Which of the following involves assigning an opaque value to sensitive data fields to protect confidentiality?

Obfuscation involves making data difficult to understand or interpret, often by confusing its form, but it does not necessarily replace the data with an opaque, unrelated value like tokenization does.

Masking replaces sensitive data with realistic, but non-sensitive, data (e.g., replacing actual credit card numbers with 'XXXX-XXXX-XXXX-1234') often for use in non-production environments, rather than with an opaque, unrelated token.

Tokenization is the process of replacing sensitive data with a unique, randomly generated, non-sensitive substitute value, called a token, that has no intrinsic meaning or value. The original sensitive data is stored securely in a separate data store (token vault), while the token can be used in its place to protect confidentiality without exposing the actual sensitive information.

Anonymization involves removing or modifying personally identifiable information (PII) to prevent re-identification, often by aggregating data or removing direct identifiers, rather than replacing specific sensitive fields with tokens.