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Encrypt and decrypt a plaintext with AES-GCM in Go. Plaintext is passed in as command line argument.
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| package main | |
| import ( | |
| "crypto/aes" | |
| "crypto/cipher" | |
| "crypto/rand" | |
| "fmt" | |
| "io" | |
| "os" | |
| ) | |
| func main() { | |
| if len(os.Args) < 2 { | |
| fmt.Println("Usage: aesgcm <plaintext>") | |
| os.Exit(0) | |
| } | |
| fmt.Println("Plaintext = " + os.Args[1]) | |
| // Get plaintext as a byte slice | |
| plaintext := []byte(os.Args[1]) | |
| // Randomly generate a 32 byte (128 bit) AES key | |
| key := make([]byte, 32) | |
| if _, err := io.ReadFull(rand.Reader, key); err != nil { | |
| panic(err.Error()) | |
| } | |
| fmt.Printf("Key = %x\n", key) | |
| // Get an AES cipher instance using the key | |
| block, err := aes.NewCipher(key) | |
| if err != nil { | |
| panic(err.Error()) | |
| } | |
| // Generate a nonce for GCM | |
| nonce := make([]byte, 12) | |
| if _, err := io.ReadFull(rand.Reader, nonce); err != nil { | |
| panic(err.Error()) | |
| } | |
| // Get GCM instance that uses the AES cipher | |
| aesgcm, err := cipher.NewGCM(block) | |
| if err != nil { | |
| panic(err.Error()) | |
| } | |
| // Perform AES-GCM encryption with generated nonce | |
| ciphertext := aesgcm.Seal(nil, nonce, plaintext, nil) | |
| fmt.Printf("Ciphertext = %x\n", ciphertext) | |
| // Now perform decryption of the ciphertext | |
| plaintextNew, err := aesgcm.Open(nil, nonce, ciphertext, nil) | |
| if err != nil { | |
| panic(err.Error()) | |
| } | |
| fmt.Printf("Decrypted Plaintext = %s\n", plaintextNew) | |
| } |
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