Kryptografie

Pro?? integrujeme kryptografii?

T??emi slovy: Proto??e my m????eme.

OpenBSD projekt s??dl?? v Kanad??.

Export Control List of Canada neomezuje export kryptografick??ho software a je dokonce v??ce otev??en?? pro export voln?? dostupn??ho kryptografick??ho software. Marc Plumb provedl v??zkum k otestov??n?? kryptografick??ch z??kon??.

Z toho d??vodu OpenBSD projekt pou??il kryptografii na n??kolika m??stech v opera??n??m syst??mu. Po??adujeme,aby kryptografick?? software,kter?? pou????v??me byl voln?? dostupn?? a s dobrou licenc??. Nepou????v??me kryptografii s odporn??mi patenty.Tak?? po??adujeme,??e tento software je ze zem?? s pou??itelnou exportn?? licenc??,proto??e nechceme poru??ovat z??kony jak??koliv zem??. Komponenty kryptografick??ho software,kter?? aktu??ln?? pou????v??me byly naps??ny v Argentin??, Austr??lii,Kanad??,N??mecku,??ecku,Norsku a ??v??dsku.

Kdy?? vytv??????me release nebo snapshot,tak sestavujeme jejich bin??rn?? verze ve svobodn??ch zem??ch abychom zajistili,??e zdroje a bin??rky,kter?? poskytujeme u??ivatel??m jsou bez poskvrny. V minulosti byly na??e vydan?? bin??rn?? buildy ud??l??ny v Kanad??,??v??dsku a N??mecku.

OpenBSD je vyd??v??n s Kerberos V.K??d kter?? pou????v??me je exportovateln?? Heimdal vyd??n?? ze ??v??dska. Na??e X11 zdroje byly roz??????eny tak,aby mohli tak?? pou????vat Kerberos.

OpenBSD byl prvn?? opera??n?? syst??m distribuovan?? s IPsec stackem. Poskytujeme IPsec od vyd??n?? OpenBSD 2.1 v roce 1997.N???? pln?? do kernelu integrovan?? IPsec stack s hardware akcelerac?? pou??itou na n??kolika kart??ch a na????m vlastn??m voln??m ISAKMP daemonem je pou????v??n jako jeden z po????ta???? v testu IPsec conformance u VPNC.

Dne??n?? kryptografie je d??le??itou ????st?? zv????en?? bezpe??nosti opera??n??ho syst??mu.Kryptografie pou??it?? v OpenBSD m????e b??t pou??ita pro mnoho r??zn??ch ????el?? popsan??ch d??le.

OpenSSH

Od verze 2.6 , OpenBSD obsahuje OpenSSH, zcela bezplatnou a patenty nezane??enou verzi ssh. OpenSSH je kompatibiln?? s ssh verze 1 a m?? mnoho p??idan??ch vlastnost??,

• v??echny komponenty s n??j??k??m omezen??m (nap????klad patentov??m,pod??vejte se na ssl(8)) byly vy??aty ze zdrojov??ho k??du;jak??koliv licencovan?? nebo patentovan?? komponenty u????vaj??c?? extern?? knihovny
• byl aktualizov??n aby podporoval ssh protokol verze 1.5
• obsahuje pripadnou podporu pro Kerberos autentikaci a ticket passing
• podpora one-time password autentizace pomoc?? skey(1)

Zhruba ??e??eno jsme vzali voln?? vydanou verzi ssh a OpenBSD-fikovali jsme ji.Asi o rok pozd??ji jsme OpenSSH roz??????ili o podporu SSH protokolu verze 2.V??sledkem je podpora v??ech 3 hlavn??ch protokol?? pro SSH: 1.3, 1.5, 2.0

Pseudo Random Number gener??tory

Pseudo Random Number gener??tory (PRNG) jsou aplikace s proudy ????sel, kter?? maj?? d??le??it?? vlastnosti pro syst??movou bezpe??nost:

• M????e b??t nemo??n?? pro ??to??n??ka uh??dnout v??stup z PRNG dokonce i se znalost?? p??edchoz??ch v??stup??
• Generovan?? ????sla nemaj?? m??t opakuj??c?? se ????sti,co?? znamen??,??e PRNG m????e m??t velmi dlouhou d??lku cyklu

