GCP DLP(Data Loss prevention) getting “Decryption failed: the ciphertext is invalid.”-400 error

Question

I created a key ring and then a key.Then used import job to create a wrapped key .Thereafter used the below code to decrypt a normal text. But I am getting below error:

.InvalidArgument: 400 Received the following error message from Cloud KMS when unwrapping KmsWrappedCryptoKey "projects/XXXXXXXXXXXX/location s/global/keyRings/demo-keyring/cryptoKeys/demo_v1": Decryption failed: the ciphertext is invalid.

Below is the code:

# Import the client library
import google.cloud.dlp

# Instantiate a client
dlp = google.cloud.dlp_v2.DlpServiceClient()
project = 'XXXXXX'
stringVal = 'My name is Sonal Singh and my email id is : sonalsingh@gmail.com'
alphabet='ALPHA_NUMERIC'
surrogate_type='EMAIL_ADDRESS'
wrapped_key=('XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+gr'
'l+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+'
'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX+/+'
'//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx=')

#key_name = ('projects/XXXXXXXXXXXXX/locations/global/keyRings/demo-keyring/cryptoKeys/demo_key')


parent = dlp.project_path(project)
# The wrapped key is base64-encoded, but the library expects a binary
# string, so decode it here.
import base64

wrapped_key = base64.b64decode(wrapped_key)

# Construct FPE configuration dictionary
crypto_replace_ffx_fpe_config = {
        "crypto_key": {
            "kms_wrapped": {
                "wrapped_key": wrapped_key,
                "crypto_key_name": key_name,
            }
        },
        "common_alphabet": alphabet,
}

# Add surrogate type
if surrogate_type:
        crypto_replace_ffx_fpe_config["surrogate_info_type"] = {
            "name": surrogate_type
        }

# Construct inspect configuration dictionary
inspect_config = {
        "info_types": [{"name": info_type} for info_type in ["FIRST_NAME", "LAST_NAME", "EMAIL_ADDRESS"]]
        }

# Construct deidentify configuration dictionary
deidentify_config = {
        "info_type_transformations": {
            "transformations": [
                {
                    "primitive_transformation": {
                        "crypto_replace_ffx_fpe_config": crypto_replace_ffx_fpe_config
                    }
                }
            ]
        }
    }

# Convert string to item
item = {"value": stringVal}

# Call the API
response = dlp.deidentify_content(
        parent,
        inspect_config=inspect_config,
        deidentify_config=deidentify_config,
        item=item
    )

# Print results
print(response.item.value)

I could see another stack overflow post with same issue: GCP DLP(Data Loss prevention) getting "Decryption failed: the ciphertext is invalid." but was not sure what does this step meant : Use this generated value in your request to Google Cloud DLP API.

How to use this value in the above code?

score 0 · Answer 1 · answered Mar 19 '20 at 15:52

Yes I think that the other StackOverflow question you found can help us here.

I’m not well versed on python, but I saw some things that I would like to point out. I think that you’re doing Steps 1 & 3 from the other StackOverflow post 1 correctly, but you’re missing the Step 2 in which you encrypt using Cloud KMS (decrypt on your case).

Did you have the chance to go over:

https://cloud.google.com/kms/docs/reference/libraries#client-libraries-usage-python https://cloud.google.com/kms/docs/encrypt-decrypt#kms-howto-encrypt-python

Also, please know you have posted your email on the code, you may want to edit it.

GCP DLP(Data Loss prevention) getting “Decryption failed: the ciphertext is invalid.”-400 error

1 Answers1