# Client Changes for Rekor v2

This document outlines the changes clients need to make to support
Rekor v2.

## Rekor v2 API

Rekor v2 supports HTTP or gRPC, like Fulcio. For Go, we have implemented a client
already. For other languages, they can either use the
[OpenAPI docs](https://github.com/sigstore/rekor-tiles/tree/main/docs/openapi),
[gRPC service proto](https://github.com/sigstore/rekor-tiles/tree/main/api/proto),
or create their own client. 

The service implements one write API, `/api/v2/log/entries`. Example JSON request bodies
below:

```jsonc
// Request with a Fulcio certificate
{
    "hashedRekordRequestV002": {
        // Must use hash algorithm from key_details
        "digest": "<base64 digest of artifact>",
        "signature": {
            "content": "<base64 signature>",
            "verifier": {
                "x509Certificate": {
                    "rawBytes": "<base64 DER-encoded certificate>"
                },
                // Must match signing algorithm
                "keyDetails": "PKIX_ECDSA_P256_SHA_256"
            }
        }
    }
}

// Request with a self-managed key
{
    "hashedRekordRequestV002": {
        "digest": "<base64 digest of artifact>",
        "signature": {
            "content": "<base64 signature>",
            "verifier": {
                "publicKey": {
                    "rawBytes": "<base64 DER-encoded public key>"
                },
                "keyDetails": "PKIX_ECDSA_P256_SHA_256"
            }
        }
    }
}

// Request with an attestation
{
    "dsseRequestV002": {
        "envelope": {
            "payload": "<base64-encoded message>",
            "payloadType": "<type, e.g. application/vnd.in-toto+json>",
            "signatures": [
                {
                    "sig": "<base64-encoded signature>",
                    "keyid": ""
                }
            ]
        },
        "verifier": {
            "x509Certificate": {
                "rawBytes": "<base64 DER-encoded certificate>"
            },
            // Must match signing algorithm
            "keyDetails": "PKIX_ECDSA_P256_SHA_256"
        }
    }
}

// Request with an attestation with a self-managed key
{
    "dsseRequestV002": {
        "envelope": {
            "payload": "<base64-encoded message>",
            "payloadType": "<type, e.g. application/vnd.in-toto+json>",
            "signatures": [
                {
                    "sig": "<base64-encoded signature>",
                    "keyid": ""
                }
            ]
        },
        "verifier": {
            "publicKey": {
                "rawBytes": "<base64 DER-encoded public key>"
            },
            // Must match signing algorithm
            "keyDetails": "PKIX_ECDSA_P256_SHA_256"
        }
    }
}
```

The response will be a
[`TransparencyLogEntry` message](https://github.com/sigstore/protobuf-specs/blob/5296f13d62e7fad428581d969f664c30cc52f549/protos/sigstore_rekor.proto#L94),
which should be persisted in a bundle (example at the bottom of this doc).
Clients no longer need to transform the Rekor response into a `TLE` message to store in the bundle.

The `canonicalized_body`, aka the entry stored in the log, matches what Rekor v1 stores as the canonicalized body.
Clients MUST use `kind` and `apiVersion` to parse the `spec`.
The client MUST gracefully fail when the client is not aware of a `kind` and `apiVersion`.

```jsonc
// HashedRekord entry with public key
{
    "apiVersion": "0.0.2",
    "kind": "hashedrekord",
    "spec": {
        "hashedRekordV002": {
            "data": {
                "algorithm": "<hash algorithm, e.g. 'SHA2_256'>",
                "digest": "<base64-encoded digest of artifact>"
            },
            "signature": {
                "content": "<base64-encoded signature",
                "verifier": {
                    // Must match signing algorithm
                    "keyDetails": "PKIX_ECDSA_P256_SHA_256",
                    "publicKey": {
                        "rawBytes": "<base64 DER-encoded public key>"
                    }
                }
            }
        }
    }
}

// DSSE entry
{
    "apiVersion": "0.0.2",
    "kind": "dsse",
    "spec": {
        "dsseV002": {
            "data": {
                "algorithm": "SHA2_256",
                // Note that we no longer include the envelope hash, since there is no
                // canonicalization scheme for a DSSE envelope
                "digest": "<base64-encoded digest of payload hash>"
            },
            "signatures": [
                {
                    "content": "<base64-encoded signature",
                    "verifier": {
                        // Must match signing algorithm
                        "keyDetails": "PKIX_ECDSA_P256_SHA_256",
                        "publicKey": {
                            "rawBytes": "<base64 DER-encoded public key>"
                        }
                    }
                }
            ]
        }
    }
}
```

