isSigned

In computing, isSigned is a term used as an identifier for a binary property that may denote two different concepts depending on context: the signedness of numeric data types, or the presence of a digital signature on a data artifact.

Signedness refers to whether an integer type can represent negative values. In languages like C and C++, integers are categorized as signed or unsigned; the signedness of a type can be checked at compile time with type traits such as std::is_signed. Some languages provide dedicated signed integer types (for example, Rust's i32) and unsigned types (for example, u32).

Digital signatures: For software artifacts, documents, or messages, isSigned indicates that the item carries a verifiable digital signature. Verification uses a public key infrastructure; common schemes include PGP/GPG, RSA/X.509, or Ed25519. A valid signature provides authenticity and integrity and can support non-repudiation.

In data models and APIs, isSigned may be a boolean field in metadata indicating the presence of a signature. Often, it accompanies fields that carry the actual signature value, signer identity, and certificate chain. Correct handling requires ensuring the signature is current and the signer is trusted.

See also: Digital signature, Signed data, Public key infrastructure, Type traits, Commit signing.