Getting a public key for signature verification

Use a GPG public key to verify the signature of signed images in a Continuous Deployment (CD) pipeline.

You can get a GPG public key as follows:

Using the continuous integration (CI) pipeline.
Using your local computer.

Getting a GPG public key by using the continuous integration (CI) pipeline

To get a public key, add the environment variable print-code-signing-certificate with a value of 1 in your CI pipeline. After you run the CI pipeline, the GPG public key is printed on the console in the build-sign-artifact stage. You can then copy the public key into a file and encode it in base64 format by running the following command:
```
cat copied_key.txt | base64 
```
Copy the encoded key into your continuous deployment (CD) pipeline.

Getting a GPG public key by using your local computer

If you have the GPG private key in your key ring, you can export the public key directly.

Check whether your machine has a GPG key ring. Key rings are groupings of keys that allow those groupings to be managed independently. For more information, see Grouping keys together using key rings. Run the following command:

 gpg --list-keys

/home/user/.gnupg/pubring.kbx
-------------------------------
pub   rsa3072 2021-04-15 [SC] [expires: 2023-04-15]
      88DC11E8FDDF028F02E4184719D6C4C5990F144F
uid           [ unknown] user name <user.name@email.com>
sub   rsa3072 2021-04-15 [E] [expires: 2023-04-15]

If the GPG key exists on your computer, export the GPG public key by running the following command:

gpg --armor --export  <Email Address>


    -----BEGIN PGP PUBLIC KEY BLOCK-----
    xsBNBGQICw0BCADS5GwuET5rkH6n1e6bM8sYod5Apbf06yQqhAFz5hkAWCu50Nw0
    GEyxRQCAxp+9xERSr43W0StSaL9KGHBaB3oS9evkcIrlOkTwncvAZODAsaorcRtW
    1IkICPhztRHyN+wR2TWadatHz/RvOlEDVAg51XLfFIQibTStgweB3rV2c5jTsCUc
    C6N6sNoHx4OhLZ7BNJSSZBByyt4qf3d2yErOULjjUCYsvcTaOM4gtXx4Cbsk7F/y
    kZnCCqFimPOJKjsXjc+6hyAKgG0xRIGtv/zzU+nwew2fDblWTwZjDx4V9KZl1o07
    XBHfNu0hKgvQhJURxY7gCtYtIHoDF5xI2/OfABEBAAHNGmV0c3QgPHVzZXIubmFt
    ZUBlbWFpbC5jb20+wsBtBBMBCgAXBQJkCAsNAhsvAwsJBwMVCggCHgECF4AACgkQ
    8aKO5nwRdmhECwf9Flyfu2VBMQabeU4IIZESgDjPxl4m7yiIpOdLNcWPxTS9S3th
    3x84/wQE9ZwX8vpBv/1KN8cZROJDnVAmZhVGVa3CBOI4dhFfMAU9mwzAWH0owjmt
    QtHOoQ+cajcQEvvkl4UTnScoEXwVVqKHNWAAq/myDRtZr1yCMokmbc0PjCftIfHr
    a+50dYZEVL9D8Cq1dQKFsmPCPPZvUmHQKXQTUr4usY72zf9IUPH6n5D2tkpNo253
    lWEVptVKHH21XhNpp+ROY7DTB0xLFzIirXh5Rwx5OkGO7n1gfUM4B1i1z3A6uXhX
    sP7wf45OaFscPMVGmVFOgP1VRdNsBfPodT1NG87ATQRkCAsNAQgAoMcJTSrAPMrj
    u0kMHGlE2/D+7TkKnJ5Gtw38EMxDX/kKBiKhI7WoT3OKjT/GrpXSIn1TfMWHh2oQ
    mBP9g0dXnr9dNB7eQMtq8dVU9cVg63U05tSbckoCiLqnVU5nG7NdUGd8n1QPFPw5
    wRdT/BWZ/NsruWZ9DLIoCqSE73Ez4p7KVu0Nfm62D4Z87ejOfsObcLRZuLkjK9Mn
    0te5LMZ4xTTTzSSia3mxNwVtKE8r7ihf+f6vCvDzCD23OnqeSeQnOoxlvdBLOyWT
    QkFWP/OdYIPBLAVG12aUAPq79TW4B04LWIw7LjbXenszI6M1LqUQgP+PHegMTs2O
    EQtLJHJJNQARAQABwsGEBBgBCgAPBQJkCAsNBQkPCZwAAhsuASkJEPGijuZ8EXZo
    wF0gBBkBCgAGBQJkCAsNAAoJEKLCBxPVXHfTJPQH/3mUPJGxlsdRFsFW3xvNEfRX
    EGdV9sQOhgcV+/ZLmnrWTpjBFfzWXJDetyM3awKmrMbggnPmavJyXjCB+Skrsqjf
    qO7mlc4oi9MGdSnsZ8UBjKQhNJYGSQWN7AmfFs+FOLopvlpDh5nmfxEiS+4DAxu2
    3Ur0GN93QJ7FbIpKGhtH20XtVl1Gfj6ZA7jwY50kY3rhw7qzw22e4a+URAi52ReN
    ZlElL7qQCiYGk2FYwhPYj4WCGmrx7mAGAdI/Xsqtgpwon1YkFuo3psZP9IXrskls
    XP2Y9NDnYZM/nV0RCBRoJKvJL2daJyQ9iHmfeF0Hh7AxmboQWZo2tnnOqprOwAVU
    dAgArROMqK7Ng+j3yAAY9xuHmI2GVHSqK/UPiO+XGvuGWDLzlrgT7ehpCSIeg/sF
    0ZfE5fYV3758kAQEclpejV71mL2pedBwzigD3IH6Mlit5slwqlmsBWCN64DwGJLp
    aKsdbBcglUixuO5q0dLEHHXYVgUUqrV7rEdW5s+4LiROcHgQCLIDzZOYjCqGYex4
    YhWPFPmReFd48qDQAFDtU0teUeeMTMWHQCGQq2eZLJtHpG0axrqKi3kl5K5TbFR6
    FpwkW3HhQn8p48PWS78MJVZZvFD+GDOa8xLQR3ylkzdI3ODO9Cuzfo+sWJIQk/gB
    bGCnEBJJosoJebVF8ZpXI+Qbg87ATQRkCAsNAQgAwPpK+5OCM0OuNoErYCTNHama
    5VrlHjc3glUQUIIGYhZtfQiINPIB0gjPURkOmJHZdFWQccE+JLlX0hVLHVaisr7q
    izSI8VZ4/YUYfTJHltTLiu9PoYw922UQo7fRLglUmvv4nctBkT+T2YWzJNNQaffR
    Ac1wLhFSklDPxAvY+xJ1vCYABYF5gml6lLNEy0BD3+w8rGIfmXi92P6CtxSi6Msx
    zD+p8jib4rKuWICj79+DtDvzglmeoSCzFjINQ2UkbULRAOZWDwoJlt247SPWSKpi
    0fabbaAwHIeoCPYoOWlpx/3jdXDmBB9HEGUUk2q8eHaHUkQdyfm5uxU188VUfwAR
    AQABwsGEBBgBCgAPBQJkCAsNBQkPCZwAAhsuASkJEPGijuZ8EXZowF0gBBkBCgAG
    BQJkCAsNAAoJEFIxvQO1BHFkFNUIAKNXypvVxFXm7w97+6teXRUWlL8N+qlCaJlO
    dVmAeLXZTE7k/r+IeYR53Xf4oS9kAqVkB9VzyBSvBjNmpKHv84UMbPMm44M8ESsc
    Cf9drVrW9Cuw3qwkuVYXnlnhukxLm/1ivSl2Tw/ywwpShGdhQc9KnPPSYtGEMAhM
    /dqXUtZs/akOScoyaU9cNNEEQVlzGmKh0T1Qb4xuFd9dqNC9wJ2aGDXcGFnDvAoq
    YSZZl5KWY/11AqBR9smeMyZrK8SAAw8dFPpVNsLWGdTKrywfSjcBUqasoI2QvFJB
    Nbmu7JILvEsMXtA2vjJ3SQtOVZs744mo9fi8Jpu/V7P7v+88u8EYWwf+OgQUJT/e
    WzslyV2/ST9+ozxfsGwpl9hlzmPQ4B+a7wNPTqRwCrJgaVIz3Q3LzV06wv7b0YmU
    Vz1j3Zv2SrQntYGR6F4Whi/j4vLl19eI0LhnxcOw4/Ry4pQ8NnypF63Vz7XpNEaf
    vF/P82FwXHR0OvOhEt3UgGdxvC69VF8tHlqaXjMLvmoBMrk1oi2ZDONo/3v9xwzO
    EnxlN5I7ah3n9aBt+D0NZ8EU2qfclMNEEI4viGzB++BEUMbflmbnFdt2Nmbqk1pe
    bknJV8p6m/r56kBPDvk5uqd/L2+j50MrAu4RFNIy4qx+ub1MxqU+MZGjFa3O46Al
    ftfswLBW+es4fQ==
    =0FYC
    -----END PGP PUBLIC KEY BLOCK-----