### Two Entry Types

Rekor v2 only supports `hashedrekord` (`HashedRekordLogEntryV002`) and
`dsse` (`DSSELogEntryV002`) entry types, dropping a number of unused types
such as `jar`, `alpine`, `rpm`, and the older types `rekord` and `intoto`.
Additional types may be added in the future if there is demand, but this
will require updating the client specification so that all clients implement
support for these types.

As with Rekor v1, the entry, aka `canonicalized_body`, will include the entry's
kind (`hashedrekord`, `dsse`) and version (`0.0.2`) along with the entry itself
in a `spec` field. Clients MUST gracefully fail when given a bundle with a
kind or version that the client doesn't know how to parse. This is necessary
so that clients gracefully fail when given a Rekor v2 entry.

There are three possible scenarios for how clients should use kind and version
to parse an entry:

1. With a verification bundle with `canonicalized_body`, clients can use the
   bundle's `kind` and `version` or `canonicalized_body.kind` and
   `canonicalized_body.api_version` to parse `canonicalized_body.spec`.
2. Clients that do not persist `canonicalized_body` must reconstruct the body
   in order to compute the leaf hash to verify the inclusion proof. Clients can
   use the bundle's `kind` and `version` to reconstruct the log entry given
   the artifact. Remember to JSON-canonicalize the entry before computing the leaf hash.
3. Monitors reading the entry from a tiled entry bundle will not have the verification
   bundle, but will have the canonicalized body. A monitor must use the `kind` and
   `apiVersion` to parse `spec`.

#### DSSE

For DSSE entries, the entry payload hash will always be SHA-256, regardless of
the signature hashing algorithm specified in the key details. If non-default
signing key algorithms (e.g. not ECDSA-P256) are supported, when verifying an entry,
clients will need to handle computing the digest of the payload using SHA-256
and computing the digest to verify based on the key details.

### Certificate and Public Key Verifiers

Rekor v2 only supports signature verification using a certificate or a
public key, dropping support for PGP, minisign, pkcs7, SSH and TUF.
Additional verifiers may be added in the future, but this will also require
updating the client specification.

### Handling Longer Requests

Clients need to increase request timeouts when creating entries to at least 20 seconds.

Rekor now blocks on returning a response until a checkpoint has been published
whose tree size includes the newly uploaded entry index. Checkpoint intervals
have been increased to reduce the frequency of checkpoint publishing.
Additionally, we plan to support synchronous witnessing, where third-party
witnesses independently verify the consistency of the log and Rekor provides
co-signed checkpoints with each upload response.

If a client needs to create multiple entries, it is recommended to upload those
entries in parallel.

## Signed RFC 3161 Timestamps

Rekor will no longer return SignedEntryTimestamps or include integrated time
in the response. Clients must fetch an RFC 3161 signed timestamp from a trusted
timestamp authority and include the signed timestamp in the bundle.

Sigstore now operates a timestamp authority at `timestamp.sigstore.dev` and
`timestamp.sigstage.dev` for staging, and the roots for these services will
be included in the TrustedRoot distributed via TUF. Clients may request timestamps
from other trusted timestamp authorities as well. As with other services,
users should specify the verification material for the additional timestamp
authorities in the TrustedRoot.

## Miscellaneous verification bundle changes

In addition to all of the changes listed above, there are a few smaller updates
that clients may need to handle:

