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Stencil Subtractor
The Stencil Subtractor frame was a ciphered text recyphering tool that was invented by British Army Intelligence Officer and cryptographer John Tiltman and was ready for trial by April 1941 but was not adopted officially by the British Forces until March 1942, and not brought into service until June 1943. It was used together with Subtractor tables, placed on top of the table and the numerical values visible in the gaps of the SS Frame were used to encipher the underlying numerical code (such as the War Office Cipher, RAF cipher or Naval cipher etc.). References {{Reflist Cryptographic hardware Encryption devices World War II military equipment of the United Kingdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciphertext
In cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher to decrypt it. This process prevents the loss of sensitive information via hacking. Decryption, the inverse of encryption, is the process of turning ciphertext into readable plaintext. Ciphertext is not to be confused with codetext because the latter is a result of a code, not a cipher. Conceptual underpinnings Let m\! be the plaintext message that Alice wants to secretly transmit to Bob and let E_k\! be the encryption cipher, where _k\! is a cryptographic key. Alice must first transform the plaintext into ciphertext, c\!, in order to securely send the message to Bob, as follows: : c = E_k(m). \! In a symmetric-key system, Bob knows Alice's encryption key. Once the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Army
The British Army is the principal land warfare force of the United Kingdom, a part of the British Armed Forces along with the Royal Navy and the Royal Air Force. , the British Army comprises 79,380 regular full-time personnel, 4,090 Gurkhas, and 28,330 volunteer reserve personnel. The modern British Army traces back to 1707, with antecedents in the English Army and Scots Army that were created during the Restoration in 1660. The term ''British Army'' was adopted in 1707 after the Acts of Union between England and Scotland. Members of the British Army swear allegiance to the monarch as their commander-in-chief, but the Bill of Rights of 1689 and Claim of Right Act 1689 require parliamentary consent for the Crown to maintain a peacetime standing army. Therefore, Parliament approves the army by passing an Armed Forces Act at least once every five years. The army is administered by the Ministry of Defence and commanded by the Chief of the General Staff. The British ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security (data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synony ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Tiltman
Brigadier John Hessell Tiltman, (25 May 1894 – 10 August 1982) was a British Army officer who worked in intelligence, often at or with the Government Code and Cypher School (GC&CS) starting in the 1920s. His intelligence work was largely connected with cryptography, and he showed exceptional skill at cryptanalysis. His work in association with Bill Tutte on the cryptanalysis of the Lorenz cipher, the German teleprinter cipher, called " Tunny" (for tunafish) at Bletchley Park, led to breakthroughs in attack methods on the code, without a computer. It was to exploit those methods, at extremely high speed with great reliability, that Colossus, the first digital programmable electronic computer, was designed and built. Biography Tiltman's parents were from Scotland, though he was born in London. He joined the British Army in 1914, and saw service at the front during World War I with the King's Own Scottish Borderers. He was wounded in France, and won the Military Cross for brave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtractor Tables
In electronics, a subtractor – a digital circuit that performs subtraction of numbers – can be designed using the same approach as that of an adder. The binary subtraction process is summarized below. As with an adder, in the general case of calculations on multi-bit numbers, three bits are involved in performing the subtraction for each bit of the difference: the minuend (X_), subtrahend (Y_), and a borrow in from the previous (less significant) bit order position (B_). The outputs are the difference bit (D_) and borrow bit B_. The subtractor is best understood by considering that the subtrahend and both borrow bits have negative weights, whereas the X and D bits are positive. The operation performed by the subtractor is to rewrite X_-Y_-B_ (which can take the values -2, -1, 0, or 1) as the sum -2B_+D_. : D_ = X_ \oplus Y_ \oplus B_ : B_ = X_ < (Y_ + B_) Subtractors are usually implemented within a binary adder for only a small cost when using the standard [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Hardware
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security ( data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption Devices
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in militar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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