Cryptographic key types

A cryptographic key is a string of data that is used to lock or unlock cryptographic functions, including authentication, authorization and encryption. Cryptographic keys are grouped into cryptographic key types according to the functions they perform.[1]

Description

Consider a keyring that contains a variety of keys. These keys might be various shapes and sizes, but one thing is certain, each will generally serve a separate purpose. One key might be used to start an automobile, while another might be used to open a safety deposit box. The automobile key will not work to open the safety deposit box and vice versa. This analogy provides some insight on how cryptographic key types work. These keys are categorized in respect to how they are used and what properties they possess.

A cryptographic key is categorized according to how it will be used and what properties it has. For example, a key might have one of the following properties: Symmetric, Public or Private. Keys may also be grouped into pairs that have one private and one public key, which is referred to as an Asymmetric key pair.

Asymmetric versus symmetric keys

Asymmetric keys differ from symmetric keys in that the algorithms use separate keys for encryption and decryption while a symmetric key’s algorithm uses a single key for both processes. Because multiple keys are used with an asymmetric algorithm, the process takes longer to produce than a symmetric key algorithm would. However, the benefits lay in the fact that an asymmetric algorithm is much more secure than a symmetric key algorithm is.

With a symmetric key, the key needs to be transmitted to the receiver where there is always the possibility that the key could be intercepted or tampered with. With an asymmetric key, the message and/or accompanying data can be sent or received by using a public key; however, the receiver or sender would use his or her personal private key to access the message and/or accompanying data. Thus, asymmetric keys are suited for use for transmitting confidential messages and data and when authentication is required for assurance that the message has not been tampered with. Only the receiver, whom is in possession of the public key’s corresponding private key, has the ability to decode the message. A public key can be sent back and forth between recipients, but a private key remains fixed to one location and is not sent back and forth, which keeps it safe from being intercepted during transmission.[1]

Long term versus single use

Cryptographic keys may also have keys that designate they can be used for long-term (static, archived) use or used for a single session (ephemeral). The latter generally applies to the use of an Ephemeral Key Agreement Key. Most other key types are designed to last for long crypto-periods from about one to two years. When a shorter crypto-period is designed different key types may be used, such as Data Encryption keys, Symmetric Authentication keys, Private Key-Transport keys, Key-Wrapping keys, Authorization keys or RNG keys.[1]

Key types

This page shows the classification of key types from the point of view of key management. In a key management system, each key should be labeled with one such type and that key should never be used for a different purpose.

According to NIST SP 800-57 (Revision 4) the following types of keys exist[2][1][3]:

Private signature key
Private signature keys are the private keys of asymmetric (public) key pairs that are used by public key algorithms to generate digital signatures with possible long-term implications. When properly handled, private signature keys can be used to provide authentication, integrity and non-repudiation.
Public signature verification key
A public signature verification key is the public key of an asymmetric key pair that is used by a public key algorithm to verify digital signatures, either to authenticate a user's identity, to determine the integrity of the data, for non-repudiation, or a combination thereof.
Symmetric authentication key
Symmetric authentication keys are used with symmetric key algorithms to provide assurance of the integrity and source of messages, communication sessions, or stored data.
Private authentication key
A private authentication key is the private key of an asymmetric key pair that is used with a public key algorithm to provide assurance as to the integrity of information, and the identity of the originating entity or the source of messages, communication sessions, or stored data.
Public authentication key
A public authentication key is the public key of an asymmetric key pair that is used with a public key algorithm to determine the integrity of information and to authenticate the identity of entities, or the source of messages, communication sessions, or stored data.
Symmetric data encryption key
These keys are used with symmetric key algorithms to apply confidentiality protection to information.
Symmetric key wrapping key
Symmetric key wrapping keys are used to encrypt other keys using symmetric key algorithms. Key wrapping keys are also known as key encrypting keys.
Symmetric and asymmetric random number generation keys
These are keys used to generate random numbers.
Symmetric master key
A symmetric master key is used to derive other symmetric keys (e.g., data encryption keys, key wrapping keys, or authentication keys) using symmetric cryptographic methods.
Private key transport key
Private key transport keys are the private keys of asymmetric key pairs that are used to decrypt keys that have been encrypted with the associated public key using a public key algorithm. Key transport keys are usually used to establish keys (e.g., key wrapping keys, data encryption keys or MAC keys) and, optionally, other keying material (e.g., initialization vectors).
Public key transport key
Public key transport keys are the public keys of asymmetric key pairs that are used to encrypt keys using a public key algorithm. These keys are used to establish keys (e.g., key wrapping keys, data encryption keys or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors).
Symmetric key agreement key
These symmetric keys are used to establish keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors) using a symmetric key agreement algorithm.
Private static key agreement key
Private static key agreement keys are the private keys of asymmetric key pairs that are used to establish keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors).
Public static key agreement key
Public static key agreement keys are the public keys of asymmetric key pairs that are used to establish keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors).
Private ephemeral key agreement key
Private ephemeral key agreement keys are the private keys of asymmetric key pairs that are used only once to establish one or more keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors).
Public ephemeral key agreement key
Public ephemeral key agreement keys are the public keys of asymmetric key pairs that are used in a single key establishment transaction to establish one or more keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., Initialization Vectors).
Symmetric authorization key
Symmetric authorization keys are used to provide privileges to an entity using a symmetric cryptographic method. The authorization key is known by the entity responsible for monitoring and granting access privileges for authorized entities and by the entity seeking access to resources.
Private authorization key
A private authorization key is the private key of an asymmetric key pair that is used to provide privileges to an entity.
Public authorization key
A public authorization key is the public key of an asymmetric key pair that is used to verify privileges for an entity that knows the associated private authorization key.
References
  1. Reinholm, James H. "Classification of Cryptographic Keys (Functions & Properties)". Cryptomathic. Retrieved 12 June 2017.
  2. Barker, Elaine. "NIST Special Publication 800-57 Part 1 Revision 4: Recommendation for Key Management" (PDF). National Institute of Standards and Technology (NIST). Retrieved 12 June 2017.
  3. Spacey, John. "12 Types of Cryptographic Key". Simplicable. Retrieved 12 June 2017.
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Public key certificate

