In
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 #8 is a standard syntax for storing
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 ...
information. PKCS #8 is one of the family of standards called
Public-Key Cryptography Standards (PKCS) created 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 latest version, 1.2, is available as
RFC 5208.
The PKCS #8 private key may be encrypted with a
passphrase
A passphrase is a sequence of words or other text used to control access to a computer system, program or data. It is similar to a password in usage, but a passphrase is generally longer for added security. Passphrases are often used to control ...
using the
PKCS #5 standards, which supports multiple ciphers.
[ - Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2]
A new version 2 was proposed by S. Turner in 2010 as
RFC 5958 [ - Asymmetric Key Packages] and might obsolete
RFC 5208 someday in the future.
PKCS #8 private keys are typically exchanged in the
PEM base64
In computer programming, Base64 is a group of binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits.
Common to all bina ...
-encoded format, for example:
-----BEGIN PRIVATE KEY-----
MIIBVgIBADANBgkqhkiG9w0BAQEFAASCAUAwggE8AgEAAkEAq7BFUpkGp3+LQmlQ
Yx2eqzDV+xeG8kx/sQFV18S5JhzGeIJNA72wSeukEPojtqUyX2J0CciPBh7eqclQ
2zpAswIDAQABAkAgisq4+zRdrzkwH1ITV1vpytnkO/NiHcnePQiOW0VUybPyHoGM
/jf75C5xET7ZQpBe5kx5VHsPZj0CBb3b+wSRAiEA2mPWCBytosIU/ODRfq6EiV04
lt6waE7I2uSPqIC20LcCIQDJQYIHQII+3YaPqyhGgqMexuuuGx+lDKD6/Fu/JwPb
5QIhAKthiYcYKlL9h8bjDsQhZDUACPasjzdsDEdq8inDyLOFAiEAmCr/tZwA3qeA
ZoBzI10DGPIuoKXBd3nk/eBxPkaxlEECIQCNymjsoI7GldtujVnr1qT+3yedLfHK
srDVjIT3LsvTqw
-----END PRIVATE KEY-----
-----BEGIN ENCRYPTED PRIVATE KEY-----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-----END ENCRYPTED PRIVATE KEY-----
References
Cryptography standards
{{Crypto-stub