PRNG je norm??ln?? pouze algoritmus,kde stejn?? po????te??n?? hodnoty poskytuj?? stejn?? sekvence v??stupu. Na v??ceu??ivatelsk??m opera??n??m syst??mu je mnoho zdroj??,kter?? dovoluj?? naplnit PRNG n??hodn??mi daty. OpenBSD j??dro vyu????v?? p??eru??en?? od my??i,zpo??d??n?? p??i p??enosu s????ov??ch dat,pauz mezi stisknut??m kl??ves a I/O informace z disku k vypln??n?? po????te??n??ho z??sobn??ku.N??hodn?? ????sla z PRNG jsou k dispozici pro rutiny j??dra a jsou exportov??ny p??es za????zen?? k u??ivatelsk??m program??m.Tak??e n??hodn?? ????sla z PRNG jsou pou????v??na v n??sleduj??c??ch oblastech:

• Dynamick?? p??id??lov??n?? sin_port v bind(2)
• PID ????sla proces??
• IP datagramy;????sla ID
• RPC p??enosy;????sla ID (XID)
• NFS RPC p??enosy;????sla ID (XID)
• DNS Query;????sla ID
• Generov??n?? ????sel inod??, ??t??te getfh(2) a fsirand(8)
• P??eru??en?? ??asova??e v traceroute(8)
• Siln??j???? do??asn?? jm??na pro mktemp(3) a mkstemp(3)
• P??idan?? n??hodnost do TCP ISS hodnoty pro ochranu proti tzv. spoofing ??tok??m
• N??hodn?? v??pl?? v IPsec esp_old paketech
• Ke generov??n?? salts pro r??zn?? algoritmy hesel
• Pro generov??n?? fale??n??ch S/Key v??zev
• V isakmpd(8) k vytvo??en?? d??kazu o v??m??n?? kl??????.

Kryptografick?? ha??ovac?? funkce

Ha??ovac?? funkce provede kompresi vstupn??ch dat na ??et??zec konstantn?? d??lky.Pro kryptografickou ha??ovac?? funkci je nemo??n?? naj??t:

• dva vstupy,kter?? maj?? stejn?? v??stup (odoln?? proti koliz??m)
• jin?? vstup,pro ji?? definovan?? vstup,kter?? by m??l stejn?? v??stup (2nd preimage resistant)

V OpenBSD jsou pou??ity MD5, SHA1 a RIPEMD-160 pro kryptografick?? ha??ovac?? funkce, nap??.:

• V S/Key(1) pro one-time-password
• V IPsec(4) a isakmpd(8) pro ov????en?? p??vodu dat v paketech a kontrolu jejich integrity
• Pro FreeBSD-styl MD5 hesel (nen?? standardn?? povoleno),v??ce v passwd.conf(5)
• V libssl pro digit??ln?? podepisov??n?? zpr??v

Kryptografick?? transformace

Kryptografick?? transformace jsou pou??ity pro ??ifrov??n?? a de??ifrov??n?? dat. Tyto jsou b????n?? pou????v??ny se ??ifrovac??m kl????em pro ??ifrov??n?? dat a de??ifrovac??m kl????em pro de??ifrov??n?? dat.Bezpe??nost krypto- grafick?? transformace m?? z??viset pouze na kl??????ch.

OpenBSD poskytuje transformace jako DES, 3DES, Blowfish a Cast pro j??dro a u??ivatelsk?? programy,je?? jsou pou????v??ny na mnoha m??stech jako:

• V libc pro tvorbu Blowfish hesel. Pod??vejte se tak?? na USENIX dokument o tomto t??matu
• V IPsec(4) pro poskytnut?? utajen?? pro s????ovou vrstvu
• V isakmpd(8) k ochran?? v??m??ny kl?????? p??i vyjedn??v??n?? spojen??
• V AFS k ochran?? zpr??v putuj??ch p??es s????,umo????uj??c?? utajen?? p????stupu ke vzd??len??mu syst??mu
• V libssl k umo??n??n?? aplikac??m komunikovat defakto p??es standardn?? kryptograficky zabezpe??en?? SSL protokol

Podpora kryptografick??ho hardware

OpenBSD od verze 2.7 za??alo podporovat vybran?? kryptografick?? hardware jako nap????klad akceler??tory a random number gener??tory.