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Public key certificate

Server certificate of *.wikipedia.org In cryptography, a public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the ownership of a public key. The certificate includes information about the key, information about the identity of its owner (called the subject), and the digital signature of an entity that has verified the certificate's contents (called the issuer). If the signature is valid, and the software examining the certificate trusts the issuer, then it can use that key to communicate securely with the certificate's subject.[1] In email encryption, code signing, and e-signature systems, a certificate's subject is typically a person or organization. However, in Transport Layer Security (TLS) a certificate's subject is typically a computer or other device, though TLS certificates may identify organizations or individuals in addition to their core role in identifying devices. TLS, sometimes called by its older name Secure Sockets Layer ( ...more...

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Index of cryptography articles

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Index of cryptography articles

Articles related to cryptography include: kzs 0–9 3-D Secure • 3-subset meet-in-the-middle attack • 3-Way • 40-bit encryption • 56-bit encryption • 5-UCO A A5/1 • A5/2 • ABA digital signature guidelines • ABC (stream cipher) • Abraham Sinkov • Acoustic cryptanalysis • Adaptive chosen-ciphertext attack • Adaptive chosen plaintext and chosen ciphertext attack • Advantage (cryptography) • ADFGVX cipher • Adi Shamir • Advanced Access Content System • Advanced Encryption Standard • Advanced Encryption Standard process • Adversary • AEAD block cipher modes of operation • Affine cipher • Agnes Meyer Driscoll • AKA (security) • Akelarre (cipher) • Alan Turing • Alastair Denniston • Al Bhed language • Alex Biryukov • Alfred Menezes • Algebraic Eraser • Algorithmically random sequence • Alice and Bob • All-or-nothing transform • Alphabetum Kaldeorum • Alternating step generator • American Cryptogram Association • AN/CYZ-10 • Anonymous Internet banking • Anonymous publication • Anonymous remailer • Antoni Palluth • ...more...

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Export of cryptography from the United States

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Export of cryptography from the United States

Export-restricted RSA encryption source code printed on a T-shirt made the T-shirt an export-restricted munition, as a freedom of speech protest against U.S. encryption export restrictions (Back side).[1] Changes in the export law means that it is no longer illegal to export this T-shirt from the U.S., or for U.S. citizens to show it to foreigners. The export of cryptographic technology and devices from the United States was severely restricted by U.S. law until 1992, but was gradually eased until 2000; some restrictions still remain. Since World War II, many governments, including the U.S. and its NATO allies, have regulated the export of cryptography for national security reasons, and, as late as 1992, cryptography was on the U.S. Munitions List as an Auxiliary Military Equipment.[2] Due to the enormous impact of cryptanalysis in World War II, these governments saw the military value in denying current and potential enemies access to cryptographic systems. Since the U.S. and U.K. believed they had bette ...more...

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List of hash functions

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List of hash functions

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Arxan Technologies

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Arxan Technologies

Arxan Technologies is an American technology company specializing in Application Attack Prevention and Self-Protection solution for IoT, Mobile, and other applications. The company reports that applications secured by it are running on over 500 million devices. Arxan solutions are used to protect applications across a range of industries, including: Mobile Payments & Banking, Automotive IoT, Healthcare IoT, Gaming, DRM,[1][2][3] and High-Tech. Arxan's security products are used to protect the confidentiality of applications (which can be breached by reverse-engineering, code analysis and other means) and the integrity of applications (which can be compromised through code modification, malware insertion and other types of attacks). History Arxan is privately held and private equity-backed. In the fall of 2013, TA Associates, a private equity firm, completed a majority investment in Arxan Technologies. Previously, the company received Series B funding in 2003,[4] followed by $13 million in series C fund ...more...

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Cryptosystem

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Cryptosystem

In cryptography, a cryptosystem is a suite of cryptographic algorithms needed to implement a particular security service, most commonly for achieving confidentiality (encryption).[1] Typically, a cryptosystem consists of three algorithms: one for key generation, one for encryption, and one for decryption. The term cipher (sometimes cypher) is often used to refer to a pair of algorithms, one for encryption and one for decryption. Therefore, the term cryptosystem is most often used when the key generation algorithm is important. For this reason, the term cryptosystem is commonly used to refer to public key techniques; however both "cipher" and "cryptosystem" are used for symmetric key techniques. Formal definition Mathematically, a cryptosystem or encryption scheme can be defined as a tuple ( P , C , K , E , D ) {\displaystyle ({\mathcal {P}},{\mathcal {C}},{\mathcal {K}},{\mathcal {E}},{\mathcal {D}})} with the following properties. P {\displaystyle {\mathcal {P}}} i ...more...

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Elliptic Curve Digital Signature Algorithm

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Elliptic Curve Digital Signature Algorithm

In cryptography, the Elliptic Curve Digital Signature Algorithm (ECDSA) offers a variant of the Digital Signature Algorithm (DSA) which uses elliptic curve cryptography. Key and signature-size comparison to DSA As with elliptic-curve cryptography in general, the bit size of the public key believed to be needed for ECDSA is about twice the size of the security level, in bits. For example, at a security level of 80 bits (meaning an attacker requires a maximum of about 2 80 {\displaystyle 2^{80}} operations to find the private key) the size of an ECDSA public key would be 160 bits, whereas the size of a DSA public key is at least 1024 bits. On the other hand, the signature size is the same for both DSA and ECDSA: approximately 4 t {\displaystyle 4t} bits, where t {\displaystyle t} is the security level measured in bits, that is, about 320 bits for a security level of 80 bits. Signature generation algorithm Suppose Alice wants to send a signed message to Bob. Initially, they must agre ...more...

