SymmetricalEncriptionSSI (RFC-016)

Document Maintainers: Andi Gabriel Tan 2024. List of other contributors in Annex. 1.

Copyright: MIT license

Copyright © 2018-2024 Axiologic Research and Contributors.

This document is licensed under MIT license.


SymmetricalEncryptionSSIs are used to encrypt the data bricks from the Brick Storage. Each brick is encrypted using a different SymmetricalEncryptionSSI, in order to make it very difficult for attackers to steal data from DSUs. Special bricks called BrickMaps keep track of each SymmetricalEncryptionSSI along with its associated HashLinkSSIs. They are used to reconstruct DSUs in the client execution environment.

1. SymmetricalEncryptionSSI subtype description with example

It is not possible to derive the SymmetricalEncryptionSSI. There is only one type: ‘se’.

Type Description
se SymmetricalEncryptionSSI is used as a symmetric encryption key to encrypt data from the DSU to the Brick storage when anchoring it to the blockchain. Moreover, it is used to decrypt the bricks from the Brick Storage when reconstructing the DSU in your local execution environment.

2. Type-specific and control substring

The identifier contains the subtype and the domain. That is very important in order to find the correct brick storage and anchoring services associated with the keySSI and the DSU. After these two attributes, we have the type-specific and the control substring. The table below presents the content of these attributes.

Type Type Specific substring Control substring
se An encryption key (by default it is a symmetric key generated with aes-256-gcm algorithm). empty

3. SymmetricalEncryptionSSI specific functions

Function symKey.getEncryptionKey()

Description: Get the encryption key associated with the KeySSI. By default, the encryption key is a symmetric key generated with the aes-256-gcm algorithm (equal to its specific string).


Name Description
String The encryption key.

Function symKey.load(subtype, dlDomain, encryptionKey, control, vn, hint)

Description: Load the SymmetricalEncryptionSSI with your own parameters. If the encryptionKey is empty, it will generate a new one.

Name Type Value Description
subtype string *required The subtype (should be ‘se’).
dlDomain string *required The blockchain domain wanted to be used.
encryptionKey string *required The encryption key you want to use for symmetric encryption of bricks.
If left empty, the function will generate an encryption key for you.
control string *required Should be empty for the SymmetricalEncryptionSSI.
vn (optional) string   The version number of the SymmetricalEncryptionSSI you want to use.
Default value: “v0”.
hint (optional) string   Optional information for the SymmetricalEncryptionSSI resolver.
Default value: undefined.


Name Description
string Return the abbreviation for SymmetricalEncryptionSSI: ‘se’.

Function symKey.getTypeName()

Description: Returns

Name Description
SSITypes.SYMMETRICAL_ENCRYPTION_SSI A string representing the type of the SSI.


  1. Axiologic Research: New content and improvements. Original texts under PharmaLedger Association and Novartis funding. MIT licensed content accordingly with the contracts. Publish and maintain the site.

  2. PharmaLedger Project: Review, feedback, observations, new content, and corrections MIT licensed accordingly with the consortium agreements.

  3. PrivateSky Research Project: MIT licensed content accordingly with the contracts.

Annex 1. Contributors

Current Editors Email
Sînică Alboaie
Cosmin Ursache
Teodor Lupu
Andi-Gabriel Țan
Contributors Axiologic Research Email
Adrian Ganga
Andi-Gabriel Țan
Cosmin Ursache
Daniel Sava
Nicoleta Mihalache
Valentin Gérard
PrivateSky Contributors Email
Alex Sofronie (DPO)
Cosmin Ursache (UAIC)
Daniel Sava (HVS, AQS)
Daniel Visoiu (SGiant)
Lenuța Alboaie (UAIC)
Rafael Mastaleru (RMS)
Sînică Alboaie (UAIC)
Vlad Balmos (Code932)
PharmaLedger Contributors Email
Ana Balan (RMS)
Bogdan Mastahac (RMS)
Cosmin Ursache (RMS)
Rafael Mastaleru (RMS)