README
¶
bletchley 
Bletchley is a simple command line application for basic public key based file exchange.
Usage
Suppose Alice has a file of secret information that she wants to share with her coworker, Bob. They regularly communicate, so authentication is not an issue. The issue is that Alice does not want her secrets to be in some email attachment, Slack history, or S3 bucket for an indefinite period of time, and she doesn't necessarily trust the network not to eavesdrop on her file exchange. Alice and Bob agree to exchange the file using bletchley.
- Alice asks Bob to run
bletchley-createto create a public/private key pair for himself. - Bob sends Alice his
public.pemfile through their normal communication channel. She saves it asbob.pem. - Alice runs
bletchley-encode -key-src bob.pem -msg-src secrets.txt -cipher-dest secrets.pem. - Alice sends Bob her
secrets.pemfile through their normal communication channel. - Bob runs
bletchley-decode -key-src private.pem -cipher-src secrets.pem -msg-dst secrets.txt. - Alice and Bob go back to work.
Installation
First install Go.
If you just want to install the binary to your current directory and don't care about the source code, run
GOBIN="$(pwd)" GOPATH="$(mktemp -d)" go get github.com/carlmjohnson/bletchley/...
Screenshots
$ bletchley-create -h
bletchley-create generates a new public/private RSA key pair.
Use -src to extract the public component out of an existing private key PEM
file. In that case, -bit-size and -private-dest will be ignored.
Usage of bletchley-create:
-bit-size int
bit size for RSA key (default 4096)
-private-dest string
file to save private key to (default "private.pem")
-public-dest string
file to save public key to (default "public.pem")
-src string
private key to extract public key from
$ bletchley-encode -h
bletchley-encode generates a one time use password and encodes it with a public
RSA key so that only the possessor of the private key can decode it, then
encodes the message with the one time use password.
Usage of bletchley-encode:
-cipher-dest string
file to save encrypted ciphertext into (default "cipher.pem")
-key-src string
public key to encode message with (default "public.pem")
-msg-src string
file to encrypt (default "-")
$ bletchley-decode -h
bletchley-decode decodes a bletchley cipher PEM file.
Usage of bletchley-decode:
-cipher-src string
file to decrypt (default "cipher.pem")
-key-src string
private key to decode cipher with (default "private.pem")
-msg-dest string
file to save decrypted message into (default "-")
Bob $ bletchley-create -private-dest private.pem -public-dest public.pem
... Bob sends public.pem ...
Alice $ bletchley-encode -key-src public.pem -msg-src <(echo 'Hello, World!') -cipher-dest cipher.txt
... Alice sends cipher.txt ...
Bob $ bletchley-decode -key-src private.pem -cipher-src cipher.txt
Hello, World!
Acknowledgements
Bletchley is based on code from github.com/gtank/cryptopasta/.
Documentation
¶
Index ¶
- func DecodeMessage(key, ciphertext []byte, prv *rsa.PrivateKey) ([]byte, error)
- func DecodeMessagePEM(w io.Writer, cipherpems []byte, prv *rsa.PrivateKey) error
- func DecodePEMType(pemContents []byte, blockType string) ([]byte, error)
- func DecodePrivateKeyPEM(pemContents []byte) (*rsa.PrivateKey, error)
- func DecodePublicKeyPEM(pemContents []byte) (*rsa.PublicKey, error)
- func Decrypt(ciphertext []byte, key *[32]byte) (plaintext []byte, err error)
- func EncodeMessage(plaintext []byte, pub *rsa.PublicKey) (otp *[32]byte, key, ciphertext []byte, err error)
- func EncodeMessagePEM(w io.Writer, plaintext []byte, pub *rsa.PublicKey) error
- func EncodePrivateKeyPEM(w io.Writer, key *rsa.PrivateKey) error
- func EncodePublicKeyPEM(w io.Writer, key *rsa.PublicKey) error
- func Encrypt(plaintext []byte, key *[32]byte) (ciphertext []byte, err error)
- func NewEncryptionKey() *[32]byte
- func NewRSAPrivateKey(bitSize int) *rsa.PrivateKey
- func ReadPrivateKeyPEM(fileName string) (*rsa.PrivateKey, error)
- func ReadPublicKeyPEM(fileName string) (*rsa.PublicKey, error)
- func SavePrivateKeyPEM(fileName string, key *rsa.PrivateKey) error
- func SavePublicKeyPEM(fileName string, key *rsa.PublicKey) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DecodeMessage ¶
func DecodeMessage(key, ciphertext []byte, prv *rsa.PrivateKey) ([]byte, error)
func DecodeMessagePEM ¶
func DecodePrivateKeyPEM ¶
func DecodePrivateKeyPEM(pemContents []byte) (*rsa.PrivateKey, error)
func Decrypt ¶
Decrypt decrypts data using 256-bit AES-GCM. This both hides the content of the data and provides a check that it hasn't been altered. Expects input form nonce|ciphertext|tag where '|' indicates concatenation.
func EncodeMessage ¶
func EncodeMessagePEM ¶
func EncodePrivateKeyPEM ¶
func EncodePrivateKeyPEM(w io.Writer, key *rsa.PrivateKey) error
func Encrypt ¶
Encrypt encrypts data using 256-bit AES-GCM. This both hides the content of the data and provides a check that it hasn't been altered. Output takes the form nonce|ciphertext|tag where '|' indicates concatenation.
func NewEncryptionKey ¶
func NewEncryptionKey() *[32]byte
NewEncryptionKey generates a random 256-bit key for Encrypt() and Decrypt(). It panics if the source of randomness fails.
func NewRSAPrivateKey ¶
func NewRSAPrivateKey(bitSize int) *rsa.PrivateKey
func ReadPrivateKeyPEM ¶
func ReadPrivateKeyPEM(fileName string) (*rsa.PrivateKey, error)
func SavePrivateKeyPEM ¶
func SavePrivateKeyPEM(fileName string, key *rsa.PrivateKey) error
Types ¶
This section is empty.
Source Files
Directories