GNU Privacy Guard Copyright ? 1999 The Free Software Foundation Copyright ? 2000-2002 . . . , / GNU Free Documentation License, Version 1.1 , Free Software Foundation; , . "GNU Free Documentation License". , (Mike Ashley) (). ( ) (< zwon@e-mail.ru>). , , (Matthew Copeland), (Joergen Grahn), . (David A. Wheeler). http://www.gnupg.org/ docs.html. ------------------------------------------------------------------------------- ?????????? 1. . (Clearsigned) ? 2. 3. . 4. GnuPG . GnuPG 5. A. (History) B. GNU Free Documentation License 0. PREAMBLE 1. APPLICABILITY AND DEFINITIONS 2. VERBATIM COPYING 3. COPYING IN QUANTITY 4. MODIFICATIONS 5. COMBINING DOCUMENTS 6. COLLECTIONS OF DOCUMENTS 7. AGGREGATION WITH INDEPENDENT WORKS 8. TRANSLATION 9. TERMINATION 10. FUTURE REVISIONS OF THIS LICENSE How to use this License for your documents ?????? ??????????? 3-1. ------------------------------------------------------------------------------- ????? 1. GnuPG - . GnuPG, , , , . , , 2. , , GnuPG, 3 4. GnuPG . (keypair), (private) (public) . , . , . GnuPG , , , . , , , , , . ------------------------------------------------------------------------------- --gen-key alice% gpg --gen-key gpg (GnuPG) 1.2.0; Copyright (C) 2002 Free Software Foundation, Inc. This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions. See the file COPYING for details. Please select what kind of key you want: (1) DSA and ElGamal (default) (2) DSA (sign only) (5) RSA (sign only) Your selection? GnuPG , (signature). . 1 . DSA - , . ElGamal - , . 2 , DSA, . 5 RSA, . , . , , 5. . DSA 512 1024 . ElGamal RSA . GnuPG 768 . 1, DSA 1024 ElGamal. Your selection? 1 DSA keypair will have 1024 bits. About to generate a new ELG-E keypair. minimum keysize is 768 bits default keysize is 1024 bits highest suggested keysize is 2048 bits What keysize do you want? (1024) , . . . , . 1, . Please specify how long the key should be valid. 0 = key does not expire = key expires in n days w = key expires in n weeks m = key expires in n months y = key expires in n years Key is valid for? (0) . ; , , . , . , . You need a User-ID to identify your key; the software constructs the user id from Real Name, Comment and Email Address in this form: "Heinrich Heine (Der Dichter) " Real name: Alice Email address: alice@wonderland.uk Comment: test key You selected this USER-ID: "Alice (test key) " Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? , , ; , . . GnuPG , . You need a Passphrase to protect your private key. Enter passphrase: , . , GnuPG ( ), . . , . , . GnuPG. GnuPG . , . , . ------------------------------------------------------------------------------- , (revokation certificate) , --gen-revoke. , , , . , . , , . alice% gpg --output revoke.asc --gen-revoke mykey [...] mykey - . revoke.asc. --output , . , GnuPG . alice% gpg --output revoke.asc --gen-revoke alice@wonderland.uk sec 1024R/B115BDB6 2002-05-01 Alice (test key) Create a revocation certificate for this key? y Please select the reason for the revocation: 0 = No reason specified 1 = Key has been compromised 2 = Key is superseded 3 = Key is no longer used Q = Cancel (Probably you want to select 1 here) Your decision? 1 Enter an optional description; end it with an empty line: > Reason for revocation: Key has been compromised (No description given) Is this okay? y - ( ). , . ------------------------------------------------------------------------------- - , . , --list-keys. alice% gpg --list-keys /home/alice/.gnupg/pubring.gpg --------------------------------------- pub 1024R/B115BDB6 2002-05-01 Alice (test key) ------------------------------------------------------------------------------- - , . --export. , , , , --gen-revoke. alice% gpg --output alice.gpg --export alice@wonderland.uk , . GnuPG --armor, ASCII. GnuPG, . . , , , ASCII.