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Trusted third party

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Trusted third party

In cryptography, a trusted third party (TTP) is an entity which facilitates interactions between two parties who both trust the third party; the Third Party reviews all critical transaction communications between the parties, based on the ease of creating fraudulent digital content. In TTP models, the relying parties use this trust to secure their own interactions. TTPs are common in any number of commercial transactions and in cryptographic digital transactions as well as cryptographic protocols, for example, a certificate authority (CA) would issue a digital identity certificate to one of the two parties in the next example. The CA then becomes the Trusted-Third-Party to that certificates issuance. Likewise transactions that need a third party recordation would also need a third-party repository service of some kind or another. 'Trusted' means that a system need to be trusted to act in your interests. But it has the option (either at will or involuntarily) to act against your interest. 'Trusted' also means ...more...

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Cryptanalysis

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Cryptanalysis

Close-up of the rotors in a Fialka cipher machine Cryptanalysis (from the Greek kryptós, "hidden", and analýein, "to loosen" or "to untie") is the study of analyzing information systems in order to study the hidden aspects of the systems.[1] Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown. In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation. Even though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematicall ...more...

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Advanced Encryption Standard

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Advanced Encryption Standard

The Advanced Encryption Standard (AES), also known by its original name Rijndael (Dutch pronunciation: ),[3] is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001.[4] AES is a subset of the Rijndael block cipher[3] developed by two Belgian cryptographers, Vincent Rijmen and Joan Daemen, who submitted a proposal[5] to NIST during the AES selection process.[6] Rijndael is a family of ciphers with different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits. AES has been adopted by the U.S. government and is now used worldwide. It supersedes the Data Encryption Standard (DES),[7] which was published in 1977. The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data. In the United States, AES was announced by the NIST as U.S. F ...more...

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Homomorphic encryption

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Homomorphic encryption

Homomorphic encryption is a form of encryption that allows computation on ciphertexts, generating an encrypted result which, when decrypted, matches the result of the operations as if they had been performed on the plaintext. The purpose of homomorphic encryption is to allow computation on encrypted data. Cloud computing platforms can perform difficult computations on homomorphically encrypted data without ever having access to the unencrypted data. Homomorphic encryption can also be used to securely chain together different services without exposing sensitive data. For example, services from different companies can calculate 1) the tax, 2) the currency exchange rate, and 3) shipping on a transaction without exposing the unencrypted data to each of those services.[1] Homomorphic encryption can also be used to create other secure systems such as secure voting systems,[2] collision-resistant hash functions, and private information retrieval schemes. Homomorphic encryption schemes are inherently malleable. In ...more...

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Brute-force attack

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Brute-force attack

The EFF's US$250,000 DES cracking machine contained over 1,800 custom chips and could brute-force a DES key in a matter of days. The photograph shows a DES Cracker circuit board fitted on both sides with 64 Deep Crack chips. In cryptography, a brute-force attack consists of an attacker trying many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct one is found. Alternatively, the attacker can attempt to guess the key which is typically created from the password using a key derivation function. This is known as an exhaustive key search. A brute-force attack is a cryptanalytic attack that can, in theory, be used to attempt to decrypt any encrypted data[1] (except for data encrypted in an information-theoretically secure manner). Such an attack might be used when it is not possible to take advantage of other weaknesses in an encryption system (if any exist) that would make the task easier. When pa ...more...

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S/KEY

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S/KEY

S/KEY is a one-time password system developed for authentication to Unix-like operating systems, especially from dumb terminals or untrusted public computers on which one does not want to type a long-term password. A user's real password is combined in an offline device with a short set of characters and a decrementing counter to form a single-use password. Because each password is only used once, they are useless to password sniffers. Because the short set of characters does not change until the counter reaches zero, it is possible to prepare a list of single-use passwords, in order, that can be carried by the user. Alternatively, the user can present the password, characters, and desired counter value to a local calculator to generate the appropriate one-time password that can then be transmitted over the network in the clear. The latter form is more common and practically amounts to challenge-response authentication. S/KEY is supported in Linux (via pluggable authentication modules), OpenBSD, NetBSD, and ...more...

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Codebook

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Codebook

A codebook is a type of document used for gathering and storing codes. Originally codebooks were often literally books, but today codebook is a byword for the complete record of a series of codes, regardless of physical format. Cryptography In cryptography, a codebook is a document used for implementing a code. A codebook contains a lookup table for coding and decoding; each word or phrase has one or more strings which replace it. To decipher messages written in code, corresponding copies of the codebook must be available at either end. The distribution and physical security of codebooks presents a special difficulty in the use of codes, compared to the secret information used in ciphers, the key, which is typically much shorter. The United States National Security Agency documents sometimes use codebook to refer to block ciphers; compare their use of combiner-type algorithm to refer to stream ciphers. A codebook is usually made in two parts, one part being for converting plaintext to ciphertext, the othe ...more...

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Trusted Platform Module

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Trusted Platform Module

Components of a Trusted Platform Module complying with the TPM version 1.2 standard Trusted Platform Module (TPM, also known as ISO/IEC 11889) is an international standard for a secure cryptoprocessor, a dedicated microcontroller designed to secure hardware through integrated cryptographic keys. History Trusted Platform Module (TPM) was conceived by a computer industry consortium called Trusted Computing Group (TCG), and was standardized by International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) in 2009 as ISO/IEC 11889.[1] TCG continued to revise the TPM specifications. The last revised edition of TPM Main Specification Version 1.2 was published on March 3, 2011. It consisted of three parts, based on their purpose.[2] For the second major version of TPM, however, TCG released TPM Library Specification 2.0, which builds upon the previously published TPM Main Specification. Its latest edition was released on September 29, 2016, with several errata with the l ...more...

