Sunday, February 18, 2007

Feistel networks were first seen commercially in IBM's Lucifer cipher, designed by.......

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Feistel cipher
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In cryptography, a Feistel cipher is a block cipher with a particular structure, named after IBM cryptographer Horst Feistel; it is also commonly known as a Feistel network. A large proportion of block ciphers use the scheme, including the Data Encryption Standard (DES). The Feistel structure has the advantage that encryption and decryption operations are very similar, even identical in some cases, requiring only a reversal of the key schedule. Therefore the size of the code or circuitry required to implement such a cipher is nearly halved.

Feistel networks and similar constructions are product ciphers, and so combine multiple rounds of repeated operations, such as:

* Bit-shuffling (often called permutation boxes or P-boxes)
* Simple non-linear functions (often called substitution boxes or S-boxes)
* Linear mixing (in the sense of modular algebra) using XOR

to produce a function with large amounts of what Claude Shannon described as "confusion and diffusion".

Bit shuffling creates the diffusion effect, while substitution is used for confusion.
Contents
[hide]

* 1 History
* 2 Theoretical Work
* 3 Construction Details
* 4 List of Feistel ciphers
* 5 References
* 6 See also

[edit] History

Feistel networks were first seen commercially in IBM's Lucifer cipher, designed by Feistel and Don Coppersmith. Feistel networks gained respectability when the US Federal Government adopted the DES (a cipher based on Lucifer, with changes made by the NSA). Like other components of the DES, the iterative nature of the Feistel construction makes implementing the cryptosystem in hardware easier (particularly on the hardware available at the time of DES' design). Things have changed through the decades as hardware has become more capable.

[edit] Theoretical Work

Many modern symmetric block ciphers are based on Feistel networks, and the structure and properties of Feistel ciphers have been extensively explored by cryptographers. Specifically, Michael Luby and Charles Rackoff analyzed the Feistel block cipher construction, and proved that if the round function is a cryptographically secure pseudorandom function, with Ki used as the seed, then 3 rounds is sufficient to make the block cipher a pseudorandom permutation, while 4 rounds is sufficient to make it a "strong" pseudorandom permutation (which means that it remains pseduorandom even to an adversary who gets oracle access to its inverse permutation).[1] Because of this very important result of Luby and Rackoff, Feistel ciphers are sometimes inaccurately called Luby-Rackoff block ciphers. Further theoretical work has generalized the construction somewhat, and given more precise bounds for security.[2]

[edit] Construction Details

The basic operation is as follows:

Split the plaintext block into two equal pieces, (L0, R0)

For each round i =1,2,\dots,n, compute

Li = Ri − 1
R_i = L_{i-1} \oplus f(R_{i-1}, K_{i-1})

where f is the round function and Ki is the sub-key.

Then the ciphertext is (Ln, Rn).

Decryption is accomplished via

Ri − 1 = Li
L_{i-1} = R_i \oplus f(L_i, K_i)

One advantage of this model is that the round function f used does not have to be invertible, and can be very complex.

This diagram illustrates both encryption and decryption. Note the reversal of the subkey order for decryption; this is the only difference between encryption and decryption:

Image:Feistel.png

Unbalanced Feistel ciphers use a modified structure where L0 and R0 are not of equal lengths. The Skipjack encryption algorithm is an example of such a cipher. The Texas Instruments Digital Signature Transponder uses a proprietary unbalanced Feistel cipher to perform challenge-response authentication.[3]

The Feistel construction is also used in cryptographic algorithms other than block ciphers. For example, the Optimal Asymmetric Encryption Padding (OAEP) scheme uses a simple Feistel network to randomize ciphertexts in certain asymmetric key encryption schemes.

[edit] List of Feistel ciphers

Feistel or modified Feistel: Blowfish, Camellia, CAST-128, DES, FEAL, KASUMI, LOKI97, Lucifer, MARS, MAGENTA, MISTY1, RC5, TEA, Triple DES, Twofish, XTEA

Generalised Feistel: CAST-256, MacGuffin, RC2, RC6, Skipjack

[edit] References

1. ^ M. Luby and C. Rackoff. "How to Construct Pseudorandom Permutations and Pseudorandom Functions." In SIAM J. Comput., vol. 17, 1988, pp. 373-386.
2. ^ Jacques Patarin, Luby-Rackoff: 7 Rounds Are Enough for Security, Lecture Notes in Computer Science, Volume 2729, Oct 2003, Pages 513 - 529
3. ^ S. Bono, M. Green, A. Stubblefield, A. Rubin, A. Juels, M. Szydlo. "Security Analysis of a Cryptographically-Enabled RFID Device". In Proceedings of the USENIX Security Symposium, August 2005. (pdf)

[edit] See also

* Cryptography
* Stream cipher
* Substitution-permutation network


Block ciphers
v • d • e
Algorithms: 3-Way | AES | Akelarre | Anubis | ARIA | BaseKing | Blowfish | C2 | Camellia | CAST-128 | CAST-256 | CIKS-1 | CIPHERUNICORN-A | CIPHERUNICORN-E | CMEA | Cobra | COCONUT98 | Crab | CS-Cipher | DEAL | DES | DES-X | DFC | E2 | FEAL | FROG | G-DES | GOST | Grand Cru | Hasty Pudding Cipher | Hierocrypt | ICE | IDEA | IDEA NXT | Iraqi | Intel Cascade Cipher | KASUMI | KHAZAD | Khufu and Khafre | KN-Cipher | Libelle | LOKI89/91 | LOKI97 | Lucifer | M6 | MacGuffin | Madryga | MAGENTA | MARS | Mercy | MESH | MISTY1 | MMB | MULTI2 | NewDES | NOEKEON | NUSH | Q | RC2 | RC5 | RC6 | REDOC | Red Pike | S-1 | SAFER | SC2000 | SEED | Serpent | SHACAL | SHARK | Skipjack | SMS4 | Square | TEA | Triple DES | Twofish | UES | Xenon | xmx | XTEA | Zodiac
Design: Feistel network | Key schedule | Product cipher | S-box | SPN

Attacks: Brute force | Linear / Differential / Integral cryptanalysis | Mod n | Related-key | Slide | XSL
Standardization: AES process | CRYPTREC | NESSIE

Misc: Avalanche effect | Block size | IV | Key size | Modes of operation | Piling-up lemma | Weak key
Cryptography
v • d • e
History of cryptography | Cryptanalysis | Cryptography portal | Topics in cryptography
Symmetric-key algorithm | Block cipher | Stream cipher | Public-key cryptography | Cryptographic hash function | Message authentication code | Random numbers
Retrieved from "http://en.wikipedia.org/wiki/Feistel_cipher"

Category: Block ciphers
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Wednesday, February 07, 2007

A listening Heart ....is to stay and see .....but yet pay dreaming you are going to get money for ....Justice for all blood relatives....not just you!

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Sarita''s secret: once the seat of a famous ranching empire, this sleepy town has kept hidden for eighty years the answer to one of South Texas''s greatest riddles: is Ray Fernandez, the descendant of a Mexican maid, the heir to the gigantic Kenedy fortune?(Biography)
Publication Date: 01-SEP-04
Publication Title: Texas Monthly
Format: Online - approximately 6574 words
Author: Cartwright, Gary
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Description
THE TRAIN DOESN'T STOP IN SARITA ANYMORE. They tore down the depot years ago, along with the hotel, the lumberyard, and the cotton gin. It has been a century since anyone referred to this part of South Texas as "the French Reviera of Texas," as land speculators once did. Driving a desolate stretch of U.S. 77, twenty miles south of Kingsville, I almost missed Sarita entirely: The only visible landmarks are a green sign identifying the town, a blinking yellow light, and a water tower off in some distant trees. Sarita has an elementary school and a Catholic church but no shops, cafes, or even a convenience store. The closest supermarket is in Kingsville; the nearest major medical center is in Corpus Christi, sevently miles north; and the pharmacy of choice is in Nuevo Progreso, Mexico, an hour-and-thirty-minute drive for cheap drugs. The only place to spend the night is a one-suite bed-and-breakfast run by Patti Fain, who is also the justice of the peace; her husband, Mike, a retired game warden, is the local gunsmith. The only source of soft drinks is a vending machine at the Kenedy County courthouse, a dim cavern of mostly empty hallways and faded photographs. When I was there in June, a dog slept in the dusty street between the courthouse and the former home of the old Kenedy Pasture Company, now a museum.

