.asc

What is a .asc file?

ASC is a GPG encrypted, signed, or public key file in ASCII-armored (Base64 text) format.

Use caution
Type Security
By Werner Koch (GNU Project)
MIME application/pgp-keys

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What is it

An .asc file is a GPG file in ASCII armor — Base64-encoded text instead of raw binary. It starts with `-----BEGIN PGP MESSAGE-----` (encrypted), `-----BEGIN PGP SIGNATURE-----` (signed), or `-----BEGIN PGP PUBLIC KEY BLOCK-----` (public key). The content is functionally identical to a .gpg file, just encoded for safe transport through text-only channels.

ASCII armor exists because email, web forms, and chat systems can mangle binary data. By encoding in Base64 with clear text markers, ASC files survive copy-paste, email transport, and web posting intact. GPG public keys on keyservers, signed git commits, and PGP-encrypted emails all use ASCII armor.

To create: `gpg --armor -e file.txt` produces `file.txt.asc` instead of `file.txt.gpg`. To decrypt: `gpg -d file.txt.asc`. The `--armor` flag is the only difference — the encryption strength is identical.

Technical details
Full Name
ASCII-Armored GPG File
MIME Type
application/pgp-keys
Developer
Werner Koch (GNU Project)
Magic Bytes
N/A
Safety
.asc requires caution. Same caution as .gpg — verify the source. Public key .asc files are safe to share.
What opens it
gpg (CLI)
FREE Windows / Mac / Linux
Any text editor (to view)
FREE Windows / Mac / Linux
Kleopatra (Gpg4win)
FREE Windows
FAQ
What's the difference between .asc and .gpg?
.asc is ASCII-armored (Base64 text, safe for email/paste). .gpg is binary (smaller, but can be corrupted by text-based transport). The encryption is identical — only the encoding differs.
How do I import a public key from an .asc file?
`gpg --import publickey.asc` adds the key to your keyring. You can then encrypt files to the key's owner or verify their signatures.
Related formats