diff --git a/bitcoin b/bitcoin
new file mode 100644
index 0000000..c1048e2
--- /dev/null
+++ b/bitcoin
@@ -0,0 +1,137 @@
+
+start daemon:
+
+bitcoind -daemon --datadir=/data/bitcoin --printtoconsole --rpcuser=ger --rpcpassword=<secret>
+
+memory-conservative options:
+
+bitcoin-d -daemon --datadir=/data/bitcoin --printtoconsole --rpcuser=ger --rpcpassword=<secret> --blocksonly --dbcache=50 --maxsigcachesize=4 --maxconnections=4 --rpcthreads=1 --banscore=1 --maxmempool=100  --maxorphantx=10
+
+
+check if node is online on bitcoin-network:
+
+https://bitnodes.io/nodes/94.212.140.57-8333/
+
+check if you can get hash of genesis block 0:
+
+bitcoin@raspberrypi:~$ bitcoin-cli getblockhash 0
+000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
+
+
+create backup of wallet:
+
+bitcoin@raspberrypi:~$ bitcoin-cli backupwallet ~/walletbackup.dat
+
+create new pubkey/address to sent bitcoin to:
+
+bitcoin@raspberrypi:~$ bitcoin-cli -named getnewaddress address_type=bech32
+bc1qc2ykz4fvru7x5a03ulrt7lu08qmmqandkrc4xh
+
+<sent 1 EU to address..>
+
+
+check unconfirmed_balance:
+
+bitcoin@raspberrypi:~$ bitcoin-cli getunconfirmedbalance
+0.00000000
+
+check which block we are at/sync:
+
+bitcoin@raspberrypi:~$ bitcoin-cli getblockcount 
+369100
+
+check number of connections:
+
+bitcoin@raspberrypi:~$ bitcoin-cli getconnectioncount
+4
+
+check blockchaininfo:
+
+bitcoin@raspberrypi:~$ bitcoin-cli getblockchaininfo 
+{
+  "chain": "main",
+  "blocks": 369130,
+  "headers": 664786,
+  "bestblockhash": "0000000000000000117a24b7765058486ff569c9db743c3ba262fa3d47719159",
+  "difficulty": 52699842409.34701,
+  "mediantime": 1439149569,
+  "verificationprogress": 0.1329346278189584,
+  "initialblockdownload": true,
+  "chainwork": "00000000000000000000000000000000000000000009204346abde553d962c70",
+  "size_on_disk": 48331158857,
+  "pruned": false,
+  "softforks": {
+    "bip34": {
+      "type": "buried",
+      "active": true,
+      "height": 227931
+    },
+    "bip66": {
+      "type": "buried",
+      "active": true,
+      "height": 363725
+    },
+    "bip65": {
+      "type": "buried",
+      "active": false,
+      "height": 388381
+    },
+    "csv": {
+      "type": "buried",
+      "active": false,
+      "height": 419328
+    },
+    "segwit": {
+      "type": "buried",
+      "active": false,
+      "height": 481824
+    }
+  },
+  "warnings": ""
+}
+
+bitcoin@raspberrypi:~$ bitcoin-cli getnetworkinfo
+{
+  "version": 200100,
+  "subversion": "/Satoshi:0.20.1/",
+  "protocolversion": 70015,
+  "localservices": "0000000000000409",
+  "localservicesnames": [
+    "NETWORK",
+    "WITNESS",
+    "NETWORK_LIMITED"
+  ],
+  "localrelay": true,
+  "timeoffset": -13,
+  "networkactive": true,
+  "connections": 4,
+  "networks": [
+    {
+      "name": "ipv4",
+      "limited": false,
+      "reachable": true,
+      "proxy": "",
+      "proxy_randomize_credentials": false
+    },
+    {
+      "name": "ipv6",
+      "limited": false,
+      "reachable": true,
+      "proxy": "",
+      "proxy_randomize_credentials": false
+    },
+    {
+      "name": "onion",
+      "limited": true,
+      "reachable": false,
+      "proxy": "",
+      "proxy_randomize_credentials": false
+    }
+  ],
+  "relayfee": 0.00001000,
+  "incrementalfee": 0.00001000,
+  "localaddresses": [
+  ],
+  "warnings": ""
+}
+
diff --git a/openssl-enc b/openssl-enc
new file mode 100644
index 0000000..400cf15
--- /dev/null
+++ b/openssl-enc
@@ -0,0 +1,9 @@
+
+encrypt file:
+
+$ openssl aes-256-cbc -a -salt -in hoi.test -out hoi.test.enc
+
+decrypt file:
+
+openssl aes-256-cbc -d -a -in hoi.test.enc -out hoi.test.new
+