1 cfa37a7b 2004-04-10 devnull .TH DSA 3
  2 cfa37a7b 2004-04-10 devnull .SH NAME
  3 cfa37a7b 2004-04-10 devnull dsagen, dsasign, dsaverify, dsapuballoc, dsapubfree, dsaprivalloc, dsaprivfree, dsasigalloc, dsasigfree, dsaprivtopub - digital signature algorithm
  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 DSApriv*	dsagen(DSApub *opub)
 15 cfa37a7b 2004-04-10 devnull .PP
 16 cfa37a7b 2004-04-10 devnull .B
 17 cfa37a7b 2004-04-10 devnull DSAsig*	dsasign(DSApriv *k, mpint *m)
 18 cfa37a7b 2004-04-10 devnull .PP
 19 cfa37a7b 2004-04-10 devnull .B
 20 cfa37a7b 2004-04-10 devnull int		dsaverify(DSApub *k, DSAsig *sig, mpint *m)
 21 cfa37a7b 2004-04-10 devnull .PP
 22 cfa37a7b 2004-04-10 devnull .B
 23 cfa37a7b 2004-04-10 devnull DSApub*	dsapuballoc(void)
 24 cfa37a7b 2004-04-10 devnull .PP
 25 cfa37a7b 2004-04-10 devnull .B
 26 cfa37a7b 2004-04-10 devnull void		dsapubfree(DSApub*)
 27 cfa37a7b 2004-04-10 devnull .PP
 28 cfa37a7b 2004-04-10 devnull .B
 29 cfa37a7b 2004-04-10 devnull DSApriv*	dsaprivalloc(void)
 30 cfa37a7b 2004-04-10 devnull .PP
 31 cfa37a7b 2004-04-10 devnull .B
 32 cfa37a7b 2004-04-10 devnull void		dsaprivfree(DSApriv*)
 33 cfa37a7b 2004-04-10 devnull .PP
 34 cfa37a7b 2004-04-10 devnull .B
 35 cfa37a7b 2004-04-10 devnull DSAsig*	dsasigalloc(void)
 36 cfa37a7b 2004-04-10 devnull .PP
 37 cfa37a7b 2004-04-10 devnull .B
 38 cfa37a7b 2004-04-10 devnull void		dsasigfree(DSAsig*)
 39 cfa37a7b 2004-04-10 devnull .PP
 40 cfa37a7b 2004-04-10 devnull .B
 41 cfa37a7b 2004-04-10 devnull DSApub*	dsaprivtopub(DSApriv*)
 42 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
 43 cfa37a7b 2004-04-10 devnull .PP
 44 cfa37a7b 2004-04-10 devnull DSA is the NIST approved digital signature algorithm.  The owner of a key publishes
 45 cfa37a7b 2004-04-10 devnull the public part of the key:
 46 cfa37a7b 2004-04-10 devnull .EX
 47 cfa37a7b 2004-04-10 devnull 	struct DSApub
 48 cfa37a7b 2004-04-10 devnull 	{
 49 cfa37a7b 2004-04-10 devnull 		mpint	*p;	// modulus
 50 cfa37a7b 2004-04-10 devnull 		mpint	*q;	// group order, q divides p-1
 51 cfa37a7b 2004-04-10 devnull 		mpint	*alpha;	// group generator
 52 cfa37a7b 2004-04-10 devnull 		mpint	*key;	// alpha**secret mod p
 53 cfa37a7b 2004-04-10 devnull 	};
 54 cfa37a7b 2004-04-10 devnull .EE
 55 cfa37a7b 2004-04-10 devnull This part can be used for verifying signatures (with
 56 cfa37a7b 2004-04-10 devnull .IR dsaverify )
 57 cfa37a7b 2004-04-10 devnull created by the owner.
 58 cfa37a7b 2004-04-10 devnull The owner signs (with
 59 cfa37a7b 2004-04-10 devnull .IR dsasign )
 60 cfa37a7b 2004-04-10 devnull using his private key:
 61 cfa37a7b 2004-04-10 devnull .EX
 62 cfa37a7b 2004-04-10 devnull 	struct DSApriv
 63 cfa37a7b 2004-04-10 devnull 	{
 64 cfa37a7b 2004-04-10 devnull 		DSApub	pub;
 65 cfa37a7b 2004-04-10 devnull 		mpint	*secret; // (decryption key)
 66 cfa37a7b 2004-04-10 devnull 	};
 67 cfa37a7b 2004-04-10 devnull .EE
 68 cfa37a7b 2004-04-10 devnull .PP
 69 cfa37a7b 2004-04-10 devnull Keys are generated using
 70 cfa37a7b 2004-04-10 devnull .IR dsagen .
