mirror of https://github.com/schollz/croc.git
80 lines
1.7 KiB
Go
80 lines
1.7 KiB
Go
package crypt
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import (
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"crypto/sha1"
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"golang.org/x/crypto/pbkdf2"
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"golang.org/x/crypto/scrypt"
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)
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// Key defines the key derivation function interface.
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type Key interface {
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// Derive returns the AES key and HMAC-SHA key, for the given password,
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// salt combination.
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Derive(salt []byte) (aesKey, hmacKey []byte)
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// Size returns the key-size. Key-size should either 16, 24, or 32 to
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// select AES-128, AES-192, or AES-256.
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Size() int
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// Reset resets/flushes the key.
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Reset()
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}
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type pbkdf2Key struct {
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password []byte
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size int
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}
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// NewPbkdf2Key returns the key derivation function PBKDF2 as defined in
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// RFC 2898.
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func NewPbkdf2Key(password []byte, size int) Key {
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return pbkdf2Key{password: password, size: size}
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}
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func (k pbkdf2Key) Derive(salt []byte) (aesKey, hmacKey []byte) {
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key := pbkdf2.Key(k.password, salt, 4096, 2*k.size, sha1.New)
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aesKey = key[:k.size]
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hmacKey = key[k.size:]
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return aesKey, hmacKey
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}
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func (k pbkdf2Key) Size() int { return k.size }
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func (k pbkdf2Key) Reset() {
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for i := range k.password {
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k.password[i] = 0
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}
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}
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type scryptKey struct {
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password []byte
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size int
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}
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// NewScryptKey returns the scrypt key derivation function as defined in
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// Colin Percival's paper "Stronger Key Derivation via Sequential
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// Memory-Hard Functions".
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func NewScryptKey(password []byte, size int) Key {
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return scryptKey{password: password, size: size}
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}
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func (k scryptKey) Derive(salt []byte) (aesKey, hmacKey []byte) {
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key, err := scrypt.Key(k.password, salt, 16384, 8, 1, 2*k.size)
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if err != nil {
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panic(err)
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}
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aesKey = key[:k.size]
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hmacKey = key[k.size:]
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return aesKey, hmacKey
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}
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func (k scryptKey) Size() int { return k.size }
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func (k scryptKey) Reset() {
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for i := range k.password {
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k.password[i] = 0
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}
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}
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