NAME

	eggen, egencrypt, egdecrypt, egsign, egverify, egpuballoc, egpubfree, egprivalloc, egprivfree, egsigalloc, egsigfree, egprivtopub - elgamal encryption

SYNOPSIS

#include <u.h> #include <libc.h> #include <mp.h> #include <libsec.h> EGpriv*     eggen(int nlen, int nrep) mpint*      egencrypt(EGpub *k, mpint *in, mpint *out) mpint*      egdecrypt(EGpriv *k, mpint *in, mpint *out) EGsig*      egsign(EGpriv *k, mpint *m) int         egverify(EGpub *k, EGsig *sig, mpint *m) EGpub*      egpuballoc(void) void        egpubfree(EGpub*) EGpriv*     egprivalloc(void) void        egprivfree(EGpriv*) EGsig*      egsigalloc(void) void        egsigfree(EGsig*) EGpub*      egprivtopub(EGpriv*)

DESCRIPTION

Elgamal is a public key encryption and signature algorithm. The owner of a key publishes the public part of the key: struct EGpub { mpint       *p;    // modulus mpint       *alpha;     // generator mpint       *key;       // (encryption key) alpha**secret mod p }; This part can be used for encrypting data (with egencrypt) to be sent to the owner. The owner decrypts (with egdecrypt) using his private key: struct EGpriv { EGpub       pub; mpint       *secret; // (decryption key) }; Keys are generated using eggen. Eggen takes both bit length of the modulus and the number of repetitions of the Miller-Rabin primality test to run. If the latter is 0, it does the default number of rounds. Egprivtopub returns a newly allocated copy of the public key corresponding to the private key. The routines egpuballoc, egpubfree, egprivalloc, and egprivfree are provided to manage key storage. Egsign signs message m using a private key k yielding a struct EGsig { mpint       *r, *s; }; Egverify returns 0 if the signature is valid and –1 if not. The routines egsigalloc and egsigfree are provided to manage signature storage.

SOURCE

	/usr/local/plan9/src/libsec

SEE ALSO

	mp(3), aes(3), blowfish(3), des(3), dsa(3), rc4(3), rsa(3), sechash(3), prime(3), rand(3)