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Quantum key distribution

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Quantum key distribution

Quantum key distribution (QKD) is a secure communication method which implements a cryptographic protocol involving components of quantum mechanics. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages. It is often incorrectly called quantum cryptography, as it is the best-known example of a quantum cryptographic task. An important and unique property of quantum key distribution is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key. This results from a fundamental aspect of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the key must in some way measure it, thus introducing detectable anomalies. By using quantum superpositions or quantum entanglement and transmitting information in quantum states, a communication system can be implemented that detects eavesdropping. If the leve ...more...

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QKD

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Key

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Key

Look up key in Wiktionary, the free dictionary. Key may refer to: Common meanings Cay, also spelled key, a small, low-elevation, sandy island formed on the surface of a coral reef Key (cryptography), a piece of information that controls the operation of a cryptography algorithm Key (engineering), a type of coupling used to transmit rotation between a shaft and an attached item Key (electrical), mechanical component in a plug and/or socket which prevents mating except with a correctly oriented matching connector Key (lock), a device used to open a lock such as in a door, safe, or other openings to objects or places. Key (map), a guide to a map's symbology Key, a guide to colours and symbols used in a data chart, graph, plot or diagram Places In the United States Key, Alabama Key, Ohio Key, West Virginia Keys, Oklahoma Florida Keys, an archipelago of about 1700 islands in the southeast United States Elsewhere Key Island, Tasmania, Australia Key, Iran, a village in Isfahan Provinc ...more...



Zeroisation

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Zeroisation

"Emergency Erase" (АВАРИЙНОЕ СТИРАНИЕ) switch, zeroize in NSA parlance, on a cryptographic device of the Soviet Rocket Forces In cryptography, zeroisation (also spelled zeroization) is the practice of erasing sensitive parameters (electronically stored data, cryptographic keys, and Critical Security Parameters) from a cryptographic module to prevent their disclosure if the equipment is captured. This is generally accomplished by altering or deleting the contents to prevent recovery of the data.[1] When encryption was performed by mechanical devices, this would often mean changing all the machine's settings to some fixed, meaningless value, such as zero. On machines with letter settings rather than numerals, the letter 'O' was often used instead. Some machines had a button or lever for performing this process in a single step. Zeroisation would typically be performed at the end of an encryption session to prevent accidental disclosure of the keys, or immediately when there was a risk of capture by an adversa ...more...

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Hash function

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Hash function

A hash function that maps names to integers from 0 to 15. There is a collision between keys "John Smith" and "Sandra Dee". A hash function is any function that can be used to map data of arbitrary size to data of a fixed size. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. Hash functions are often used in combination with a hash table, a common data structure used in computer software for rapid data lookup. Hash functions accelerate table or database lookup by detecting duplicated records in a large file. One such application is finding similar stretches in DNA sequences. They are also useful in cryptography. A cryptographic hash function allows one to easily verify that some input data maps to a given hash value, but if the input data is unknown, it is deliberately difficult to reconstruct it (or any equivalent alternatives) by knowing the stored hash value. This is used for assuring integrity of transmitted data, and is the building block for HMACs, wh ...more...

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Security token

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Security token

Security tokens are physical devices used to gain access to an electronically restricted resource. The token is used in addition to or in place of a password. It acts like an electronic key to access something. Examples include a wireless keycard opening a locked door, or in the case of a customer trying to access their bank account online, the use of a bank provided token can prove that the customer is who they claim to be. Some tokens may store cryptographic keys, such as a digital signature, or biometric data, such as fingerprint details. Some may also store passwords.[1] Some designs\tamper resistant packaging, while others may include small keypads to allow entry of a PIN or a simple button to start a generating routine with some display capability to show a generated key number. Special designs include a USB connector, RFID functions or Bluetooth wireless interface to enable transfer of a generated key number sequence to a client system. Password types All tokens contain some secret information that ...more...

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CEK

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CEK

CEK may refer to: College of Engineering, Karunagappally, a Government Engineering College in Kollam district of Kerala, India Cek (Quba), a village in the Quba Rayon of Azerbaijan Cek dialect, a dialect of the Kryts language, a Samur language of Azerbaijan Chelyabinsk Airport, in Russia Content encryption key, a cryptographic key type Eastern Khumi language (ISO 639-3: cek), Kukish language of Burma Özgür Çek (born 1991), Turkish footballer ...more...



Ssh-keygen

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Ssh-keygen

ssh-keygen is a standard component of the Secure Shell (SSH) protocol suite found on Unix and Unix-like computer systems used to establish secure shell sessions between remote computers over insecure networks, through the use of various cryptographic techniques. The ssh-keygen utility is used to generate, manage, and convert authentication keys. ssh-keygen is able to generate a key using one of three different digital signature algorithms. With the help of the ssh-keygen tool, a user can create passphrase keys for any of these key types (to provide for unattended operation, the passphrase can be left empty, at increased risk). These keys differ from keys used by the related tool GNU Privacy Guard. Key formats supported Originally, with SSH protocol version 1 (now deprecated) only the RSA algorithm was supported. As of 2016, RSA is still considered strong, but the recommended key length has increased over time. The SSH protocol version 2 additionally introduced support for the DSA algorithm. As the DSA a ...more...

