crypto/x509:x509.ParsePKCS1PrivateKey pkcs1 length 2048 error

[itcuihao]

What version of Go are you using (go version)?

$ go version
go version go1.12.5 windows/amd64

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GOARCH=amd64
set GOBIN=D:\mygo\bin;D:\mygo\src\golang.org\x\tools\cmd\present;
set GOCACHE=C:\Users\abc\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=D:\mygo
set GOPROXY=
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\haoc7\AppData\Local\Temp\go-build109643150=/tmp/go-build -gno-record-gcc-switches

What did you do?

pkcs1 private_key length 2048

func ParsePKCS1PrivateKey(data []byte) (key *rsa.PrivateKey, err error) {
	var block *pem.Block
	block, _ = pem.Decode(data)
	if block == nil {
		return nil, errors.New("private key error")
	}

	key, err = x509.ParsePKCS1PrivateKey(block.Bytes)
	if err != nil {
		return nil, err
	}

	return key, err
}

What did you expect to see?

err is nil

What did you see instead?

ERROR

asn1: structure error: tags don't match (2 vs {class:0 tag:16 length:13 isCompound:true}) {optional:false explicit:false application:false private:false defaultValue:<nil> tag:<nil> stringType:0 timeType:0 set:false omitEmpty:false}  @5