HashedPassword

Replace a password hash with a bcrypt hash of one known password, so test accounts can log in.

Parameters

Name	Description	Default	Required	Supported DB types
column	The name of the column to be affected		Yes	text, varchar, char, bpchar, citext
password	The password to hash. Use resolve_env and ${VAR} to keep it out of the config file		Yes	-
bcrypt_variant	The bcrypt version prefix: 2a, 2b or 2y	2a	No	-
cost	The bcrypt cost, from 4 to 31	10	No	-
per_row_salt	Hash every row with its own salt. By default all rows get one shared hash	false	No	-
keep_null	Indicates whether NULL values should be replaced with transformed values or not	true	No	-

Description

The HashedPassword transformer writes a bcrypt hash of the given password into the column. After the restore, every user can log in with that password. The original hash is not kept.

2a, 2b and 2y are the same algorithm with a different prefix. Choose the one your application accepts:

• PostgreSQL pgcrypto (crypt()) understands only 2a. With 2b or 2y it gives no error, but the password check is always false.
• PHP password_hash() writes 2y.
• Go, Python and Spring Security accept all three.

bcrypt is slow on purpose. With the default per_row_salt: false the password is hashed once and the same hash goes to every row, so the dump stays fast. Set per_row_salt: true when rows must not share a hash; each row then costs one bcrypt run, which is expensive and adds a large overhead per record.

warning

Never put a real password into the config file. Pass it through an environment variable with resolve_env: true, as in the example below.

Example: Test logins for the users table

HashedPassword transformer example

- schema: "public"
  name: "users"
  transformers:
    - name: "HashedPassword"
      resolve_env: true
      params:
        column: "password_hash"
        password: "${TEST_LOGIN_PASSWORD?set TEST_LOGIN_PASSWORD}"
        bcrypt_variant: "2a"

export TEST_LOGIN_PASSWORD="Password123!"
greenmask --config config.yml dump

After the restore, this query returns true for every row:

SELECT crypt('Password123!', password_hash) = password_hash FROM users;