Verify CLI Signature

The SuprSend CLI is signed and notarised starting from release 0.2.19. Before installing, you can cryptographically confirm that the binary you downloaded was built by SuprSend and has not been modified in transit.

How it works

SuprSend signs the CLI using Cosign. At every release, checksums.txt - a SHA-256 hash manifest of every release archive - is signed and the resulting bundle is published alongside checksums.txt.sig and public_key.pem as GitHub release assets. Running cosign verify-blob confirms the signature is valid and that checksums.txt has not been modified since signing.

Prerequisites

You need Cosign installed. It is a single binary with no runtime dependencies.

macOS
Linux (amd64)
Windows

brew install cosign

curl -O -L https://github.com/sigstore/cosign/releases/latest/download/cosign-linux-amd64
sudo mv cosign-linux-amd64 /usr/local/bin/cosign
sudo chmod +x /usr/local/bin/cosign

winget install -e --id Sigstore.Cosign

Confirm it is working:

cosign version

Step 1 - Download the verification files

macOS / Linux
Windows

VERSION="0.2.19"

curl -sL -O https://github.com/suprsend/cli/releases/download/${VERSION}/checksums.txt.sig
curl -sL -O https://github.com/suprsend/cli/releases/download/${VERSION}/checksums.txt
curl -sL -O https://github.com/suprsend/cli/releases/download/${VERSION}/public_key.pem

$VERSION = "0.2.19"
$BASE    = "https://github.com/suprsend/cli/releases/download/$VERSION"

Invoke-WebRequest "$BASE/checksums.txt.sig" -OutFile checksums.txt.sig
Invoke-WebRequest "$BASE/checksums.txt"     -OutFile checksums.txt
Invoke-WebRequest "$BASE/public_key.pem"    -OutFile public_key.pem

File	Description
`checksums.txt`	SHA-256 hashes of all platform archives in the release. This is what gets signed.
`checksums.txt.sig`	The Cosign bundle - contains the signature over `checksums.txt` and its verification metadata.
`public_key.pem`	SuprSend’s PEM-encoded public key, published with every release on GitHub. Used to verify the signature.

Always download public_key.pem directly from the official SuprSend CLI releases page. Do not copy it from mirrors or third-party sources.

Step 2 - Verify the signature

With all three files in the same directory, run:

cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

This command is identical on macOS, Linux, and Windows (PowerShell). What each argument does:

Argument	Description
`--key public_key.pem`	SuprSend’s PEM-encoded public key. Cosign uses this to validate the signature.
`--bundle checksums.txt.sig`	The Cosign bundle containing the signature and its metadata.
`checksums.txt`	The artifact being verified - the SHA-256 manifest of all release archives.

Expected output:

Verified OK

Verified OK confirms:

The signature was produced using SuprSend’s private key - the key that corresponds to public_key.pem. Only SuprSend’s release pipeline has access to it.
checksums.txt is byte-for-byte identical to what was signed at release time.

If you see invalid signature when validating ASN1 encoded signature, do not proceed with installation. Re-download all three files from the same release and retry. If the failure persists, contact SuprSend support.

Step 3 - Verify the archive checksum

This step confirms your downloaded CLI archive matches the hash in checksums.txt - ruling out any corruption or substitution of the binary.

Your platform archive must be downloaded and present in the same directory as checksums.txt before running this command. If you haven’t downloaded it yet, see the Installation page. If the archive is not in the directory, the command will return no output rather than an error - which can look like a pass but means nothing was actually verified.

macOS
Linux
Windows

shasum -a 256 --check checksums.txt --ignore-missing

Expected output (filename matches the archive you downloaded):

darwin.arm64.suprsend.tar.gz: OK

sha256sum --check checksums.txt --ignore-missing

Expected output (filename matches the archive you downloaded):

linux.x64.suprsend.tar.gz: OK

# Auto-detects whichever Windows archive is present in the current directory
$archives = @(
  "suprsend_Windows_x86_64.zip",
  "suprsend_Windows_arm64.zip",
  "win32.x64.suprsend.zip",
  "win32.arm64.suprsend.zip"
)

$archive = $archives | Where-Object { Test-Path ".\$_" } | Select-Object -First 1

if (-not $archive) {
  Write-Error "No Windows archive found in the current directory. Download it first."
  exit 1
}

$line     = Get-Content checksums.txt | Where-Object { $_ -match [regex]::Escape($archive) }
$expected = ($line -split '\s+')[0].ToLower()
$actual   = (Get-FileHash ".\$archive" -Algorithm SHA256).Hash.ToLower()

if ($expected -eq $actual) {
  Write-Host "Checksum OK - $archive"
} else {
  Write-Error "CHECKSUM MISMATCH - do not use this archive"
}

Expected output:

Checksum OK - suprsend_Windows_x86_64.zip

The filename in the output will match whichever archive you downloaded.

