57 lines
2.2 KiB
Go
57 lines
2.2 KiB
Go
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package kdf
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import (
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"bytes"
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)
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// KDF is a type of KDF (Key Derivation Function).
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type KDF interface {
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// Name returns the string form of the KDF name.
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Name() (name string)
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// NameBytes returns the Name result but in bytes with a leading uint32 bytecount packed in.
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NameBytes() (name []byte)
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// Rounds returns the number of rounds used in derivation.
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Rounds() (rounds uint32)
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// Salt returns the salt bytes.
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Salt() (salt []byte)
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// Setup initializes the KDF with the given derivation secret (password) and KDF options.
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Setup(secret, salt []byte, rounds, keyLen uint32) (err error)
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// DeriveKey derives the key. Setup (or SetupAuto) must have been run first.
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DeriveKey() (key []byte, err error)
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// SetupAuto configures a partially reconstructed KDF options that were parsed from GetKdfFromBytes (if KDF.AutoOK returns true).
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SetupAuto(secret []byte, keyLen uint32) (err error)
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// AutoOK returns true if all components were able to be parsed from GetKdfFromBytes.
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AutoOK() (ok bool)
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// IsPlain returns true if this is a "null" kdf; i.e. no derivation is actually performed.
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IsPlain() (plain bool)
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// PackedBytes returns the bytes suitable for serializing into a key file.
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PackedBytes() (buf *bytes.Reader, err error)
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// addSalt adds the salt as parsed from the private key.
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addSalt(salt []byte) (err error)
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// addRounds adds the rounds as parsed from the private key.
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addRounds(rounds uint32) (err error)
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}
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/*
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BcryptPbkdf combines bcrypt hashing algorithm with PBKDF2 key derivation.
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(bcrypt) https://www.usenix.org/legacy/events/usenix99/provos/provos_html/node1.html
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(PBKDF2) https://datatracker.ietf.org/doc/html/rfc2898
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http://www.tedunangst.com/flak/post/bcrypt-pbkdf
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*/
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type BcryptPbkdf struct {
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// salt is used to salt the hash for each round in rounds.
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salt []byte
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// rounds controls how many iterations that salting/hashing is done.
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rounds uint32
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// keyLen is how long the derived key should be in bytes.
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keyLen uint32
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// secret is the "passphrase" used to seed the key creation.
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secret []byte
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// key is used to store the derived key.
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key []byte
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}
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// Null is a dummy KDF that is used for unencrypted/plain SSH private keys. It literally does nothing.
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type Null struct{}
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