diff --git a/Cargo.lock b/Cargo.lock
index 20b9d95..387615f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,10 +23,32 @@ version = "0.3.0"
 dependencies = [
  "aero-user",
  "anyhow",
+ "hex",
  "log",
  "rand",
  "serde",
  "tokio",
+ "tracing",
+]
+
+[[package]]
+name = "aero-collections"
+version = "0.3.0"
+dependencies = [
+ "aero-bayou",
+ "aero-user",
+ "anyhow",
+ "base64 0.21.7",
+ "eml-codec",
+ "futures",
+ "hex",
+ "im",
+ "lazy_static",
+ "rand",
+ "serde",
+ "sodiumoxide",
+ "tokio",
+ "tracing",
 ]
 
 [[package]]
@@ -93,6 +115,21 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "android-tzdata"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e999941b234f3131b00bc13c22d06e8c5ff726d1b6318ac7eb276997bbb4fef0"
+
+[[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.79"
@@ -616,6 +653,15 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "bitmaps"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "031043d04099746d8db04daf1fa424b2bc8bd69d92b25962dcde24da39ab64a2"
+dependencies = [
+ "typenum",
+]
+
 [[package]]
 name = "blake2"
 version = "0.10.6"
@@ -684,7 +730,12 @@ version = "0.4.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8eaf5903dcbc0a39312feb77df2ff4c76387d591b9fc7b04a238dcf8bb62639a"
 dependencies = [
+ "android-tzdata",
+ "iana-time-zone",
+ "js-sys",
  "num-traits",
+ "wasm-bindgen",
+ "windows-targets 0.52.0",
 ]
 
 [[package]]
@@ -887,6 +938,27 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "eml-codec"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4499124d87abce26a57ef96ece800fa8babc38fbedd81c607c340ae83d46d2e"
+dependencies = [
+ "base64 0.21.7",
+ "chrono",
+ "encoding_rs",
+ "nom 7.1.3",
+]
+
+[[package]]
+name = "encoding_rs"
+version = "0.8.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7268b386296a025e474d5140678f75d6de9493ae55a5d709eeb9dd08149945e1"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -1284,6 +1356,29 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "iana-time-zone"
+version = "0.1.60"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7ffbb5a1b541ea2561f8c41c087286cc091e21e556a4f09a8f6cbf17b69b141"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "wasm-bindgen",
+ "windows-core",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "idna"
 version = "0.5.0"
@@ -1294,6 +1389,20 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "im"
+version = "15.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0acd33ff0285af998aaf9b57342af478078f53492322fafc47450e09397e0e9"
+dependencies = [
+ "bitmaps",
+ "rand_core",
+ "rand_xoshiro",
+ "sized-chunks",
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.2.5"
@@ -1716,6 +1825,15 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "rand_xoshiro"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f97cdb2a36ed4183de61b2f824cc45c9f1037f28afe0a322e9fff4c108b5aaa"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "regex-lite"
 version = "0.1.5"
@@ -2066,6 +2184,16 @@ dependencies = [
  "rand_core",
 ]
 
+[[package]]
+name = "sized-chunks"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16d69225bde7a69b235da73377861095455d298f2b970996eec25ddbb42b3d1e"
+dependencies = [
+ "bitmaps",
+ "typenum",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.9"
@@ -2601,6 +2729,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "windows-core"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33ab640c8d7e35bf8ba19b884ba838ceb4fba93a4e8c65a9059d08afcfc683d9"
+dependencies = [
+ "windows-targets 0.52.0",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
diff --git a/Cargo.toml b/Cargo.toml
index 56d5cf3..5654322 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ members = [
   "aero-sasl",
   "aero-dav",
   "aero-dav/fuzz",
-#  "aero-collections",
+  "aero-collections",
 #  "aero-proto",
 #  "aerogramme",
 ]
@@ -19,7 +19,7 @@ aero-user = { version = "0.3.0", path = "aero-user" }
 aero-bayou = { version = "0.3.0", path = "aero-bayou" }
 aero-sasl = { version = "0.3.0", path = "aero-sasl" }
 aero-dav = { version = "0.3.0", path = "aero-dav" }
-#aero-collections = { version = "0.3.0", path = "aero-collections" }
+aero-collections = { version = "0.3.0", path = "aero-collections" }
 #aero-proto = { version = "0.3.0", path = "aero-proto" }
 #aerogramme = { version = "0.3.0", path = "aerogramme" }
 
diff --git a/aero-bayou/Cargo.toml b/aero-bayou/Cargo.toml
index d271f4a..cade216 100644
--- a/aero-bayou/Cargo.toml
+++ b/aero-bayou/Cargo.toml
@@ -10,6 +10,8 @@ description = "A simplified version of Bayou by Terry et al. (ACM SIGOPS 1995)"
 aero-user.workspace = true
 
 anyhow.workspace = true
+hex.workspace = true
+tracing.workspace = true
 log.workspace = true
 rand.workspace = true
 serde.workspace = true
diff --git a/aero-bayou/src/lib.rs b/aero-bayou/src/lib.rs
index 7756964..159dbbf 100644
--- a/aero-bayou/src/lib.rs
+++ b/aero-bayou/src/lib.rs
@@ -1,4 +1,4 @@
-mod timestamp
+pub mod timestamp;
 
 use std::sync::{Arc, Weak};
 use std::time::{Duration, Instant};
@@ -9,9 +9,9 @@ use rand::prelude::*;
 use serde::{Deserialize, Serialize};
 use tokio::sync::{watch, Notify};
 
