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Histories of Digital Cryptography

Hash Algorithms, Public Key Crypto, and Digital Signatures, oh my!

Digital Cryptography

  • The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography [ϟ]

    “Simon Singh offers the first sweeping history of encryption, tracing its evolution and revealing the dramatic effects codes have had on wars, nations, and individual lives. From Mary, Queen of Scots, trapped by her own code, to the Navajo Code Talkers who helped the Allies win World War II, to the incredible (and incredibly simple) logisitical breakthrough that made Internet commerce secure, The Code Book tells the story of the most powerful intellectual weapon ever known: secrecy.”

Hash Algorithms

Public Key Cryptography

  • Publishing a new idea by Ralph C. Merkle

    In the Fall of 1974, as an undergraduate, I enrolled in CS244, the Computer Security course offered at UC Berkeley and taught by Lance Hoffman. We were required to submit two project proposals, one of which we would complete for the course. I submitted a proposal for what would eventually become known as Public Key Cryptography – which Hoffman rejected. I dropped the course, but kept working on the idea.

  • Part 1Part 2 about the development of public-key cryptography.

    For a more complete version, read:
  • CRYPTO— how the code rebels beat the government— saving privacy in the digital age -Steven Levy
  • THE OPEN SECRET —Public key cryptography - the breakthrough that revolutionized email and ecommerce - was first discovered by American geeks. Right? Wrong.

    The story of the invention of public key cryptography is a cypherpunk sacred text: In 1976, an iconoclastic young hacker named Whitfield Diffie hooked up with Stanford professor Martin Hellman, and together they devised what experts hailed as the most important development in crypto since the invention of polyalphabetic ciphers during the Renaissance. The duo produced a system that allowed an unlimited number of people to communicate with total privacy.

  • How to Time-Stamp a Digital Document 1991
  • The Eureka Moment That Made Bitcoin Possible [ϟ]

    A key insight for the technology came to a physicist almost three decades ago at a Friendly’s restaurant in New Jersey.

  • Why I wrote PGP - CryptoQuikRead_150

    “If we do nothing, new technologies will give the government new automatic surveillance capabilities that Stalin could never have dreamed of. The only way to hold the line on privacy in the information age is strong cryptography.” -Phil Zimmerman Explore this article & …

  • 𝓡𝓪𝓶𝓹𝓪𝓰𝓮 🦍 (@Thrillmex)

    NSA: HOW TO MAKE A MINT: THE CRYPTOGRAPHY OF ANONYMOUS ELECTRONIC CASH References two articles written by “Tatsuaki Okamoto” from 1991. Titled; An Efficient Divisible Electronic Cash Scheme Universal Electronic Cash Is this the OG Satoshi Nakamoto?

  • bitrawr⚡🦖 (@bitrawr)

    #Bitcoin’s building blocks. All hail #Satoshi 🌿 1979: Hash trees 🗝 1980: Public key cryptography ⌛ 1991: Cryptographic timestamps ⛓ 1992-3: PoW for spam 💸 1997: HashCash 💰 1998: BitGold 💷 1998: B-money 🏰 1999: pBFT 💾 ~2000: MojoNation/BitTorrent ⚔ 2001: SHA-256

  • Today In Infosec (@todayininfosec)

    1977: Alice and Bob became a thing. Ron Rivest first introduced Alice and Bob in the paper “A Method for Obtaining Digital Signatures and Public-Key Cryptosystems”.

  • Matthew Green (@matthew_d_green)

    Since key escrow is cool again, here are some classic posters from the Clipper era. Courtesy of Ron Rivest.

  • Whitfield Diffie on the History of Cryptography — What Bitcoin Did

    In this episode, I talk with legend of cryptography, Whitfield Diffie. Whit was working on cryptography long before Bitcoin existed, building the foundations for which Bitcoin relies upon. We discuss his history, Bitcoin and his views on privacy.

