Envelope encryption

An envelope contains ciphertext along with an encrypted session key and optionally and initialization vector. The encrypt_envelope() generates a random IV and session-key which is used to encrypt the data with AES() stream cipher. The session key itself is encrypted using the given RSA key (see rsa_encrypt()) and stored or sent along with the encrypted data. Each of these outputs is required to decrypt the data with the corresponding private key.

Usage

encrypt_envelope(data, pubkey = my_pubkey())

decrypt_envelope(data, iv, session, key = my_key(), password)

Arguments

data

raw data vector or file path for message to be signed. If hash == NULL then data must be a hash string or raw vector.

pubkey

public key or file path. See read_pubkey().

iv

16 byte raw vector returned by encrypt_envelope.

session

raw vector with encrypted session key as returned by encrypt_envelope.

key

private key or file path. See read_key().

password

string or a function to read protected keys. See read_key().

References

https://wiki.openssl.org/index.php/EVP_Asymmetric_Encryption_and_Decryption_of_an_Envelope

Examples

# Requires RSA key
key <- rsa_keygen()
pubkey <- key$pubkey
msg <- serialize(iris, NULL)

# Encrypt
out <- encrypt_envelope(msg, pubkey)
str(out)
#> List of 3
#>  $ iv     : raw [1:16] 5f dd f5 7f ...
#>  $ session: raw [1:256] 00 79 17 6a ...
#>  $ data   : raw [1:5808] 86 38 7b d7 ...

# Decrypt
orig <- decrypt_envelope(out$data, out$iv, out$session, key)
stopifnot(identical(msg, orig))