Solving the Mysterious Error: “"package crypto/ecdh is not in std" when using gccgo

Are you tired of hitting a roadblock when trying to use the `crypto/ecdh` package with `gccgo`? You’re not alone! The error message “"package crypto/ecdh is not in std"” can be frustrating, especially when you’re new to Go programming. Fear not, dear reader, for we’re about to embark on a journey to overcome this obstacle once and for all!

What is the `crypto/ecdh` package, and why do I need it?

The `crypto/ecdh` package in Go provides functions for Elliptic Curve Diffie-Hellman (ECDH) key exchange. It’s a crucial component in many cryptographic applications, including secure communication protocols and digital signatures. If you’re building a project that requires secure data exchange, you’ll likely need to use the `crypto/ecdh` package.

What is `gccgo`, and why am I using it?

`gccgo` is a Go compiler based on the GNU Compiler Collection (GCC). It’s an alternative to the standard Go compiler, `gc`, and offers some unique features, such as better compatibility with C code. If you’re working on a project that requires seamless integration with C code or libraries, `gccgo` might be the perfect choice.

The Error: “"package crypto/ecdh is not in std"”

Now, let’s dive into the error that’s been plaguing you. When you try to use the `crypto/ecdh` package with `gccgo`, you might encounter the following error message:

$ gccgo -o myprog myprog.go
# command-line-arguments
myprog.go:4:2: fatal error: import "crypto/ecdh" packages "crypto/ecdh" is not in std
 compilation terminated.

This error occurs because the `crypto/ecdh` package is not part of the standard library in `gccgo`. But don’t worry, we’ll explore a few solutions to overcome this hurdle.

Solution 1: Use the `gc` compiler instead of `gccgo`

The simplest solution is to switch to the standard Go compiler, `gc`. Since the `crypto/ecdh` package is part of the standard library in `gc`, you won’t encounter any issues:

$ go build myprog.go
$ ./myprog

However, this solution might not be feasible if you need the specific features and compatibility of `gccgo`.

Solution 2: Use a custom Go build with `GCCGO_EXTERNAL_CRYPT_LIB=1`

Another solution is to build your own custom Go compiler with `gccgo` and enable the external crypto library. Here’s a step-by-step guide:

1. Clone the Go repository:
   git clone https://github.com/golang/go.git
2. Configure the build with GCCGO_EXTERNAL_CRYPT_LIB=1:
   ./make.bash GCCGO_EXTERNAL_CRYPT_LIB=1
3. Build and install the custom Go compiler:
   ./make.bash install
4. Verify the installation:
   $GOROOT/bin/gccgo -v

Once you’ve built and installed the custom Go compiler, you can use it to compile your program:

$ $GOROOT/bin/gccgo -o myprog myprog.go
$ ./myprog

Solution 3: Use a third-party crypto library

If you can’t or don’t want to use the standard `crypto/ecdh` package, consider using a third-party crypto library that provides ECDH functionality. One popular option is the `github.com/gtank/crypto` package:

$ go get -u github.com/gtank/crypto/...

In your code, import the package and use its ECDH functions:

package main

import (
    "fmt"
    "github.com/gtank/crypto/ecdh"
)

func main() {
    // Use the ecdh package from github.com/gtank/crypto
    curve, _ := ecdh.NewCurve(ecdh.P256())
    priv, _ := curve.GenerateKey(nil)
    pub := priv.Public().(*ecdh.PublicKey)
    fmt.Println(pub.X, pub.Y)
}

Conclusion

In this article, we’ve explored the error “"package crypto/ecdh is not in std"” when using `gccgo` and presented three solutions to overcome it. Whether you choose to use the `gc` compiler, build a custom Go compiler with `gccgo`, or opt for a third-party crypto library, you’re now equipped to tackle ECDH-related projects with confidence!

Additional Resources

For further reading and exploration, check out these resources:

• Go Documentation: crypto/ecdh package
• GCCGo Documentation
• github.com/gtank/crypto: A Go library for elliptic curve cryptography

Stay curious, stay coding, and happy crypting!

Frequently Asked Question

Get answers to the most frequently asked questions about “"package crypto/ecdh is not in std" when using gccgo”