  • Geoff Sullivan, Esq. (@geoffsengine)

    @emmataylorwords @tnmoc “Codebreakers- The inside story of Bletchley Park”. Edited by Hinsley & Stripp is a good place to start. Paperback or Kindle If you really get hooked on the Polish contribution, Dermot Turing’s X, Y & Z is good. but rather complex spy story, based a…

  • The Open Secret

    Public key cryptography – the breakthrough that revolutionized email and ecommerce – was first discovered by American geeks. Right? Wrong. The story of the invention of public key cryptography is a cypherpunk sacred text: In 1976, an iconoclastic young hacker named Whitfi…

  • The Alternative History of Public-Key Cryptography

    Over the past twenty years, Diffie, Hellman and Merkle have become world famous as the cryptographers who invented the concept of public-key cryptography, while Rivest, Shamir and Adleman have been credited with developing RSA, the most beautiful implementation of public-key cryptography. However, a recent announcement means that the history books are having to be rewritten. According to the British Government, public-key cryptography was originally invented at the Government Communications Headquarters (GCHQ) in Cheltenham, the top-secret establishment that was formed from the remnants of Bletchley Park after the Second World War. This is a story of remarkable ingenuity, anonymous heroes and a government cover-up that endured for decades.

  • GCHQ trio recognised for key to secure shopping online

    The computer code was developed in the 1970s for military use, but it is now used to protect customers security when shopping online.

    A group of US researchers had been credited with the discovery until 1997 when the work was declassified and made public and the trio from GCHQ received the recognition.

  • Sam Hart (@hxrts)

    @cedarshims @DisincarnateEVL @srrhhamerman There’s a lot out there, but here are a couple papers to get started: Six Answers to the Question “What is Secrecy Studies?”, Clare Birchall Communication Theory of Secrecy Systems, Claude Shannon

  • Gabriel Peyré (@gabrielpeyre)(

    Oldies but goldies: Claude Shannon, A Mathematical Theory of Communication, 1948. Defines, among many things, the notion of entropy as a fundamental limit for compression.

  • Martin and Mitchell defection

    The Martin and Mitchell Defection occurred in September 1960 when two U.S. National Security Agency (NSA) cryptologists, William Hamilton Martin and Bernon F. Mitchell, defected to the Soviet Union. A secret 1963 NSA study said that: “Beyond any doubt, no other event has had…

  • The Shakespearean Ciphers Examined

    William F. Friedman was introduced to the question of the authorship of the works of Shakespeare, and to the field of cryptography itself, while working as the director of the department of genetics at Riverbank Laboratories. Shortly thereafter, Elizebeth Smith arrived at Riverbank to work in the Department of Cryptography on the question of Shakespeare authorship. Both William and Elizebeth shared the opinion that the method employed by Elizabeth Wells Gallup, the director of the Department of Cryptography at Riverbank Laboratories, to reach the conclusion that the works of Shakespeare were written by Francis Bacon was questionable.

  • Data Encryption Standard - cryptology

    Data Encryption Standard (DES), an early data encryption standard endorsed by the U.S. National Bureau of Standards (NBS; now the National Institute of Standards and Technology). It was phased out at the start of the 21st century by a more secure encryption standard, known as…

  • Feistel, H. (1973) Cryptography and Computer Privacy. Scientific American, 228, 15-23

    This paper proposes a new involutive light-weight block cipher for resource-constraint environments called I-PRESENTTM. The design is based on the Present block cipher which is included in the ISO/IEC 29192 standard on lightweight cryptography. The advantage of I-PRESENTTM is that the cipher is involutive such that the encryption circuit is identical to decryption. This is an advantage for environments which require the implementation of both circuits. The area requirement of I-PRESENTTM compares reasonably well with other similar ciphers such as PRINCE

  • Multiuser cryptographic techniques

    This paper deals with new problems which arise in the application of cryptography to computer commu- nication systems with large numbers of users. Fore- most among these is the key distribution problem. We suggest two techniques for dealing with this problem. The first employs current technology and requires sub- version of several separate key distribution nodes to compromise the system’s security. Its disadvantage is a high overhead for single message connections. The second technique is still in the conceptual phase, but promises to eliminate completely the need for a secure key distribution channel, by making the sender’s key- ing information public. It is also shown how such a public key cryptosystem would allow the development of an authentication system which generates an un- forgeable, message dependent digital signature.

