Reference

The words we use.

Fertility and privacy are full of jargon. This glossary explains what we mean when we use a term — in plain language, with no marketing fluff.

Privacy & security

Zero-knowledge encryption: A cryptographic architecture where the service provider cannot decrypt user data because the encryption keys are generated and stored solely on the user’s device. Avelia implements zero-knowledge encryption using AES-256-GCM with Argon2id key derivation.
End-to-end encryption (E2EE): A system where data is encrypted on the sender’s device and can only be decrypted by the intended recipient. No intermediary — including the service provider — can read the content. Avelia uses E2EE for all cloud sync and partner sharing.
AES-256-GCM: Advanced Encryption Standard with 256-bit keys in Galois/Counter Mode. A modern authenticated encryption algorithm that provides both confidentiality and integrity. Used by Avelia for all content encryption.
Argon2id: A memory-hard password hashing function, winner of the 2015 Password Hashing Competition and recommended by OWASP. Resistant to GPU-accelerated brute-force attacks. Avelia uses Argon2id to derive the Master Encryption Key from the user’s passphrase.
Secure enclave: A tamper-resistant hardware chip separate from a phone’s main processor, used to store cryptographic keys. Even if the operating system is compromised, the secure enclave remains protected. Apple calls it the Secure Enclave; Android calls it StrongBox or TEE.
Safe Mode: An Avelia feature that displays a plausible decoy profile when unlocked with an alternate PIN or fingerprint. Designed to protect users under coercion from abusive partners or restrictive regimes. The decoy profile is cryptographically separate from the real profile and indistinguishable from normal use.
GDPR: The General Data Protection Regulation — the European Union’s comprehensive data protection law. Grants rights to access, correct, delete, and port personal data. Avelia is fully GDPR-compliant and subject to EU jurisdiction.
Plausible deniability: The ability to credibly deny the existence of hidden information or activity. In privacy tools, this means an observer cannot prove that additional data exists beyond what is visible. Avelia’s Safe Mode provides plausible deniability for fertility and cycle data.

Fertility & cycle tracking

Natural Family Planning (NFP): A set of methods for identifying fertile and infertile days in a menstrual cycle based on observable signs (basal body temperature, cervical mucus, cervix position). When used consistently and correctly, NFP has an effectiveness rate of 95-99% for avoiding or achieving pregnancy.
Basal body temperature (BBT): The lowest body temperature in a 24-hour period, measured immediately after waking. BBT rises by 0.3-0.5°C after ovulation due to progesterone. Tracking BBT helps identify the fertile window and confirm ovulation has occurred.
Ovulation: The release of an egg from the ovary, typically occurring 12-14 days before the next menstrual period. The egg survives 12-24 hours; sperm can survive up to 5 days, creating a fertile window of roughly 6 days per cycle.
Fertile window: The 5-6 day period each cycle when pregnancy is possible: the 5 days before ovulation plus the day of ovulation itself. Identifying this window is central to both trying to conceive and natural family planning.
Symptothermal method: A natural family planning method combining basal body temperature, cervical mucus observation, and calendar calculations. Considered one of the most reliable NFP methods when practised consistently.
Luteal phase: The phase of the menstrual cycle between ovulation and the next period, typically 12-14 days. A luteal phase shorter than 10 days may indicate a luteal phase defect, which can affect conception.

IVF & assisted reproduction

IVF (In Vitro Fertilisation): A medical procedure where eggs are retrieved from the ovaries, fertilised with sperm in a laboratory, and transferred back to the uterus. A full IVF cycle typically spans 4-6 weeks including stimulation, retrieval, fertilisation, and transfer.
ICSI (Intracytoplasmic Sperm Injection): A variant of IVF where a single sperm is injected directly into an egg using a microscopic needle. Used when sperm count, motility, or morphology is a concern.
Egg retrieval / oocyte pickup (OPU): A minor surgical procedure performed under sedation where mature eggs are aspirated from the ovaries using an ultrasound-guided needle. Typically yields 8-15 eggs per cycle.
Embryo transfer (ET): The procedure where one or more embryos are placed into the uterus via a thin catheter. Usually performed 3 or 5 days after fertilisation (cleavage-stage or blastocyst transfer).
Stimulation protocol: A regimen of hormonal medications used in IVF to stimulate the ovaries to produce multiple mature eggs in one cycle. Common protocols include long agonist, antagonist, and mini-IVF.

Avelia-specific terms

Partner linking: The Avelia feature that connects two separate accounts via an invite code. Each partner maintains their own account and private data; shared entries appear in both accounts’ timelines. Partner linking uses a separate cryptographic key exchange so that each partner holds a share of the other’s data keys.
Selective sharing: An Avelia feature where each journal entry, log, or note can be individually marked as private or shared with a linked partner. The default is private; sharing is always explicit. No entry is ever shared automatically.
Shared timeline: The unified chronological view of all entries explicitly shared between linked partners. Each entry shows who logged it. Private entries never appear in the shared timeline.
Master Encryption Key (MEK): The root cryptographic key from which all Avelia data encryption keys are derived. Generated on the user’s device during onboarding from a passphrase via Argon2id. The MEK never leaves the device and is not transmitted to Avelia’s servers.
Recovery Kit: An optional printable QR code generated during Avelia onboarding that encodes a recovery key. Used to restore access if the user loses their phone. The kit is generated client-side and should be stored offline (printed, in a safe).