Busk at 03:18, 30 December 2021

2021-12-30T03:18:26Z

Busk: Created page with "https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af"

2021-12-30T03:16:54Z

Created page with "https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af"

New page

https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af

← Older revision		Revision as of 03:18, 30 December 2021
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	https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af		https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af
		+
		+
		+	```
		+	package main
		+	import (
		+	"crypto/rand"
		+	"crypto/rsa"
		+	"crypto/sha256"
		+	"fmt"
		+	"io"
		+	"os"
		+	)
		+	// RSA
		+	const (
		+	rsaKeySize = 2048
		+	)
		+	type keypair struct {
		+	priv *rsa.PrivateKey
		+	pub *rsa.PublicKey
		+	}
		+	var kp keypair
		+	var ciphertext, signedMessage []byte
		+	var rng io.Reader
		+	func generateKeypair() error {
		+	var err error
		+	kp.priv, err = rsa.GenerateKey(rand.Reader, rsaKeySize)
		+	if err != nil {
		+	return err
		+	}
		+	kp.pub = &kp.priv.PublicKey
		+	return nil
		+	}
		+	func encrypt() {
		+	var err error
		+	secretMessage := []byte("This is the plaintext to be encrypted")
		+	label := []byte("mediumpost")
		+	ciphertext, err = rsa.EncryptOAEP(sha256.New(), rng, kp.pub, secretMessage, label)
		+	if err != nil {
		+	fmt.Fprintf(os.Stderr, "Error from encryption: %s\n", err)
		+	return
		+	}
		+	// Since encryption is a randomized function, ciphertext will be
		+	// different each time.
		+	fmt.Printf("Ciphertext: %x\n", ciphertext)
		+	}
		+	func decrypt() {
		+	label := []byte("mediumpost")
		+	plaintext, err := rsa.DecryptOAEP(sha256.New(), rng, kp.priv, ciphertext, label)
		+	if err != nil {
		+	fmt.Fprintf(os.Stderr, "Error from decryption: %s\n", err)
		+	return
		+	}
		+	fmt.Printf("Plaintext: %s\n", string(plaintext))
		+	}
		+	func sign() {
		+	var err error
		+	message := []byte("This is the plaintext to be signed")
		+	signedMessage, err = rsa.EncryptPKCS1v15(rng, kp.pub, message)
		+	if err != nil {
		+	fmt.Fprintf(os.Stderr, "Error from encryption: %s\n", err)
		+	return
		+	}
		+	fmt.Printf("Signed Message: %x\n", signedMessage)
		+	}
		+	func verify() {
		+	msgVerified, err := rsa.DecryptPKCS1v15(rng, kp.priv, signedMessage)
		+	if err != nil {
		+	fmt.Fprintf(os.Stderr, "Error from decryption: %s\n", err)
		+	return
		+	}
		+	fmt.Printf("Verified Message: %s\n", string(msgVerified))
		+	}
		+	func main() {
		+	// crypto/rand.Reader is a good source of entropy for randomizing
		+	// encryption function.
		+	rng = rand.Reader
		+	// generates pair of keys
		+	generateKeypair()
		+	// encrypt message
		+	encrypt()
		+	// decrypt message
		+	decrypt()
		+	// sign message
		+	sign()
		+	// verify message
		+	verify()
		+	}
		+	```

Rsa go - Revision history

Busk at 03:18, 30 December 2021

Busk: Created page with "https://medium.com/@rafaelescrich/modern-cryptography-using-go-50e85f0f65af"