cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adver ...

, PKCS #12 defines an

archive file format In computing, an archive file is a computer file that is composed of one or more files along with metadata. Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compres ...

for storing many cryptography objects as a single file. It is commonly used to bundle a

private key Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with cryptographic alg ...

with its

X.509 In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secu ...

certificate or to bundle all the members of a

chain of trust In computer security, a chain of trust is established by validating each component of hardware and software from the end entity up to the root certificate. It is intended to ensure that only trusted software and hardware can be used while still ...

. A PKCS #12 file may be encrypted and signed. The internal storage containers, called "SafeBags", may also be encrypted and signed. A few SafeBags are predefined to store certificates, private keys and CRLs. Another SafeBag is provided to store any other data at individual implementer's choice. PKCS #12 is one of the family of standards called Public-Key Cryptography Standards (PKCS) published by

RSA Laboratories RSA Security LLC, formerly RSA Security, Inc. and doing business as RSA, is an American computer and network security company with a focus on encryption and encryption standards. RSA was named after the initials of its co-founders, Ron Rivest, ...

. The

filename extension A filename extension, file name extension or file extension is a suffix to the name of a computer file (e.g., .txt, .docx, .md). The extension indicates a characteristic of the file contents or its intended use. A filename extension is typically ...

for PKCS #12 files is .p12 or .pfx. These files can be created, parsed and read out with the OpenSSL pkcs12 command.

Relationship to PFX file format

PKCS #12 is the successor to

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washin ...

's "PFX"; however, the terms "PKCS #12 file" and "PFX file" are sometimes used interchangeably. The PFX format has been criticised for being one of the most complex cryptographic protocols.

Normal usage

The full PKCS #12 standard is very complex. It enables buckets of complex objects such as PKCS #8 structures, nested deeply. But in practice it is normally used to store just one private key and its associated certificate chain. PKCS #12 files are usually created using OpenSSL, which only supports a single private key from the command line interface. The Java keytool can be used to create multiple "entries" since Java 8, but that may be incompatible with many other systems. As of Java 9, PKCS #12 is the default keystore format. A simpler, alternative format to PKCS #12 is PEM which just lists the certificates and possibly private keys as Base 64 strings in a text file.

GnuTLS GnuTLS (, the GNU Transport Layer Security Library) is a free software implementation of the TLS, SSL and DTLS protocols. It offers an application programming interface (API) for applications to enable secure communication over the network trans ...

's ''certtool'' may also be used to create PKCS #12 files including certificates, keys, and CA certificates via --to-p12. However, beware that for interchangeability with other software, if the sources are in PEM Base64 text, then --outder should also be used.

References

External links

* - PKCS #12: Personal Information Exchange Syntax v1.1 * * Overview about PKCS#12 capabilities, usage, implementations, history and future: Cryptography standards {{Crypto-stub