🛡️Information Security: Digital Signature (Definitions)

"A form of electronic authentication of a digital document. Digital signatures are created and verified using public key cryptography and serve to tie the document being signed to the signer." (J P Getty Trust, "Introduction to Metadata" 2nd Ed., 2008)

"Data which proves that a document, message, or other piece of data was not modified since being processed and sent from a particular party." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"cryptographic transformations of data that allow a recipient of the data to prove the source (non-repudiation) and integrity of the data." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"Data that is appended to a message, made from the message itself and the sender’s private key, to ensure the authenticity of the message" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"Ensuring the authenticity and integrity of a message through the use of hashing algorithms and asymmetric algorithms. The message digest is encrypted with the sender’s private key." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A means of authenticating that a message or data came from a particular source with a known system identity." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"An electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified." (Shon Harris & Fernando Maymi, "CISSP All-in-One Exam Guide, 8th Ed", 2018)

"An encrypted means of identification that cannot be forged and that enables clients to validate servers and vice versa." (Microfocus)

"The combination of the private key, public key, message and hashing generates a digital signature. A digital signature is unique for every transaction and is a way to prove that the originator of the message has access to the private key." (AICPA)

🛡️Information Security: Cryptanalysis (Definitions)

"Cryptanalysis is the science of analyzing cryptographic methods and algorithms, generally probing them for weaknesses. Cryptanalysts devise new methods of defeating cryptographic algorithms." (Michael Coles & Rodney Landrum, , "Expert SQL Server 2008 Encryption", 2008)

"The science (or art) of breaking cryptographic algorithms." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"The study of mathematical techniques designed to defeat cryptographic techniques. Collectively, a branch of science that deals with cryptography and cryptanalysis is called cryptology. " (Alex Berson & Lawrence Dubov, "Master Data Management and Data Governance", 2010)

"The art of breaking ciphertext." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"Practice of uncovering flaws within cryptosystems." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"The process of decrypting a message without knowing the cipher or key used to encrypt it" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"The practice of breaking cryptosystems and algorithms used in encryption and decryption processes." (Shon Harris & Fernando Maymi, "CISSP All-in-One Exam Guide" 8th Ed., 2018)

"The process of breaking encryption without the benefit of the key under which data was encrypted." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"Cryptanalysis refers to the study of the cryptosystem or ciphertext to crack the confidentiality of the underlying information and try to gain unauthorized access to the content." (Shafali Agarwal, "Preserving Information Security Using Fractal-Based Cryptosystem", Handbook of Research on Cyber Crime and Information Privacy, 2021)

🛡️Information Security: Public Key Cryptography [PKC] (Definitions)

"Also known as asymmetric cryptography, a form of cryptography in which a user has a pair of cryptographic keys - a public key and a private key. The private key is kept secret, while the public key may be widely distributed. The keys are related mathematically, but the private key cannot be practically derived from the public key. A message encrypted with the public key can be decrypted only with the corresponding private key." (Martin Oberhofer et al, "Enterprise Master Data Management", 2008)

"Cryptography involving public keys, as opposed to cryptography making use of shared secrets. See Symmetric cryptography." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"An approach to cryptography in which each user has two related keys, one public and one private" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"An asymmetric cryptosystem where the encrypting and decrypting keys are different and it is computationally infeasible to calculate one form the other, given the encrypting algorithm. In public key cryptography, the encrypting key is made public, but the decrypting key is kept secret." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK 4th Ed.", 2015)

"An encryption method that uses a two-part key: a public key and a private key. Users generally distribute their public key but keep their private key to themselves. This is also known as asymmetric cryptography." (James R Kalyvas & Michael R Overly, "Big Data: A business and legal guide", 2015)

"Encryption system using a public-private key pair for encryption or digital signature. The encrypt and decrypt keys are different, and one cannot derive the private key from the public key." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"Public-key cryptography refers to a cryptographic system requiring two separate keys, one of which is secret and one of which is public. Although different, the two parts of the key pair are mathematically linked. One key locks or encrypts the plaintext, and the other unlocks or decrypts the cipher text. Neither key can perform both functions by itself. The public key may be published without compromising security, while the private key must not be revealed to anyone not authorized to read the messages." (Addepalli V N Krishna & M Balamurugan, "Security Mechanisms in Cloud Computing-Based Big Data", 2019)

"A cryptographic system that requires public and private keys. The private key can decrypt messages encrypted with the corresponding public key, and vice versa. The public key can be made available to the public without compromising security and used to verify that messages sent by the holder of the private key must be genuine." (Daniel Leuck et al, "Learning Java" 5th Ed., 2020)

