The Cryptographic Application Programming Interface (also known variously as CryptoAPI, Microsoft Cryptography API, or simply CAPI) is an application programming interface included with Microsoft Windows operating systems that provides services to enable developers to secure Windows-based applications using cryptography. It is a set of dynamically-linked libraries that provides an abstraction layer which isolates programmers from the code used to encrypt the data. An application programming interface (API) is a source code interface that a computer system or program library provides to support requests for services to be made of it by a Length. ... Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ... An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write) is the study of message secrecy. ... Illustration of an application which may use libvorbisfile. ...

CryptoAPI supports both public-key and symmetric key cryptography. It includes functionality for encrypting and decrypting data and for authentication using digital certificates. It also includes a cryptographically secure pseudorandom number generator function CryptGenRandom. A big random number is used to make a public-key pair. ... Symmetric-key algorithms are a class of algorithms for cryptography that use trivially related cryptographic keys for both decryption and encryption. ... Authentication (from Greek αυθεντικός; real or genuine, from authentes; author) is the act of establishing or confirming something (or someone) as authentic, that is, that claims made by or about the thing are true. ... In cryptography, a public key certificate (or identity certificate) is a certificate which uses a digital signature to bind together a public key with an identity — information such as a the name of a person or an organisation, their address, and so forth. ... A cryptographically secure pseudo-random number generator (CSPRNG) is a pseudo-random number generator (PRNG) with properties that make it suitable for use in cryptography. ... CryptGenRandom is a random number generator function that is included in Microsofts Cryptographic Application Programming Interface. ...

CryptoAPI works with a number of CSPs (Cryptographic Service Providers) installed on the machine. CSPs are the modules that do the actual work of encoding and decoding data by performing the cryptographic functions. In Microsoft Windows, a Cryptographic Service Provider (CSP) is a software library that implements the Cryptographic Application Programming Interface (CAPI). ...

Crypto NexGen (CNG), is an update to the Crypto API introduced in Windows Vista, featuring support for plugging in custom cryptographic APIs into the CNG runtime. Also, CNG supports Elliptic Curve Cryptography. The CNG API integrates with the smart card subsystem by including a Base Smart Card Cryptographic Service Provider (Base CSP) module which encapsulates the smart card API. Smart card manufacturers just have to make their devices compatible with this, rather than provide a from-scratch solution. Windows Vista is a line of graphical operating systems used on personal computers, including home and business desktops, notebook computers, Tablet PCs, and media centers. ... Elliptic curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ... Smart card used for health insurance in France. ...

NSA Backdoor

In 1999 a careless mistake by Microsoft programmers revealed access keys for the US National Security Agency had been secretly built into the heart of the Windows Cryptographic API. Windows NT 4 Service Pack 5 was released with its source code comments left intact and Andrew D. Fernandes of Cryptonym Corporation discovered a second key labelled '_NSAKEY'. _NSAKEY is a variable name discovered in Windows NT 4 Service Pack 5 (which had been released unstripped of its symbolic debugging data) in August 1999 by Andrew D. Fernandes of Cryptonym Corporation. ...

The NSA access system is built into every version of the Windows operating system now in use. Since the CryptoAPI is the fundamental building block of cryptographic security in Windows, the flaw opens every Microsoft Windows computer to access by the US security agency.

See also

• DPAPI
• Public-key cryptography
• Cryptographic Service Provider

Image File history File links This is a lossless scalable vector image. ... DPAPI (Data Protection Application Programming Interface) is a relatively simple cryptography API available as a standard component in Microsoft Windows 2000 and later versions of Windows operating systems. ... A big random number is used to make a public-key pair. ... In Microsoft Windows, a Cryptographic Service Provider (CSP) is a software library that implements the Cryptographic Application Programming Interface (CAPI). ...

External links

• Cryptography Reference on MSDN
• Microsoft CAPI at CryptoDox

• Microsoft, the NSA, and You

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