Nitrokey is a brand of open-source hardware security devices designed to enhance the security of digital information and cryptographic keys. Nitrokey devices are typically used for secure storage of cryptographic keys, two-factor authentication (2FA), password management, and secure communications. They aim to provide users with a way to protect sensitive data and ensure secure access to various online services.

The Schlüsselgerät 41, or "Key Device 41," was an encryption device used by the German military during World War II. It was primarily employed for secure communications within the Wehrmacht and other branches of the German armed forces. The device was designed to encrypt and decrypt messages, making it difficult for enemy forces to intercept and understand the communications. The Schlüsselgerät 41 was notable for its use of a system of wheels and mechanical components to generate ciphers.

Computational hardness assumptions are conjectures in theoretical computer science and cryptography that relate to the difficulty of solving certain computational problems. These assumptions underpin the security of cryptographic protocols and algorithms. They assert that certain problems cannot be solved efficiently (in polynomial time) by any algorithm, making them suitable as the foundation for secure cryptographic systems.

Black-box obfuscation is a technique in computer science and cryptography that aims to make a program or algorithm difficult to understand or reverse-engineer while still preserving its original functionality. The goal is to ensure that an adversary, given access to the obfuscated program (or "black box"), cannot efficiently glean any useful information about its internal structure, logic, or sensitive data, apart from its inputs and outputs.

A cryptographic hash function is a mathematical algorithm that transforms any input (or "message") into a fixed-size string of characters, which is typically a sequence of numbers and letters. The output is referred to as the hash value or digest. Cryptographic hash functions perform several key functions in the field of security and data integrity: 1. **Deterministic**: The same input will always produce the same output.

A commitment scheme is a cryptographic construct that allows one party, known as the "committer," to commit to a chosen value while keeping it hidden from another party, known as the "receiver." The committer can later reveal the committed value, at which point the receiver can verify that the value corresponds to the original commitment. The main features of a commitment scheme are: 1. **Hiding:** The committed value is hidden from the receiver until the committer chooses to reveal it.

A cryptographic primitive is a basic building block used in cryptography that provides essential security properties. These primitives serve as the foundational components for constructing more complex cryptographic algorithms and protocols. Cryptographic primitives are designed to ensure confidentiality, integrity, authentication, and non-repudiation.

Key exchange is a method in cryptography that allows two or more parties to establish a shared secret key, which can be used for secure communications. This shared secret is typically used to encrypt and decrypt messages exchanged between the parties, ensuring confidentiality and integrity.

AS1, or Applicability Statement 1, is a specification developed by the Internet Engineering Task Force (IETF) as part of the ASxx series, which defines the protocols for exchanging electronic business documents over the Internet. Specifically, AS1 is designed for the secure and reliable exchange of business documents, such as purchase orders and invoices, using simple email protocols along with encryption and digital signatures.

Anti-replay refers to a security mechanism used to protect against replay attacks, which are a type of network attack where a valid transmission is maliciously or fraudulently repeated or delayed. In a replay attack, an adversary can capture a valid data transmission and resend it to trick the recipient into believing it is a new or valid request.

Authentication protocols are sets of rules and procedures that enable the verification of the identity of users, devices, or services in a network or system. These protocols ensure that parties involved in a communication can trust each other's identities before any sensitive information is exchanged or actions are performed. Authentication is a critical component of security in information systems, as it helps to prevent unauthorized access and potential breaches.

Key transport protocols refer to methods used to securely transfer cryptographic keys between parties, typically in the context of establishing secure communications. The main goal of these protocols is to ensure that the keys used for encryption and decryption remain confidential and are only accessible to authorized parties. Here are some key aspects and examples of key transport protocols: ### Key Aspects 1. **Authentication**: Ensures that the parties exchanging keys are who they claim to be, which helps prevent man-in-the-middle attacks.

3-D Secure (Three-Domain Secure) is an online payment security protocol designed to add an additional layer of authentication for online credit and debit card transactions. The goal of 3-D Secure is to reduce fraud and unauthorized use of cards during online transactions by enabling cardholders to authenticate themselves through a verification process during checkout.

The ANSI ASC X9.95 standard is part of a set of standards developed by the Accredited Standards Committee (ASC) X9, which focuses on financial services and electronic transactions. Specifically, X9.95 addresses the requirements for the management of financial services data, particularly pertaining to the protection and security of sensitive information, such as personal financial information. The main goals of the ANSI ASC X9.

The Anshel-Anshel-Goldfeld (AAG) key exchange is a cryptographic protocol developed for secure key exchange based on group theory, specifically through the use of braid groups. It was introduced in the context of providing an alternative to traditional key exchange methods, such as Diffie-Hellman, by leveraging the computational properties of braid groups, which are believed to be resistant to certain types of mathematical attacks.

BitTorrent protocol encryption refers to the methods used to secure the communication between peers in a BitTorrent network. The primary goal of this encryption is to enhance privacy and security while transferring files and to mitigate the throttling of BitTorrent traffic by Internet Service Providers (ISPs).

Cryptographic Message Syntax (CMS) is a data format that provides a way to encapsulate, encrypt, and sign arbitrary data in a secure manner. It is defined in the IETF RFC 5652, which is part of the standards for cryptographic protocols used in secure communications. CMS is widely used for securing messages in various applications, such as email and file transfer.

Delegated credentials are a feature used in the context of transport layer security (TLS) to enhance performance and security, particularly in scenarios involving certificate management and session establishment. They allow a server to issue temporary credentials that can be used by specific applications or services without needing to manage the full lifecycle of a certificate.

The High Assurance Internet Protocol Encryptor (HAIPE) is a type of encryption device used to secure Internet Protocol (IP) communications for sensitive government and military information. HAIPE devices provide end-to-end encryption, ensuring that data transmitted over public and private networks remains confidential and protected from unauthorized access. Key features of HAIPE include: 1. **High Assurance**: HAIPE devices meet stringent security standards set by the U.S.

I2P, or the Invisible Internet Project, is an anonymous overlay network designed to provide privacy and protection for its users' communications and activities online. It allows users to access websites, share files, and communicate in a way that aims to keep their identities and locations hidden. I2P operates on the principle of decentralized routing, where data is encrypted and sent through multiple nodes within the network, making it difficult to trace the origin and destination of the data.