Sarita is not a ghost town in the usual sense. But the ghosts of the Kenedys--Captain Mifflin Kenedy and his star-crossed heirs, especially his two grandchildren, John G. Kenedy Jr. and Sarita Kenedy East, for whom this unincorporated county seat is named--hover like the hot blue sky over the tiny town of around 250, which appears as a footnote to the huge ranch that the captain founded after the Civil War. Though all the Kenedys are dead, their legend is as alive as the front page of your morning newspaper. It crackles with the legacy of the patron system: tales of stolen land and inheritance, racial and religions conflict, endless courtroom battles, violence, avarice, and shadowy family secrets, all of which connect the cultures and histories of South Texas and northern Mexico.

Mifflin Kenedy was one of the three great ranchers of far South Texas, the others being his close friends Richard King and Major John Armstrong. Though he was a Quaker from Pennsylvania, he never let religion get in his way. He met and fell in love with a beautiful 26-yearold devout Catholic from Mier, Mexico, Petra Vela de Vidal. Depending on which version of history you believe, Petra was the wife, mistress, or widow of Luis Vidal, a captain in the Mexican army. Some historians believe that Kenedy arranged the murder of Luis, who had already fathered at least six children by Petra. Kenedy moved his bride to Brownsville, where they had six more children. Most of their sons lived fast and died young. Tom Kenedy, the eldest, was killed by a deputy sheriff in Brownsville whose estranged wife the young ranching heir was courting. Adrian Vidal, Mifflin's adopted son, was executed in a Mexican prison while the captain stood helplessly outside the prison walls. After driving a herd of cattle to Dodge City and getting into a fight with the town's mayor, James Kenedy barely survived a shoot-out with a posse that included Wyatt Earp and Bat Masterson, only to succumb later to typhoid fever. When Mifflin died intestate, in 1895, the 400,000-acre ranch ended up in the hands of his sole surviving son, John Gregory Kenedy, known as Don Gregorio.

The dynasty might have gone on indefinitely, except that neither of Don Gregorio's two surviving children produced an heir. John G. Kenedy Jr., known all his life as Johnny, was a boozer and a womanizer who died in 1948 in Saltillo, the home of his Mexican-born wife, Elena, who inherited his half of the fortune. According to family legend, Johnny was rendered sterile by a childhood ease of the mumps, and his sister, Sarita, the last of the Kenedys, died childless in 1961, leaving the bulk of her estate to the John G. and Marie Stella Kenedy Memorial Foundation, named for her parents. Elena died in 1984, leaving her estate to the John G. Kenedy Jr. Charitable Trust. The two institutions are handled by administrators and lawyers; together, they control assets valued between $500 million and $1 billion, of which about 80 percent of the income goes to the Catholic Diocese of Corpus Christi, the Chrisms Spohn Health System, and various Catholic charities. In the final years of her life, Sarita was attended by a number of ambitious men, including clerics, with designs on her millions. "Vultures," she called them. Lawsuits over her fortune began two months after her death and continue to this day.

