# AEON GP Encryption v1 Convention identifier: `aeon.gp.encryption.v1` --- ## 1. Purpose `aeon.gp.encryption.v1` defines a minimal structure for representing encrypted AEON payloads inside `aeon:envelope`. It allows AEON documents to carry confidential data while preserving the deterministic document model. This convention is designed to work with: - `aeon.gp.security.v1` - `aeon.gp.integrity.v1` - `aeon.gp.signature.v1` --- ## 2. Scope `aeon.gp.encryption.v1` defines: - where encrypted content lives - how ciphertext is represented - how recipient keys are identified - minimal encryption metadata It does **not** define: - key exchange protocols - trust models - certificate infrastructure - algorithm approval policies --- ## 3. Encryption Model Encryption replaces the plaintext body with ciphertext while preserving the AEON document structure. The envelope carries: - encryption algorithm - recipient key identifier - encrypted payload bytes The decrypted payload must resolve to a valid AEON document body. --- ## 4. Envelope Placement Encryption is declared inside the envelope: ```aeon "aeon:envelope":securityEnvelope = { encryption:encryptionBlock = { ... } } ``` Only one encryption section is allowed per envelope unless another convention explicitly defines multiple encryption layers. --- ## 5. Encryption Entry Structure ### Required fields | field | meaning | | :--- | :--- | | `alg` | encryption algorithm | | `kid` | recipient key identifier | | `ciphertext` | encrypted payload | *Required encryption fields* Minimal form: ```aeon encryption:encryptionBlock = { alg:string = "xchacha20-poly1305" kid:string = "bob" ciphertext:bytes = #... } ``` --- ## 6. Field Definitions ### 6.1 `alg` Encryption algorithm identifier. Example: ```aeon alg = "xchacha20-poly1305" ``` Other possible values: - `aes-256-gcm` - `chacha20-poly1305` The convention does not restrict allowed algorithms. Profiles may. --- ### 6.2 `kid` Recipient key identifier. Example: ```aeon kid = "bob" ``` This identifies the key used to decrypt the ciphertext. The identifier format is intentionally flexible. Possible examples: ```aeon kid = "bob" kid = "org.example.recipient.1" kid = "did:example:bob#key1" ``` --- ### 6.3 `ciphertext` Encrypted payload. Example: ```aeon ciphertext = #AABBCC... ``` This field contains the encrypted AEON payload bytes. The exact encoding is determined by AEON binary literal rules. --- ## 7. Optional Fields Optional metadata may appear if required by the encryption algorithm. | field | meaning | | :--- | :--- | | `nonce` | encryption nonce | | `aad` | additional authenticated data | | `tag` | authentication tag | | `epk` | ephemeral public key | *Optional encryption fields* Example: ```aeon encryption:encryptionBlock = { alg:string = "xchacha20-poly1305" kid:string = "bob" nonce:bytes = #112233... ciphertext:bytes = #AABBCC... tag:bytes = #998877... } ``` These fields are algorithm dependent. --- ## 8. Encryption Scope Encryption covers the **document body**. The envelope itself remains visible so processors know how to decrypt the document. Conceptually: ```text aeon:header ciphertext(body) aeon:envelope ``` --- ## 9. Combined Signing and Encryption Documents may combine encryption with signatures. Example workflow: 1. encrypt payload 2. compute integrity hash 3. sign hash Example: ```aeon "aeon:envelope":securityEnvelope = { encryption:encryptionBlock = { alg:string = "xchacha20-poly1305" kid:string = "bob" ciphertext:bytes = #... } integrity:integrityBlock = { alg:string = "sha256" hash:bytes = #... } signatures:signatureSet = [ { alg:string = "ed25519" kid:string = "alice" sig:bytes = #... } ] } ``` This allows recipients to verify authenticity after decryption. --- ## 10. Verification / Decryption Flow A processor decrypting a document should: 1. parse AEON document 2. locate `aeon:envelope.encryption` 3. resolve recipient key using `kid` 4. decrypt `ciphertext` 5. reconstruct the AEON body 6. optionally verify integrity and signatures --- ## 11. Failure Conditions Decryption must fail if: - `alg` is missing - `kid` cannot be resolved - ciphertext cannot be decrypted - authentication tag fails - payload cannot be parsed as AEON Decryption failure is not a syntax error; it is a processor-level security failure. --- ## 12. Example Encrypted Document ```aeon aeon:header = { encoding = "utf-8" mode = "strict" } "aeon:envelope":securityEnvelope = { encryption:encryptionBlock = { alg:string = "xchacha20-poly1305" kid:string = "bob" nonce:bytes = #AA11... ciphertext:bytes = #BB22... tag:bytes = #CC33... } } ``` In this case the body is encrypted and only recoverable after decryption. --- ## 13. Relationship to Other Conventions `aeon.gp.encryption.v1` works with: - `aeon.gp.security.v1` - `aeon.gp.integrity.v1` - `aeon.gp.signature.v1` Encryption may appear alongside integrity and signatures. --- ## 14. One-Line Definition `aeon.gp.encryption.v1` defines a minimal encryption envelope for AEON documents in which the document body is represented as ciphertext inside `aeon:envelope.encryption`. --- ## 15. Minimal Encryption Envelope ```aeon "aeon:envelope":securityEnvelope = { encryption:encryptionBlock = { alg:string = "xchacha20-poly1305" kid:string = "bob" ciphertext:bytes = #... } } ``` --- --- ## Related documents - [AEON GP Security Envelope v1](./aeon-gp-security-envelope-v1.md) - [AEON GP Integrity v1](./aeon-gp-integrity-v1.md) - [AEON GP Signature v1](./aeon-gp-signature-v1.md)