[1] alice% gpg --armor --export alice@wonderland.uk -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v1.2.0 (FreeBSD) mIsEPNAu8wEEALf1zGv9/bkEKL1fTpkr0lvsmtK5Frgymlk7uInWfFdoucjAci9t wyU8HXNdFNCx1utWT5GNDD1aDhiFukc7UrFVuVbAjtOikFrZ939RrLKqOEoVd8XI ZXbgiSjs2ZqG32PpB+9X+3Z4OM64tna0NTvyqYP9LtOPHZpYGHwd5McfAAYptCZB bGljZSAodGVzdCBrZXkpIDxhbGljZUB3b25kZXJsYW5kLnVrPoiyBBMBAgAcBQI8 0C7zAhsDBAsHAwIDFQIDAxYCAQIeAQIXgAAKCRDHOpmHsRW9tvsYBACmRyUoCnj5 Awh/bFTcmsZi687ec4EzCby8OF586FAQSj4HX4LvAUc/u+4NHVbQRkKW2RJVnaHv YHUmjgteywMN3YqKd80/fbWIjyIgKNY+vgSEPMwiNMo6hR1frtfTMBnmwIWADMn0 3I1kxP2GfreSCHgy+FA3k5lrxvFnZwkXcA== =RowZ -----END PGP PUBLIC KEY BLOCK----- ------------------------------------------------------------------------------- --import. alice% gpg --import blake.asc gpg: key 01A1FE63: public key "Blake (dumb) pub 1024R/01A1FE63 2002-05-01 Blake (dumb) sub 1024R/526C7F7F 2002-05-01 [expires: 2003-05-01] . GnuPG , , . , . (fingerprint) , , , . --fingerprint. alice% gpg --fingerprint alice@wonderland.uk pub 1024R/B115BDB6 2002-05-01 Alice (test key) Key fingerprint = DE49 CDEF 12A3 8B7B 272B A572 C73A 9987 B115 BDB6 alice% gpg --fingerprint /home/test/.gnupg/pubring.gpg ----------------------------- pub 1024R/B115BDB6 2002-05-01 Alice (test key) Key fingerprint = DE49 CDEF 12A3 8B7B 272B A572 C73A 9987 B115 BDB6 pub 1024R/01A1FE63 2002-05-01 Blake (dumb) Key fingerprint = 80B8 1955 7D68 FE4F D882 DAD1 D85C 124A 01A1 FE63 sub 1024R/526C7F7F 2002-05-01 [expires: 2003-05-01] . , , , , . , , . . , , , . --edit-key. alice% gpg --edit-key blake@anywhere.ru pub 1024R/01A1FE63 created: 2002-05-01 expires: never trust: -/- sub 1024R/526C7F7F created: 2002-05-01 expires: 2003-05-01 (1). Blake (dumb) Command> sign pub 1024R/01A1FE63 created: 2002-05-01 expires: never trust: -/- Primary key fingerprint: 80B8 1955 7D68 FE4F D882 DAD1 D85C 124A 01A1 FE63 Blake (dumb) How carefully have you verified the key you are about to sign actually belongs to the person named above? If you don't know what to answer, enter "0". (0) I will not answer. (default) (1) I have not checked at all. (2) I have done casual checking. (3) I have done very careful checking. Your selection? 3 Are you really sure that you want to sign this key with your key: "Alice (test key) " Really sign? y GnuPG . , . , . Command> check uid Blake (dumb) sig!3 01A1FE63 2002-05-01 [self-signature] sig! B115BDB6 2002-05-01 Alice (test key) ------------------------------------------------------------------------------- . 2 (DSA) 5 (RSA), . , , , . . alice%gpg --edit-key alice@wonderland.uk Secret key is available. pub 1024R/B115BDB6 created: 2002-05-01 expires: never trust: u/u (1). Alice (test key) Command> addkey Key is protected. You need a passphrase to unlock the secret key for user: "Alice (test key) " 1024-bit RSA key, ID B115BDB6, created 2002-05-01 Please select what kind of key you want: (2) DSA (sign only) (3) ElGamal (encrypt only) (5) RSA (sign only) (6) RSA (encrypt only) Your selection? , 3 6. Your selection? 6 What keysize do you want? (1024) Requested keysize is 1024 bits Please specify how long the key should be valid. 0 = key does not expire = key expires in n days w = key expires in n weeks m = key expires in n months y = key expires in n years Key is valid for? (0) Key does not expire at all Is this correct (y/n)? y Really create? y We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. +++++ ..+++++ pub 1024R/B115BDB6 created: 2002-05-01 expires: never trust: u/u sub 1024R/89D3ED33 created: 2002-05-03 expires: never (1). Alice (test key) Command> save , . , , , save. ------------------------------------------------------------------------------- , . . , . - , , . , , . , , . , , . --encrypt. . , , . , --output. . alice% gpg --output message.gpg --encrypt --recipient blake@anywhere.ru message.txt --recipient , , . , . , , . --decrypt. , . , . blake% gpg --output message.txt --decrypt message.gpg You need a passphrase to unlock the secret key for user: "Blake (dumb) " 1024-bit RSA key, ID 526C7F7F, created 2002-05-01 (main key ID 01A1FE63) Enter