Full script

Downloads the verification files and your platform archive, verifies both, then installs.

#!/usr/bin/env bash
set -euo pipefail

VERSION="0.2.19"
ARCHIVE="darwin.arm64.suprsend.tar.gz"
BASE="https://github.com/suprsend/cli/releases/download/${VERSION}"

echo "-> Downloading release files..."
curl -sL -O "${BASE}/checksums.txt.sig"
curl -sL -O "${BASE}/checksums.txt"
curl -sL -O "${BASE}/public_key.pem"
curl -sL -O "${BASE}/${ARCHIVE}"

echo "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

echo "-> Verifying archive checksum..."
shasum -a 256 --check checksums.txt --ignore-missing

echo "-> Extracting and installing..."
tar -xzf "${ARCHIVE}"
sudo mv suprsend /usr/local/bin/suprsend

echo "Done. SuprSend CLI ${VERSION} installed and verified."

#!/usr/bin/env bash
set -euo pipefail

VERSION="0.2.19"
ARCHIVE="darwin.x64.suprsend.tar.gz"
BASE="https://github.com/suprsend/cli/releases/download/${VERSION}"

echo "-> Downloading release files..."
curl -sL -O "${BASE}/checksums.txt.sig"
curl -sL -O "${BASE}/checksums.txt"
curl -sL -O "${BASE}/public_key.pem"
curl -sL -O "${BASE}/${ARCHIVE}"

echo "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

echo "-> Verifying archive checksum..."
shasum -a 256 --check checksums.txt --ignore-missing

echo "-> Extracting and installing..."
tar -xzf "${ARCHIVE}"
sudo mv suprsend /usr/local/bin/suprsend

echo "Done. SuprSend CLI ${VERSION} installed and verified."

#!/usr/bin/env bash
set -euo pipefail

VERSION="0.2.19"
ARCHIVE="linux.x64.suprsend.tar.gz"
BASE="https://github.com/suprsend/cli/releases/download/${VERSION}"

echo "-> Downloading release files..."
curl -sL -O "${BASE}/checksums.txt.sig"
curl -sL -O "${BASE}/checksums.txt"
curl -sL -O "${BASE}/public_key.pem"
curl -sL -O "${BASE}/${ARCHIVE}"

echo "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

echo "-> Verifying archive checksum..."
sha256sum --check checksums.txt --ignore-missing

echo "-> Extracting and installing..."
tar -xzf "${ARCHIVE}"
sudo mv suprsend /usr/local/bin/suprsend

echo "Done. SuprSend CLI ${VERSION} installed and verified."

#!/usr/bin/env bash
set -euo pipefail

VERSION="0.2.19"
ARCHIVE="linux.arm64.suprsend.tar.gz"
BASE="https://github.com/suprsend/cli/releases/download/${VERSION}"

echo "-> Downloading release files..."
curl -sL -O "${BASE}/checksums.txt.sig"
curl -sL -O "${BASE}/checksums.txt"
curl -sL -O "${BASE}/public_key.pem"
curl -sL -O "${BASE}/${ARCHIVE}"

echo "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

echo "-> Verifying archive checksum..."
sha256sum --check checksums.txt --ignore-missing

echo "-> Extracting and installing..."
tar -xzf "${ARCHIVE}"
sudo mv suprsend /usr/local/bin/suprsend

echo "Done. SuprSend CLI ${VERSION} installed and verified."

