revocation

Documentation

Index

• func Blind(password string, payload []byte) ([]byte, error)
• func BlindRevocation(credentialID string, r *ledger.Revocation) ([]byte, error)
• func Unblind(bits []byte, password string) (opened []byte, err error)
• func UnblindRevocation(bits []byte, credentialID string, r *ledger.Revocation) (err error)

Functions

func Blind

func Blind(password string, payload []byte) ([]byte, error)

Blind password-encrypts the supplied byte array. The password and a random 8-byte salt are used as inputs to the PBKDF2 key generation algorithm, and the resulting key plus a random 12-byte nonce are used to encrypt the payload using Galois Counter Mode (GCM) block encryption. The salt and nonce are prepended to the encrypted output, i.e. output = salt + nonce + ciphertext.

func BlindRevocation

func BlindRevocation(credentialID string, r *ledger.Revocation) ([]byte, error)

BlindRevocation password-encrypts the revocation using the credential ID. Why encrypt revocations? If revocations are stored on a public ledger, then it is possible to correlate behaviors of credential issuers by data mining the revocation transactions. The purpose of storing the revocation on the ledger is to provide a strong trust anchor for monitoring the validity of a credential. This is useful in the context of credentials that have been shared by the holder with a set of verifiers. In other words, this information is useful for anybody that has seen the credential--presumably with the permission of the holder. Therefore, we have chosen to use the credential ID as the password, since it is a readily available, unique piece of information.

See Blind for details on the encryption scheme.

func Unblind

func Unblind(bits []byte, password string) (opened []byte, err error)

Unblind decrypts a password-encrypted object using the supplied password.

See Blind for details on the encryption scheme.

func UnblindRevocation

func UnblindRevocation(bits []byte, credentialID string, r *ledger.Revocation) (err error)

UnblindRevocation decrypts a password-encrypted revocation using the credential ID.

See Blind for details on the encryption scheme.