passphrase: , , . . , , . , . , . --symmetric. alice% gpg --output message.gpg --symmetric message.txt Enter passphrase: ------------------------------------------------------------------------------- . - , . , . GnuPG, , , , ? . / . , . , Alice , . , , Alice, , Alice . --sign. alice% gpg --output doc.sig --sign doc You need a passphrase to unlock the secret key for user: "Alice (test key) " 1024-bit RSA key, ID B115BDB6, created 2002-05-01 Enter passphrase: , . . . , , . --verify. --decrypt. blake% gpg --output doc --decrypt doc.sig gpg: Signature made Sat May 4 19:04:21 2002 MSD using RSA key ID B115BDB6 gpg: Good signature from "Alice (test key) " ------------------------------------------------------------------------------- (Clearsigned) usenet e-mail. . --clearsign ASCII, . alice% gpg --output doc.asc --clearsign doc You need a passphrase to unlock the secret key for user: "Alice (test key) " 1024-bit RSA key, ID B115BDB6, created 2002-05-01 Enter passphrase: alice% cat doc.asc -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 GnuPG - . GnuPG, , , , . , . 2. , , GnuPG. 3 4. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iQCVAwUBPNP8VMc6mYexFb22AQLdAAP/SXHINHglH00hLlscGoVE1FCiFX7qTSO3 qwUFQi29WhqCXCq4DFTfZGTs4XQzb7592KpDy9swwNZ2sB7vaxQjqukffBdWrksZ ERSZsz+xxKLWPiiBURg958Nym/eIRFY7nislv9Kc4V0UFDD9CjuE0rA7eWCg1XEX 0RcI2Zxiiv4= =UV8s -----END PGP SIGNATURE----- ------------------------------------------------------------------------------- ? . , , . , ? (detached signature). ? --detach-sign. alice% gpg --output doc.sig --detach-sign doc You need a passphrase to unlock the secret key for user: "Alice (test key) " 1024-bit RSA key, ID B115BDB6, created 2002-05-01 Enter passphrase: , . --verify. blake% gpg --verify doc.sig doc gpg: Signature made Sat May 4 19:34:08 2002 MSD using RSA key ID B115BDB6 gpg: Good signature from "Alice (test key) " ------------------------------------------------------------------------------- ????? 2. GnuPG , , , . GnuPG , , , - . - , GnuPG. . , : Bruce Schneier ``Applied Cryptography''. ( : . . . , , .- .: , 2002 - 816 .: .) ------------------------------------------------------------------------------- . , , . , , , , , . , Enigma - , . . . : 3DES, Blowfish, IDEA . , . , . , . , GnuPG, . , , . , , . . , . , . , . , , . , . , . Enigma , , "Bombes", . , . "Bombes" , . , . DES 56 , . . 2^56 . 2^56 72,057,594,037,927,936 . , , . , - 3DES, Blowfish IDEA 128 , 2^128 . , , , , , , . ------------------------------------------------------------------------------- - . , , ? , , . - . n , n(n-1)/2 , , . , . , . . . (public key) . (private key) . , , , . , . . , . , . , n n , . "c ". , , , . . . , , . " " , . , , . , , , , , . , , . , , , , , . , . , . 80 , 2^81-1 . 512 , 512 ( 155 ). . , , 128 , 1024 . ------------------------------------------------------------------------------- . , , / , . , , . . . , , . , , . PGP GnuPG . , , , , . , , . . PGP GnuPG, , , . , , , . , . ------------------------------------------------------------------------------- " - - ", . - . - f(x) = 0 x. f(x) = x mod 37, x x 37. - . , . - , . - , . [2] . . , . , , . , . SHA MD5 . , , . , , . , . , . , , . , . - . , . , . , , , , . , . . , , . , , , , , . , , . , , . . DSA , . DSA - , GnuPG. ------------------------------------------------------------------------------- ????? 