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Software token

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Software token

A software token (a.k.a. soft token) is a type of two-factor authentication security device that may be used to authorize the use of computer services. Software tokens are stored on a general-purpose electronic device such as a desktop computer, laptop, PDA, or mobile phone and can be duplicated. (Contrast hardware tokens, where the credentials are stored on a dedicated hardware device and therefore cannot be duplicated (absent physical invasion of the device).) Because software tokens are something one does not physically possess, they are exposed to unique threats based on duplication of the underlying cryptographic material - for example, computer viruses and software attacks. Both hardware and software tokens are vulnerable to bot-based man-in-the-middle attacks, or to simple phishing attacks in which the one-time password provided by the token is solicited, and then supplied to the genuine website in a timely manner. Software tokens do have benefits: there is no physical token to carry, they do not cont ...more...

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Ring learning with errors key exchange

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Ring learning with errors key exchange

In cryptography, a public key exchange algorithm is a cryptographic algorithm which allows two parties to create and share a secret key, which they can use to encrypt messages between themselves. The ring learning with errors key exchange (RLWE-KEX) is one of a new class of public key exchange algorithms that are designed to be secure against an adversary that possesses a quantum computer. This is important because the vast majority of public key algorithms in use today are easily broken by a quantum computer and scientists are making steady progress toward creating such a computer. RLWE-KEX is one of a set of post-quantum cryptographic algorithms which are based on the difficulty of solving certain mathematical problems involving lattices. Unlike older lattice based cryptographic algorithms, the RLWE-KEX is provably reducible to a known hard problem in lattices. Background Since the 1980s the security of cryptographic key exchanges and digital signatures over the Internet has been primarily based on a smal ...more...

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IPsec

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IPsec

In computing, Internet Protocol Security (IPsec) is a secure network protocol suite of IPv4 that authenticates and encrypts the packets of data sent over an IPv4 network. Because of the complexity or immaturity of the IP security protocols, the initial IPv4 was developed without or barely with security protocols such that the IP version was incomplete, open or left for further research development. IPsec includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to use during the session. IPsec can protect data flows between a pair of hosts (host-to-host), between a pair of security gateways (network-to-network), or between a security gateway and a host (network-to-host).[1] Internet Protocol security (IPsec) uses cryptographic security services to protect communications over Internet Protocol (IP) networks. IPsec supports network-level peer authentication, data-origin authentication, data integrity, data confidentiality (encr ...more...

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Snake oil (cryptography)

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Snake oil (cryptography)

In cryptography, snake oil is any cryptographic method or product considered to be bogus or fraudulent. The name derives from snake oil, one type of patent medicine widely available in 19th century United States. Distinguishing secure cryptography from insecure cryptography can be difficult from the viewpoint of a user. Many cryptographers, such as Bruce Schneier and Phil Zimmermann, undertake to educate the public in how secure cryptography is done, as well as highlighting the misleading marketing of some cryptographic products. The Snake Oil FAQ describes itself as, "a compilation of common habits of snake oil vendors. It cannot be the sole method of rating a security product, since there can be exceptions to most of these rules. [...] But if you're looking at something that exhibits several warning signs, you're probably dealing with snake oil." Some examples of snake oil cryptography techniques This is not an exhaustive list of snake oil signs. A more thorough list is given in the external articles lin ...more...

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Man-in-the-middle attack

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Man-in-the-middle attack

In cryptography and computer security, a man-in-the-middle attack (MITM) is an attack where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other. One example of man-in-the-middle attacks is active eavesdropping, in which the attacker makes independent connections with the victims and relays messages between them to make them believe they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker. The attacker must be able to intercept all relevant messages passing between the two victims and inject new ones. This is straightforward in many circumstances; for example, an attacker within reception range of an unencrypted wireless access point (Wi-Fi) could insert himself as a man-in-the-middle.[1] As an attack that aims at circumventing mutual authentication, or lack thereof, a man-in-the-middle attack can succeed only when the attacker can imperson ...more...

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RSA (cryptosystem)

topic

RSA (cryptosystem)

RSA (Rivest–Shamir–Adleman) is one of the first public-key cryptosystems and is widely used for secure data transmission. In such a cryptosystem, the encryption key is public and it is different from the decryption key which is kept secret (private). In RSA, this asymmetry is based on the practical difficulty of the factorization of the product of two large prime numbers, the "factoring problem". The acronym RSA is made of the initial letters of the surnames of Ron Rivest, Adi Shamir, and Leonard Adleman, who first publicly described the algorithm in 1978. Clifford Cocks, an English mathematician working for the British intelligence agency Government Communications Headquarters (GCHQ), had developed an equivalent system in 1973, but this was not declassified until 1997.[1] A user of RSA creates and then publishes a public key based on two large prime numbers, along with an auxiliary value. The prime numbers must be kept secret. Anyone can use the public key to encrypt a message, but with currently published ...more...

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S/MIME

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S/MIME

S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for public key encryption and signing of MIME data. S/MIME is on an IETF standards track and defined in a number of documents, most importantly RFC 3369, 3370, 3850 and 3851. It was originally developed by RSA Data Security Inc. and the original specification used the IETF MIME specification[1] with the de facto industry standard PKCS#7 secure message format. Change control to S/MIME has since been vested in the IETF and the specification is now layered on Cryptographic Message Syntax, an IETF specification that is identical in most respects with PKCS #7. S/MIME functionality is built into the majority of modern email software and interoperates between them. Function S/MIME provides the following cryptographic security services for electronic messaging applications: Authentication Message integrity Non-repudiation of origin (using digital signatures) Privacy Data security (using encryption) S/MIME specifies the MIME type applicatio ...more...