-use aero_foundations::cryptoblob::*;
-use aero_foundations::login::Credentials;
-use aero_foundations::storage;
+use aero_user::cryptoblob::*;
+use aero_user::login::Credentials;
+use aero_user::storage;
 
 use crate::timestamp::*;
 
diff --git a/aero-collections/Cargo.toml b/aero-collections/Cargo.toml
new file mode 100644
index 0000000..90d285e
--- /dev/null
+++ b/aero-collections/Cargo.toml
@@ -0,0 +1,24 @@
+[package]
+name = "aero-collections"
+version = "0.3.0"
+authors = ["Alex Auvolat <alex@adnab.me>", "Quentin Dufour <quentin@dufour.io>"]
+edition = "2021"
+license = "EUPL-1.2"
+description = "Aerogramme own representation of the different objects it manipulates"
+
+[dependencies]
+aero-user.workspace = true
+aero-bayou.workspace = true
+
+anyhow.workspace = true
+base64.workspace = true
+futures.workspace = true
+lazy_static.workspace = true
+serde.workspace = true
+hex.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+rand.workspace = true
+im.workspace = true
+sodiumoxide.workspace = true
+eml-codec.workspace = true
diff --git a/aero-collections/src/calendar/mod.rs b/aero-collections/src/calendar/mod.rs
new file mode 100644
index 0000000..19e3340
--- /dev/null
+++ b/aero-collections/src/calendar/mod.rs
@@ -0,0 +1 @@
+//@FIXME Event Index
diff --git a/aero-collections/src/lib.rs b/aero-collections/src/lib.rs
new file mode 100644
index 0000000..adcfc93
--- /dev/null
+++ b/aero-collections/src/lib.rs
@@ -0,0 +1,3 @@
+pub mod user;
+pub mod mail;
+pub mod calendar;
diff --git a/aero-collections/mail/incoming.rs b/aero-collections/src/mail/incoming.rs
similarity index 98%
rename from aero-collections/mail/incoming.rs
rename to aero-collections/src/mail/incoming.rs
index e2ad97d..8220461 100644
--- a/aero-collections/mail/incoming.rs
+++ b/aero-collections/src/mail/incoming.rs
@@ -1,6 +1,3 @@
-//use std::collections::HashMap;
-use std::convert::TryFrom;
-
 use std::sync::{Arc, Weak};
 use std::time::Duration;
 
@@ -11,15 +8,16 @@ use futures::{future::BoxFuture, FutureExt};
 use tokio::sync::watch;
 use tracing::{debug, error, info, warn};
 
-use crate::cryptoblob;
-use crate::login::{Credentials, PublicCredentials};
+use aero_user::cryptoblob;
+use aero_user::login::{Credentials, PublicCredentials};
+use aero_user::storage;
+use aero_bayou::timestamp::now_msec;
+
 use crate::mail::mailbox::Mailbox;
 use crate::mail::uidindex::ImapUidvalidity;
 use crate::mail::unique_ident::*;
 use crate::user::User;
 use crate::mail::IMF;
-use crate::storage;
-use crate::timestamp::now_msec;
 
 const INCOMING_PK: &str = "incoming";
 const INCOMING_LOCK_SK: &str = "lock";
diff --git a/aero-collections/mail/mailbox.rs b/aero-collections/src/mail/mailbox.rs
similarity index 98%
rename from aero-collections/mail/mailbox.rs
rename to aero-collections/src/mail/mailbox.rs
index d1a5473..a767678 100644
--- a/aero-collections/mail/mailbox.rs
+++ b/aero-collections/src/mail/mailbox.rs
@@ -2,14 +2,15 @@ use anyhow::{anyhow, bail, Result};
 use serde::{Deserialize, Serialize};
 use tokio::sync::RwLock;
 
-use crate::bayou::Bayou;
-use crate::cryptoblob::{self, gen_key, open_deserialize, seal_serialize, Key};
-use crate::login::Credentials;
+use aero_user::cryptoblob::{self, gen_key, open_deserialize, seal_serialize, Key};
+use aero_user::login::Credentials;
+use aero_user::storage::{self, BlobRef, BlobVal, RowRef, RowVal, Selector, Store};
+use aero_bayou::Bayou;
+use aero_bayou::timestamp::now_msec;
+
 use crate::mail::uidindex::*;
 use crate::mail::unique_ident::*;
 use crate::mail::IMF;
-use crate::storage::{self, BlobRef, BlobVal, RowRef, RowVal, Selector, Store};
-use crate::timestamp::now_msec;
 