3. - . . , , , . , (man in the middle). . , , . , . , , . , , . , . GnuPG . : , , , . (web of trust), , , . , , GnuPG. ------------------------------------------------------------------------------- . , , , . . -- , , . . -- , email. , . --edit-key. , joe% gpg --edit-key joe@duck.zu Secret key is available. pub 1024R/3AA48DCE created: 2002-05-05 expires: never trust: u/u sub 1024D/13375D62 created: 2002-05-06 expires: never sub 2048G/3745CA64 created: 2002-05-06 expires: 2004-05-05 sub 1024g/015418C9 created: 2002-05-06 expires: 2004-05-05 (1) Joe Duck (2). Joe Duck (cook) Command> , . . . pub , sub . , . D DSA, R - RSA, g - ElGamal, , G - ElGamal, . . . . toggle , . Command> toggle sec 1024R/3AA48DCE created: 2002-05-05 expires: never ssb 1024D/13375D62 created: 2002-05-06 expires: never ssb 2048G/3745CA64 created: 2002-05-06 expires: never ssb 1024g/015418C9 created: 2002-05-06 expires: never (1) Joe Duck (2) Joe Duck (cook) Command> . sec , sbb . . ------------------------------------------------------------------------------- . . , , , . . . , . , , . , , , . . , . , , . , , , . (self-signing), , , , (certificate). , . check . joe% gpg --edit-key joe Secret key is available. pub 1024R/3AA48DCE created: 2002-05-05 expires: never trust: u/u sub 1024D/13375D62 created: 2002-05-06 expires: never sub 2048G/3745CA64 created: 2002-05-06 expires: 2004-05-05 sub 1024g/015418C9 created: 2002-05-06 expires: 2004-05-05 (1) Joe Duck (2). Joe Duck (cook) Command> check uid Joe Duck sig!3 3AA48DCE 2002-05-05 [self-signature] uid Joe Duck (cook) sig!3 3AA48DCE 2002-05-06 [self-signature] , 0x3AA48DCE. , GnuPG. ------------------------------------------------------------------------------- , . adduid. , , . addkey. . DSA , ElGamal , ElGamal RSA , . , , , ? . , . , - , , . . , . , . . , , , , , , . , . , . , , , . , . . , , key uid. . , key 2 , key 2 . , . , , , deluid . , delkey , , . , -- . , , , . . . , , , . , . , . , . , , , , - . , , . ------------------------------------------------------------------------------- . , revkey. . --gen-revoke, . Command> revkey Do you really want to revoke this key? y Please select the reason for the revocation: 0 = No reason specified 1 = Key has been compromised 2 = Key is superseded 3 = Key is no longer used Q = Cancel Your decision? 2 Enter an optional description; end it with an empty line: > Reason for revocation: Key is superseded (No description given) Is this okay? y You need a passphrase to unlock the secret key for user: "Joe Duck (cook) " 1024-bit RSA key, ID 3AA48DCE, created 2002-05-05 pub 1024R/3AA48DCE created: 2002-05-05 expires: never trust: u/u sub 1024D/13375D62 created: 2002-05-06 expires: never sub 2048G/3745CA64 created: 2002-05-06 expires: 2004-05-05 rev! subkey has been revoked: 2002-05-07 sub 1024g/015418C9 created: 2002-05-06 expires: 2004-05-05 (1) Joe Duck (2). Joe Duck (cook) . , , . , , . . . , , , , , . OpenPGP , . , , . revsig. . . , . Command> revsig You have signed these user IDs: Joe Duck signed by 3AA48DCE at 2002-05-05 Joe Duck (cook) signed by 3AA48DCE at 2002-05-06 user ID: "Joe Duck " signed with your key 3AA48DCE at 2002-05-05 Create a revocation certificate for this signature? (y/N) n user ID: "Joe Duck (cook) " signed with your key 3AA48DCE at 2002-05-06 Create a revocation certificate for this signature? (y/N) y You are about to revoke these signatures: Joe Duck (cook) signed by 3AA48DCE at 2002-05-06 Really create the revocation certificates? (y/N) y Please select the reason for the revocation: 0 = No reason specified 4 = User ID is no longer valid Q = Cancel Your decision? 4 Enter an optional description; end it with an empty line: > Reason for revocation: User ID is no longer valid (No description given) Is this okay? y You need a passphrase to unlock the secret key for user: "Joe Duck (cook) " 1024-bit RSA key, ID 3AA48DCE, created 2002-05-05 pub 1024R/3AA48DCE created: 2002-05-05 expires: never trust: u/u sub 1024D/13375D62 created: 2002-05-06 expires: never sub 2048G/3745CA64 created: 2002-05-06 expires: 2004-05-05 rev! subkey has been revoked: 2002-05-07 sub 1024g/015418C9 created: 2002-05-06 expires: 2004-05-05 (1) Joe Duck (2). Joe Duck (cook) . Command> check uid Joe Duck sig!3 3AA48DCE 2002-05-05 [self-signature] uid Joe Duck (cook) rev! 3AA48DCE 2002-05-07 [revocation] sig!3 3AA48DCE 2002-05-06 [self-signature] , . . . , , . , , , . ------------------------------------------------------------------------------- expire . , . . . . , . , . ------------------------------------------------------------------------------- 1 : , . , , , , , . , , . GnuPG (web of trust). , . , * , * . , , , , . . , , , , , , , . ------------------------------------------------------------------------------- . , , . . , , , . , , . . . unknown ( ) . , , . none ( ) . marginal ( ) , . full ( ) , . ultimate ( ) . , , . ; . trust . , . alice% gpg --edit-key blake pub 1024R/01A1FE63 created: 2002-05-01 expires: never trust: -/f sub 1024R/526C7F7F created: 2002-05-01 expires: 2003-05-01 (1). Blake (dumb) Command> trust pub 1024R/01A1FE63 created: 2002-05-01 expires: never trust: -/f sub 1024R/526C7F7F created: 2002-05-01 expires: 2003-05-01 (1). Blake (dumb) Please decide how far you trust this user to correctly verify other users' keys (by looking at passports, checking fingerprints from different sources...)? 1 = Don't know 2 = I do NOT trust 3 = I trust marginally 4 = I trust fully 5 = I trust ultimately i = please show me more information m = back to the main menu Your decision? 3 pub 1024R/01A1FE63 created: 2002-05-01 expires: never trust: m/f sub 1024R/526C7F7F created: 2002-05-01 expires: 2003-05-01 (1). Blake (dumb) , . , [3]. / : (q), (n), (m), (f), (u). , , . . . , . ------------------------------------------------------------------------------- . , , . K , : 1. , . . + ( , ), + , + ; 2. K . , --max-cert-depth, --marginals-needed --completes-needed. - GnuPG . ???. 3-1 . . , . , . . , , , . . . . , , . , . . . , , . , , . , . . , , , . . , , , , . . , . . GnuPG . K . , . - , K , . , , , . . , . ??????? 3-1. [signatures] +-----------------------------------------------------------------------------+ | | | |------------------------------------+----------------------------------------| | | | | | |------------------+-----------------+------------+---------------------------| | | | | , , , | | | | | | |------------------+-----------------+------------+---------------------------| | , | | | , , | |------------------+-----------------+------------+---------------------------| | , | | , | , | | | | | | |------------------+-----------------+------------+---------------------------| | , , | | | , , , | | | | | | |------------------+-----------------+------------+---------------------------| | | , , | | , , , | | | | | | +-----------------------------------------------------------------------------+ ------------------------------------------------------------------------------- , . , , . , , - . , , , , . , . , , . , , , . . , , , , , . PGP. . . . . , . . --send-keys. . , --keyserver. , --recv-keys , --recv-keys . certserver.pgp.com . alice% gpg --keyserver certserver.pgp.com --recv-key 0xBB7576AC gpg: requesting key B115BDB6 from certserver.pgp.com ... gpg: key B115BDB6: 1 new signature gpg: Total number processed: 1 gpg: new signatures: 1 alice% gpg --keyserver certserver.pgp.com --send-key blake@anywhere.ru gpg: success sending to 'certserver.pgp.com' (status=200) . , . ------------------------------------------------------------------------------- ????? 4. GnuPG GnuPG , , . , . . , GnuPG . GnuPG, . , , , , GnuPG . . GnuPG . GnuPG GnuPG. , GnuPG, . ------------------------------------------------------------------------------- GnuPG . . , GnuPG, , . , , , , , . GnuPG GnuPG - . , , , . GnuPG : * , * , * , * . . - . . , , , GnuPG, , . ------------------------------------------------------------------------------- . OpenPGP, / . , , . , DSA , ElGamal . DSA 1024 . , , , . DSA , 1024 . ElGamal RSA . . . GnuPG , 128- , . , . . . . , , , . , . 