110 lines
2.2 KiB
Markdown
110 lines
2.2 KiB
Markdown
# otp
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Go library for generating and using One Time Passwords. Supports both HOTP ([RFC4226](https://tools.ietf.org/html/rfc4226)) and TOTP ([RFC6238](https://tools.ietf.org/html/rfc6238)). Can be used for both server and client roles.
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[](https://godoc.org/dev.justinjudd.org/justin/otp)
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## Examples
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### OTP Server
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```go
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import (
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"dev.justinjudd.org/justin/otp"
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)
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var Issuer = "example.com"
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func CreateKeyForUser(user string) {
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opts := otp.NewHOTPKeyOptions()
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opts.Issuer = Issuer
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opts.Label = user
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key := otp.NewHOTPKey(opts)
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keyURL := key.URL()
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Store(user, keyURL)
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// Provide the URL to the customer so they can include it in their 2FA client.
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// Can email URL, or present QR code encoding of the URL
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}
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// Store this string variable in your database
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func Store(user, url string) {
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}
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// Retrieve the url string variable from your database
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func GetURL(user string) string {
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return ""
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}
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func CheckUsersCode(user string, code string) (bool, error) {
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keyURL := GetURL(user)
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key, err := otp.FromURL(keyURL)
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if err != nil {
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return false, err
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}
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// Ensure you are using the correct key
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if key.Label() != user {
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return false, nil
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}
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success := key.Verify(code)
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// Counter has been updated, update this info in the database
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// Don't need this step for TOTP keys as the counter is time-based
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keyURL = key.URL()
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return success, nil
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}
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```
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### OTP Client
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```go
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import (
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"dev.justinjudd.org/justin/otp"
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)
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// Just an example for storing OTP keys on the client
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var keys map[Key]string
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// Key is used as keys for the otp key storing map
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type Key struct {
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Issuer, Label string
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}
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func GetCode(issuer, username string) (string, error) {
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mapKey := Key{issuer, username}
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// Get the stored Key URL
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keyURL, ok := keys[mapKey]
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if !ok {
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return "", nil
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}
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// Build the key from the URL
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key, err := otp.FromURL(keyURL)
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if err != nil {
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return "", err
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}
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// Verify Issuer and Label are correct
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if key.Issuer() != issuer || key.Label() != username {
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return "", nil
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}
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code := key.OTP()
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// If using HOTP, than need to save the state
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keyURL = key.URL()
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keys[mapKey]= keyURL
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return code, nil
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}
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```
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