mirror of
https://github.com/Luzifer/go-dhparam.git
synced 2024-11-08 15:20:03 +00:00
104 lines
2.4 KiB
Go
104 lines
2.4 KiB
Go
package dhparam
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import (
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"math/big"
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"github.com/pkg/errors"
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)
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const dh_check_p_not_prime = 0x01
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const dh_check_p_not_safe_prime = 0x02
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const dh_unable_to_check_generator = 0x04
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const dh_not_suitable_generator = 0x08
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const dh_check_q_not_prime = 0x10
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const dh_check_invalid_q_value = 0x20
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const dh_check_invalid_j_value = 0x40
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// ErrAllParametersOK is defined to check whether the returned error from Check is indeed no error
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// For simplicity reasons it is defined as an error instead of an additional result parameter
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var ErrAllParametersOK = errors.New("DH parameters appear to be ok.")
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// Check returns a number of errors and an "ok" bool. If the "ok" bool is set to true, still one
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// error is returned: ErrAllParametersOK. If "ok" is false, the error list will contain at least
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// one error not being equal to ErrAllParametersOK.
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func (d DH) Check() ([]error, bool) {
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var (
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result = []error{}
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ok = true
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)
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i := d.check()
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if i&dh_check_p_not_prime > 0 {
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result = append(result, errors.New("WARNING: p value is not prime"))
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ok = false
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}
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if i&dh_check_p_not_safe_prime > 0 {
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result = append(result, errors.New("WARNING: p value is not a safe prime"))
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ok = false
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}
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if i&dh_check_q_not_prime > 0 {
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result = append(result, errors.New("WARNING: q value is not a prime"))
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ok = false
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}
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if i&dh_check_invalid_q_value > 0 {
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result = append(result, errors.New("WARNING: q value is invalid"))
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ok = false
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}
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if i&dh_check_invalid_j_value > 0 {
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result = append(result, errors.New("WARNING: j value is invalid"))
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ok = false
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}
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if i&dh_unable_to_check_generator > 0 {
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result = append(result, errors.New("WARNING: unable to check the generator value"))
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ok = false
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}
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if i&dh_not_suitable_generator > 0 {
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result = append(result, errors.New("WARNING: the g value is not a generator"))
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ok = false
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}
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if i == 0 {
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result = append(result, ErrAllParametersOK)
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}
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return result, ok
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}
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func (d DH) check() int {
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var ret int
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// Check generator
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switch d.G {
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case 2:
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l := new(big.Int)
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if l.Mod(d.P, big.NewInt(24)); l.Int64() != 11 {
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ret |= DH_NOT_SUITABLE_GENERATOR
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}
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case 5:
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l := new(big.Int)
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if l.Mod(d.P, big.NewInt(10)); l.Int64() != 3 && l.Int64() != 7 {
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ret |= DH_NOT_SUITABLE_GENERATOR
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}
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default:
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ret |= DH_UNABLE_TO_CHECK_GENERATOR
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}
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if !d.P.ProbablyPrime(1) {
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ret |= DH_CHECK_P_NOT_PRIME
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} else {
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t1 := new(big.Int)
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t1.Rsh(d.P, 1)
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if !t1.ProbablyPrime(1) {
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ret |= DH_CHECK_P_NOT_SAFE_PRIME
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}
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}
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return ret
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}
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