diff --git a/crypto sysarch.md b/crypto sysarch.md
index 00bb406..24e4705 100644
--- a/crypto sysarch.md	
+++ b/crypto sysarch.md	
@@ -2,8 +2,8 @@
 
 Yigid BALABAN, <fyb@fybx.dev>
 
-Revision 1
-21/08/2024
+Revision 2
+23/08/2024
 
 ## System Elements
 
@@ -12,7 +12,7 @@ The system elements are/will be described and discussed in the ZKL System Archit
 ### 1. Key Derivation Service
 
 The Key Derivation Service (or KDS for short) provides 
-1. a deterministic Curve25519 keypair generator from BIP-39 mnemonics,
+1. a deterministic secp256k1 keypair generator from BIP-39 mnemonics,
 2. a pseudo-random BIP-39 mnemonic generator through web-bip-39 package.
 
 ### 2. Cross-chain Identity Registry
@@ -32,9 +32,9 @@ The client (the sender) generates the encrypted payload to be sent to the reciev
 ### Sending a file
 
 #### Definitions
-$K_{r}:\text{Recipient's public key on Curve25519}$
-$K_{e}:\text{A symmetric key derived for the file to be sent, 256 bits}$
-$E(K_{e}):\text{The symmetric key, encrypted using ECIES}$
+$Q_{r}:\text{Recipient's public key on curve secp256k1}$
+$G:\text{The generator point on curve secp256k1}$
+$Z:\text{A symmetric key derived for the file to be sent, the shared secret}$
 $F:\text{The file contents, in plaintext}$
 $F_{c}:\text{The file contents, in ciphertext}$
 $IV:\text{The initialization vector required for AES-GCM-256}$
@@ -42,9 +42,12 @@ $P:\text{The payload, what is sent to the recipient}$
 
 #### Workflow
 
-1. The $K_{r}$ is retrieved from the CCIR.
-2. The $K_{e}$ is generated randomly for the file, $F$.
-3. File $F$ is encrypted using AES-GCM-256 with encryption key $K_{e}$, and a randomly generated initialization vector, $IV$.
-4. The $K_{e}$ is encrypted using ECIES, which is discussed in detail, in section “Key Encryption through ECIES”. This results in a new encrypted data, $E(K_{e})$.
-5. The payload $P$ is created by concatenating $F_{e},\;IV\;E(K_{e})$
-6. The payload is uploaded to the EFS.
\ No newline at end of file
+1. The $Q_{r}$ is retrieved from the CCIR.
+2. An ephemeral keypair is generated, $Q_{e}$ and $d_{e}$.
+3. The shared secret which will be used in symmetric encryption is computed from $Z=d_{e}\times Q_{r}$.
+5. File $F$ is encrypted using AES-GCM-256 with encryption key $Z$, and a randomly generated initialization vector, $IV$.
+7. The payload $P$ is created by concatenating $Q_{e},\;IV,\;\text{MAC},\;F_{e}$.
+8. The payload is uploaded to the EFS.
+
+> [!info] Reminder
+> The MAC in the payload $P$ at step 7 is a result of using AES-GCM-256, which is selected in ECIES implementation in the Rust crate we consume through ecies/rs-wasm package.
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