  • Hellman, M. E. (2002). An overview of public key cryptography. IEEE Communications Magazine, 40(5), 42-49.
  • A. M. Turing Award Oral History Interview with Whitfield Diffie by Hugh Williams Sept. 15, 2017, Portola Valley CA
  • Secure Communications Over Insecure Channels
  • New Directions in Cryptography Invited Paper - WHITFIELD DIFFIE AND MARTIN E. HELLMAN, MEMBER, IEEE

    Abstract-Two kinds of contemporary developments in cryptography are examined. Widening applications of teleprocessing have given rise to a need for new types of cryptographic systems, which minimize the need for secure key distribution channels and supply the equivalent of a written signature. This paper suggests ways to solve these currently open problems. It also discusses how the theories of communication and computation are beginning to provide the tools to solve cryptographic problems of long standing.

  • Method for Obtaining Digital Signatures and Public-Key Cryptosystems - R.L. Rivest, A. Shamir, and L. Adleman∗
  • Puzzle Palace - Chapter 9 - Competition

    What must have come as NSA’s biggest blow took place in 1976, when the two anti-DES scientists from Stanford, Hellman and Diffie, came up with what David Kahn called “the most revolutionary new concept in the field since polyalphabetic substitution emerged in the Renaissance.” Later refined by three scientists at MIT, Ronald Rivest, Adi Shamir, and Leonard Adleman, the system was labeled public-key cryptography and offered a radical new twist to an old concept. Rather than using the same key, as with the DES, to encrypt and decrypt, the public-key system allows for two separate keys–one limited to encryption and the other to decryption. What this means is that a person can now freely distribute his computer’s encryption key, such as in a national directory, permitting anyone to send secret information to him. But only he is able to decrypt the messages, since he alone has the decrypt key. An added bonus of the system is that it also permits the sender of the messages to sign, in effect, in indelible code, thus ensuring the authenticity of the author.

  • Data Privacy: What Washington Doesn’t Want You to Know

    New, unbreakable codes offer people true communications privacy, for the first time. But the government is fighting to keep this amazing technology for itself.

  • THE SILENT POWER OF THE N.S.A. - The New York Times By David Burnham
  • Prehistory of Public Key Cryptography
  • ADM Bobby R. Inman, USN > National Security Agency - Central Security Service > Hall of Honor
  • National Security Agency - Central Security Service > Cryptologic Heritage > Hall of Honor
  • An Interview with JAMES BIDZOS - OH 376 - Conducted by Jeffrey R. Yost on 11 December 2004 - Mill Valley, California
  • An Interview with JAMES BIDZOS OH 376 Conducted by Jeffrey R. Yost on 11 December 2004 - Mill Valley, California

  • Infographic: The History of Digital Signature Technology

    Digital signatures have been around for decades, and they’re gaining popularity in the mainstream. Learn about their history in this infographic.

  • Full text of “Dr. Dobb’s Journal - Vol 8 - RSA: A Public Key Cryptography System, Part I

    “In this two-part series of articles, we will discuss the Rivest-Shamir-Adleman [RSA] PKS and show how to implement it on a microcomputer .”

  • Full text of “Dr. Dobb’s Journal - Vol 9”

    RSA: A Public Key Cryptography System, Part I

    “In this two-part series of articles, we will discuss the Rivest-Shamir-Adleman [RSA] PKS and show how to implement it on a microcomputer .”

