OUR SITES NetworkRADIUS FreeRADIUS

Cipher Module

The cipher module is used to transform plaintext in some way that is dependent on a key or key pair, producing encrypted ciphertext.

Registers the following expansions:

XLAT Description

%<inst>_encrypt(<plaintext>…​)

Encrypts plaintext using certificate_file

%<inst>_decrypt(<ciphertext>…​)

Decrypts ciphertext using private_key_file

%<inst>_sign(<plaintext>…​)

Signs plaintext using private_key_file

%<inst>_verify(<signature>, <plaintext>…​)

Validates a signature using certificate_file

%<inst>_certificate(serial)

Returns the serial of certificate_file

%<inst>_certificate(fingerprint, <hash>)

Produces a fingerprint of certificate_file using the specified hash.

%<inst>_certificate(not_before)

Retrieves the notBefore time from certificate_file.

%<inst>_certificate(not_after)

Retrieves the notAfter time from certificate_file.
<ciphertext> and <signature> are ingested and excreted to in their raw form. You should use armouring expansions i.e. %base64.encode(…​), %base64.decode(…​) if the values are to be passed outside of FreeRADIUS.

e.g:

%base64.encode(%cipher_encrypt(<plaintext>))
%cipher_decrypt(%base64.decode(<ciphertext>))
The supported versions are determined entirely by the version of OpenSSL used, we pass the name of the digest off to OpenSSL and it tells us whether it’s valid/supported or not.

OpenSSL >= 1.0.0 should support at least:

  • md2 (not recommended)

  • md4 (not recommended)

  • md5 (not recommended)

  • sha1 (widely used but deprecated)

  • sha224

  • sha256 (the default)

  • sha384

  • sha512

OpenSSL >= 1.1.1 also supports the sha3 family of digest functions.

  • sha3_224

  • sha3_256

  • sha3_384

  • sha3_512

Configuration Settings

type

Available schemes are:

  • rsa

RSA asymmetrically keyed ciphering

private_key_password

Private key used for decrypting and signing data.

certificate_file

The PEM encoded certificate used for encrypting data and verifying signatures.

verify_mode

How we verify certificate_file on startup

After reading the certificate file from disk and parsing it we can apply other checks to ensure it is valid. Currently we check the notBefore and notAfter fields to ensure the certificate is temporally valid. Key use checks may be added in future.

Error Description

hard

Error out if the certificate is not yet valid or has expired.

soft

Warn if the certificate is not yet valid or has expired.

none

Stay silent if the certificate is not yet valid.

The default is hard.

oaep { …​ }

Parameters for the OAEP RSA padding scheme.

signature_digest

Digest used to ingest the plaintext before signing or verification.

padding_type

The type of padding applied to the plaintext being one of:

  • none (no padding)

  • pkcs

  • oaep

  • x931 (signing only)

  • ssl (v1/v2)

Defaults to pkcs.
random_file

Provides random number generator.

Default Configuration

cipher {
	type = rsa
	rsa {
		private_key_password = whatever
		private_key_file = ${certdir}/rsa/server.pem
		certificate_file = ${certdir}/rsa/server.pem
#		verify_mode = "hard"
		oaep {
#			oaep_digest = "sha256"
#			mgf1_digest = "sha256"
#			label = ""
		}
#		signature_digest = "sha256"
#		padding_type = pkcs
#		random_file = /dev/urandom
	}
}