Describe public keys - Amazon Elastic Compute Cloud

Describe public keys

You can describe the public keys that are stored in Amazon EC2. You can also retrieve the public key material and identify the public key that was specified at launch.

Describe public keys

You can view the following information about your public keys that are stored in Amazon EC2: public key name, ID, key type, fingerprint, public key material, the date and time (in the UTC time zone) the key was created by Amazon EC2 (if the key was created by a third-party tool, then it's the date and time the key was imported to Amazon EC2), and any tags that are associated with the public key.

You can use the Amazon EC2 console or AWS CLI to view information about your public keys.

Console

To view information about your public keys

  1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

  2. In the left navigator, choose Key Pairs.

  3. You can view the information about each public key in the Key pairs table.

  4. To view a public key's tags, select the check box next to the key, and then choose Actions, Manage tags.

AWS CLI

To describe a public key

Use the describe-key-pairs command and specify the --key-names parameter.

aws ec2 describe-key-pairs --key-names my-key-pair

Example output

{ "KeyPairs": [ { "KeyPairId": "key-0123456789example", "KeyFingerprint": "1f:51:ae:28:bf:89:e9:d8:1f:25:5d:37:2d:7d:b8:ca:9f:f5:f1:6f", "KeyName": "my-key-pair", "KeyType": "rsa", "Tags": [], "CreateTime": "2022-04-28T11:37:26.000Z" } ] }

Alternatively, instead of --key-names, you can specify the --key-pair-ids parameter to identify the public key.

aws ec2 describe-key-pairs --key-pair-ids key-0123456789example

To view the public key material in the output, you must specify the --include-public-key parameter.

aws ec2 describe-key-pairs --key-names my-key-pair --include-public-key

Example output – In the output, the PublicKey field contains the public key material.

{ "KeyPairs": [ { "KeyPairId": "key-0123456789example", "KeyFingerprint": "1f:51:ae:28:bf:89:e9:d8:1f:25:5d:37:2d:7d:b8:ca:9f:f5:f1:6f", "KeyName": "my-key-pair", "KeyType": "rsa", "Tags": [], "PublicKey": "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIj7azlDjVHAsSxgcpCRZ3oWnTm0nAFM64y9jd22ioI/ my-key-pair", "CreateTime": "2022-04-28T11:37:26.000Z" } ] }

Retrieve the public key material

You can use various methods to get access to the public key material. You can retrieve the public key material from the matching private key on your local computer, or from the instance metadata or the authorized_keys file on the instance that was launched with the public key, or by using the describe-key-pairs AWS CLI command.

Use one of the following methods to retrieve the public key material.

From the private key

To retrieve the public key material from the private key

On your local Linux or macOS computer, you can use the ssh-keygen command to retrieve the public key for your key pair. Specify the path where you downloaded your private key (the .pem file).

ssh-keygen -y -f /path_to_key_pair/my-key-pair.pem

The command returns the public key, as shown in the following example.

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuSevGj3eYhCe53pcjqP3maAhDFcvBS7O6V hz2ItxCih+PnDSUaw+WNQn/mZphTk/a/gU8jEzoOWbkM4yxyb/wB96xbiFveSFJuOp/d6RJhJOI0iBXr lsLnBItntckiJ7FbtxJMXLvvwJryDUilBMTjYtwB+QhYXUMOzce5Pjz5/i8SeJtjnV3iAoG/cQk+0FzZ qaeJAAHco+CY/5WrUBkrHmFJr6HcXkvJdWPkYQS3xqC0+FmUZofz221CBt5IMucxXPkX4rWi+z7wB3Rb BQoQzd8v7yeb7OzlPnWOyN0qFU0XA246RA8QFYiCNYwI3f05p6KLxEXAMPLE

If the command fails, run the following command to ensure that you've changed the permissions on your private key pair file so that only you can view it.

chmod 400 my-key-pair.pem
From the instance metadata

You can use Instance Metadata Service Version 2 or Instance Metadata Service Version 1 to retrieve the public key from the instance metadata.

Note

If you change the key pair that you use to connect to the instance, Amazon EC2 does not update the instance metadata to show the new public key. The instance metadata continues to show the public key for the key pair that you specified when you launched the instance.

