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dbt-privacy

Package of macros for dbt to make it easier to protect your customers' data

About Privacy Dynamics

Privacy Dynamics provides tools to empower innovative and ethical data teams. Our solutions include sophisticated privacy transformations that reduce reidentification risk but leave data usable for analysts and data scientists. For more information, visit https://www.privacydynamics.io

Installation Instructions

Check dbt Hub for the latest installation instructions, or read dbt's docs for more information on installing packages.

Macros in this Package

Note that macros in this package are designed to work across Postgres, Snowflake, BigQuery, and Redshift data warehouses, but as of May 2022, we have only tested the macros against Postgres and Snowflake.

Click Here to view the dbt docs site for the macros in this package.

hash

Source

Returns a SHA2 hex digest of expr; lowercases and adds a pepper before hashing by default. For additional security, set salt_expr to a value with the same or higher cardinality as expr (e.g., if expr='email', then a good salt would be salt_expr='user_id'). Also set the DBT_PRIVACY_PEPPER_SEED environment variable to a random value; see docs for generate_pepper for more information.

NOTE: The value of DBT_PRIVACY_PEPPER_SEED will be visible in the compiled model code and in query logs. If an attacker has access to the code and the data, they will be able to construct a rainbow table for this hash method unless salt_expr is also provided.

For more information, see the docs.

Example Usage:

{{ dbt_privacy.hash(
    "email",
    lowercase=true,
    salt_expr="user_id",
    pepper_scope="model",
    pepper_persistence="permanent",
    digest_size=256
) }}
{{ dbt_privacy.hash("full_name", salt_expr="user_id") }}

hash_unique

Source

Returns a SHA2 hex digest of expr, if expr is unique* in its context; lowercases and adds a pepper before hashing by default. For additional security, set salt_expr to a value with the same or higher cardinality as expr (e.g., if expr='email', then a good salt would be salt_expr='user_id'). Also set the DBT_PRIVACY_PEPPER_SEED environment variable to a random value; see docs for generate_pepper for more information.

"Unique" means that the number of rows partitioned by expr in the current window is <= n, where n defaults to 1 but is configurable.

NOTE: The value of DBT_PRIVACY_PEPPER_SEED will be visible in the compiled model code and in query logs. If an attacker has access to the code and the data, they will be able to construct a rainbow table for this hash method unless salt_expr is also provided.

For more information, see the docs.

Example Usage:

{{ dbt_privacy.hash_unique(
    "zip_code",
    lowercase=false,
    salt_expr="state",
    pepper_scope="model",
    pepper_persistence="permanent",
    digest_size=256,
    n=5
) }}
{{ dbt_privacy.hash_unique("zip_code", salt_expr="state") }}

mask

Source

Unless expr is null, replaces expr with a string of the same length, but with the contents replaced by mask_char.

If keep_n > 0, includes keep_n characters from the original expr, from the direction keep_dir.

For more information, see the docs.

Example Usage:

{{ dbt_privacy.mask("first_name") }}
# input: Ted
# output: ***
# input: Matthew
# output: *******

{{ dbt_privacy.mask(
    "phone_number",
    keep_n=4,
    keep_dir="right"
) }}
# input: +12125551234
# output: ********1234

mask_email

Source

Splits an email address into its address and domain parts. Will safe_mask the address and also safe_mask the domain, if there are fewer than domain_n records with that domain.

Returns null if expr is null, but does not return null if expr is not a valid email address (with no "@").

Note: Masking unique domains is important for protecting individuals with addresses like personal@famouscelebrity.com

For more information, see the docs.

Example Usage:

{{ dbt_privacy.mask_email("email") }}
# input: ted@example.com
# output: ********@********

{{ dbt_privacy.mask_email(
    "email", 
    n=4,
    domain_n=0,
) }}
# input: ted@example.com
# output: ****@example.com

redact_unique

Source

Returns redact_expr instead of expr, if expr is unique* in its context; lowercases before checking for uniqueness by default.

"Unique" means that the number of rows partitioned by expr in the current window is <= n, where n defaults to 1 but is configurable.

For more information, see the docs.

Example Usage:

{{ dbt_privacy.redact_unique(
    "zip_code", 
    lowercase=false, 
    redact_expr="'**REDACTED**'", 
    n=5
) }}

safe_mask

Source

Unless expr is null, replaces expr with a string of length n + keep_n, consisting of a fixed number (n) of mask_chars.

If keep_n > 0, includes keep_n characters from the original expr, from the direction keep_dir.

For more information, see the docs.

Example Usage:

{{ dbt_privacy.safe_mask("phone_number") }}
# input: +12125551234
# output: ********

{{ dbt_privacy.safe_mask(
    "phone_number", 
    n=8,
    keep_n=4,
    keep_dir="right"
) }}
# input: +12125551234
# output: ********1234