* Multiple fields in `TransparencyLogEntry.inclusion_proof` are repeated elsewhere
  and should be ignored, including `inclusion_proof.log_index`, `inclusion_proof.root_hash`,
  and `inclusion_proof.tree_size`.
  * The log index should be read from the top-level `TransparencyLogEntry.log_index`.
    It is duplicated because in Rekor v1, there were two log indices - a global index
    and a shard-specific index. This is no longer true in Rekor v2 due to simplified sharding.
  * The root hash and tree size should be parsed from a verified checkpoint, after
    verifying `TransparencyLogEntry.inclusion_proof.checkpoint`. Do not use the unverified
    root hash and tree size unless the client compares these values to the values
    in the verified checkpoint (which is needlessly repetitive). Note that `root_hash`
    is no longer hex-encoded.
* `TransparencyLogEntry.log_id.key_id` is no longer hex-encoded.
  * Reiterating, `TransparencyLogEntry.log_id.key_d` will be the non-truncated checkpoint
    key ID as documented in the C2SP signed-note
    [spec](https://github.com/C2SP/C2SP/blob/main/signed-note.md#signatures).
    If clients treat `log_id` as an opaque string to lookup the correct instance
    in the TrustedRoot, then no changes are needed.
* `TransparencyLogEntry.integrated_time` will always be `0`. It MUST be ignored and
   clients MUST use an RFC3161 timestamp. Clients MUST already be ignoring `integrated_time`
   if `inclusion_promise` is not set.
*  The log index is a uint64. `TransparencyLogEntry.log_index` contains an int64, so Rekor v2
   will never have a log index larger than `2^63 - 1`. When verifying an inclusion proof,
   the log index may need to be cast to a uint64.

## TrustedRoot changes

### TrustedRoot lookup by checkpoint key ID rather than log ID

Log ID, the SHA-256 digest of the log's public key, is used as a "unique"
identifier for a log. The TransparencyLogEntry message includes it in a
bundle, and clients use that log ID to lookup the correct log public key
in the TrustedRoot to verify the bundle.

A checkpoint key ID is a truly unique log identifier, which incorporates
the log origin, public key, and the signature type as per the C2SP signed-note
spec linked above.

Rekor will specify a log ID value that matches the non-truncated checkpoint
key ID as specified in the
[C2SP spec](https://github.com/C2SP/C2SP/blob/main/signed-note.md#signatures).
In the trust root, the `log_id` and `checkpoint_key_id` fields will be set
to the same value for a Rekor v2 log.

A client can use one of the following algorithms to select the correct instance
of a transparency log to verify a bundle's checkpoint and proof:

1. Using the `log_id` from the `TransparencyLogEntry` in the verification
   bundle, look up the corresponding `TransparencyLogInstance` in the trust root 
   matching on `checkpoint_key_id` or `log_id` (`log_id` will be deprecated)
2. Enumerate all `TransparencyLogInstance` entries in the `TrustedRoot`. For a checkpoint,
   compare the key ID from a signature line on the checkpoint to `checkpoint_key_id[0:4]`
3. Enumerate all `TransparencyLogInstance` entries in the the `TrustedRoot`. Calculate
   the checkpoint key ID from each instance using the instance's public key and the
   origin (the origin should be the scheme-less log URL) following the
   [C2SP spec](https://github.com/C2SP/C2SP/blob/main/signed-note.md#signatures).
   Compare that computed key ID truncated to 4 bytes to the key ID on the checkpoint
   signature line.
   Below is a copy from the TrustedRoot documentation:
   ```proto
    For Ed25519 signatures, the key ID is computed per the C2SP spec:
    * key ID = SHA-256(key name || 0x0A || 0x01 || 32-byte Ed25519 public key)[:4]
    For ECDSA signatures, the key ID is computed per the C2SP spec:
    * key ID = SHA-256(PKIX ASN.1 DER-encoded public key, in SubjectPublicKeyInfo format)[:4]
    For RSA signatures, the signature type will be 0xFF with an appended identifier for the format, "PKIX-RSA-PKCS#1v1.5":
    * key ID = SHA-256(key name || 0x0A || 0xFF || PKIX-RSA-PKCS#1v1.5 || PKIX ASN.1 DER-encoded public key)[:4]
    ```

Rekor will no longer include log IDs in the response, and instead clients
should use the checkpoint key ID as specified in the
[C2SP spec](https://github.com/C2SP/C2SP/blob/main/signed-note.md#signatures)
to lookup the correct log public key to verify a bundle. Each transparency
log instance in the TrustedRoot will include a `checkpoint_key_id` instead
of a `log_id`.

For more information, log IDs are not necessarily unique identifiers for
a log, since a log may reuse its public key among instances. Additionally,
the log origin is not necessarily a unique identifier, because multiple logs
may be hosted by one origin. Even the combination of both is not necessarily
unique, as a log may create signatures for different purposes with the same
key, though log deployments SHOULD NOT reuse origins and keys. For the public
instance, we will always create a new key and origin for each log deployment.

### TrustedRoot With Multiple Logs

Clients must verify that verification works with a TrustedRoot
with multiple logs with overlapping validity windows. Confirm that
the client will fetch the correct verification key from the TrustedRoot
by using the above algorithms. Also confirm that the client does not
assume only one transparency log in the TrustedRoot.

## SigningConfig support

Clients must implement support for the SigningConfig message, which specifies
the list of URLs that clients should use during signing. Since Rekor shards
will now have unique URLs, we will use the SigningConfig to distribute
the URLs for new shards.

We have published a v2 SigningConfig message to support handling log
sharding, with validity windows (which will prevent a client from writing to a
log before the TrustedRoot is fully distributed) and services with different API
versions (for the transition between Rekor v1 and v2).

A more detailed description of how clients must, should and may handle
the SigningConfig message is in the
[protobuf-specs repo](https://github.com/sigstore/protobuf-specs/blob/a4c70fea6889694dfbceea11e0f9147335a95d79/protos/sigstore_trustroot.proto#L180),
along with documentation on
[service selection](https://github.com/sigstore/protobuf-specs/blob/a4c70fea6889694dfbceea11e0f9147335a95d79/protos/sigstore_trustroot.proto#L262-L275).

An example SigningConfig with annotations is below:

```jsonc
{
    // Clients do not need to support v0.1
    "mediaType": "application/vnd.dev.sigstore.signingconfig.v0.2+json",

    // Fulcio service URLs.
    // Clients must select the first service from the list whose validity window
    // is active and the API version is supported by the client. Clients must
    // select the highest supported API version.
    // Clients can assume that this list is sorted from most recent to oldest.
    "caUrls": [
        {
            "url": "https://fulcio.sigstore.dev",
            "majorApiVersion": 1,
            "validFor": {
                // When clients should start using this service
                "start": "<UTC timestamp>",
                // Optional, when a service is turned down and clients should
                // treat the service as offline
                "end": "<UTC timestamp>"
            },
            "operator": "sigstore.dev",
        }
    ],

    // OIDC service URLs
    "oidcUrls": [
        {
            "url": "https://oauth2.sigstore.dev/auth",
            "majorApiVersion": 1,
            "validFor": {
                "start": "<UTC timestamp>"
            },
            "operator": "sigstore.dev",
        }
    ],

    // Rekor service URLs. This example shows multiple active logs.
    // The client must select the log with the highest API version
    // it supports.
    // The client must group log deployments by operator and, when
    // selecting multiple, select at most one from an operator.
    "rekorTlogUrls": [
        {
            "url": "https://log2025-01.rekor.sigstore.dev",
            "majorApiVersion": 2,
            "validFor": {
                "start": "<UTC timestamp>"
            },
            "operator": "sigstore.dev",
        },
        {
            "url": "https://rekor.sigstore.dev",
            "majorApiVersion": 1,
            "validFor": {
                "start": "<UTC timestamp>"
            },
            "operator": "sigstore.dev",
        }
    ],

    // Rekor service selection
    // "Valid" is defined above to mean the service's validity window is
    // active and the API version is supported by the client.
    "rekorTlogConfig": {
        // EXACT specifies that a client must upload entries to exactly
        // "count" number of valid logs. Clients must throw an error
        // if less than "count" logs are valid. Clients should select
        // logs from the highest available API version, even if "count"
        // logs are not available.
        // May also be ANY, meaning the client should select exactly
        // one valid log. The client can decide how to select it, e.g. random
        // or round-robin if the client tracks state.
        // May also be ALL, which should be all valid logs.
        "selector": "EXACT",
        // Optional, only when EXACT is specified
        "count": 2
    },

    // Timestamp authority URLs
    // Like Rekor, clients should use the TSA config which dictates
    // how many TSAs should be used to request timestamps from.
    "tsaUrls": [
        {
            "url": "https://oauth2.sigstore.dev/auth",
            "majorApiVersion": 1,
            "validFor": {
                "start": "<UTC timestamp>"
            },
            "operator": "sigstore.dev",
        }
    ],

