aes_cbc: Symmetric AES encryption

In openssl: Toolkit for Encryption, Signatures and Certificates Based on OpenSSL

Symmetric AES encryption

Description

Low-level symmetric encryption/decryption using the AES block cipher in CBC mode. The key is a raw vector, for example a hash of some secret. When no shared secret is available, a random key can be used which is exchanged via an asymmetric protocol such as RSA. See rsa_encrypt() for a worked example or encrypt_envelope() for a high-level wrapper combining AES and RSA.

Usage

aes_ctr_encrypt(data, key, iv = rand_bytes(16))

aes_ctr_decrypt(data, key, iv = attr(data, "iv"))

aes_cbc_encrypt(data, key, iv = rand_bytes(16))

aes_cbc_decrypt(data, key, iv = attr(data, "iv"))

aes_gcm_encrypt(data, key, iv = rand_bytes(12))

aes_gcm_decrypt(data, key, iv = attr(data, "iv"))

aes_keygen(length = 16)

Arguments

data	raw vector or path to file with data to encrypt or decrypt
key	raw vector of length 16, 24 or 32, e.g. the hash of a shared secret
iv	raw vector of length 16 (aes block size) or NULL. The initialization vector is not secret but should be random
length	how many bytes to generate. Usually 16 (128-bit) or 12 (92-bit) for aes_gcm

Examples

# aes-256 requires 32 byte key
passphrase <- charToRaw("This is super secret")
key <- sha256(passphrase)

# symmetric encryption uses same key for decryption
x <- serialize(iris, NULL)
y <- aes_cbc_encrypt(x, key = key)
x2 <- aes_cbc_decrypt(y, key = key)
stopifnot(identical(x, x2))

openssl documentation built on Sept. 20, 2024, 9:07 a.m.