🛡️Information Security: Cryptosystem (Definitions)

"Hardware or software implementation of cryptography that contains all the necessary software, protocols, algorithms, and keys." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"The hardware or software implementation of cryptography." (Shon Harris & Fernando Maymi, "CISSP All-in-One Exam Guide" 8th Ed., 2018)

"A set of cryptographic algorithms together with the key management processes that support use of the algorithms in some application context." (William Stallings, "Effective Cybersecurity: A Guide to Using Best Practices and Standards", 2018)

"A cryptosystem includes a complete process of key generation, encryption, and decryption techniques for secure data communication over the insecure channel." (Shafali Agarwal, "Preserving Information Security Using Fractal-Based Cryptosystem", Handbook of Research on Cyber Crime and Information Privacy, 2021)

"Associated information security (INFOSEC) items interacting to provide a single means of encryption or decryption." (CNSSI 4009-2015)

[manual cryptosystem:] "Cryptosystem in which the cryptographic processes are performed without the use of crypto-equipment or auto-manual devices." (CNSSI 4009-2015)

[online cryptosystem:] "Cryptographic system in which encryption and decryption are performed in association with the transmitting and receiving functions." (CNSSI 4009-2015)

[off-line cryptosystem:] "Cryptographic system in which encryption and decryption are performed independently of the transmission and reception functions." (CNSSI 4009-2015)

🛡️Information Security: Certificate (Definitions)

"An asymmetric key, usually issued by a certificate authority, that contains the public key of a public/private key pair as well as identifying information, expiration dates, and other information and that provides the ability to authenticate its holder. Certificates are used in SQL Server 2005 to secure logins or other database objects." (Victor Isakov et al, "MCITP Administrator: Microsoft SQL Server 2005 Optimization and Maintenance (70-444) Study Guide", 2007)

"A certificate is an electronic document consisting of an asymmetric key with additional metadata such as an expiration date and a digital signature that allows it to be verified by a third-party like a certificate authority (CA)." (Michael Coles, "Pro T-SQL 2008 Programmer's Guide", 2008)

"A certificate is an electronic document that uses a digital signature to bind an asymmetric key with a public identity. In its simplest form, a certificate is essentially an asymmetric key which can have additional metadata, like a certificate name, subject, and expiration date. A certificate can be selfsigned or issued by a certificate authority." (Michael Coles & Rodney Landrum, , "Expert SQL Server 2008 Encryption", 2008)

"A data object that binds information about a person or some other entity to a public key. The binding is generally done using a digital signature from a trusted third party (a certification authority)." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"(1) A token of authorization or authentication. (2) In data security, a computer data security object that includes identity information, validity specification, and a key." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"A digital document that is commonly used for authentication and to help secure information on a network. A certificate binds a public key to an entity that holds the corresponding private key. Certificates are digitally signed by the certification authority that issues them, and they can be issued for a user, a computer, or a service." (Microsoft, "SQL Server 2012 Glossary", 2012)

"A bundle of information containing the encrypted public key of the server, and the identification of the key provider." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"An electronic document used to identify an individual, a system, a server, a company, or some other entity, and to associate a public key with the entity. A digital certificate is issued by a certification authority and is digitally signed by that authority." (IBM, "Informix Servers 12.1", 2014)

"A representation of a sender’s authenticated public key used to minimize malicious forgeries" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"A small electronic file that serves to validate or encrypt a message or browser session. Digital certificates are often used to create a digital signature which offers non-repudiation of a user or a Web site." (Mike Harwood, "Internet Security: How to Defend Against Attackers on the Web" 2nd Ed., 2015)

"An electronic document consisting of an asymmetric key with additional metadata such as an expiration date and a digital signature that allows it to be verified by a third party like a certificate authority (CA)." (Miguel Cebollero et al, "Pro T-SQL Programmer’s Guide 4th Ed", 2015)

"Cryptography-related electronic documents that allow for node identification and authentication. Digital certificates require more administrative work than some other methods but provide greater security." (Weiss, "Auditing IT Infrastructures for Compliance" 2nd Ed., 2015)

"Digital identity used within a PKI. Generated and maintained by a certificate authority and used for authentication." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A cryptographic binding between a user identifier and their public key as signed by a recognized authority called a certificate authority." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"In computer security, a digital document that binds a public key to the identity of the certificate owner, thereby enabling the certificate owner to be authenticated. A certificate is issued by a certificate authority and is digitally signed by that authority." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)