    // Timestamp authority service selection
    "tsaConfig": {
        "selector": "ANY"
    }
}
```

## Removing Online Verification and Search

Rekor no longer provides an API for online verification and search. This includes
the APIs for requesting inclusion proofs by index, by leaf hash and by entry,
and searching for an entry by artifact hash or identity. In the near future,
we will spin up a separate service to support search.

Clients must be given the inclusion proof and checkpoint for an entry,
which must be stored in a bundle.

This should have no impact on clients as inclusion proofs were already
required in bundles. This will only impact monitors, and the read API
changes are detailed below.

## No Attestation Storage

Rekor v1's `intoto` type persisted attestations. Rekor v1's `dsse` type
removed attestation storage as Rekor was not designed to be used as storage
for verification metadata.

In Rekor v2, the `DSSELogEntryV0_0_2` type will also not support attestation
storage. Attestations should be persisted alongside an artifact, e.g. in
OCI or a package registry, or in a dedicated attestation storage service.

## C2SP Checkpoints

The checkpoints the log provides will conform to the
[C2SP checkpoint spec](https://github.com/C2SP/C2SP/blob/main/tlog-checkpoint.md).
Clients must check that their checkpoint verification implementation properly
handles these checkpoints, which could include:

* Multiple signatures
* Optional extension lines
* Updated key names, which will match the shard URL
* Key IDs calculated per the [signed note spec](https://github.com/C2SP/C2SP/blob/main/signed-note.md#signatures)
  * Ed25519 and ECDSA key IDs are based on the spec
    * Ed25519: `key ID = SHA-256(key name || 0x0A || 0x01 || 32-byte Ed25519 public key)[:4]`
    * ECDSA: `key ID = SHA-256(PKIX ASN.1 DER-encoded public key, in SubjectPublicKeyInfo format)[:4]`
  * For RSA, the signature type is `0xFF` and we append `PKIX-RSA-PKCS#1v1.5`,
    `key ID = SHA-256(key name || 0x0A || 0xFF || PKIX-RSA-PKCS#1v1.5 || PKIX ASN.1 DER-encoded public key)[:4]`

## Monitoring/Auditing

One of the more significant changes in a tile-backed log is the changes
to the read API. Inclusion and consistency proofs are not served via an
API, rather the client requests the set of tiles necessary to compute
the inclusion or consistency proof.

When monitoring the log searching for entries, the monitor will not request
entries by index, but by tile. Monitors can choose to only fetch complete
tiles or request [partial tiles](https://github.com/C2SP/C2SP/blob/main/tlog-tiles.md#partial-tiles),
which are the rightmost tiles in a tree that may contain somewhere between 1 and 255 hashes.
It is recommended to request partial tiles, or else the monitor might lag behind
if tiles are not filled frequently.

The APIs to request checkpoints, tiles, and entry bundles are defined
in the
[tlog-tiles spec](https://github.com/C2SP/C2SP/blob/main/tlog-tiles.md#apis).
For Go, [trillian-tessera](https://github.com/transparency-dev/trillian-tessera/tree/main/client)
provides a client to compute proofs and fetch tiles.

## Future: Witnessing

Witnessing provides independent verification that the log
remains consistent (append-only). Witnessing can either be
asynchronous, where a client requests witnesses verify consistency
proofs, or synchronous, where the log requests witnesses
verify proofs for every checkpoint issued. This results in a
longer request times and a dependency on third-party witnesses,
but results in a strong offline proof of log inclusion. We
will publish a doc later on with more details.

In the initial launch of Rekor v2, checkpoints will not be
witnessed, while we wait for the launch of a public witness
network. Clients do not need to implement verification of
witness signatures initially, but clients should increase
request timeouts to account for the additional time to
sign checkpoints, which we estimate to be <10s.

To verify cosignatures, see the
[spec](https://github.com/C2SP/C2SP/blob/main/tlog-cosignature.md).

The log will determine which set of witnesses is trusted and the
M-of-N witnesses to fetch signatures from, and this policy will
be distributed by Sigstore's TUF root.

Co-signed checkpoints will also be timestamped, so they can serve
as an independent signed timestamp instead of an RFC 3161 timestamp.

# Rekor v2, the bash way

Clone the service if you haven't already: `git clone https://github.com/sigstore/rekor-tiles.git`

Spin up the service: `docker compose up --build --wait`

Create a signed artifact:

```bash
openssl ecparam -genkey -name prime256v1 > ec_private.pem && openssl ec -in ec_private.pem -pubout > ec_public.pem
head -c 128 < /dev/urandom > artifact
openssl dgst -sha256 -sign ec_private.pem artifact > artifact.sig
openssl dgst -sha256 -verify ec_public.pem -signature artifact.sig artifact # Should return Verified OK
```

Generate artifact digest:

```bash
cat artifact | openssl dgst -binary -sha256 > artifact_dgst
```

Post an entry:

```bash
curl  -H \
 "Accept: application/json" -X \
POST http://localhost:3003/api/v2/log/entries -o rekor_response -d "{ \"hashedRekordRequestV002\":{ \"digest\":\"$(cat artifact_dgst | base64 | tr -d '\n')\", \"signature\":{ \"content\": \"$(cat artifact.sig | base64 | tr -d '\n')\", \"verifier\": { \"key_details\": \"PKIX_ECDSA_P256_SHA_256\", \"public_key\": { \"raw_bytes\": \"$(openssl base64 -d -in ec_public.pem | base64 | tr -d '\n')\" } } } } }"
```

View the response with `cat rekor_response | jq .` Example:

```json
{
  "logIndex": "0",
  "logId": {
    "keyId": "2AtEIMfG6Y41yK0tcwRTBS2tjhOrjKGIpDkHFgp65g0="
  },
  "kindVersion": {
    "kind": "hashedrekord",
    "version": "0.0.2"
  },
  "integratedTime": "0",
  "inclusionPromise": null,
  "inclusionProof": {
    "logIndex": "0",
    "rootHash": "OWI5MjU1MWIxZTA0NGIzNmQ0ZGE0MTU0M2UwNjEwZjVhNzQyMDNiN2JiOWEzOWYwNDExOTZlMTI2MTg5NmM3NQ==",
    "treeSize": "1",
    "hashes": [],
    "checkpoint": {
      "envelope": "rekor-local\n1\nm5JVGx4ESzbU2kFUPgYQ9adCA7e7mjnwQRluEmGJbHU=\n\n— rekor-local 2AtEIIwnbtxrneJ7L1lQebfBRl7TxK84DTmx+kcZi7A25cBDgESI23f9ylThAlOireJ7U+H8eZF/4kJQcn9o5Qt8mQU=\n"
    }
  },
  "canonicalizedBody": "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"
}
```

Parse the entry (i.e. canonicalized body) with `cat rekor_response | jq -r .canonicalizedBody | base64 -d`

```json
{
  "apiVersion": "0.0.2",
  "kind": "hashedrekord",
  "spec": {
    "hashedRekordV002": {
      "data": {
        "algorithm": "SHA2_256",
        "digest": "dyj4ednYHjN4/zsjjBeeLahS9slp97Z67LTAVxjrjXw="
      },
      "signature": {
        "content": "MEQCIB+YPa9o3SN0sQ4uduGf+mZxwFfOhFZ0Cgy+p7Vt1o2SAiAPFDHqOAJLYmvtCWOsDyNY1H4V3zm4NEDYs3NyvHh1Pg==",
        "verifier": {
          "keyDetails": "PKIX_ECDSA_P256_SHA_256",
          "publicKey": {
            "rawBytes": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE2slOf8eZcj2moW2t4UFj7vCL6QpDzkDqqSUmm4OJCVvIauKLxm0aGs3VMPPfauMPaMutn0/s3jg0rroFxoicyg=="
          }
        }
      }
    }
  }
}
```

## gRPC

To query the server using gRPC, follow the above instructions to set up the server and generate an artifact.

Install grpcurl to query the server:

```bash
brew install grpcurl
```

List available methods:

```bash
grpcurl -plaintext localhost:3001 list dev.sigstore.rekor.v2.Rekor
```

Only `CreateEntry` is implemented currently.

Post an entry:

```bash
grpcurl -d "{ \"hashed_rekord_request_v002\":{ \"digest\":\"$(cat artifact_dgst|base64)\", \"signature\":{ \"content\": \"$(cat artifact.sig | base64)\", \"verifier\": { \"key_details\": \"PKIX_ECDSA_P256_SHA_256\", \"public_key\": { \"raw_bytes\": \"$(openssl base64 -d -in ec_public.pem | base64)\" } } } } }" -plaintext localhost:3001 dev.sigstore.rekor.v2.Rekor.CreateEntry > rekor_response
```

View the response with `cat rekor_response | jq .`.
