//  2. the server certificate in response contains no SAN. This indicates that this binary run
//     with the GODEBUG=x509ignoreCN=0 in env
//
// It increases the `sha1` counter whenever:
//  1. we get a x509.InsecureAlgorithmError with string `SHA1`
//     which indicates an error caused by an insecure SHA1 signature
//  2. the server certificate in response contains a SHA1WithRSA or ECDSAWithSHA1 signature.

pkg crypto/tls, type RecordHeaderError struct, Msg string
pkg crypto/tls, type RecordHeaderError struct, RecordHeader [5]uint8
pkg crypto/x509, method (InsecureAlgorithmError) Error() string
pkg crypto/x509, method (SignatureAlgorithm) String() string
pkg crypto/x509, type InsecureAlgorithmError int
pkg database/sql, method (*DB) SetConnMaxLifetime(time.Duration)
pkg debug/dwarf, const ClassUnknown = 0
pkg debug/dwarf, const ClassUnknown Class

// An InsecureAlgorithmError indicates that the [SignatureAlgorithm] used to
// generate the signature is not secure, and the signature has been rejected.
//
// To temporarily restore support for SHA-1 signatures, include the value
// "x509sha1=1" in the GODEBUG environment variable. Note that this option will
// be removed in a future release.
type InsecureAlgorithmError SignatureAlgorithm

	}
	if err = cert.CheckSignatureFrom(cert); err == nil {
		t.Fatalf("certificate verification succeeded incorrectly")
	}
	if _, ok := err.(InsecureAlgorithmError); !ok {
		t.Fatalf("certificate verification returned %v (%T), wanted InsecureAlgorithmError", err, err)
	}
}

func TestSHA1(t *testing.T) {
	pemBlock, _ := pem.Decode([]byte(ecdsaSHA1CertPem))
	cert, err := ParseCertificate(pemBlock.Bytes)

There is no plan to remove this setting.

### Go 1.18

Go 1.18 removed support for SHA1 in most X.509 certificates,
controlled by the [`x509sha1` setting](/pkg/crypto/x509#InsecureAlgorithmError).
This setting will be removed in a future release, Go 1.22 at the earliest.

### Go 1.10

Go 1.10 changed how build caching worked and added test caching, along

		{"(*RevocationList).CheckSignatureFrom", Method, 19},
		{"(CertificateInvalidError).Error", Method, 0},
		{"(ConstraintViolationError).Error", Method, 0},
		{"(HostnameError).Error", Method, 0},
		{"(InsecureAlgorithmError).Error", Method, 6},
		{"(OID).Equal", Method, 22},
		{"(OID).EqualASN1OID", Method, 22},
		{"(OID).String", Method, 22},
		{"(PublicKeyAlgorithm).String", Method, 10},