10 devnull .I Egprivtopub
 82 cfa37a7b 2004-04-10 devnull returns a newly allocated copy of the public key
 83 cfa37a7b 2004-04-10 devnull corresponding to the private key.
 84 cfa37a7b 2004-04-10 devnull .PP
 85 cfa37a7b 2004-04-10 devnull The routines
 86 cfa37a7b 2004-04-10 devnull .IR egpuballoc ,
 87 cfa37a7b 2004-04-10 devnull .IR egpubfree ,
 88 cfa37a7b 2004-04-10 devnull .IR egprivalloc ,
 89 cfa37a7b 2004-04-10 devnull and
 90 cfa37a7b 2004-04-10 devnull .I egprivfree
 91 cfa37a7b 2004-04-10 devnull are provided to manage key storage.
 92 cfa37a7b 2004-04-10 devnull .PP
 93 cfa37a7b 2004-04-10 devnull .I Egsign
 94 cfa37a7b 2004-04-10 devnull signs message
 95 cfa37a7b 2004-04-10 devnull .I m
 96 cfa37a7b 2004-04-10 devnull using a private key
 97 cfa37a7b 2004-04-10 devnull .I k
 98 cfa37a7b 2004-04-10 devnull yielding a
 99 cfa37a7b 2004-04-10 devnull .EX
100 cfa37a7b 2004-04-10 devnull 	struct EGsig
101 cfa37a7b 2004-04-10 devnull 	{
102 cfa37a7b 2004-04-10 devnull 		mpint	*r, *s;
103 cfa37a7b 2004-04-10 devnull 	};
104 cfa37a7b 2004-04-10 devnull .EE
105 cfa37a7b 2004-04-10 devnull .I Egverify
106 cfa37a7b 2004-04-10 devnull returns 0 if the signature is valid and \-1 if not.
107 cfa37a7b 2004-04-10 devnull .PP
108 cfa37a7b 2004-04-10 devnull The routines
109 cfa37a7b 2004-04-10 devnull .I egsigalloc
110 cfa37a7b 2004-04-10 devnull and
111 cfa37a7b 2004-04-10 devnull .I egsigfree
112 cfa37a7b 2004-04-10 devnull are provided to manage signature storage.
113 cfa37a7b 2004-04-10 devnull .SH SOURCE
114 c3674de4 2005-01-11 devnull .B \*9/src/libsec
115 cfa37a7b 2004-04-10 devnull .SH SEE ALSO
116 d32deab1 2020-08-16 rsc .MR mp (3) ,
117 d32deab1 2020-08-16 rsc .MR aes (3) ,
118 d32deab1 2020-08-16 rsc .MR blowfish (3) ,
119 d32deab1 2020-08-16 rsc .MR des (3) ,
120 d32deab1 2020-08-16 rsc .MR dsa (3) ,
121 d32deab1 2020-08-16 rsc .MR rc4 (3) ,
122 d32deab1 2020-08-16 rsc .MR rsa (3) ,
123 d32deab1 2020-08-16 rsc .MR sechash (3) ,
124 d32deab1 2020-08-16 rsc .MR prime (3) ,
125 d32deab1 2020-08-16 rsc .MR rand (3)