To retrieve the public key material from the instance metadata

Use one of the following commands from your instance.

IMDSv2

[ec2-user ~]$ TOKEN=`curl -X PUT "http://169.254.169.254/latest/api/token" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600"` \ && curl -H "X-aws-ec2-metadata-token: $TOKEN" –v http://169.254.169.254/latest/meta-data/public-keys/0/openssh-key

IMDSv1

[ec2-user ~]$ curl http://169.254.169.254/latest/meta-data/public-keys/0/openssh-key

Example output

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuSevGj3eYhCe53pcjqP3maAhDFcvBS7O6V hz2ItxCih+PnDSUaw+WNQn/mZphTk/a/gU8jEzoOWbkM4yxyb/wB96xbiFveSFJuOp/d6RJhJOI0iBXr lsLnBItntckiJ7FbtxJMXLvvwJryDUilBMTjYtwB+QhYXUMOzce5Pjz5/i8SeJtjnV3iAoG/cQk+0FzZ qaeJAAHco+CY/5WrUBkrHmFJr6HcXkvJdWPkYQS3xqC0+FmUZofz221CBt5IMucxXPkX4rWi+z7wB3Rb BQoQzd8v7yeb7OzlPnWOyN0qFU0XA246RA8QFYiCNYwI3f05p6KLxEXAMPLE my-key-pair

For more information about instance metadata, see Retrieve instance metadata.

From the instance

If you specify a key pair when launching a Linux instance, when the instance boots for the first time, the content of the public key is placed on the instance in an entry within ~/.ssh/authorized_keys.

To retrieve the public key material from an instance

  1. Connect to your instance.

  2. In the terminal window, open the authorized_keys file using your favorite text editor (such as vim or nano).

    [ec2-user ~]$ nano ~/.ssh/authorized_keys

    The authorized_keys file opens, displaying the public key followed by the name of the key pair. The following is an example entry for the key pair named my-key-pair.

    ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuSevGj3eYhCe53pcjqP3maAhDFcvBS7O6V hz2ItxCih+PnDSUaw+WNQn/mZphTk/a/gU8jEzoOWbkM4yxyb/wB96xbiFveSFJuOp/d6RJhJOI0iBXr lsLnBItntckiJ7FbtxJMXLvvwJryDUilBMTjYtwB+QhYXUMOzce5Pjz5/i8SeJtjnV3iAoG/cQk+0FzZ qaeJAAHco+CY/5WrUBkrHmFJr6HcXkvJdWPkYQS3xqC0+FmUZofz221CBt5IMucxXPkX4rWi+z7wB3Rb BQoQzd8v7yeb7OzlPnWOyN0qFU0XA246RA8QFYiCNYwI3f05p6KLxEXAMPLE my-key-pair
From describe-key-pairs

To retrieve the public key material from the describe-key-pairsAWS CLI command

Use the describe-key-pairs command and specify the --key-names parameter to identify the public key. To include the public key material in the output, specify the --include-public-key parameter.

aws ec2 describe-key-pairs --key-names my-key-pair --include-public-key

Example output – In the output, the PublicKey field contains the public key material.

{ "KeyPairs": [ { "KeyPairId": "key-0123456789example", "KeyFingerprint": "1f:51:ae:28:bf:89:e9:d8:1f:25:5d:37:2d:7d:b8:ca:9f:f5:f1:6f", "KeyName": "my-key-pair", "KeyType": "rsa", "Tags": [], "PublicKey": "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIj7azlDjVHAsSxgcpCRZ3oWnTm0nAFM64y9jd22ioI/ my-key-pair", "CreateTime": "2022-04-28T11:37:26.000Z" } ] }

Alternatively, instead of --key-names, you can specify the --key-pair-ids parameter to identify the public key.

aws ec2 describe-key-pairs --key-pair-ids key-0123456789example --include-public-key

Identify the public key specified at launch

If you specify a public key when you launch an instance, the public key name is recorded by the instance.

To identify the public key that was specified at launch

  1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

  2. In the navigation pane, choose Instances, and then select your instance.

  3. On the Details tab, under Instance details, the Key pair name field displays the name of the public key that you specified when you launched the instance.

Note

The value of the Key pair name field does not change even if you change the public key on the instance, or add public keys.