openssl (version 2.3.0)

rsa_encrypt: Low-level RSA encryption

Description

Asymmetric encryption and decryption with RSA. Because RSA can only encrypt messages smaller than the size of the key, it is typically used only for exchanging a random session-key. This session key is used to encipher arbitrary sized data via a stream cipher such as aes_cbc. See encrypt_envelope or pkcs7_encrypt for a high-level wrappers combining RSA and AES in this way.

Usage

rsa_encrypt(data, pubkey = my_pubkey(), oaep = FALSE)
rsa_decrypt(data, key = my_key(), password = askpass, oaep = FALSE)

Arguments

data

raw vector of max 245 bytes (for 2048 bit keys) with data to encrypt/decrypt

pubkey

public key or file path. See read_pubkey().

oaep

if TRUE, changes padding to EME-OAEP as defined in PKCS #1 v2.0

key

private key or file path. See read_key().

password

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

Examples

# Generate test keys
key <- rsa_keygen()
pubkey <- key$pubkey

# Encrypt data with AES
tempkey <- rand_bytes(32)
iv <- rand_bytes(16)
blob <- aes_cbc_encrypt(system.file("CITATION"), tempkey, iv = iv)

# Encrypt tempkey using receivers public RSA key
ciphertext <- rsa_encrypt(tempkey, pubkey)

# Receiver decrypts tempkey from private RSA key
tempkey <- rsa_decrypt(ciphertext, key)
message <- aes_cbc_decrypt(blob, tempkey, iv)
out <- rawToChar(message)