| rsc | cfa37a7 | 2004-04-10 18:53:55 +0000 | [diff] [blame] | 1 | .TH ELGAMAL 3 |
| 2 | .SH NAME |
| 3 | eggen, egencrypt, egdecrypt, egsign, egverify, egpuballoc, egpubfree, egprivalloc, egprivfree, egsigalloc, egsigfree, egprivtopub - elgamal encryption |
| 4 | .SH SYNOPSIS |
| 5 | .B #include <u.h> |
| 6 | .br |
| 7 | .B #include <libc.h> |
| 8 | .br |
| 9 | .B #include <mp.h> |
| 10 | .br |
| 11 | .B #include <libsec.h> |
| 12 | .PP |
| 13 | .B |
| 14 | EGpriv* eggen(int nlen, int nrep) |
| 15 | .PP |
| 16 | .B |
| 17 | mpint* egencrypt(EGpub *k, mpint *in, mpint *out) |
| 18 | .PP |
| 19 | .B |
| 20 | mpint* egdecrypt(EGpriv *k, mpint *in, mpint *out) |
| 21 | .PP |
| 22 | .B |
| 23 | EGsig* egsign(EGpriv *k, mpint *m) |
| 24 | .PP |
| 25 | .B |
| 26 | int egverify(EGpub *k, EGsig *sig, mpint *m) |
| 27 | .PP |
| 28 | .B |
| 29 | EGpub* egpuballoc(void) |
| 30 | .PP |
| 31 | .B |
| 32 | void egpubfree(EGpub*) |
| 33 | .PP |
| 34 | .B |
| 35 | EGpriv* egprivalloc(void) |
| 36 | .PP |
| 37 | .B |
| 38 | void egprivfree(EGpriv*) |
| 39 | .PP |
| 40 | .B |
| 41 | EGsig* egsigalloc(void) |
| 42 | .PP |
| 43 | .B |
| 44 | void egsigfree(EGsig*) |
| 45 | .PP |
| 46 | .B |
| 47 | EGpub* egprivtopub(EGpriv*) |
| 48 | .SH DESCRIPTION |
| 49 | .PP |
| 50 | Elgamal is a public key encryption and signature algorithm. The owner of a key publishes |
| 51 | the public part of the key: |
| 52 | .EX |
| 53 | struct EGpub |
| 54 | { |
| 55 | mpint *p; // modulus |
| 56 | mpint *alpha; // generator |
| 57 | mpint *key; // (encryption key) alpha**secret mod p |
| 58 | }; |
| 59 | .EE |
| 60 | This part can be used for encrypting data (with |
| 61 | .IR egencrypt ) |
| 62 | to be sent to the owner. |
| 63 | The owner decrypts (with |
| 64 | .IR egdecrypt ) |
| 65 | using his private key: |
| 66 | .EX |
| 67 | struct EGpriv |
| 68 | { |
| 69 | EGpub pub; |
| 70 | mpint *secret; // (decryption key) |
| 71 | }; |
| 72 | .EE |
| 73 | .PP |
| 74 | Keys are generated using |
| 75 | .IR eggen . |
| 76 | .I Eggen |
| 77 | takes both bit length of the modulus |
| 78 | and the number of repetitions of the Miller-Rabin |
| 79 | primality test to run. If the latter is 0, it does the default number |
| 80 | of rounds. |
| 81 | .I Egprivtopub |
| 82 | returns a newly allocated copy of the public key |
| 83 | corresponding to the private key. |
| 84 | .PP |
| 85 | The routines |
| 86 | .IR egpuballoc , |
| 87 | .IR egpubfree , |
| 88 | .IR egprivalloc , |
| 89 | and |
| 90 | .I egprivfree |
| 91 | are provided to manage key storage. |
| 92 | .PP |
| 93 | .I Egsign |
| 94 | signs message |
| 95 | .I m |
| 96 | using a private key |
| 97 | .I k |
| 98 | yielding a |
| 99 | .EX |
| 100 | struct EGsig |
| 101 | { |
| 102 | mpint *r, *s; |
| 103 | }; |
| 104 | .EE |
| 105 | .I Egverify |
| 106 | returns 0 if the signature is valid and \-1 if not. |
| 107 | .PP |
| 108 | The routines |
| 109 | .I egsigalloc |
| 110 | and |
| 111 | .I egsigfree |
| 112 | are provided to manage signature storage. |
| 113 | .SH SOURCE |
| rsc | c3674de | 2005-01-11 17:37:33 +0000 | [diff] [blame] | 114 | .B \*9/src/libsec |
| rsc | cfa37a7 | 2004-04-10 18:53:55 +0000 | [diff] [blame] | 115 | .SH SEE ALSO |
| rsc | bf8a59f | 2004-04-11 03:42:27 +0000 | [diff] [blame] | 116 | .IR mp (3), |
| 117 | .IR aes (3), |
| 118 | .IR blowfish (3), |
| 119 | .IR des (3), |
| 120 | .IR dsa (3), |
| 121 | .IR rc4 (3), |
| 122 | .IR rsa (3), |
| 123 | .IR sechash (3), |
| 124 | .IR prime (3), |
| 125 | .IR rand (3) |