$VERSION = "0.2.19"
$ARCHIVE = "suprsend_Windows_x86_64.zip"
$BASE    = "https://github.com/suprsend/cli/releases/download/$VERSION"

Write-Host "-> Downloading release files..."
Invoke-WebRequest "$BASE/checksums.txt.sig" -OutFile checksums.txt.sig
Invoke-WebRequest "$BASE/checksums.txt"     -OutFile checksums.txt
Invoke-WebRequest "$BASE/public_key.pem"    -OutFile public_key.pem
Invoke-WebRequest "$BASE/$ARCHIVE"          -OutFile $ARCHIVE

Write-Host "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

Write-Host "-> Verifying archive checksum..."
$line     = Get-Content checksums.txt | Where-Object { $_ -match "suprsend_Windows_x86_64" }
$expected = ($line -split '\s+')[0].ToLower()
$actual   = (Get-FileHash ".\$ARCHIVE" -Algorithm SHA256).Hash.ToLower()
if ($expected -eq $actual) { Write-Host "Checksum OK" } else { Write-Error "CHECKSUM MISMATCH - do not use this archive" }

Write-Host "-> Extracting and installing..."
Expand-Archive -Path $ARCHIVE -DestinationPath .\suprsend_install -Force
Move-Item -Force .\suprsend_install\suprsend.exe "C:\Windows\System32\suprsend.exe"

Write-Host "Done. SuprSend CLI $VERSION installed and verified."

$VERSION = "0.2.19"
$ARCHIVE = "suprsend_Windows_arm64.zip"
$BASE    = "https://github.com/suprsend/cli/releases/download/$VERSION"

Write-Host "-> Downloading release files..."
Invoke-WebRequest "$BASE/checksums.txt.sig" -OutFile checksums.txt.sig
Invoke-WebRequest "$BASE/checksums.txt"     -OutFile checksums.txt
Invoke-WebRequest "$BASE/public_key.pem"    -OutFile public_key.pem
Invoke-WebRequest "$BASE/$ARCHIVE"          -OutFile $ARCHIVE

Write-Host "-> Verifying signature..."
cosign verify-blob --key public_key.pem --bundle checksums.txt.sig checksums.txt

Write-Host "-> Verifying archive checksum..."
$line     = Get-Content checksums.txt | Where-Object { $_ -match "suprsend_Windows_arm64" }
$expected = ($line -split '\s+')[0].ToLower()
$actual   = (Get-FileHash ".\$ARCHIVE" -Algorithm SHA256).Hash.ToLower()
if ($expected -eq $actual) { Write-Host "Checksum OK" } else { Write-Error "CHECKSUM MISMATCH - do not use this archive" }

Write-Host "-> Extracting and installing..."
Expand-Archive -Path $ARCHIVE -DestinationPath .\suprsend_install -Force
Move-Item -Force .\suprsend_install\suprsend.exe "C:\Windows\System32\suprsend.exe"

Write-Host "Done. SuprSend CLI $VERSION installed and verified."

Reference

Available platform archives

All archives are available on the GitHub releases page.

Platform	Archive filename
macOS (Apple Silicon)	`darwin.arm64.suprsend.tar.gz`
macOS (Intel)	`darwin.x64.suprsend.tar.gz`
macOS (Universal - Apple Silicon + Intel)	`suprsend_Darwin_all.tar.gz`
Linux (x86_64)	`linux.x64.suprsend.tar.gz`
Linux (x86_64)	`suprsend_Linux_x86_64.tar.gz`
Linux (ARM64)	`linux.arm64.suprsend.tar.gz`
Linux (ARM64)	`suprsend_Linux_arm64.tar.gz`
Windows (x86_64)	`suprsend_Windows_x86_64.zip`
Windows (x86_64)	`win32.x64.suprsend.zip`
Windows (ARM64)	`suprsend_Windows_arm64.zip`
Windows (ARM64)	`win32.arm64.suprsend.zip`

Security model

SuprSend’s signing private key is held exclusively by the automated release pipeline and never leaves the secure signing environment. public_key.pem is the public counterpart - it is published openly with every release and carries no risk of compromise.

If you encounter an unexpected verification failure, reach out at support@suprsend.com or open an issue on the SuprSend CLI GitHub repository.

Getting Started with CLI

Updates and Versioning

Sync

Workflow

Template

Schema

Event

Preference Category

Translation

How it works

Prerequisites

Step 1 - Download the verification files

Step 2 - Verify the signature

Step 3 - Verify the archive checksum

Full script

Reference

​How it works

​Prerequisites

​Step 1 - Download the verification files

​Step 2 - Verify the signature

​Step 3 - Verify the archive checksum

​Full script

​Reference

How it works

Prerequisites

Step 1 - Download the verification files

Step 2 - Verify the signature

Step 3 - Verify the archive checksum

Full script

Reference