subtle vs ring

Short answerBy steady daily use, subtle is bigger: 2,159,165 real downloads a day against 2,112,308 for ring (1.0x). 2,362 crates depend on subtle and 1,837 on ring. subtle last shipped 2.3 years ago, ring 19 months ago.

subtle

Widely used

Widely used and quiet for years.

2,362 crates depend on it; no release in the last 90 days, so its count is all steady use.

Pure-Rust traits and utilities for constant-time cryptographic implementations.

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.

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

How they relate

Often used together: 1 tracked crate depend on both (rustls). They are not always either/or.

Every number, side by side

Same window, same method	subtle	ring
Real downloads a day	2,159,165	2,112,308
Crates that depend on it	2,362	1,837
Last release	2.6.1, 2.3 years ago	0.17.14, 19 months ago
Trend vs the field	-1%	-2%
Release-window share	0.0%	0.0%
Downloads in the window	200,229,434	194,741,593
All-time downloads	799,309,141	833,501,264
Versions published	29	133
License	BSD-3-Clause	Apache-2.0 AND ISC
MSRV	not set	1.66.0
First published	May 31, 2017	Aug 15, 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 (subtle, 2,362 dependents): more eyes, more answered questions, and you may already have it in your tree.
Check the release dates against your own pace: subtle 2.3 years ago, ring 19 months ago.

Also in this space

cmovPulled inConditional move CPU intrinsics which are guaranteed on major platforms (ARM32/ARM64, x86/x86_64, RISC-V) to...852,311 a day, 3 dependents aws-lc-rsEstablishedaws-lc-rs is a cryptographic library using AWS-LC for its cryptographic operations. This library strives to...1,156,444 a day, 474 dependents digestWidely usedTraits for cryptographic hash functions and message authentication codes3,862,411 a day, 1,197 dependents crypto-commonPulled inCommon traits used by cryptographic algorithms3,766,260 a day, 85 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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