Name: OpaqueString. Base Class: FreeformClass. Applicability: Passwords and other opaque strings in security and application protocols. Replaces: The SASLprep profile of Stringprep. Width-Mapping Rule: None. Additional Mapping Rule: Map non-ASCII space code points to SPACE (U+0020). Case-Mapping Rule: None. Normalization Rule: NFC. Directionality Rule: None. Enforcement: To be defined by security or application protocols that use this profile. Specification: RFC8265 Section 4.2.