• IPsec crypto dequeue
  Our IPsec stack has been modified so that cryptographic functions get done out-of-line. Most simple software IPsec stacks need to do cryptography when processing each packet. This results in synchronous performance. To use hardware properly and speedily one needs to separate these two components, as we have done. Actually, doing this gains some performance even for the software case.

• Hifn 7751
  Cards using the Hifn 7751 can be used as a symmetric cryptographic accelerator, i.e., the Soekris VPN1201 or VPN1211 (to buy) or PowerCrypt. Current performance using a single Hifn 7751 on each end of a tunnel is 64Mbit/sec for 3DES/SHA1 ESP, nearly a 600% improvement over using a P3/550 CPU. Further improvements are under way to resolve a few more issues, but as of April 13, 2000 the code is considered stable. We wrote our own driver for supporting this chip, rather than using the (USA-written) PowerCrypt driver, as well our driver links in properly to the IPsec stack. The 7751 is now considered slow by industry standards and many vendors have faster chips (even Hifn now has a faster but more expensive chip). Peak performance with 3DES SHA1 ESP is around 64Mbit/sec.

  After 2.9 shipped, support was added for the Hifn 7951 chip, a simplified version of the 7751 which adds a public key accelerator (unsupported) and a random number generator (supported). Cards were donated by Soekris Engineering.

  After 3.0 shipped, support was added for the Hifn 7811 chip, a faster version of the 7751 (around 130Mbit/s) with a random number generator. A card was donated by GTGI.

  After 3.2 shipped, support was added for the LZS compression algorithm used by ipcomp(4).

  After 3.4 shipped, support was added for the 7955 and 7956 chips. In addition to all the features of the previous 7951 chip, these add AES.

  Hifn was initially a difficult company to deal with (threatening to sue us over our non-USA reverse engineering of their crypto unlock algorithm), but more recently they have been very helpful in providing boards and support.

• Hifn 6500
  This device is an asymmetric crypto unit. It has support for RSA, DSA, and DH algorithms, as well as other major big number functions. It also contains a very high performance random number generator. We have one device, full documentation, and sample code. As of OpenBSD 3.1, both the random number generator and big number unit are working.

• Hifn 7814/7851/7854
  This device is a packet processor and asymmetric crypto unit. It has support for RSA, DSA, and DH algorithms, as well as other major big number functions and also has a random number generator. Currently, only the big number engine and the random number generator are supported (no packet transforms).

• Broadcom BCM5801/BCM5802/BCM5805/BCM5820/BCM5821/BCM5822/5823/5825/5860/5861/5862 (or beta chip Bluesteelnet 5501/5601)
  Just after the OpenBSD 2.7 release, we succeeded at adding preliminary support for these early release parts provided to us by the vendor, specifically starting with the test chip 5501. These devices provide the highest performance symmetric cryptography we have seen.

  Bluesteelnet was bought by Broadcom and started making real parts. Their new BCM5805 is similar, except that they also add an asymmetric engine for running DSA, RSA, and other such algorithms. With approximate performance starting at more than four times as fast as the Hifn, hopefully this chip will become more common soon.

  The Broadcom/Bluesteelnet people have been great to deal with. They gave us complete documentation and sample code for their chips and a sufficient number of cards to test with.

  Post 2.8, this driver was also modified to generate random numbers on the BCM5805 and similar versions, and feed that data into the kernel entropy pool.

  Post 2.9, support was added for the BCM5820, which is mostly just a faster (64bit, higher clock speed) version of the BCM5805. Untested support for the BCM5821 was also added post 3.0.

  As of 3.1, the big num engine is supported, and RSA/DH/DSA operations can be accelerated.

  Support for the BCM5801, BCM5802, BCM5821 and BCM5822 was added before OpenBSD 3.2 (the untested BCM5821 support in 3.1 was broken because of some undocumented interrupt handling requirements).

  Partial support for BCM5823 was added for 3.4.

  Support for the BCM5825, BCM5860, BCM5861, and BCM5862 including support for AES with the BCM5823 or newer was added after 4.5.

• Securealink PCC-ISES
  The PCC-ISES is a new chipset from the Netherlands. We have received sample hardware and documentation, and work on a driver is in progress. At the moment, the driver is capable of feeding random numbers into the kernel entropy pool.

• SafeNet SafeXcel 1141/1741
  After 3.4 shipped, support was for added for these two chips (found on various SafeNet crypto cards. Supports DES, Triple-DES, AES, MD5, and SHA-1 symmetric crypto operations, RNG, public key operations, and full IPsec packet processing.

