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What is a private key?

A private key is a sensitive piece of cryptographic information that is used in asymmetric encryption systems, such as RSA or ECC (Elliptic Curve Cryptography). In these systems, a pair of keys is used: a public key and a private key.

The private key is kept secret and is known only to the owner. It's used to decrypt data that has been encrypted with its corresponding public key. Additionally, the private key is used to sign digital messages, ensuring that they came from the owner of the private key and have not been tampered with.

On this page, you can find guides on creating private keys with parameters that match your specific needs.

Generate an RSA private key​

In this guide, you'll create the simplest possible RSA key and verify its validity with the OpenSSL command-line tool:

  1. Navigate to Digital Certificates → Private keys and click Create private key button
  2. Configure a new private key with the following values:
Name
RSA
Key algorithm
RSA
Key size
2048 bit
Encryption
None
  1. Click the Save button to save the private key
  2. Once the key is set up, it will appear in the private keys grid
  3. Click the key's Export button and use the following values for the export:
Format
PEM
Encryption
None
  1. Click the Export button to generate and download the private key as RSA.pem
  2. Use the OpenSSL command-line tool to view the key's content and verify its validity:
View the RSA key's content
$ openssl rsa -in ~/Downloads/RSA.pem | openssl pkey -inform PEM -text -noout
writing RSA key
Private-Key: (2048 bit, 2 primes)
modulus:
    00:c4:96:a7:80:e4:45:19:47:3f:55:48:0e:eb:da:
    ...
publicExponent: 65537 (0x10001)
privateExponent:
    2d:c0:94:3e:4a:a2:0c:46:89:26:5b:6d:61:95:cd:
    ...
prime1:
    00:f9:9f:52:03:48:2d:bf:a7:c1:9a:e5:68:51:7d:
    ...
prime2:
    00:c9:9c:75:f6:ab:49:4a:6b:85:6b:61:cc:04:20:
    ...
exponent1:
    00:be:75:85:49:e3:c4:a4:3b:07:49:7c:48:40:05:
    ...
exponent2:
    00:94:db:de:49:8b:fc:e8:62:ed:36:f5:15:92:f2:
    ...
coefficient:
    27:bf:26:e8:31:41:0c:2f:88:c7:5e:2d:af:46:c4:
    ...

Watch the video demo below to see all the steps mentioned earlier in action:

Generate an ECDSA elliptic curve private key​

In this guide, you'll generate an ECDSA elliptic curve private key protected by a passphrase:

  1. Navigate to Digital Certificates → Private keys and click Create private key button
  2. Configure a new private key with the following values:
Name
ECC
Key algorithm
ECDSA
Curve name
secp384r1 / NIST P-384
Encryption
Passphrase
Passphrase
pass
Repeat passphrase
pass
  1. Click the Save button to save the private key
  2. Once the key is set up, it will appear in the private keys grid
  3. Click the key's Export button and use the following values for the export:
Format
PKCS#8
Encryption
Passphrase
Current passphrase
pass
Export passphrase
pass-export
Repeat export passphrase
pass-export
  1. Click the Export button to generate and download the private key as ECC.p8
  2. Use the OpenSSL command-line tool to view the key's content and verify its validity:
View the ECDSA key's content
$ openssl pkcs8 -inform DER -in ~/Downloads/ECC.p8 -passin pass:pass-export | \
    openssl pkey -inform PEM -text -noout
Private-Key: (384 bit)
priv:
    8c:30:d7:b2:df:7c:9d:75:cb:a0:ec:93:53:ea:91:
    ...
pub:
    04:f8:94:f2:28:f7:be:e7:75:ff:8d:3a:0d:c9:d3:
    ...
ASN1 OID: secp384r1
NIST CURVE: P-384

Watch the video demo below to see all the steps mentioned earlier in action: