GPG key creation and retrieval

gpgkey.sh

#!/bin/bash
# This makes sure that a pgp public key for a given email exists.
# If it already exists it prints the info, if not it creates one, then prints the info
# If we create the keypair, the secret is exported and removed from the keyring

# Minimum requirement is a key
if [[ -z "$1" ]];then
  echo -e "\nUsage\n\t$(basename $0) key [ name ] [ comment ]\n\n"
  exit 1
fi

# Sane defaults
          key=$1
         name=${2:-${key%%@*}}
      comment=${3:-${key%%@*}}
     KEY_TYPE=${KEY_TYPE:-RSA}
   KEY_LENGTH=${KEY_LENGTH:-2048}
  SUBKEY_TYPE=${SUBKEY_TYPE:-RSA}
SUBKEY_LENGTH=${KEY_LENGTH:-2048}
       EXPIRE=${EXPIRE:-0}

key_details () {

  local key=$1

  output="$(gpg --fingerprint --with-colons --list-public-keys -a "$key" 2>/dev/null)"
  if (( $? == 0 ));then
    echo "$output" | awk -F: '{
      key[$1]=$5
      if ($1=="pub") {
        key["name"]=key["comment"]=key["key"]=$10
        sub(/ \(.*/,"",key["name"])
        gsub(/.*\(|\).*/,"",key["comment"])
        gsub(/.*<|>.*/,"",key["key"])
      }
      if ($1=="fpr") {
        key["fpr"]=$10
      }
    }
    END {
      print "key="key["key"]";name="key["name"]";comment="key["comment"]";keyid="key["pub"]";subkeyid="key["sub"]";fingerprint="key["fpr"]
    } '
    return 0
  else
    return 1
  fi

}

export_key () {

  local     key=$1
  local keytype=${2:-public}

  [[ -d ~/exported_pgpkeys ]] || mkdir ~/exported_pgpkeys

  output="$(gpg --yes --batch --output ~/exported_pgpkeys/"${key}.${keytype}" --armor --export-${keytype}-key "$key" 2>&1)"
  if (( $? == 0 ));then
    echo "The $keytype key for $key has been exported to exported_pgpkeys/${key}.${keytype}" >&2
  else
    echo "$output"
    return 1
  fi

}

delete_key () {

  local fingerprint=$1
  local     keytype=${2:-public}

  case $keytype in
    secret|private) keytype=secret;option="--delete-secret-keys";;
            public) keytype=public;option="--delete-keys";;
  esac

  output="$(gpg --yes --batch --delete-${keytype}-keys $fingerprint)"
  if (( $? != 0 ));then
    echo "$output"
    return 1
  fi

}


create_key () {

  # Create the key
  local     key=$1
  local    name=$2
  local comment=$3

  error="$(cat <<-EOF | gpg --gen-key --batch - 2>&1 1>/dev/null
        Key-Type: ${KEY_TYPE}
        Key-Length: ${KEY_LENGTH}
        Key-Usage: sign
        Subkey-Type: ${SUBKEY_TYPE}
        Subkey-Length: ${SUBKEY_LENGTH}
        Subkey-Usage: encrypt
        Name-Real: $name
        Name-Comment: $comment
        Name-Email: $key
        Expire-Date: ${EXPIRE}
        %commit
EOF
  )"

  if (( $? == 0 ));then
    details=$(key_details "$key")
    if (( $? == 0 ));then
      echo $details
      fingerprint=${details##*fingerprint=}
      export_key "$key" secret || return 1
      delete_key "$fingerprint" secret || return 1
      return 0
    else
      return 1
    fi
  else
    echo "$error" >&2
    return 1
  fi

}

key_details "$key" || create_key "$key" "$name" "$comment"

exit $?