OP Corporate Service Provider API (1.0)

Authentication in OP Corporate Service Provider API is based on practices from OpenID Connect (OIDC) 1.0 and OAuth 2.0.

It is extremely important that the Client ID, Client Secret and certificate private key are not exposed at any point. Together they represent the identity of the client and thereby the corporation. In the possession of an attacker they could be used to make fraudulent API calls potentially causing considerable damage.

To test the API in the sandbox environment, please request sandbox credentials by email at corp-payment-APIs@op.fi.

You can get production access for this API by registering as a service provider on OP API Admin.

To use these APIs in production you should replace the host in the API examples below with https://corporate-api.apiauth.services.op.fi/

V1.0 (12/2021)

Initial version

#!/bin/bash

# To run this you need openssl and jq installed.

# Steps for registering the required keys and certificates
# 1. A valid service provider agreement created on OP API Admin
# 2. OAuth clientId and clientSecret provisioned
# 3. MTLS private key generated: openssl genrsa -out sandbox-mtls.key 4096
# 4. MTLS certificate signing request (CN and other attributes are ignored): openssl req -new -key sandbox-mtls.key -out sandbox-mtls.csr
# 5. Valid MTLS certificate acquired from OP API Admin using the csr from step 4 and in "sandbox-mtls.crt" file
# 6. Payment signing private key generated: openssl genrsa -out sandbox-signing.key 4096
# 7. Signing csr request: openssl req -new -key sandbox-signing.key -out sandbox-signing.csr
# 8. Signing KID (key identifier) received from OP API Admin by submitting the sandbox-signing.csr.

# OAuth credentials
clientId="TODO put here oauth client id"
clientSecret="TODO and here client secret"
# MTLS credentials
mtlsKey="sandbox-mtls.key"
mtlsCertificate="sandbox-mtls.crt"

# Credentials request signing keys
signingKey="sandbox-signing.key"
signingKid="TODO and here signing KID"

API_SERVER="https://sandbox-api.apiauth.aws.op-palvelut.net"

echo "Getting access token"
reply=$(curl -s ${API_SERVER}/corporate-oidc/v1/token \
    --key ${mtlsKey} \
    --cert ${mtlsCertificate} \
    -H 'Content-Type: application/x-www-form-urlencoded' \
    -d "grant_type=client_credentials&client_id=${clientId}&client_secret=${clientSecret}")

token=$(echo $reply | jq -r .access_token)
echo "Access token is: $token"

echo "Fetching mandate listing"
contracts=$(curl -s ${API_SERVER}/corporate-service-provider/v1/mandates \
--key ${mtlsKey} \
--cert ${mtlsCertificate} \
-H "Authorization: Bearer $token")

echo $contracts | jq -C .

COMPANYID=$(echo $contracts | jq -r .[0].companyId)

echo "Fetching mandate info for company $COMPANYID"
contractinfo=$(curl -s ${API_SERVER}/corporate-service-provider/v1/mandates/$COMPANYID \
--key ${mtlsKey} \
--cert ${mtlsCertificate} \
-H "Authorization: Bearer $token")

echo $contractinfo | jq -C .

## Generate credentials with signature

# Sample credential request with dummy data
credentialRequest="{\"contractId\":\"1234567\"}"

## Signing the payload is mandatory for credential generation requests

# Issued at, in unix timestamp format
IAT=$(date +%s)

# Form the JWS header with mandatory fields
HEADER="{\"b64\":false,\"crit\":[\"b64\",\"urn:op.api.iat\"],\"alg\":\"RS256\",\"urn:op.api.iat\":${IAT},\"kid\":\"${signingKid}\"}"

# Base64 encode the header. JWT-encoding is slightly different from default output of base64, so do some transforming to make the output url-safe, and remove trailing padding (=).
HEADER_ENC=$(echo -n "${HEADER}" | base64 | tr -- '+/=' '-_ ' | tr -d '[:space:]')

# Sign the header and payload. The signature calculation in the detached body JWS is slightly different from the standard way, as the payload is not base64-encoded
# before signing, but included as-is in the signature plaintext. The signing algorithm is RS256, also known as "RSA Digital Signature Algorithm with SHA-256".
# The resulting signature is base64-encoded, and the same url-safe transformations are applied.
SIGNATURE=$(echo -n "${HEADER_ENC}.${credentialRequest}" | openssl dgst -sha256 -sign ${signingKey} -binary | openssl base64 -e -A | tr -- '+/=' '-_ ' | tr -d '[:space:]')

# The signature header includes the base64-encoded JWS header, followed by two dots (..), and the base64-urlsafe-encoded signature. The actual message payload is not
# repeated in the signature
REQ_SIGNATURE="${HEADER_ENC}..${SIGNATURE}"

# The signature is included in the "X-Req-Signature" header.
echo "Sending request to get Client ID and Secret"
clientCredentials=$(curl -s ${API_SERVER}/corporate-service-provider/v1/mandates/$COMPANYID/keys \
    --key ${mtlsKey} \
    --cert ${mtlsCertificate} \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $token" \
    -H "X-Req-Signature: ${REQ_SIGNATURE}" \
    -d "$credentialRequest")

echo $clientCredentials | jq -C .