ring vs curve25519-dalek

Short answerBy steady daily use, ring is bigger: 2,112,308 real downloads a day against 874,887 for curve25519-dalek (2.4x). 1,837 crates depend on ring and 640 on curve25519-dalek. ring last shipped 19 months ago, curve25519-dalek 4 months ago.

ring

Widely used

Widely used and steady.

1,837 crates depend on it; no release in the last 90 days, so its count is all steady use.

An experiment.

curve25519-dalek

Established

Established and gaining.

640 crates depend on it; no release in the last 90 days, so its count is all steady use.

A pure-Rust implementation of group operations on ristretto255 and Curve25519

ringcurve25519-dalek · 100% = that crate's normal quiet day, so a spike to 300% is triple its usual traffic

Every number, side by side

Same window, same method	ring	curve25519-dalek
Real downloads a day	2,112,308	874,887
Crates that depend on it	1,837	640
Last release	0.17.14, 19 months ago	5.0.0, 4 months ago
Trend vs the field	-2%	+12%
Release-window share	0.0%	0.0%
Downloads in the window	194,741,593	81,892,348
All-time downloads	833,501,264	298,625,253
Versions published	133	104
License	Apache-2.0 AND ISC	BSD-3-Clause
MSRV	1.66.0	1.85.0
First published	Aug 15, 2016	Dec 8, 2016

Which to pick

Downloads tell you what is common, not what fits. Each crate's own description above says what it is for; when the jobs differ, pick by the job.
When both fit, prefer the one more crates depend on (ring, 1,837 dependents): more eyes, more answered questions, and you may already have it in your tree.
Check the release dates against your own pace: ring 19 months ago, curve25519-dalek 4 months ago.

Also in this space

subtleWidely usedPure-Rust traits and utilities for constant-time cryptographic implementations2,159,165 a day, 2,362 dependents pem-rfc7468Pulled inPEM Encoding (RFC 7468) for PKIX, PKCS, and CMS Structures, implementing a strict subset of the original...1,099,295 a day, 73 dependents elliptic-curveEstablishedGeneral purpose Elliptic Curve Cryptography (ECC) support, including traits and generic types...855,110 a day, 244 dependents ecdsaEstablishedPure Rust implementation of the Elliptic Curve Digital Signature Algorithm (ECDSA) as specified in FIPS 186-4...833,119 a day, 261 dependents

Compare 4 of them side by side →

Method

Real downloads = the median day with no release that day or the day before, from the crates.io API (Jul 27, 2026 to Oct 23, 2026). Raw crates.io counts include CI and bots and run high (why); the method is from our 90-day study.

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