  • Zero-knowledge proofs of identity

    In this paper we extend the notion of interactive proofs of assertions to interactive proofs of knowledge. This leads to the definition of unrestricted input zero-knowledge proofs of knowledge in…

  • Khufu and Khafre

    In cryptography, Khufu and Khafre are two block ciphers designed by Ralph Merkle in 1989 while working at Xerox’s Palo Alto Research Center. Along with Snefru, a cryptographic hash function, the ciphers were named after the Egyptian Pharaohs Khufu, Khafre and Sneferu. Under a…

  • Merkle’s “A Software Encryption Function” now published and available
  • The Possibility of Secure Non-Secret Digital Encryption ‘70
  • Digital Signature Algorithm
  • Digital Signature Algorithm - Crypto Wiki

    The Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. It was proposed by the National Institute of Standards and…

  • Uploads by Andy Greenberg - Scribd
  • Patently Absurd

    One of the best-known patents in the computer industry is patent Number 4,405,829, “Cryptographic Communications System and Method,” the patent on RSA public-key cryptography. This patent, which expires on September 20, 2000, covers every implementation of RSA encryption in the United States. Because the algorithm is patented, it is a violation of US law for a company to write its own implementation of the RSA algorithm and use it without a license from Public Key Partners, the company that has an exclusive license to the patent from the Massachusetts Institute of Technology, the university where the algorithm was developed. It’s even illegal for a public-spirited citizen to write his or her own implementation of RSA and give it away.

  • Why Cryptography Is Harder Than It Looks by Bruce Schneier - audio
  • IT Security and Hacking knowledge base - SecDocs

    IT Security and hackers documentation site, with papers, slides from conferences and training videos

  • Pricing via Processing or Combatting Junk Mail Cynthia Dwork Moni Naory

    We present a computational technique for combatting junk mail, in particular, and controlling access to a shared resource, in general. The main idea is to require a user to compute a moderately hard, but not intractable, function in order to gain access to the resource, thus preventing frivolous use. To this end we suggest several pricing functions, based on, respectively, extracting square roots modulo a prime, the Fiat-Shamir signature scheme, and the Ong-Schnorr-Shamir (cracked) signature scheme.

  • Cryptography - IEEE - D. Coppersmith

    Abstract: This paper is concerned with two aspects of cryptography in which the author has been working. One is the Data Encryption Standard (DES), developed at IBIM and now in wide use for commercial cryptographic applications. This is a “private key” system; the communicants share a secret key, and the eavesdropper will succeed if he can guess this key among its quadrillions of possibilities. The other is the Diffie-Hellman key exchange protocol, a typical “public key” cryptographic system. Its security is based on the difficulty of taking “discrete logarithms” (reversing the process of exponentiation in a finite field). We describe the system and some analytic attacks against it.

  • An Interview with MARTIN HELLMAN

    Leading cryptography scholar Martin Hellman begins by discussing his developing interest in cryptography, factors underlying his decision to do academic research in this area, and the circumstances and fundamental insights of his invention of public key cryptography with collaborators Whitfield Diffie and Ralph Merkle at Stanford University in the mid-1970s. He also relates his subsequent work in cryptography with Steve Pohlig (the Pohlig-Hellman system) and others. Hellman addresses his involvement with and the broader context of the debate about the federal government’s cryptography policy—regarding to the National Security Agency’s (NSA) early efforts to contain and discourage academic work in the field, the Department of Commerce’s encryption export restrictions (under the International Traffic of Arms Regulation, or ITAR), and key escrow (the so-called Clipper chip). He also touches on the commercialization of cryptography with RSA Data Security and VeriSign, as well as indicates some important individuals in academe and industry who have not received proper credit for their accomplishments in the field of cryptography.

  • An overview of public key cryptography. - Hellman, M. E. (2002). IEEE Communications Magazine, 40(5), 42-49.

    The system I called the ax1x2 system in this paper has since become known as Diffie-Hellman key exchange. While that system was first described in a paper by Diffie and me, it is a public key distribution system, a concept developed by Merkle, and hence should be called “Diffie-Hellman-Merkle key exchange” if names are to be associated with it. I hope this small pulpit might help in that endeavor to recognize Merkle’s equal contribution to the invention of public key cryptography. Space does not permit an explanation of the quirk of fate that seems to have deprived Merkle of the credit he deserves, but a quirk it is.

  • Nick Szabo 🔑 (@NickSzabo4)

    Inventors of the most important technologies in Bitcoin: digital signatures and Merkle trees (Merkle), elliptic curve crypto (Koblitz), malicious-fault-tolerant consensus (Lamport), elliptic curve crypto (independent inventor: Miller).


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