signatures: Signatures

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

Signatures

Description

Sign and verify a message digest. RSA supports both MD5 and SHA signatures whereas DSA and EC keys only support SHA. ED25591 can sign any payload so you can set hash to NULL to sign the raw input data.

Usage

signature_create(data, hash = sha1, key = my_key(), password = askpass)

signature_verify(data, sig, hash = sha1, pubkey = my_pubkey())

ecdsa_parse(sig)

ecdsa_write(r, s)

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.
hash	the digest function to use. Must be one of md5(), sha1(), sha256(), sha512() or NULL.
key	private key or file path. See read_key().
password	string or a function to read protected keys. See read_key().
sig	raw vector or file path for the signature data.
pubkey	public key or file path. See read_pubkey().
r	bignum value for r parameter
s	bignum value for s parameter

Details

The ecdsa_parse and ecdsa_write functions convert (EC)DSA signatures between the conventional DER format and the raw ⁠(r,s)⁠ bignum pair. Most users won't need this, it is mostly here to support the JWT format (which does not use DER).

Examples

# Generate a keypair
key <- rsa_keygen()
pubkey <- key$pubkey

# Sign a file
data <- system.file("DESCRIPTION")
sig <- signature_create(data, sha256, key = key)
stopifnot(signature_verify(data, sig, sha256, pubkey = pubkey))

# Sign raw data
data <- serialize(iris, NULL)
sig <- signature_create(data, sha256, key = key)
stopifnot(signature_verify(data, sig, sha256, pubkey = pubkey))

# Sign a hash
md <- md5(data)
sig <- signature_create(md, hash = sha256, key = key)
stopifnot(signature_verify(md, sig, hash = sha256, pubkey = pubkey))
#
# ECDSA example
data <- serialize(iris, NULL)
key <- ec_keygen()
pubkey <- key$pubkey
sig <- signature_create(data, sha256, key = key)
stopifnot(signature_verify(data, sig, sha256, pubkey = pubkey))

# Convert signature to (r, s) parameters and then back
params <- ecdsa_parse(sig)
out <- ecdsa_write(params$r, params$s)
identical(sig, out)

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