In the heyday of the Kenedys, the ranch headquarters was located far from town, down along, narrow road toward the coast that dead-ended at La Casa Grande, the thirty-room family estate. Sarita bequeathed the house and the 10,000 acres surrounding it, including the family chapel and cemetery, to the Missionary Oblates of Mary Immaculate. Today the Oblate fathers use the property--since reduced by settlements to 1,010 acres--as a religious retreat called Lebh Shomea House of Prayer. ("Lebh shomea" is Hebrew for "listening heart.") This veneer of peace and tranquillity is profoundly deceptive, however. One of several lawsuits still pending threatens to expose the darkest secret of all: that Johnny Kenedy may have sired a child by one of the Kenedy maids in 1925. The allegation started bubbling to the surface on Mother's Day, 2000, with a chance remark to a Corpus Christi man named Ray Fernandez by his dying grandmother. Speaking in Spanish, she told her grandson: "You look just like your grandfather Johnny Kenedy." Assuming she was talking about the late son of the late president, he dismissed it as the babbling of an old woman with dementia, dying of bone cancer.

But as Ray began...to listen to his ....he was being cheated by those money men and those doing their bidding.

When Sarita died, she gave the Kenedy family home and the surrounding area to the Missionary Society of the Oblate Fathers of Texas.

Sunday, July 8, 2001
Kenedy Foundation comes out against bombing range
Foundation owns some of the targeted land; board cites community's concerns

By Stephanie L. Jordan
Caller-Times

England

A significant player has joined the roster of those opposed to the Navy opening a bombing range on ranch land in Kenedy County.
But local supporters of the proposal say the deal's not dead unless the Navy says it has lost interest in the 222,000-acre tract.
Citing overwhelming local opposition, board members of the John G. and Marie Stella Kenedy Memorial Foundation, which owns some of the targeted land, on Friday wrote a letter to Navy Secretary Gordon England objecting to the proposed military training area.
"It has become quite apparent that the local community is overwhelmingly opposed to the suggested proposal," wrote foundation Vice President Dr. E.B. Groner."The foundation requests their wishes be respected."
Groner

Copies of the letter were sent to President Bush, Vice President Dick Cheney, Gov. Rick Perry and 11 other officials.
Open-minded at first
Foundation members were surprised by news that the Navy was considering Kenedy County as possible site to replace a controversial range on the Puerto Rican island of Vieques, but remained open minded about the idea at first, said Richard Leshin, the foundation's attorney.
"The foundation was just learning about this and was leaving all of the options open," Leshin said.
"But because of the local opposition the board decided to (write the letter)."
The foundation and the John G. Kenedy Jr. Charitable Trust own more than 400,000 acres of land combined. Both donate profits to area charities.
The foundation owns about 40,000 acres of the 222,000-acre site, said Kenedy County Judge J.A. Garcia Jr., who was named the foundation board's president in February.
Nine of the board's 13 members held a special meeting Friday both in person and by telephone to discuss the issue.
'An area of concern'
Actual Letter
The Honorable Gordon R. England
Secretary of the Navy
Washington, D.C., 20350-1000

Re: Suggested Navy Training Area Kenedy County, Texas

Dear Secretary England:

On behalf of The John G. and Marie Stella Kenedy Memorial Foundation, please be informed that the Foundation respectfully objects to the suggested military training area in Kenedy County, Texas. The reasons for this objection, among others, center around the general consensus of the local citizens of Kenedy County and surrounding areas as well as the consensus of the Kenedy County Commissioners Court.

It has become quite apparent that the local community is overwhelmingly opposed to the suggested proposal. The Foundation requests their wishes be respected.

Thank you for the consideration of the Foundation’s objections.