After you export the GPG public key, encode it in base64 format before you copy it to the code-signing-certificate field.

Store the key

Provide the GPG key to the CD pipeline in one of the following ways:

Store the key in IBM® Key Protect for IBM Cloud®.
Store the key in IBM Cloud® Secrets Manager.
Store the key directly in the CI toolchain.

Make sure that the key is copied in the correct format to prevent a CI pipeline signing error. Use pbcopy (OS X) or clip (Windows Git bash) in the commands specified in the following sections to copy the key content to the clipboard.

Store the key in Key Protect

You must double base64 encode the GPG key before you store it in your Key Protect instance.

Export and copy the GPG key to the clipboard as follows:

OS X

gpg --armor --export <Email Address> | base64 | base64 | pbcopy

Windows

gpg --armor --export <Email Address> | base64 -w0 | base64 -w0 | clip

Linux

gpg --armor --export <Email Address> | base64 | base64

In your IBM Cloud console, select the Key Protect instance where you want to store the GPG key that you generated.
Click the Add icon to add new key to the instance.
Select Import your own key option.
Select key type as Standard Key.
Give an appropriate name in the Key name field. The stored GPG key can be retrieved later by using this name.
Copy the key that you exported in the Key material field.

Ensure that there is no extra line at the end of the key when you copy the key and paste it in the Key material field.
Expand the Advanced Options section and select the Choose a key ring option as default.
Add the key to your key protect by clicking Add key.

Figure 1. Add the key to key protect

For more information on Key Protect, see About Key Protect.

Store the key in Secrets Manager

You must single base64 encode the GPG key before you store it in your Secrets Manager instance.

Export and copy the GPG key to the clipboard.

OS X

gpg --armor --export <Email Address> | base64 | pbcopy

Windows

gpg --armor --export <Email Address> | base64 -w0 | clip

Linux

gpg --armor --export <Email Address> | base64

In your IBM Cloud console, select the Secrets Manager instance where you want to store the GPG Key that you generated in the previous steps.
Click the Add icon to add new key to the instance.
Select the Other secret type option.

Figure 2. Other secret type
Select key type as Standard Key.
Give an appropriate name in the Name field. The stored GPG key can be retrieved later by using this name.
Choose the option as Secret value and paste the key as exported earlier in the Secret value field.

Ensure that there is no extra line at the end of the key when you copy the key and paste it in Secret value field.
Add the key to your Key Protect instance by clicking Add.

Figure 3. Add the key

For more information on Secrets Manager, see Getting started with Secrets Manager.

Export the private key and store it directly in the CI pipeline

Use this method for testing only. Use keyprotect or secrets manager for storing keys.

You must single base64 encode the GPG key before storing it as a secured pipeline property.

Securely store the GPG key in a Key Protect or Secrets Manager instance as follows:

OS X or Linux

gpg --armor --export <Email Address> | base64

Windows

gpg --armor --export <Email Address> | base64 -w0