Below is an example of authentication script.
#!/bin/bash
PRIVATE_KEY_ES256=$2
CLIENT_ID=$1
SCOPE="das-api/office-exchange"
ISSUER="https://logindev.wipo.int/am/oauth2"
# https://logindev.wipo.int/am/oauth2/.well-known/openid-configuration
OIDC_CONFIG_JSON=$(curl -sS -k "${ISSUER}/.well-known/openid-configuration")
# Generic way to obtain the token endpoint
TOKEN_ENDPOINT=$(printf '%s' ${OIDC_CONFIG_JSON} | jq -r ".token_endpoint")
#echo $TOKEN_ENDPOINT
UTC_TIME=$(date -u +%s)
EXP_TIME=$(expr "$UTC_TIME" + 1000)
JSON='{'
JSON=${JSON}$(printf '"iss":"%s"' ${CLIENT_ID})
JSON=${JSON}$(printf ',"sub":"%s"' ${CLIENT_ID})
JSON=${JSON}$(printf ',"aud":"%s"' ${TOKEN_ENDPOINT})
JSON=${JSON}$(printf ',"exp":%s' ${EXP_TIME})
JSON=${JSON}'}'
JSON_HEADER_B64=$(printf '{"alg":"ES256","typ":"JWT"}' | jq . -cj | base64 -w0 | tr -d '\n=' | tr '+/' '-_')
# echo $JSON_HEADER_B64
JSON_PAYLOAD_B64=$(printf $JSON | jq . -cj | base64 -w0 | tr -d '\n=' | tr '+/' '-_')
JSON_SIGNATURE_ASN1_B64=$(printf '%s.%s' $JSON_HEADER_B64 $JSON_PAYLOAD_B64 | openssl dgst -sha256 -sign "${PRIVATE_KEY_ES256}" | openssl asn1parse -inform DER | base64 -w0)
JSON_SIGNATURE_HEX=$(printf $JSON_SIGNATURE_ASN1_B64 | base64 -d | sed -n '/INTEGER/p' | sed 's/.*INTEGER\s*://g' | sed -z 's/[^0-9A-F]//g')
JSON_SIGNATURE_B64=$(printf $JSON_SIGNATURE_HEX | xxd -p -r | base64 -w0 | tr -d '\n=' | tr '+/' '-_')
JWT_ASSERTION=$(printf '%s.%s.%s' $JSON_HEADER_B64 $JSON_PAYLOAD_B64 $JSON_SIGNATURE_B64)
echo
#echo $JWT_ASSERTION
echo
curl --insecure --location --request POST "${TOKEN_ENDPOINT}" \
--header "Content-Type: application/x-www-form-urlencoded" \
--data-urlencode "grant_type=client_credentials" \
--data-urlencode "scope=${SCOPE}" \
--data-urlencode "client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer" \
--data-urlencode "client_assertion=${JWT_ASSERTION}"
The output of the script is as follows:
private_key_jwt authentication output
{
"access_token": "eyJ0eXAiOiJKV1QiLCJraWQiOiJmVWRmbEJSa3c5bm1tejcrL3BmMWM5d2RYdXc9I.......vvwFVnq8c8QArKsMmgBw",
"scope": "das-api/das-access",
"token_type": "Bearer",
"expires_in": 3599
}
Access_token attributes like signature, validity, audience and scopes must be verified by the client, similarly DAS API must also verify the access_token and must additionally check if the client id (=sub claim) is authorized. DAS API must maintain the whitelisted clients
access_token payload
{
"sub": "das-api-auth",
"cts": "OAUTH2_STATELESS_GRANT",
"auditTrackingId": "142b3081-d3c7-422c-b8d4-65869065f348-54991",
"iss": "https://logindev.wipo.int:443/am/oauth2",
"tokenName": "access_token",
"token_type": "Bearer",
"authGrantId": "nJ8nhylC8Kx9DY8l2SHlopwCfbg",
"aud": "das-api-auth",
"nbf": 1622454953,
"grant_type": "client_credentials",
"scope": [
"das-api/das-access"
],
"auth_time": 1622454953,
"realm": "/",
"exp": 1622458553,
"iat": 1622454953,
"expires_in": 3600,
"jti": "roG8mqa8Z1Z3F00Md20vUoyhA0I"
}
