docs: improved intro text and restore example

restored bitcoin offline wallet example

README.md

@@ -8,25 +8,14 @@ SPDX-License-Identifier: AGPL-3.0-or-later
 
 [![Zenroom logo](https://files.dyne.org/zenroom/logos/zenroom_logotype.png)](https://zenroom.org)
 
-Zenroom is a **secure language interpreter** of the secure domain
-specific language **Zencode**, it makes it very easy to execute fast
-cryptographic operations on any data structure.
-
-The Zenroom VM is very small, has **no external dependency**, is fully
-deterministic and ready to run **end-to-end encryption** on any
-platform: desktop, embedded, mobile, cloud micro-services, web
-browsers. It can be embedded inside applications written in
-Javascript, Python3, Rust or Golang.
-
-**Zencode** is a domain-specific language (DSL) similar to human
-language. With its **no-code** approach one can process large data
-structures through complex cryptographic and logical
-transformations.
-
-Zencode helps us to lower the liability of developers by leveraging
-the **agency of domain experts**: one can write and review business
-logics and data-sensitive operations **without having to learn to
-code**.
+Zenroom is a **secure language interpreter** of the domain-specific Zencode, making it easy to execute fast cryptographic operations on any data structure.
+
+The Zenroom VM is very small, has **no external dependency**, is fully deterministic and is ready to run **end-to-end encryption** on any platform: desktop, embedded mobile, cloud micro-services, and web browsers. Zenroom works inside applications written in Javascript, Python3, Rust or Golang.
+
+Zencode has a **no-code** approach. It is a domain-specific language (DSL) **similar to human language**. One can process large data structures through complex cryptographic and logical transformations.
+
+Zencode helps developers to **empower people** who know what to do with data: one can write and review business logic and data-sensitive operations **without learning to code**.
+
 
 [![software by Dyne.org](https://files.dyne.org/software_by_dyne.png)](http://www.dyne.org)
 

test/shell/README.md

@@ -0,0 +1,6 @@
+# Example use-cases using zenroom from shell code
+
+This directory contains examples that are documented in on-line tutorials
+
+- bitcoin_offline_wallet.sh :: [Bitcoin secure off-line wallet](https://medium.com/think-do-tank/bitcoin-secure-off-line-wallet-be50a57a8474)
+

test/shell/bitcoin_offline_wallet.sh

@@ -0,0 +1,85 @@
+#!/bin/bash
+
+# from the article on medium.com
+
+. ../utils.sh $*
+Z="`detect_zenroom_path` `detect_zenroom_conf`"
+
+# sequenceDiagram
+#     participant SK as Secure off-line PC
+#     participant PK as Public on-line PC
+#     participant BC as Public blockchain explorer
+#     SK->>SK: keygen.txt
+#     SK-->>PK: copy public address
+#     PK->>+BC: send public address
+#     BC->>-PK: download unspent (UTXO)
+#     PK->>PK: create transaction: amount + recipient + UTXO
+#     PK-->>SK: copy transaction to sign
+#     SK->>SK: sign transaction offline
+#     SK-->>PK: copy signed transaction
+#     PK->>BC: broadcast signed transaction
+
+cat << EOF | zexe keygen.zen | save bitcoin keys.json
+Given nothing
+When I create the testnet key
+Then print the 'keyring'
+EOF
+
+cat <<EOF | zexe pubgen.zen -k keys.json | save bitcoin address.json
+Given I have the 'keyring'
+When I create the testnet address
+Then print the 'testnet address'
+EOF
+
+
+addr=`cat address.json | jq '.testnet_address' | sed 's/\"//g'`
+
+echo "curl -s https://blockstream.info/testnet/api/address/${addr}/utxo" | tee unspent_query.sh ../../docs/examples/zencode_cookbook/bitcoin/unspent_query.sh
+
+# cat <<EOF | tee  culo.json 
+# {
+#  "satoshi amount": "1",
+#  "satoshi fee": "141",
+#  "recipient": "tb1q73czlxl7us4s6num5sjlnq6r0yuf8uh5clr2tm",
+#  "sender": "${addr}",
+#  "satoshi unspent": `curl -s https://blockstream.info/testnet/api/address/${addr}/utxo`
+# }
+# EOF
+
+cat <<EOF | tee transaction_data.json ../../docs/examples/zencode_cookbook/bitcoin/transaction_data.json
+{
+  "satoshi amount": "1",
+  "satoshi fee": "141",
+  "recipient": "tb1q73czlxl7us4s6num5sjlnq6r0yuf8uh5clr2tm",
+  "sender": "${addr}"
+}
+EOF
+
+cat <<EOF | tee unspent.json  ../../docs/examples/zencode_cookbook/bitcoin/unspent.json
+{
+  "satoshi unspent": `curl -s https://blockstream.info/testnet/api/address/${addr}/utxo`
+}
+EOF
+
+
+jq -s '.[0] * .[1]' unspent.json  transaction_data.json | save bitcoin order.json
+
+cat <<EOF | zexe sign.zen -a order.json | save bitcoin transaction.json
+Given I have a 'testnet address' named 'sender'
+and I have a 'testnet address' named 'recipient'
+and a 'satoshi fee'
+and a 'satoshi amount'
+and a 'satoshi unspent'
+When I rename 'satoshi unspent' to 'testnet unspent'
+and I create the testnet transaction
+Then print the 'testnet transaction'
+EOF
+
+cat <<EOF | zexe sign_transaction.zen -k keys.json -a transaction.json | save bitcoin rawtx.json
+Given I have the 'keyring'
+and I have a 'base64 dictionary' named 'testnet transaction'
+When I sign the testnet transaction
+and I create the testnet raw transaction
+and I create the size of 'testnet raw transaction'
+Then print the 'testnet raw transaction' as 'hex'
+EOF