Blockcerts是一種基于區塊鏈技術的數字證書系統，通過區塊鏈的可信性和去中心化特點來保證證書的可信性和安全性。

Blockcerts證書的格式采用了JSON格式，主要包括多個字段，例如id、type、name、issuedOn、issuer等等。

{
"id": "urn:uuid:9aa2d05b-c3cc-46fd-8ee8-bc8ee4152a8c",
"type": "Blockchain",
"recipient": {
"identity": "bob@example.com",
"type": "email"
},
"badge": {
"name": "Blockchain Expert",
"description": "This badge indicates that the recipient has been certified as an expert in blockchain.",
"image": "data:image/png;base64,iVBORw0KGg...",
"criteria": "https://example.com/criteria.pdf",
"issuer": {
"name": "Blockchain Education Institute",
"url": "https://example.com"
}
},
"issuedOn": "2021-01-01T00:00:00+00:00",
"verification": {
"url": "https://example.com/verify",
"publicKey": "1d0a4e0299a2f...",
"transactionId": "8e5f948c27...",
"merkleProof": "885517440aeaff0..."
}
}

其中，id字段是Blockcerts證書的唯一標識符，type字段表示證書類型，recipient字段包含證書的接收者信息，badge字段表示證書的標識信息，issuer字段包含證書頒發機構的信息，issuedOn字段表示證書頒發的時間，verification字段包含了證書驗證信息。

通過這些字段，Blockcerts證書系統可以在區塊鏈上記錄證書的頒發和驗證過程，實現證書的透明可追蹤。