securitypolicy

Documentation

Overview

Package securitypolicy implements the encryption, decryption, signing, and signature verifying algorithms for Security Policy profiles as defined in Part 7 of the OPC-UA specifications (version 1.04)

Index

• func SupportedPolicies() []string
• type EncryptionAlgorithm
  • func Asymmetric(policyURI string, localKey *rsa.PrivateKey, remoteKey *rsa.PublicKey) (*EncryptionAlgorithm, error)
  • func Symmetric(policyURI string, localNonce []byte, remoteNonce []byte) (*EncryptionAlgorithm, error)
  • func (e *EncryptionAlgorithm) BlockSize() int
  • func (e *EncryptionAlgorithm) Decrypt(ciphertext []byte) (cleartext []byte, err error)
  • func (e *EncryptionAlgorithm) Encrypt(cleartext []byte) (ciphertext []byte, err error)
  • func (e *EncryptionAlgorithm) EncryptionURI() string
  • func (e *EncryptionAlgorithm) MinPadding() int
  • func (e *EncryptionAlgorithm) Signature(message []byte) (signature []byte, err error)
  • func (e *EncryptionAlgorithm) SignatureLength() int
  • func (e *EncryptionAlgorithm) SignatureURI() string
  • func (e *EncryptionAlgorithm) VerifySignature(message, signature []byte) error

Functions

func SupportedPolicies

func SupportedPolicies() []string

SupportedPolicies returns all supported Security Policies (and therefore, valid inputs to Asymmetric(...) and Symmetric(...))

Types

type EncryptionAlgorithm

type EncryptionAlgorithm struct {
	// contains filtered or unexported fields
}

EncryptionAlgorithm wraps the functions used to return the various methods required to implement the symmetric and asymmetric algorithms Function variables were used instead of an interface to make better use of policies which implement the same algorithms in different combinations

EncryptionAlgorithm should always be instantiated through calls to SecurityPolicy.Symmetric() and SecurityPolicy.Asymmetric() to ensure correct behavior. The zero value of this struct will use SecurityPolicy#None although using in this manner is discouraged for readability

func Asymmetric

func Asymmetric(policyURI string, localKey *rsa.PrivateKey, remoteKey *rsa.PublicKey) (*EncryptionAlgorithm, error)

Asymmetric returns the EncryptionAlgorithm struct seeded with the required public and private RSA keys to fully implement. For Security Policy "None", both keys are ignored and may be nil

func Symmetric

func Symmetric(policyURI string, localNonce []byte, remoteNonce []byte) (*EncryptionAlgorithm, error)

Symmetric returns the EncryptionAlgorithm struct seeded with the client and server nonces negotiated from the OpenSecureChannel service (encrypted by the Asymmetric algorithms) For Security Policy "None", both nonces are ignored and may be nil

func (*EncryptionAlgorithm) BlockSize

func (e *EncryptionAlgorithm) BlockSize() int

BlockSize returns the underlying encryption algorithm's blocksize. Used to calculate the padding required to make the cleartext an even multiple of the blocksize

func (*EncryptionAlgorithm) Decrypt

func (e *EncryptionAlgorithm) Decrypt(ciphertext []byte) (cleartext []byte, err error)

Decrypt decrypts the input ciphertext based on the algorithms and keys passed in

func (*EncryptionAlgorithm) Encrypt

func (e *EncryptionAlgorithm) Encrypt(cleartext []byte) (ciphertext []byte, err error)

Encrypt encrypts the input cleartext based on the algorithms and keys passed in

func (*EncryptionAlgorithm) EncryptionURI

func (e *EncryptionAlgorithm) EncryptionURI() string

EncryptionURI returns the URI for the encryption algorithm as defined by the OPC-UA profiles in Part 7

func (*EncryptionAlgorithm) MinPadding

func (e *EncryptionAlgorithm) MinPadding() int

MinPadding returns the underlying encryption algorithm's minimum padding. Used to calculate the maximum plaintext blocksize that can be fed into the encryption algorithm.

func (*EncryptionAlgorithm) Signature

func (e *EncryptionAlgorithm) Signature(message []byte) (signature []byte, err error)

Signature returns the cryptographic signature of message

func (*EncryptionAlgorithm) SignatureLength

func (e *EncryptionAlgorithm) SignatureLength() int

SignatureLength returns the length in bytes for the signature algorithm

func (*EncryptionAlgorithm) SignatureURI

func (e *EncryptionAlgorithm) SignatureURI() string

SignatureURI returns the URI for the signature algorithm as defined by the OPC-UA profiles in Part 7

func (*EncryptionAlgorithm) VerifySignature

func (e *EncryptionAlgorithm) VerifySignature(message, signature []byte) error

VerifySignature validates that 'signature' is the correct cryptographic signature of 'message' or returns an error. A return value of nil means the signature is valid