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package cose_test
import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
_ "crypto/sha512"
"fmt"
"github.com/veraison/go-cose"
)
// This example demonstrates signing and verifying COSE_Sign signatures.
//
// The COSE Sign API is EXPERIMENTAL and may be changed or removed in a later
// release.
func ExampleSignMessage() {
// create a signature holder
sigHolder := cose.NewSignature()
sigHolder.Headers.Protected.SetAlgorithm(cose.AlgorithmES512)
sigHolder.Headers.Unprotected[cose.HeaderLabelKeyID] = []byte("1")
// create message to be signed
msgToSign := cose.NewSignMessage()
msgToSign.Payload = []byte("hello world")
msgToSign.Signatures = append(msgToSign.Signatures, sigHolder)
// create a signer
privateKey, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
panic(err)
}
signer, err := cose.NewSigner(cose.AlgorithmES512, privateKey)
if err != nil {
panic(err)
}
// sign message
err = msgToSign.Sign(rand.Reader, nil, signer)
if err != nil {
panic(err)
}
sig, err := msgToSign.MarshalCBOR()
if err != nil {
panic(err)
}
fmt.Println("message signed")
// create a verifier from a trusted public key
publicKey := privateKey.Public()
verifier, err := cose.NewVerifier(cose.AlgorithmES512, publicKey)
if err != nil {
panic(err)
}
// verify message
var msgToVerify cose.SignMessage
err = msgToVerify.UnmarshalCBOR(sig)
if err != nil {
panic(err)
}
err = msgToVerify.Verify(nil, verifier)
if err != nil {
panic(err)
}
fmt.Println("message verified")
// tamper the message and verification should fail
msgToVerify.Payload = []byte("foobar")
err = msgToVerify.Verify(nil, verifier)
if err != cose.ErrVerification {
panic(err)
}
fmt.Println("verification error as expected")
// Output:
// message signed
// message verified
// verification error as expected
}
// This example demonstrates signing and verifying COSE_Sign1 signatures.
func ExampleSign1Message() {
// create message to be signed
msgToSign := cose.NewSign1Message()
msgToSign.Payload = []byte("hello world")
msgToSign.Headers.Protected.SetAlgorithm(cose.AlgorithmES512)
msgToSign.Headers.Unprotected[cose.HeaderLabelKeyID] = []byte("1")
// create a signer
privateKey, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
panic(err)
}
signer, err := cose.NewSigner(cose.AlgorithmES512, privateKey)
if err != nil {
panic(err)
}
// sign message
err = msgToSign.Sign(rand.Reader, nil, signer)
if err != nil {
panic(err)
}
sig, err := msgToSign.MarshalCBOR()
if err != nil {
panic(err)
}
fmt.Println("message signed")
// create a verifier from a trusted public key
publicKey := privateKey.Public()
verifier, err := cose.NewVerifier(cose.AlgorithmES512, publicKey)
if err != nil {
panic(err)
}
// verify message
var msgToVerify cose.Sign1Message
err = msgToVerify.UnmarshalCBOR(sig)
if err != nil {
panic(err)
}
err = msgToVerify.Verify(nil, verifier)
if err != nil {
panic(err)
}
fmt.Println("message verified")
// tamper the message and verification should fail
msgToVerify.Payload = []byte("foobar")
err = msgToVerify.Verify(nil, verifier)
if err != cose.ErrVerification {
panic(err)
}
fmt.Println("verification error as expected")
// Output:
// message signed
// message verified
// verification error as expected
}
// This example demonstrates signing COSE_Sign1_Tagged signatures using Sign1().
func ExampleSign1() {
// create a signer
privateKey, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
panic(err)
}
signer, err := cose.NewSigner(cose.AlgorithmES512, privateKey)
if err != nil {
panic(err)
}
// sign message
headers := cose.Headers{
Protected: cose.ProtectedHeader{
cose.HeaderLabelAlgorithm: cose.AlgorithmES512,
},
Unprotected: cose.UnprotectedHeader{
cose.HeaderLabelKeyID: []byte("1"),
},
}
sig, err := cose.Sign1(rand.Reader, signer, headers, []byte("hello world"), nil)
if err != nil {
panic(err)
}
fmt.Println("message signed")
_ = sig // further process on sig
// Output:
// message signed
}
// This example demonstrates signing COSE_Sign1 signatures using Sign1Untagged().
func ExampleSign1Untagged() {
// create a signer
privateKey, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
if err != nil {
panic(err)
}
signer, err := cose.NewSigner(cose.AlgorithmES512, privateKey)
if err != nil {
panic(err)
}
// sign message
headers := cose.Headers{
Protected: cose.ProtectedHeader{
cose.HeaderLabelAlgorithm: cose.AlgorithmES512,
},
Unprotected: cose.UnprotectedHeader{
cose.HeaderLabelKeyID: []byte("1"),
},
}
sig, err := cose.Sign1Untagged(rand.Reader, signer, headers, []byte("hello world"), nil)
if err != nil {
panic(err)
}
fmt.Println("message signed")
_ = sig // further process on sig
// Output:
// message signed
}
|