• SafeNet SafeXcel 1840
  We have received documentation and sample hardware for the SafeNet 1840 crypto chip. Work to support at least the RNG and symmetric cryptography of these devices has started.

• SafeNet SafeXcel 2141
  We have received documentation and sample hardware for the SafeNet 2141 crypto chip. Work to support at least the symmetric cryptography of these devices has started.

• 3com 3cr990
  3com gave us a driver to support the ethernet component of this chipset, and based on that, we have written our own ethernet driver. This driver has now been integrated once we were able to get a free license on the microcode. Due to poor documentation and lack of cooperation (partly because of the high turnover rates at 3Com), the IPsec functions of the chip are not supported.... so this turned out to be a less than completely useful exercise.

• Intel IPsec card
  Much like Intel does for all their networking division components, and completely unlike most other vendors, Intel steadfastly refuses to provide us with documentation. We have talked to about five technical people who are involved in the development of those products. They all want us to have documentation. They commend us on what we have done. But their hands are tied by management who does not perceive a benefit to themselves for providing documentation. Forget about Intel. (If you want to buy gigabit ethernet hardware, we recommend anything else... for the same reason: most drivers we have for Intel networking hardware were written without documentation).

• Intel 82802AB/82802AC Firmware Hub RNG
  The 82802 FWH chip (found on i810, i820, i840, i850, and i860 motherboards) contains a random number generator (RNG). High-performance IPsec requires more random number entropy. As of April 10, 2000, we support the RNG. We will add support for other RNGs found on crypto chips.

• VIA C3 RNG
  The newer VIA C3 CPU contains a random number generator as an instruction. As of 3.3 this random number generator is used inside the kernel to feed the entropy pool.

• VIA C3 AES instructions
  VIA C3 CPUs with a step 8 or later Nehemiah core contains an AES implementation accessible via simple instructions. As of 3.4 the kernel supports them to be used in an IPsec context and exported by /dev/crypto. As of 3.5 performances have been greatly improved and OpenSSL now uses the new instruction directly when available without the need to enter the kernel, resulting in vastly improved speed (AES-128 measured at 780MByte/sec) for applications using OpenSSL to perform AES encryption.

• OpenSSL
  Years ago, we had a grand scheme to support crypto cards that can do RSA/DH/DSA automatically via OpenSSL calls. As of OpenBSD 3.2, that support works, and any card that is supported with such functionality will automatically use the hardware, including OpenSSH and httpd in SSL mode. No application changes are required.

Pokud chcete pomoci s psan??m ovlada????, p??ij??te a pomo??te n??m.

Hled??me kryptografick?? odborn??ky z cel??ho sv??ta

Samoz??ejm??,??e n???? projekt pot??ebuje lidi k pr??ci na t??chto syst??mech.Pokud je n??j??k?? ne-americk?? odborn??k,kter?? souhlas?? s v????e popsan??m,m?? z??jem o zapojen?? do projektu a poskytnout pomoc s kryptografi?? v OpenBSD,tak a?? n??s pros??m kontaktuje.

Dal???? informace

Mnoho dokument?? bylo naps??no ??leny OpenBSD t??mu o kryptografick??ch zm??n??ch, kter?? ud??lali v OpenBSD.Postscript verze t??chto dokument?? jsou k dispozici n????e.

• A Future-Adaptable Password Scheme.
  Usenix 1999, by Niels Provos, David Mazieres.
  paper and slides.

• Cryptography in OpenBSD: An Overview.
  Usenix 1999, by Theo de Raadt, Niklas Hallqvist, Artur Grabowski, Angelos D. Keromytis, Niels Provos.
  paper and slides.

• Implementing Internet Key Exchange (IKE).
  Usenix 2000, by Niklas Hallqvist and Angelos D. Keromytis.
  paper and slides.

• Encrypting Virtual Memory.
  Usenix Security 2000, Niels Provos.
  paper and slides.

• The Design of the OpenBSD Cryptographic Framework.
  Usenix 2003, by Angelos D. Keromytis, Jason L. Wright, and Theo de Raadt.
  paper.

• Cryptography As an Operating System Service: A Case Study.
  ACM Transactions on Computer Systems, February 2006, by Angelos D. Keromytis, Jason L. Wright, and Theo de Raadt.
  paper.