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Password-authenticated key agreement

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Password-authenticated key agreement

In cryptography, a password-authenticated key agreement method is an interactive method for two or more parties to establish cryptographic keys based on one or more party's knowledge of a password. An important property is that an eavesdropper or man in the middle cannot obtain enough information to be able to brute force guess a password without further interactions with the parties for each (few) guesses. This means that strong security can be obtained using weak passwords. Types Password-authenticated key agreement generally encompasses methods such as: Balanced password-authenticated key exchange Augmented password-authenticated key exchange Password-authenticated key retrieval Multi-server methods Multi-party methods In the most stringent password-only security models, there is no requirement for the user of the method to remember any secret or public data other than the password. Password authenticated key exchange (PAKE) is where two or more parties, based only on their knowledge of a passw ...more...

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Classical cipher

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Classical cipher

In cryptography, a classical cipher is a type of cipher that was used historically but now has fallen, for the most part, into disuse. In contrast to modern cryptographic algorithms, most classical ciphers can be practically computed and solved by hand. However, they are also usually very simple to break with modern technology. The term includes the simple systems used since Greek and Roman times, the elaborate Renaissance ciphers, World War II cryptography such as the Enigma machine and beyond. In contrast, modern strong cryptography relies on new algorithms and computers developed since the 1970s. Types of Classical ciphers Classical ciphers are often divided into transposition ciphers and substitution ciphers. Substitution ciphers In a substitution cipher, letters (or groups of letters) are systematically replaced throughout the message for other letters (or groups of letters). A well-known example of a substitution cipher is the Caesar cipher. To encrypt a message with the Caesar cipher, each letter ...more...

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List of telecommunications encryption terms

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List of telecommunications encryption terms

George W. Bush using a Motorola STU-III immediately after the September 11 attacks KSD-64 "Crypto-ignition keys" on display at the National Cryptologic Museum in 2005 This is a list of telecommunications encryption terms. This list is derived in part from the Glossary of Telecommunication Terms published as Federal Standard 1037C. A5/1 – a stream cipher used to provide over-the-air communication privacy in the GSM cellular telephone standard. Bulk encryption Cellular Message Encryption Algorithm – a block cipher which was used for securing mobile phones in the United States. Cipher Cipher system Cipher text Ciphony [1] Civision Codress message COMSEC equipment Cryptanalysis Cryptographic key CRYPTO (International Cryptology Conference) Crypto phone Crypto-shredding Data Encryption Standard (DES) [2] Decipher Decode Decrypt DECT Standard Cipher Descrambler Dncipher Encode Encoding law Encrypt End-to-end encryption group IMSI-catcher – an eavesdropping device used for ...more...

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SIV

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SIV

SIV or Siv may refer to: Organizations Federal Executive Council (Yugoslavia) or Savezno izvršno veće (SIV) Sydney Intervarsity Choral Festival Sheffield International Venues, a facilities management company in Sheffield, UK Surinaamse Islamitische Vereniging Places SIV, the IATA and FAA airport code for Sullivan County Airport, Sullivan County, Indiana, USA Siv, Iran, a village in Kurdistan Province, Iran Science and Technology S IV, a shortcut pronoun for the Samsung Galaxy S4 Android smartphone Stress migration (Stress-induced voiding), a failure mechanism in MOSFETs Key Wrap (Synthetic Initialization Vector), a cryptographic key-wrapping algorithm Simian immunodeficiency virus, a virus found in primates and related to HIV Swine influenza virus, the cause of influenza in pigs Other Special Immigrant Visa, a type of immigrant visa in the United States Simulation d’incidents en vol, or simulation of flying incidents training Structured investment vehicle, a type of fund i ...more...



Catena

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Catena

Look up Farmacia catena or catenae in Wiktionary, the free dictionary. The word catena (Latin for chain) or catenae (plural) may refer to: Science Catena (fly), a genus in the family Tachinidae Catena (linguistics) is a unit of syntax and morphology, closely associated with dependency grammars Catena (computing), number of bits transferred in one cycle Catenary, a type of curve in mathematics Crater chain, a line of craters along the surface of an astronomical body Farmacia Catena, a trade name of the drug idebenone Catena (soil) in pedology, a sequence of soil profiles down a slope Catena (cryptography), a cryptographic algorithm used as a key derivation function Other uses Catena (surname) Catena (biblical commentary), a verse-by-verse biblical commentary A prayer said daily by members of the Legion of Mary International Masonic Union Catena, a masonic organization The monthly journal of the Catenian Association Catena Media, an online media company in Malta A term for t ...more...



Content Protection for Recordable Media

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Content Protection for Recordable Media

Content Protection for Recordable Media and Pre-Recorded Media (CPRM/CPPM) is a mechanism for controlling the copying, moving and deletion of digital media on a host device, such as a personal computer, or other player. It is a form of digital rights management (DRM) developed by The 4C Entity, LLC (consisting of IBM, Intel, Matsushita and Toshiba). The CPRM/CPPM Specification defines a renewable cryptographic method for protecting entertainment content when recorded on physical media. The currently implemented method utilizes the Cryptomeria cipher (C2) algorithm for symmetric encryption. The types of physical media supported include, but are not limited to, recordable DVD media and flash memory (note that the available 0.9 revision includes only the portions of the specification covering DVD media). The most widespread use of CPRM is arguably in Secure Digital cards. The CPRM/CPPM Specification was designed to meet the robustness and renewability requirements of content owners while balancing the implemen ...more...

