the session initialization info will be stored in a map in dynamoDB. the map's key is the device signingPublicKey, and the value is a map of initialization info component names (e.g. social proof, one-time prekeys, etc.) to their respective values.
example json (omitting irrelevant fields):
{
"userID": "12345",
"devices": {
"signingkey1": {
"otherkey1": "lorem",
"socialproof": "ipsum"
}}
}