Hawkynt

X25519

Curve25519 Diffie-Hellman key exchange using Montgomery curve arithmetic for ECDH. Provides 128-bit security with high performance and side-channel resistance. Used extensively in modern protocols like TLS 1.3, SSH, and WireGuard.

Properties

Property	Value
Category	Asymmetric Ciphers
Sub-category	Key Exchange (ECDH)
Security status	🛡️ Secure
Complexity	Advanced
Inventor	Daniel J. Bernstein
Year	2006
Origin	🇺🇸 United States
Source	algorithms/asymmetric/x25519.js

Security

Status: 🛡️ Secure

No vulnerabilities are recorded for this implementation.

Documentation

• RFC 7748 - Elliptic Curves for Security
• Original Paper: Curve25519 (Bernstein, 2006)
• Curve25519 Website

References

• NIST SP 800-186 - Digital Signature Standard
• SafeCurves: choosing safe curves for elliptic-curve cryptography
• Wycheproof Project - X25519 Test Vectors

Test vectors

18 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — RFC 7748 Section 6.1 - Test Vector 1

Field	Value
privateKey	77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a
publicKey	8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a
otherPublicKey	de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f
input	null
expected	4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742

Vector 2 — RFC 7748 Section 6.1 - Test Vector 2 (Bob’s perspective)

Field	Value
privateKey	5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb
publicKey	de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f
otherPublicKey	8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a
input	null
expected	4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742

Vector 3 — RFC 7748 Section 5.2 - Scalar Multiplication Test Vector 1

Field	Value
privateKey	a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4
otherPublicKey	e6db6867583030db3594c1a424b15f7c726624ec26b3353b10a903a6d0ab1c4c
input	null
expected	c3da55379de9c6908e94ea4df28d084f32eccf03491c71f754b4075577a28552

Vector 4 — RFC 7748 Section 5.2 - Scalar Multiplication Test Vector 2

Field	Value
privateKey	4b66e9d4d1b4673c5ad22691957d6af5c11b6421e0ea01d42ca4169e7918ba0d
otherPublicKey	e5210f12786811d3f4b7959d0538ae2c31dbe7106fc03c3efc4cd549c715a493
input	null
expected	95cbde9476e8907d7aade45cb4b873f88b595a68799fa152e6f8f7647aac7957

Vector 5 — RFC 7748 Section 5.2 - Iterated Scalar Multiplication (1 iteration)

Field	Value
privateKey	0900000000000000000000000000000000000000000000000000000000000000
iterations	1
input	null
expected	422c8e7a6227d7bca1350b3e2bb7279f7897b87bb6854b783c60e80311ae3079

Vector 6 — RFC 7748 Section 5.2 - Iterated Scalar Multiplication (1000 iterations)

Field	Value
privateKey	0900000000000000000000000000000000000000000000000000000000000000
iterations	1000
input	null
expected	684cf59ba83309552800ef566f2f4d3c1c3887c49360e3875f2eb94d99532c51

Vector 7 — Wycheproof - Public key = 0 (low-order point)

Field	Value
privateKey	207494038f2bb811d47805bcdf04a2ac585ada7f2f23389bfd4658f9ddd4debc
otherPublicKey	0000000000000000000000000000000000000000000000000000000000000000
input	null
expected	0000000000000000000000000000000000000000000000000000000000000000

Vector 8 — Wycheproof - Public key = 1 (low-order point)

Field	Value
privateKey	202e8972b61c7e61930eb9450b5070eae1c670475685541f0476217e4818cfab
otherPublicKey	0100000000000000000000000000000000000000000000000000000000000000
input	null
expected	0000000000000000000000000000000000000000000000000000000000000000

Vector 9 — Wycheproof - Edge case on twist

Field	Value
privateKey	38dde9f3e7b799045f9ac3793d4a9277dadeadc41bec0290f81f744f73775f84
otherPublicKey	0200000000000000000000000000000000000000000000000000000000000000
input	null
expected	9a2cfe84ff9c4a9739625cae4a3b82a906877a441946f8d7b3d795fe8f5d1639

Vector 10 — Wycheproof - Public key on twist

Field	Value
privateKey	588c061a50804ac488ad774ac716c3f5ba714b2712e048491379a500211998a8
otherPublicKey	63aa40c6e38346c5caf23a6df0a5e6c80889a08647e551b3563449befcfc9733
input	null
expected	b1a707519495ffffb298ff941716b06dfab87cf8d91123fe2be9a233dda22212

Vector 11 — Wycheproof - Edge case for public key (all-zeros variant)

Field	Value
privateKey	386f7f16c50731d64f82e6a170b142a4e34f31fd7768fcb8902925e7d1e21abe
otherPublicKey	0400000000000000000000000000000000000000000000000000000000000000
input	null
expected	0fcab5d842a078d7a71fc59b57bfb4ca0be6873b49dcdb9f44e14ae8fbdfa542

Vector 12 — Wycheproof - Public key >= p (reduction test)

Field	Value
privateKey	f01e48dafac9d7bcf589cbc382c878d18bda3550589ffb5d50b523bebe329dae
otherPublicKey	efffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f
input	null
expected	bd36a0790eb883098c988b21786773de0b3a4df162282cf110de18dd484ce74b

Vector 13 — Wycheproof - Low-order public key test

Field	Value
privateKey	10255c9230a97a30a458ca284a629669293a31890cda9d147febc7d1e22d6bb1
otherPublicKey	e0eb7a7c3b41b8ae1656e3faf19fc46ada098deb9c32b1fd866205165f49b800
input	null
expected	0000000000000000000000000000000000000000000000000000000000000000

Vector 14 — Wycheproof - Checking for overflow handling

Field	Value
privateKey	c81724704000b26d31703cc97e3a378d56fad8219361c88cca8bd7c5719b12b2
otherPublicKey	fd300aeb40e1fa582518412b49b208a7842b1e1f056a040178ea4141534f652d
input	null
expected	b734105dc257585d73b566ccb76f062795ccbec89128e52b02f3e59639f13c46

Vector 15 — libsodium scalarmult1 - Standard test vector

Field	Value
privateKey	77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a
otherPublicKey	0900000000000000000000000000000000000000000000000000000000000000
input	null
expected	8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a

Vector 16 — libsodium scalarmult2 - Standard test vector

Field	Value
privateKey	5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb
otherPublicKey	0900000000000000000000000000000000000000000000000000000000000000
input	null
expected	de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f

Vector 17 — curve25519-donna - Non-canonical point test

Field	Value
privateKey	0100000000000000000000000000000000000000000000000000000000000000
otherPublicKey	2500000000000000000000000000000000000000000000000000000000000000
input	null
expected	3c7777caf997b264416077665b4e229d0b9548dc0cd81998ddcdc5c8533c797f

Vector 18 — curve25519-donna - All-bits-set public key

Field	Value
privateKey	0100000000000000000000000000000000000000000000000000000000000000
otherPublicKey	ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
input	null
expected	b32d1362c248d62fe62619cff04dd43db73ffc1b6308ede30b78d87380f1e834

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