Update documentation (#63)

CHANGELOG.md

@@ -26,6 +26,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 (key *Key) GetEntity() *openpgp.Entity
 ```
 
+- Helpers for binary message encryption and decryption
+```go
+EncryptBinaryMessageArmored(key string, data []byte) (string, error)
+DecryptBinaryMessageArmored(privateKey string, passphrase []byte, ciphertext string) ([]byte, error)
+```
+
 ### Changed
 - Improved key and message armoring testing
 - `EncryptSessionKey` now creates encrypted key packets for each valid encryption key in the provided keyring. 
@@ -33,7 +39,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - Public key armoring headers
-
+- `EncryptSessionKey` throws an error when invalid encryption keys are provided
+- Session keys' size is now checked against the expected value to prevent panics
+ 
 ## [2.0.1] - 2020-05-01
 ### Security
 - Updated underlying crypto library

README.md

@@ -151,13 +151,13 @@ const passphrase = []byte(`the passphrase of the private key`) // Passphrase of
 // encrypt plain text message using public key
 armor, err := helper.EncryptMessageArmored(pubkey, "plain text")
 
+// decrypt armored encrypted message using the private key and obtain plain text
+decrypted, err := helper.DecryptMessageArmored(privkey, passphrase, armor)
+
 // encrypt binary message using public key
 armor, err := helper.EncryptBinaryMessageArmored(pubkey, []byte("plain text"))
 
-// decrypt armored encrypted message using the private key and got plain text
-decrypted, err := helper.DecryptMessageArmored(privkey, passphrase, armor)
-
-// decrypt armored encrypted message using the private key and got binary
+// decrypt armored encrypted message using the private key expecting binary data
 decrypted, err := helper.DecryptBinaryMessageArmored(privkey, passphrase, armor)
 ```
 
@@ -173,7 +173,7 @@ armor, err := helper.EncryptSignMessageArmored(pubkey, privkey, passphrase, "pla
 decrypted, err := helper.DecryptVerifyMessageArmored(pubkey, privkey, passphrase, armor)
 ```
 
-With binary data or advanced modes:
+For more advanced modes the full API (i.e. without helpers) can be used:
 ```go
 // Keys initialization as before (omitted)
 var binMessage = crypto.NewPlainMessage(data)