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Made CalculateTOTP public + new function for NewTOTP but with existing secret

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This commit is contained in:
Dennis Paul 2022-08-28 19:05:08 +02:00
parent 987ec860c3
commit 759f640132
2 changed files with 20 additions and 8 deletions
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22
totp.go
View File

@ -112,6 +112,18 @@ func makeTOTP(key []byte, account, issuer string, hash crypto.Hash, digits int)
return otp, nil return otp, nil
} }
func NewTOTPWithKey(key []byte, account, issuer string, hash crypto.Hash, digits int) (*Totp, error) {
otp := new(Totp)
otp.key = key
otp.account = account
otp.issuer = issuer
otp.digits = digits
otp.stepSize = 30 // we set it to 30 seconds which is the recommended value from the RFC
otp.clientOffset = 0
otp.hashFunction = hash
return otp, nil
}
// This function validates the user provided token // This function validates the user provided token
// It calculates 3 different tokens. The current one, one before now and one after now. // It calculates 3 different tokens. The current one, one before now and one after now.
// The difference is driven by the TOTP step size // The difference is driven by the TOTP step size
@ -149,9 +161,9 @@ func (otp *Totp) Validate(userCode string) error {
// 1 calculate the 3 tokens // 1 calculate the 3 tokens
tokens := make([]string, 3) tokens := make([]string, 3)
token0Hash := sha256.Sum256([]byte(calculateTOTP(otp, -1))) token0Hash := sha256.Sum256([]byte(CalculateTOTP(otp, -1)))
token1Hash := sha256.Sum256([]byte(calculateTOTP(otp, 0))) token1Hash := sha256.Sum256([]byte(CalculateTOTP(otp, 0)))
token2Hash := sha256.Sum256([]byte(calculateTOTP(otp, 1))) token2Hash := sha256.Sum256([]byte(CalculateTOTP(otp, 1)))
tokens[0] = hex.EncodeToString(token0Hash[:]) // 30 seconds ago token tokens[0] = hex.EncodeToString(token0Hash[:]) // 30 seconds ago token
tokens[1] = hex.EncodeToString(token1Hash[:]) // current token tokens[1] = hex.EncodeToString(token1Hash[:]) // current token
@ -219,12 +231,12 @@ func (otp *Totp) OTP() (string, error) {
} }
// it uses the index 0, meaning that it calculates the current one // it uses the index 0, meaning that it calculates the current one
return calculateTOTP(otp, 0), nil return CalculateTOTP(otp, 0), nil
} }
// Private function which calculates the OTP token based on the index offset // Private function which calculates the OTP token based on the index offset
// example: 1 * steps or -1 * steps // example: 1 * steps or -1 * steps
func calculateTOTP(otp *Totp, index int) string { func CalculateTOTP(otp *Totp, index int) string {
var h hash.Hash var h hash.Hash
switch otp.hashFunction { switch otp.hashFunction {

6
totp_test.go
View File

@ -355,17 +355,17 @@ func TestCounterSynchronization(t *testing.T) {
t.Fatal(err) t.Fatal(err)
} }
token0 := calculateTOTP(otp, 0) token0 := CalculateTOTP(otp, 0)
if err != nil { if err != nil {
t.Fatal(err) t.Fatal(err)
} }
token_1 := calculateTOTP(otp, -1) token_1 := CalculateTOTP(otp, -1)
if err != nil { if err != nil {
t.Fatal(err) t.Fatal(err)
} }
token1 := calculateTOTP(otp, 1) token1 := CalculateTOTP(otp, 1)
if err != nil { if err != nil {
t.Fatal(err) t.Fatal(err)
} }