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ISO/IEC 18014

topic

ISO/IEC 18014

ISO/IEC 18014 Information technology — Security techniques — Time-stamping services is an international standard that specifies time-stamping techniques. It comprises four parts: Part 1: Framework[1] Part 2: Mechanisms producing independent tokens[2] Part 3: Mechanisms producing linked tokens[3] Part 4: Traceability of time sources[4] Part 1: Framework In this first part of ISO/IEC 18014, several things are explained and developed: The identification of the objectives of a time authority. The description of a general model on which time stamping services are based. The definition of time stamping services. The definition of the basic protocols of time stamping. The specifications of the protocols between the involved entities. Key words: audit, non-repudiation, security, time-stamp Part 2: Mechanisms producing independent tokens A time-stamping service provides evidence that a data item existed before a certain point in time. Time-stamp services produce time-stamp tokens, which are d ...more...

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Attack model

topic

Attack model

In cryptanalysis, attack models or attack types[1] are a classification of cryptographic attacks specifying the kind of access a cryptanalyst has to a system under attack when attempting to "break" an encrypted message (also known as ciphertext) generated by the system. The greater the access the cryptanalyst has to the system, the more useful information he can get to utilize for breaking the cypher. In cryptography, a sending party uses a cipher to encrypt (transform) a secret plaintext into a ciphertext, which is sent over an insecure communication channel to the receiving party. The receiving party uses an inverse cipher to decrypt the ciphertext to obtain the plaintext. A secret knowledge is required to apply the inverse cipher to the ciphertext. This secret knowledge is usually a short number or string called a key. In a cryptographic attack a third party cryptanalyst analyzes the ciphertext to try to "break" the cipher, to read the plaintext and obtain the key so that future enciphered messages can be ...more...

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Digital signature forgery

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Digital signature forgery

In a cryptographic digital signature or MAC system, digital signature forgery is the ability to create a pair consisting of a message, m {\displaystyle m} , and a signature (or MAC), σ {\displaystyle \sigma } , that is valid for m {\displaystyle m} , where m {\displaystyle m} has not been signed in the past by the legitimate signer. There are three types of forgery: existential, selective, and universal.[1] Types Besides the following attacks, there is also a total break: when adversary can compute the signer's private key and therefore forge any possible signature on any message.[2] Existential forgery (existential unforgeability, EUF) Existential forgery is the creation (by an adversary) of at least one message/signature pair, ( m , σ ) {\displaystyle (m,\sigma )} , where σ {\displaystyle \sigma } was not produced by the legitimate signer. The adversary need not have any control over m {\displaystyle m} ; m {\displaystyle m} need not have any particular ...more...

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RC4

topic

RC4

In cryptography, RC4 (Rivest Cipher 4 also known as ARC4 or ARCFOUR meaning Alleged RC4, see below) is a stream cipher. While remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure.[3][4] It is especially vulnerable when the beginning of the output keystream is not discarded, or when nonrandom or related keys are used. Particularly problematic uses of RC4 have led to very insecure protocols such as WEP.[5] As of 2015, there is speculation that some state cryptologic agencies may possess the capability to break RC4 when used in the TLS protocol.[6] IETF has published RFC 7465 to prohibit the use of RC4 in TLS;[3] Mozilla and Microsoft have issued similar recommendations.[7][8] A number of attempts have been made to strengthen RC4, notably Spritz, RC4A, VMPC, and RC4+. History RC4 was designed by Ron Rivest of RSA Security in 1987. While it is officially termed "Rivest Cipher 4", the RC acronym is alternatively understood to stand for ...more...

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Certificate authority

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Certificate authority

In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party—trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The format of these certificates is specified by the X.509 standard. One particularly common use for certificate authorities is to sign certificates used in HTTPS, the secure browsing protocol for the World Wide Web. Another common use is in issuing identity cards by national governments for use in electronically signing documents. Overview Trusted certificates can be used to create secure connections to a server via the Internet. A certificate is essential in order to circumvent a malicious party which h ...more...

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Substitution cipher

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Substitution cipher

In cryptography, a substitution cipher is a method of encrypting by which units of plaintext are replaced with ciphertext, according to a fixed system; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing the inverse substitution. Substitution ciphers can be compared with transposition ciphers. In a transposition cipher, the units of the plaintext are rearranged in a different and usually quite complex order, but the units themselves are left unchanged. By contrast, in a substitution cipher, the units of the plaintext are retained in the same sequence in the ciphertext, but the units themselves are altered. There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters is termed polygraphic. A monoalphabetic cipher uses fixed substitution over the entire ...more...

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Code signing

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Code signing

Code signing is the process of digitally signing executables and scripts to confirm the software author and guarantee that the code has not been altered or corrupted since it was signed. The process employs the use of a cryptographic hash to validate authenticity and integrity.[1] Code signing can provide several valuable features. The most common use of code signing is to provide security when deploying; in some programming languages, it can also be used to help prevent namespace conflicts. Almost every code signing implementation will provide some sort of digital signature mechanism to verify the identity of the author or build system, and a checksum to verify that the object has not been modified. It can also be used to provide versioning information about an object or to store other meta data about an object.[2] The efficacy of code signing as an authentication mechanism for software depends on the security of underpinning signing keys. As with other public key infrastructure (PKI) technologies, the int ...more...

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Chaotic cryptology

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Chaotic cryptology

Chaotic cryptology includes two integral opposite parts: Chaotic cryptography and Chaotic cryptanalysis. Chaotic cryptography is the application of the mathematical chaos theory to the practice of the cryptography, the study or techniques used to privately and securely transmit information with the presence of a third-party or adversary. The use of chaos or randomness in cryptography has long been sought after by entities wanting a new way to encrypt messages. However, because of the lack of thorough, provable security properties and low acceptable performance, chaotic cryptography has encountered setbacks.[1][2][3][4] In order to use chaos theory efficiently in cryptography, the chaotic maps should be implemented such that the entropy generated by the map can produce required Confusion and diffusion. Properties in chaotic systems and cryptographic primitives share unique characteristics that allow for the chaotic systems to be applied to cryptography.[5] If chaotic parameters, as well as cryptographic keys, ...more...