 71 cfa37a7b 2004-04-10 devnull If
 72 cfa37a7b 2004-04-10 devnull .IR dsagen 's
 73 cfa37a7b 2004-04-10 devnull argument
 74 cfa37a7b 2004-04-10 devnull .I opub
 75 cfa37a7b 2004-04-10 devnull is
 76 cfa37a7b 2004-04-10 devnull .BR nil ,
 77 cfa37a7b 2004-04-10 devnull a key is created using a new
 78 cfa37a7b 2004-04-10 devnull .B p
 79 cfa37a7b 2004-04-10 devnull and
 80 cfa37a7b 2004-04-10 devnull .B q
 81 cfa37a7b 2004-04-10 devnull generated by
 82 058b0118 2005-01-03 devnull .IR DSAprimes
 83 058b0118 2005-01-03 devnull (see
 84 058b0118 2005-01-03 devnull .IR prime (3)).
 85 cfa37a7b 2004-04-10 devnull Otherwise,
 86 cfa37a7b 2004-04-10 devnull .B p
 87 cfa37a7b 2004-04-10 devnull and
 88 cfa37a7b 2004-04-10 devnull .B q
 89 cfa37a7b 2004-04-10 devnull are copied from the old key.
 90 cfa37a7b 2004-04-10 devnull .PP
 91 cfa37a7b 2004-04-10 devnull .I Dsaprivtopub
 92 cfa37a7b 2004-04-10 devnull returns a newly allocated copy of the public key
 93 cfa37a7b 2004-04-10 devnull corresponding to the private key.
 94 cfa37a7b 2004-04-10 devnull .PP
 95 cfa37a7b 2004-04-10 devnull The routines
 96 cfa37a7b 2004-04-10 devnull .IR dsapuballoc ,
 97 cfa37a7b 2004-04-10 devnull .IR dsapubfree ,
 98 cfa37a7b 2004-04-10 devnull .IR dsaprivalloc ,
 99 cfa37a7b 2004-04-10 devnull and
100 cfa37a7b 2004-04-10 devnull .I dsaprivfree
101 cfa37a7b 2004-04-10 devnull are provided to manage key storage.
102 cfa37a7b 2004-04-10 devnull .PP
103 cfa37a7b 2004-04-10 devnull .I Dsasign
104 cfa37a7b 2004-04-10 devnull signs message
105 cfa37a7b 2004-04-10 devnull .I m
106 cfa37a7b 2004-04-10 devnull using a private key
107 cfa37a7b 2004-04-10 devnull .I k
108 cfa37a7b 2004-04-10 devnull yielding a
109 cfa37a7b 2004-04-10 devnull .EX
110 cfa37a7b 2004-04-10 devnull 	struct DSAsig
111 cfa37a7b 2004-04-10 devnull 	{
112 cfa37a7b 2004-04-10 devnull 		mpint	*r, *s;
113 cfa37a7b 2004-04-10 devnull 	};
114 cfa37a7b 2004-04-10 devnull .EE
115 cfa37a7b 2004-04-10 devnull .I Dsaverify
116 cfa37a7b 2004-04-10 devnull returns 0 if the signature is valid and \-1 if not.
117 cfa37a7b 2004-04-10 devnull .PP
118 cfa37a7b 2004-04-10 devnull The routines
119 cfa37a7b 2004-04-10 devnull .I dsasigalloc
120 cfa37a7b 2004-04-10 devnull and
121 cfa37a7b 2004-04-10 devnull .I dsasigfree
122 cfa37a7b 2004-04-10 devnull are provided to manage signature storage.
123 cfa37a7b 2004-04-10 devnull .SH SOURCE
124 c3674de4 2005-01-11 devnull .B \*9/src/libsec
125 cfa37a7b 2004-04-10 devnull .SH SEE ALSO
126 bf8a59fa 2004-04-11 devnull .IR mp (3),
127 bf8a59fa 2004-04-11 devnull .IR aes (3),
128 bf8a59fa 2004-04-11 devnull .IR blowfish (3),
129 bf8a59fa 2004-04-11 devnull .IR des (3),
130 bf8a59fa 2004-04-11 devnull .IR rc4 (3),
131 bf8a59fa 2004-04-11 devnull .IR rsa (3),
132 bf8a59fa 2004-04-11 devnull .IR sechash (3),
133 bf8a59fa 2004-04-11 devnull .IR prime (3),
134 bf8a59fa 2004-04-11 devnull .IR rand (3)