1024 - . , . ------------------------------------------------------------------------------- ? GnuPG. - , . , . . , GnuPG . , - . , , . , , , , . , GnuPG . . . , : (1) , (2) . - . , , . . , , , GnuPG , GnuPG. , , , , . . GnuPG. , , . , , , . , , , 128 . , . , , k3wldood, . . , , . . . , . , , . . , , , } |. , . ------------------------------------------------------------------------------- , , DSA ElGamal . , . . , , . , , , , . , . , , , , , , , . , , , . . , , . . . - , . , . , , , , , . , . , . , . , , , , . . . , , . , . . , , , . , . , . . , , , , . , , . . , , , , . ------------------------------------------------------------------------------- . , GnuPG, . GnuPG , . , , - , . , . . , , , . , GnuPG. , , , , . , --marginals-needed --completes-needed. , , , , , , . , , . , , GnuPG . , , , , , , . , --completes-needed 1 --marginals-needed 2. , 1 3 2 3 . , 1 1. , , , , , . ------------------------------------------------------------------------------- GnuPG . , , . . , , GnuPG[4], , . , . , , GnuPG. GnuPG, , . , , . . . , , , . , , GnuPG. , , : (1) , GnuPG, (2) , , . , , GnuPG. , , GnuPG. : , - , . , . , , GnuPG. . , , . , . , - . , . . GnuPG , , . , , GnuPG . ------------------------------------------------------------------------------- GnuPG , , , , . Bert-Japp Koops Crypto Law Survey, , . ------------------------------------------------------------------------------- ????? 5. . . , . , , ! ------------------------------------------------------------------------------- Alma Whitten Doug Tygar PGP 5.0 , PGP . , , . . . PGP 5.0 , OpenPGP. , , , , . Whitten' Tygar' . . , , , . , , . , GnuPG. , . , , GUI , , , . . , , . * , ; , . . . * . , , . * . , ``encrypt'' ``encipher''. * . , . . . OpenPGP, , . , : (none), (marginal), ( omplete). , , . , ``marginals needed'' ``completes needed''. , , . , , , , . . * , . * , , , , , , . ------------------------------------------------------------------------------- ?????????? A. (History) 1. GNU Privacy Handbook. 1999 . Mike Ashley. 2. GNU Privacy Guard. 2001 . . . 3. GNU Privacy Guard. 2002 . . gnupg 1.0.7. RSA. , . ------------------------------------------------------------------------------- ?????????? B. GNU Free Documentation License Version 1.1, March 2000 Copyright (C) 2000 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. ------------------------------------------------------------------------------- 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other written document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. ------------------------------------------------------------------------------- 1. APPLICABILITY AND DEFINITIONS This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (For example, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, whose contents can be viewed and edited directly and straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent. A copy that is not "Transparent" is called "Opaque". Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML designed for human modification. Opaque formats include PostScript, PDF, proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML produced by some word processors for output purposes only. The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text. ------------------------------------------------------------------------------- 2. VERBATIM COPYING You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. You may also lend copies, under the same conditions stated above, and you may publicly display copies. ------------------------------------------------------------------------------- 3. COPYING IN QUANTITY If you publish printed copies of the Document numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a publicly-accessible computer-network location containing a complete Transparent copy of the Document, free of added material, which the general network-using public has access to download anonymously at no charge using public-standard network protocols. