forked from Deuxfleurs/bottin
65 lines
1.9 KiB
Go
65 lines
1.9 KiB
Go
// Package ssha256 provides functions to generate and validate {SSHA256} styled
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// password schemes.
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// The method used is defined in RFC 2307 and uses a salted SHA256 secure hashing
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// algorithm
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package ssha256
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"errors"
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"fmt"
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)
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// ErrNotSshaPassword occurs when Validate receives a non-SSHA256 hash
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var ErrNotSshaPassword = errors.New("string is not a SSHA256 hashed password")
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// ErrBase64DecodeFailed occurs when the given hash cannot be decode
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var ErrBase64DecodeFailed = errors.New("base64 decode of hash failed")
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// ErrNotMatching occurs when the given password and hash do not match
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var ErrNotMatching = errors.New("hash does not match password")
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// Generate encrypts a password with a random salt of definable length and
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// returns the {SSHA256} encoding of the password
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func Generate(password string, length uint8) (string, error) {
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salt := make([]byte, length)
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_, err := rand.Read(salt)
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if err != nil {
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return "", err
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}
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hash := createHash(password, salt)
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ret := fmt.Sprintf("{SSHA256}%s", base64.StdEncoding.EncodeToString(hash))
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return ret, nil
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}
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// Validate compares a given password with a {SSHA256} encoded password
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// Returns true is they match or an error otherwise
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func Validate(password string, hash string) (bool, error) {
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if len(hash) < 10 || string(hash[0:9]) != "{SSHA256}" {
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return false, ErrNotSshaPassword
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}
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data, err := base64.StdEncoding.DecodeString(hash[9:])
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if len(data) < 33 || err != nil {
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return false, ErrBase64DecodeFailed
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}
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newhash := createHash(password, data[32:])
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hashedpw := base64.StdEncoding.EncodeToString(newhash)
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if hashedpw == hash[9:] {
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return true, nil
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}
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return false, ErrNotMatching
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}
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// createHash appends password and salt together to a byte array
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func createHash(password string, salt []byte) []byte {
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pass := []byte(password)
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str := append(pass[:], salt[:]...)
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sum := sha256.Sum256(str)
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result := append(sum[:], salt[:]...)
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return result
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}
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