"An electronic document using a digital signature to assert the identity of a person, group, or organization. Certificates attest to the identity of a person or group and contain that organization’s public key. A certificate is signed by a certificate authority with its digital signature." (Daniel Leuck et al, "Learning Java" 5th Ed., 2020)

🛡️Information Security: Cryptography (Definitions)

"Cryptography is the science of hiding information through ciphers and codes. Cryptographers devise new cryptographic algorithms." (Michael Coles & Rodney Landrum, , "Expert SQL Server 2008 Encryption", 2008)

"The process of converting data into an unreadable form via an encryption algorithm. Cryptography enables information to be sent across communication networks that are assumed to be insecure, without losing confidentiality or the integrity of the information being sent." (Alex Berson & Lawrence Dubov, "Master Data Management and Data Governance", 2010)

"The science (or art) of providing secrecy, integrity, and non-repudiation for data." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"The art or science of rendering plain information unintelligible, and for restoring encrypted information to intelligible form." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"Science of secret writing that enables an entity to store and transmit data in a form that is available only to the intended individuals." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"The encoding of data so that it can be decoded only by certain persons. The role of cryptography is to protect data integrity, confidentiality, nonrepudiation, and authentication." (Mike Harwood, "Internet Security: How to Defend Against Attackers on the Web" 2nd Ed., 2015)

"The field of study related to encoded information" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"The science of secret writing that enables storage and transmission of data in a form that is available only to the intended individuals." (Shon Harris & Fernando Maymi, "CISSP All-in-One Exam Guide" 8th Ed., 2018)

"The study of algorithmic transformations from plain text to encrypted forms in which the unencrypted data cannot be ascertained without possession of the encryption key." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"A technique to secure communication or data." (AICPA)

"Art or science concerning the principles, means, and methods for rendering plain information unintelligible and for restoring encrypted information to intelligible form."(CNSSI 4009-2015 NSA/CSS) 

"The art and science of using mathematics to secure information and create a high degree of trust in the electronic realm." (NISTIR 7316) 

"The discipline that embodies principles, means and methods for providing information security, including confidentiality, data integrity, non-repudiation, and authenticity." (NISTIR 8040)

"The discipline that embodies the principles, means, and methods for the transformation of data in order to hide their semantic content, prevent their unauthorized use, or prevent their undetected modification." (NIST SP 800-59)

🔬Data Science: Hash Function (Definition)

"A function that maps a set of keys onto a set of addresses." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"A function that maps a string of arbitrary length to a fixed size value in a deterministic manner. Such a function may or may not have cryptographic applications." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

[cryptographic hash function:] "A function that takes an input string of arbitrary length and produces a fixed-size output for which it is unfeasible to find two inputs that map to the same output, and it is unfeasible to learn anything about the input from the output." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

[one-way hash function:] "A hash function for which it is computationally unfeasible to determine anything about the input from the output." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"A function that operates on an arbitrary-length input value and returns a fixed-length hash value." (Oracle, "Database SQL Tuning Guide Glossary", 2013)

[one-way hash:] "A one-way hash is an algorithm that transforms one string into another string (a fixed-length sequence of seemingly random characters) in such a way that the original string cannot be calculated by operations on the one-way hash value (i.e., the calculation is one way only). One-way hash values can be calculated for any string, including a person’s name, a document, or an image. For any input string, the resultant one-way hash will always be the same. If a single byte of the input string is modified, the resulting one-way hash will be changed and will have a totally different sequence than the one-way hash sequence calculated for the unmodified string. One-way hash values can be made sufficiently long (e.g., 256 bits) that a hash string collision (i.e., the occurrence of two different input strings with the same one-way hash output value) is negligible." (Jules H Berman, "Principles of Big Data: Preparing, Sharing, and Analyzing Complex Information", 2013)

"A hash function is an algorithm that maps from an input, for example, a string of characters, to an output string. The size of the input can vary, but the size of the output is always the same." (Dan Sullivan, "NoSQL for Mere Mortals®", 2015)

[one-way hash:] "Cryptographic process that takes an arbitrary amount of data and generates a fixed-length value. Used for integrity protection." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A function that takes as input the key of an element and produces an integer as output" (Nell Dale et al, "Object-Oriented Data Structures Using Java" 4th Ed., 2016)

"encryption methods that use no keys." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"A function that operates on an arbitrary-length input value and returns a fixed-length hash value." (Oracle, "Oracle Database Concepts")