# Alphanumeric String Key Generates unique alphanumeric strings of the same length as the input. For example, for the origin value `ABC123`, the output value is a six-character alphanumeric string such as `D24N05`. You can configure the generator to: * Preserve a value prefix. For example, if the origin value always starts with `acct_`, you might want to preserve that in the output value, and only mask the unique part of the identifier. * Only replace numerical characters, and keep other types of characters as is. ## Characteristics


Consistency	Yes, can be made self-consistent.
Linking	No, cannot be linked.
Differential privacy	No
Data-free	No
Allowed for primary keys	Yes
Allowed for unique columns	Yes
Uses format-preserving encryption (FPE)	Yes
Privacy ranking	3 if not consistent 4 if consistent
Generator ID (for the API)	`AlphaNumericPkGenerator`

## How to configure To configure the generator: 1. To preserve a prefix value, in the **Preserve prefix** field, type the prefix string to preserve in the output values.\ \ For example, if you set **Preserve prefix** to `acct_`, then any source values that start with `acct_` will also start with `acct_` in the destination data. 2. To only replace the numerical characters, toggle **Mask digits only** to the on position. 3. Toggle the **Consistency** setting to indicate whether to make the generator self-consistent.\ \ By default, the generator is not consistent. 4. If [Structural data encryption](/app/generation/generators-assign-config/generators-data-encryption-config.md) is enabled, then to use it for this column, in the advanced options section, toggle **Use data encryption process** to the on position. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.tonic.ai/app/generation/generators/generator-reference/alphanumeric-string-key.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.