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 adve ...
, 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 security, computer and network security company with a focus on encryption and encryption standards. RSA was named after the initials of its co-fo ...
. 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