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Standard model (cryptography)

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Standard model (cryptography)

In cryptography the standard model is the model of computation in which the adversary is only limited by the amount of time and computational power available. Other names used are bare model and plain model. Cryptographic schemes are usually based on complexity assumptions, which state that some problems, such as factorization, cannot be solved in polynomial time. Schemes which can be proven secure using only complexity assumptions are said to be secure in the standard model. Security proofs are notoriously difficult to achieve in the standard model, so in many proofs, cryptographic primitives are replaced by idealized versions. The most usual example of this technique, known as the random oracle model,[1][2] involves replacing a cryptographic hash function with a genuinely random function. Another example is the generic group model,[3][4] where the adversary is given access to a randomly chosen encoding of a group, instead of the finite field or elliptic curve groups used in practice. Other models used inv ...more...

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Device Keys

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Device Keys

Device Keys play a role in the cryptographic key management procedure in the Advanced Access Content System (AACS) specification. This specification defines a method for protecting audiovisual entertainment content, including high-definition content. Introduction The AACS’s cryptographic key management procedure uses Device Keys to decrypt one or more elements of a Media Key Block (MKB), in order to extract a secret Media Key (Km). A MKB is located on the physical support (the disc) together with the content of the disc encrypted. MKB enables system renewability. The MKB is generated by AACS LA, and allows all compliant devices, each using their set of secret Device Keys, to calculate the same Media Key (Km). If a set of Device Keys is compromised in a way that threatens the integrity of the system, an updated MKB can be released that causes a device with the compromised set of Device Keys to be unable to calculate the correct Km. In this way, the compromised Device Keys are “revoked” by the new MKB. Comm ...more...

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Encryption software

topic

Encryption software

Encryption software is software that uses cryptography to prevent unauthorized access to digital information.[1][2] Practically speaking, people use cryptography today to protect the digital information on their computers as well as the digital information that is sent to other computers over the Internet.[3] As software that implements secure cryptography is complex to develop and difficult to get right,[4] most computer users make use of the encryption software that already exists rather than writing their own. Classification As encryption software is an important component in providing protection from cybercrime, there are many software products which provide encryption. Because there are so many software products that provide encryption, a good way to begin understanding this topic is classification by categorization. Software encryption uses a cipher to obscure the content into ciphertext. One way to classify this type of software is by the type of cipher used. Ciphers can be divided into two categori ...more...

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Neural cryptography

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Neural cryptography

Neural cryptography is a branch of cryptography dedicated to analyzing the application of stochastic algorithms, especially artificial neural network algorithms, for use in encryption and cryptanalysis. Definition Artificial neural networks are well known for their ability to selectively explore the solution space of a given problem. This feature finds a natural niche of application in the field of cryptanalysis. At the same time, neural networks offer a new approach to attack ciphering algorithms based on the principle that any function could be reproduced by a neural network, which is a powerful proven computational tool that can be used to find the inverse-function of any cryptographic algorithm. The ideas of mutual learning, self learning, and stochastic behavior of neural networks and similar algorithms can be used for different aspects of cryptography, like public-key cryptography, solving the key distribution problem using neural network mutual synchronization, hashing or generation of pseudo-random ...more...

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OpenCA

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OpenCA

OpenCA, officially the OpenCA PKI Research Labs and formerly the OpenCA Project, is a PKI collaborative effort to develop a robust, full-featured and open-source out-of-the-box certification authority implementing the most used protocols with full-strength cryptography. OpenCA is based on many open-source projects; among these are OpenLDAP, OpenSSL and Apache projects. Project development is divided into 2 main tasks: studying and refining the security scheme that guarantees the best model to be used in a certificate authority, and developing software to easily set up and manage a CA. The software development side of the project is further divided into the following sub-projects: OpenCA PKI, a full-featured PKI package. LibPKI, a library for PKI application development. OpenCA OCSPD, a small, robust Online Certificate Status Protocol daemon. PRQPD Server, a PKI Resource Query Protocol daemon for use in conjunction with the PKI package. OpenCA-ng, a next-generation project planned to implement new ...more...

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Smart lock

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Smart lock

The 2nd generation August smart lock. A smart lock is an electromechanical lock which is designed to perform locking and unlocking operations on a door when it receives such instructions from an authorized device using a wireless protocol and a cryptographic key to execute the authorization process. It also monitors access and sends alerts for the different events it monitors and some other critical events related to the status of the device. Smart locks can be considered part of a smart home.[1] Most smart locks are installed on mechanical locks (simple types of locks, incl. deadbolts) and they physically upgrade the ordinary lock. Recently, smart locking controllers have also appeared at the market. Smart locks, like the traditional locks, need two main parts to work: the lock and the key. In the case of these electronic locks, the key is not a physical key but a smartphone or a special key fob configured explicitly for this purpose which wirelessly performs the authentication needed to automatically un ...more...

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Cold boot attack

topic

Cold boot attack

In cryptography, a cold boot attack (or to a lesser extent, a platform reset attack) is a type of side channel attack in which an attacker with physical access to a computer is able to retrieve encryption keys from a running operating system after using a cold reboot to restart the machine.[1][2] The attack relies on the data remanence property of DRAM and SRAM to retrieve memory contents that remain readable in the seconds to minutes after power has been removed.[2][3] Description To execute the attack, a running computer is cold-booted. A removable disk is then immediately used to boot a lightweight operating system, which is then used to dump the contents of pre-boot physical memory to a file.[4] Alternatively, the memory modules are removed from the original system and quickly placed in a compatible machine under the attacker's control, which is then booted to access the memory. Further analysis can then be performed against the information that was dumped from memory to find various sensitive data, suc ...more...

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