ASCIIArmored

ASCIIArmored refers to a text-based encoding of binary data using an armor wrapper so the data can be safely transported through channels that are not binary-safe, such as email or text forums. The term is most closely associated with the ASCII armor used by OpenPGP and its implementations (for example, GnuPG and other PGP tools). In practice, an ASCIIArmored block consists of human-readable header and footer lines that indicate the type of data, a base64-encoded payload, and optional metadata such as version or comments. The armor also includes a small checksum to help detect corruption.

Structure and content typically follow a pattern such as a header line like BEGIN PGP MESSAGE or BEGIN PGP PUBLIC KEY BLOCK, followed by a body of base64-encoded data, and ending with a corresponding END line. Within the armored block, the payload represents the original binary data—encrypted data, a cryptographic key, a digital signature, or a message. The armor may also specify the content type and include a checksum (often CRC-24) to verify integrity after transport.

Usage and variants: ASCIIArmor is widely used to embed cryptographic material in text-based communications and storage. While OpenPGP provides the most common form of ASCII armor, similar concepts exist in PEM blocks used by X.509 certificates and S/MIME, which also wrap binary data in text markers. In software libraries, a boolean or mode flag named ASCIIArmored or armor mode often toggles whether output is emitted in armored form or as raw binary. The armored format trades compactness for portability and readability.