 pub struct Mailbox {
     pub(super) id: UniqueIdent,
diff --git a/aero-collections/mail/mod.rs b/aero-collections/src/mail/mod.rs
similarity index 95%
rename from aero-collections/mail/mod.rs
rename to aero-collections/src/mail/mod.rs
index 03e85cd..85361f3 100644
--- a/aero-collections/mail/mod.rs
+++ b/aero-collections/src/mail/mod.rs
@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 pub mod incoming;
 pub mod mailbox;
 pub mod query;
diff --git a/aero-collections/mail/namespace.rs b/aero-collections/src/mail/namespace.rs
similarity index 94%
rename from aero-collections/mail/namespace.rs
rename to aero-collections/src/mail/namespace.rs
index 5e67173..452ac68 100644
--- a/aero-collections/mail/namespace.rs
+++ b/aero-collections/src/mail/namespace.rs
@@ -1,19 +1,12 @@
-use std::collections::{BTreeMap, HashMap};
-use std::sync::{Arc, Weak};
+use std::collections::BTreeMap;
 
-use anyhow::{anyhow, bail, Result};
-use lazy_static::lazy_static;
+use anyhow::{bail, Result};
 use serde::{Deserialize, Serialize};
-use tokio::sync::watch;
 
-use crate::cryptoblob::{open_deserialize, seal_serialize};
-use crate::login::Credentials;
-use crate::mail::incoming::incoming_mail_watch_process;
-use crate::mail::mailbox::Mailbox;
+use aero_bayou::timestamp::now_msec;
+
 use crate::mail::uidindex::ImapUidvalidity;
 use crate::mail::unique_ident::{gen_ident, UniqueIdent};
-use crate::storage;
-use crate::timestamp::now_msec;
 
 pub const MAILBOX_HIERARCHY_DELIMITER: char = '.';
 
diff --git a/aero-collections/mail/query.rs b/aero-collections/src/mail/query.rs
similarity index 100%
rename from aero-collections/mail/query.rs
rename to aero-collections/src/mail/query.rs
diff --git a/aero-collections/mail/snapshot.rs b/aero-collections/src/mail/snapshot.rs
similarity index 100%
rename from aero-collections/mail/snapshot.rs
rename to aero-collections/src/mail/snapshot.rs
diff --git a/aero-collections/mail/uidindex.rs b/aero-collections/src/mail/uidindex.rs
similarity index 99%
rename from aero-collections/mail/uidindex.rs
rename to aero-collections/src/mail/uidindex.rs
index 5a06670..637a1ac 100644
--- a/aero-collections/mail/uidindex.rs
+++ b/aero-collections/src/mail/uidindex.rs
@@ -3,7 +3,7 @@ use std::num::{NonZeroU32, NonZeroU64};
 use im::{HashMap, OrdMap, OrdSet};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
-use crate::bayou::*;
+use aero_bayou::*;
 use crate::mail::unique_ident::UniqueIdent;
 
 pub type ModSeq = NonZeroU64;
diff --git a/aero-collections/mail/unique_ident.rs b/aero-collections/src/mail/unique_ident.rs
similarity index 98%
rename from aero-collections/mail/unique_ident.rs
rename to aero-collections/src/mail/unique_ident.rs
index 0e629db..0987a2c 100644
--- a/aero-collections/mail/unique_ident.rs
+++ b/aero-collections/src/mail/unique_ident.rs
@@ -5,7 +5,7 @@ use lazy_static::lazy_static;
 use rand::prelude::*;
 use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
 
-use crate::timestamp::now_msec;
+use aero_bayou::timestamp::now_msec;
 
 /// An internal Mail Identifier is composed of two components:
 /// - a process identifier, 128 bits, itself composed of:
diff --git a/aero-collections/user.rs b/aero-collections/src/user.rs
similarity index 97%
rename from aero-collections/user.rs
rename to aero-collections/src/user.rs
index a38b9c1..193ce90 100644
--- a/aero-collections/user.rs
+++ b/aero-collections/src/user.rs
@@ -1,20 +1,18 @@
-use std::collections::{BTreeMap, HashMap};
+use std::collections::HashMap;
 use std::sync::{Arc, Weak};
 
 use anyhow::{anyhow, bail, Result};
 use lazy_static::lazy_static;
-use serde::{Deserialize, Serialize};
 use tokio::sync::watch;
 
-use crate::cryptoblob::{open_deserialize, seal_serialize};
-use crate::login::Credentials;
+use aero_user::cryptoblob::{open_deserialize, seal_serialize};
+use aero_user::login::Credentials;
+use aero_user::storage;
+
 use crate::mail::incoming::incoming_mail_watch_process;
 use crate::mail::mailbox::Mailbox;
 use crate::mail::uidindex::ImapUidvalidity;
-use crate::mail::unique_ident::{gen_ident, UniqueIdent};
-use crate::storage;
-use crate::timestamp::now_msec;
-
+use crate::mail::unique_ident::UniqueIdent;
 use crate::mail::namespace::{MAILBOX_HIERARCHY_DELIMITER, INBOX, DRAFTS, ARCHIVE, SENT, TRASH, MAILBOX_LIST_PK, MAILBOX_LIST_SK,MailboxList,CreatedMailbox};
 
 //@FIXME User should be totally rewriten