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Diffstat (limited to 'PROTOCOL.key')
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diff --git a/PROTOCOL.key b/PROTOCOL.key new file mode 100644 index 0000000..cbf7a70 --- /dev/null +++ b/PROTOCOL.key @@ -0,0 +1,71 @@ +This document describes the private key format for OpenSSH. + +1. Overall format + +The key consists of a header, a list of public keys, and +an encrypted list of matching private keys. + +#define AUTH_MAGIC "openssh-key-v1" + + byte[] AUTH_MAGIC + string ciphername + string kdfname + string kdfoptions + uint32 number of keys N + string publickey1 + string publickey2 + ... + string publickeyN + string encrypted, padded list of private keys + +2. KDF options for kdfname "bcrypt" + +The options: + + string salt + uint32 rounds + +are concatenated and represented as a string. + +3. Unencrypted list of N private keys + +The list of privatekey/comment pairs is padded with the +bytes 1, 2, 3, ... until the total length is a multiple +of the cipher block size. + + uint32 checkint + uint32 checkint + byte[] privatekey1 + string comment1 + byte[] privatekey2 + string comment2 + ... + string privatekeyN + string commentN + byte 1 + byte 2 + byte 3 + ... + byte padlen % 255 + +where each private key is encoded using the same rules as used for +SSH agent. + +Before the key is encrypted, a random integer is assigned +to both checkint fields so successful decryption can be +quickly checked by verifying that both checkint fields +hold the same value. + +4. Encryption + +The KDF is used to derive a key, IV (and other values required by +the cipher) from the passphrase. These values are then used to +encrypt the unencrypted list of private keys. + +5. No encryption + +For unencrypted keys the cipher "none" and the KDF "none" +are used with empty passphrases. The options if the KDF "none" +are the empty string. + +$OpenBSD: PROTOCOL.key,v 1.3 2022/07/01 04:45:50 djm Exp $ |