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. ------------------------------------------------------------------------------- 4. MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission. B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has less than five). C. State on the Title page the name of the publisher of the Modified Version, as the publisher. D. Preserve all the copyright notices of the Document. E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices. F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below. G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice. H. Include an unaltered copy of this License. I. Preserve the section entitled "History", and its title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence. J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission. K. In any section entitled "Acknowledgements" or "Dedications", preserve the section's title, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein. L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles. M. Delete any section entitled "Endorsements". Such a section may not be included in the Modified Version. N. Do not retitle any existing section as "Endorsements" or to conflict in title with any Invariant Section. If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles. You may add a section entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. ------------------------------------------------------------------------------- 5. COMBINING DOCUMENTS You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice. The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. In the combination, you must combine any sections entitled "History" in the various original documents, forming one section entitled "History"; likewise combine any sections entitled "Acknowledgements", and any sections entitled "Dedications". You must delete all sections entitled "Endorsements." ------------------------------------------------------------------------------- 6. COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. ------------------------------------------------------------------------------- 7. AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, does not as a whole count as a Modified Version of the Document, provided no compilation copyright is claimed for the compilation. Such a compilation is called an "aggregate", and this License does not apply to the other self-contained works thus compiled with the Document, on account of their being thus compiled, if they are not themselves derivative works of the Document. If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one quarter of the entire aggregate, the Document's Cover Texts may be placed on covers that surround only the Document within the aggregate. Otherwise they must appear on covers around the whole aggregate. ------------------------------------------------------------------------------- 8. TRANSLATION Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License provided that you also include the original English version of this License. In case of a disagreement between the translation and the original English version of this License, the original English version will prevail. ------------------------------------------------------------------------------- 9. TERMINATION You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. ------------------------------------------------------------------------------- 10. FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/. Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. ------------------------------------------------------------------------------- How to use this License for your documents To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (c) YEAR YOUR NAME. Permission is granted to copy, distribute and /or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. A copy of the license is included in the section entitled "GNU Free Documentation License". If you have no Invariant Sections, write "with no Invariant Sections" instead of saying which ones are invariant. If you have no Front-Cover Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise for Back-Cover Texts. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. ?????????? [1] , , . [2] , , . RSA - , ElGamal . 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