Sincerely,

E.B. Groner, M.D.
Vice President
Cc: President George W. Bush
Vice-President Dick Cheney
Secretary of Defense Donald Rumsfeld
Secretary of Interior Gayle Norton
Director of EPA Christine Todd Whitman
Senator Phil Gramm
Senator Kay Bailey Hutchison
Representative Solomon Ortiz
Governor Rick Perry
Land Commissioner David Dewhurst
Senator Carlos Truan
Representative Irma Rangel
Attorney General State of Texas John Cornyn
J.A. Garcia Jr. County Judge - County of Kenedy

"We felt this was an area of concern, especially with it being so close to Sarita," Garcia said. "I think the foundation was sensitive to the residents of Sarita and also the county. I didn't hear from anyone who was for the (practice range)."
President Bush decided to stop training on Vieques by 2003 and England is expected to soon appoint a committee to study possible replacements.
The foundation's letter was only the latest in a series of hits the proposal has taken.
'Deeply troubled'
Kenedy County Commissioners voted last week to oppose the idea. Sen. Kay Bailey Hutchison said last week she would not support the idea and Gov. Rick Perry on Friday said he was "deeply troubled" by the environmental damage a bombing range might cause.
A coalition of environmental groups has vowed to fight the idea and a study commissioned by the Navy rated the Kenedy County site lower than some other options.
Calling it quits
Some local supporters of the proposal called it quits after Hutchison's statement and said the foundation's letter was just more proof that the deal was dead.
"We were expecting (the letter) because Judge Garcia is chairman of the board of the Kenedy foundation," said Corpus Christi Mayor Loyd Neal.
'Closing the loop'
"As soon as the commissioner's court said what they did, as far I was concerned, it was dead. As soon as I saw that and what Senator Hutchison did, I thought it was over. I assume that's just closing the loop for them."
Navy officials have said they are still interested in the Kenedy County site and some proponents say the deal's alive as long as that's true.
"The Navy has known for a couple of months that the land would have to be condemned. It looks to me that the Navy is still interested in the site," said Pat Vetetoa retired Marine Corps officer and one architect of the proposal.
Power of eminent domain
Gary Bushell, a consultant with the Corpus Christi Chamber of Commerce who was an early proponent of the idea, said he didn't want to comment about the foundation's letter.
To put the bombing range in Kenedy County, the federal government would have to use its power of eminent domain and condemn the ranchland.
Both the trust and the foundation are prohibited from selling the land.
Foundation's largest asset
The land in Kenedy County is the foundation's single largest asset, said Daniel Meaney, who has been on the foundation's board since it began and now serves as the board's treasurer.
Meaney said he didn't know what would happen to the foundation if the government were to condemn the land and pay the foundation market value for it.
"When you get rid of your assets, there's no telling what would happen," said Meaney, who was acquainted with Sarita Kenedy East, who had owned the land.
Meaney said that over the years there has been interest from people wanting the buy pieces of the land.
Land's worth
"You can't own a large ranch without speculation and proposals," Meaney said. "But (the proposals have) always been nebulous, nothing positive."
The San Pedro Kenedy Ranch, one of Kenedy County's largest employers, is located on the proposed bombing site.
The land is filled with valuable oil and gas drilling operations and cattle.
Estimates of the land's worth run into the hundreds of millions of dollars.
By targeting Kenedy County, the government is getting involved in the intricate Kenedy family history.
Kenedy family history
The massive Kenedy Ranch, founded by former steamboat operator Mifflin Kenedy, was split in two after the death of John G. Kenedy Sr. and his wife Marie Stella Turcotte.
Half of the almost half-million-acre ranch went to his daughter, Sarita Kenedy East, while the other half went to John G. Kenedy Jr., who died in 1948, and his wife Elena, who died in 1984.
Sarita and Elena were deeply religious women, neither had children, and both willed their estates to charitable endeavors.
When Sarita died, she gave the Kenedy family home and the surrounding area to the Missionary Society of the Oblate Fathers of Texas.
"I don't think Sarita would have liked this," Meaney said of the proposal.


Contact Stephanie L. Jordan at 886-3724 or jordans@caller.com